Articles in press have been peer-reviewed and accepted, which are not yet assigned to volumes /issues, but are citable by Digital Object Identifier (DOI).
Comparison of four lipid droplets staining methods in Bursaphelenchus xylophilus
HUANG Linling, ZHOU Xiang, HU Jiafu, LIN Haiping, GUO Kai
doi: 10.11833/j.issn.2095-0756.20200674
[Abstract](0) [HTML](0) [PDF](0)
  Objective  With a comparison of the four commonly used methods for staining Caenorhabditis elegans lipid droplets, this study is aimed to figure out the most suitable dyeing method for Bursaphelenchus xylophilus lipid droplets.  Method  Four were used to fix and characterize After the distribution of lipid droplets in B. xylophilus was defined with its features revealed employ four dyeing methods including Sudan black B staining, Nile red staining, oil red O staining, and post-fix oil red O staining, the stained nematodes were observed and photographed microscopically, and then ImageJ software was used to count the subcutaneous and intestinal lipid droplet pixels.  Result  1) The four dyeing methods have a certain dyeing effect on the lipid droplets of B. xylophilus. 2) Upon the observation of the lipid droplets after microphotographing and the comparison of the pixel intensity after image processing by ImageJ software, the stained lipid droplets pixels with Sudan black B, Nile red, oil red O and post-fix oil red O are 200×1017 m2, 41.64×1012 m2, 52.12×1017 m2, and 83.85×1017 m2 respectively. 3) Lipid droplets stained by Sudan black have the highest average pixel intensity, and lipid droplets stained by Nile red have the lowest average pixel intensity, whereas the lipid droplets stained by post-fix oil red O, after calculation and conversion, produced a consistent characterization with the original image, with a favorable separation of individual lipid droplet.  Conclusion  In conclusion, in light of the simplicity of the dyeing method, the length of dyeing time and the effect of dyeing, the improved post-fix oil red O method is the optimal method for dyeing lipid droplets in B. xylophilus, with the size and distribution of lipid droplets clearly shown. [Ch, 4 fig. 1 tab. 17 ref.]
Dynamic monitoring of loess terraces based on Google Earth Engine and machine learning
LI Wanyuan, TIAN Jia, MA Qin, JIN Xuejuan, YANG Zekang, YANG Penghui
doi: 10.11833/j.issn.2095-0756.20200673
[Abstract](18) [HTML](0) [PDF](146)
  Objective   Terraces are the most important soil and water conservation measures and agricultural production measures in the Loess Plateau, the main region of soil and water loss and the key region of ecological environmental construction in China. The purpose of this study is to obtain the distribution information of loess terraces in a long time series efficiently and accurately, so as to monitor and evaluate soil and water loss in the Loess Plateau.   Method   Google Earth Engine (GEE), a cloud-based platform of remote sensing with high-performance computing resources, was used in this study. Guyuan City of Ningxia, a gully region of the Loess Plateau, was taken as the research area. The recognition accuracy of three machine learning algorithms, including random forest (RF), decision tree (CART) and support vector machine (SVM), was compared by using remote sensing image supervised recognition technology, and the optimized application of LandTrendr algorithm in long-time series dynamic monitoring was discussed. Finally, the distribution of terraces in Guyuan City in recent 30 years was obtained.   Result   1)The order of identification accuracy of the three algorithms from large to small was RF, CART, and SVM. 2) Using random forest algorithm to identify terraces, the overall accuracy based on sample test was 94.10%, Kappa coefficient 0.87, and the overall accuracy based on field patch test was 93.33%, Kappa coefficient 0.80. 3) LandTrendr algorithm can effectively correct the errors in the time series and improve the accuracy of time series identification. 4) From 1988 to 2019, the area of terraces in Guyuan decreased by 45.90%. 5) The time to use terraces in the west of Guyuan was longer than that in the east.   Conclusion   The RF machine learning algorithm combined with LandTrendr algorithm on GEE can efficiently and accurately monitor long-term and large-scale loess terraces. In the past 30 years, the proportion of terrace agriculture in Guyuan City has gradually declined, which promotes the sustainable development of ecological environment. [Ch, 4 fig. 3 tab. 22 ref.]
Research progress on soil organic carbon and microbial characteristics of Cunninghamia lanceolata plantation and their influencing factors
ZHU Danmiao, CHEN Junhui, JIANG Peikun
doi: 10.11833/j.issn.2095-0756.20200598
[Abstract](10) [HTML](0) [PDF](142)
As an important part of soil carbon pool, the stability, growth or attenuation of soil organic carbon are closely related to the change of atmospheric CO2 concentration. Soil microorganisms, an indispensable part of forest ecosystem, participate in the decomposition of organic matter and the transformation of soil matter and play an important role in maintaining soil quality. The relationship between soil organic carbon and microbial characteristics is extremely close. In recent years, the research on soil in Cunninghamia lanceolata plantation in China has mainly focused on litter decomposition, soil nutrient turnover, soil microbial characteristics and so on. With the wide application of high-throughput sequencing technology, the research on soil organic carbon and microbial characteristics of C. lanceolata plantation has made a lot of important progress. In this study, the research progress on pool characteristics, activity, and stability of soil organic carbon as well as community structure and diversity of soil microorganisms and their influencing factors in C. lanceolata plantation were reviewed, and the future research direction of soil organic carbon and soil microorganism in C. lanceolata plantation was put forward. [Ch, 79 ref.]
Physiological responses and evalution of cold resistance of six Osmanthus fragrans cultivars under low temperature stress
LI Chengcheng, WU Qichao, MA Yan, LI Yuhao, ZANG Dekui
doi: 10.11833/j.issn.2095-0756.20200606
[Abstract](6) [HTML](0) [PDF](140)
  Objective   The objective of this study is to investigate the physiological response of six cultivars of Osmanthus fragrans to low temperature stress and evaluate their cold resistance, so as to facilitate their popularization and application.   Method   The detached leaves of six cultivars of O. fragrans were used as experimental materials under artificial low temperature stress, with a total of 8 temperature gradients of 0, −4, −8, −12, −16, −20, −24, −28 ℃. Their physiological indexes such as relative conductivity (REC), malondialdehyde (MDA), soluble sugar (SS), soluble protein (SP), superoxide dismutase (SOD) and peroxisome (POD) were measured. The response of several cultivars of O. fragrans to low temperature stress was studied by the membership function method, and the cold resistance evaluation was completed.   Result   The changes of REC of six cultivars under different low temperature stress were S-shaped curve. Combined with logistic regression analysis, the semi-lethal temperature of each cultivar was calculated. ‘Aoshuang’ and ‘Dongrong’ had lower values, which were −12.95 and −11.80 ℃ respectively, and ‘Yinbi Shuanghui’ had the highest value of −8.15 ℃. Under low temperature stress, the MDA content in leaves of six cultivars of O. fragrans increased first, then decreased and then increased with the decrease of temperature, and the rangeability of each cultivar was different. With the decrease of temperature, the content of SS and SP of all cultivars increased first and then decreased, but the increasing range and inflection point temperature were not the same. The SOD activity of ‘Luocai No.1’ and ‘Aoshuang’ showed a trend of “up–down–up–down”, while the SOD activity of other cultivars showed a trend of first up and then down. The change trend of POD activity in different cultivars was different. The POD activity of ‘Yongfu Huancai’ and ‘Yinbi Shuanghui’ generally showed an upward trend at first and then a downward trend, and the POD activity of ‘Luocai No.1’, ‘Luocai No.2’, ‘Aoshuang’ and ‘Dongrong’ showed a trend of “down–up–down”. The cold resistance of six cultivars was evaluated by the membership function method, and the order of cold resistance from strong to weak was ‘Aoshuang’, ‘Dongrong’, ‘Luocai No.2’, ‘Luocai No.1’, ‘Yongfu Huancai’, and ‘Yinbi Shuanghui’.   Conclusion   Under low temperature stress, the physiological and biochemical indexes of leaves of six cultivars of O. fragrans change significantly. According to the membership function method, the three cultivars ‘Aoshuang’, ‘Dongrong’, and ‘Luocai No.2’ can better adapt to the temperature in northern China.[Ch, 6 fig. 2 tab. 34 ref.]
Impact of biodiversity and site factors on biomass of public welfare forests in Zhejiang Province
JIN Chao, LI Linghuan, WU Chuping, YAO Liangjin, ZHU Jinru, YUAN Weigao, JIANG Bo, JIAO Jiejie
doi: 10.11833/j.issn.2095-0756.20200696
[Abstract](72) [HTML](1) [PDF](141)
  Objective  This research aims to explore the impact of biodiversity and site factors on biomass of public welfare forest in Zhejiang Province, and to study the stability of its community structure.  Method  Based on the survey data of public welfare forest from three counties in Zhejiang, the effects of ten soil and terrain factors (soil hygroscopic water, soil pH, soil organic matter, soil available nitrogen, soil available phosphorus, soil available potassium, altitude, slope, aspect and soil thickness) and biodiversity (species richness and phylogenetic diversity) on the biomass of three forest types (coniferous forest, coniferous and broad-leaved mixed forest, and broad-leaved forests) were explored.  Result  Compared with species richness, phylogenetic diversity was better to distinguish forest types, in which broad-leaved forest and mixed forest had higher biodiversity, and coniferous forest had higher biomass. When only considering the effects of individual factors, phylogenetic diversity (P=0.041) and species richness (P<0.001) were significantly and positively correlated with biomass in broad-leaved forests. When considering the effects of environmental factors, species richness, phylogenetic diversity, soil available nitrogen, soil thickness and soil hygroscopic water had significant effects (P<0.05) on biomass of broad-leaved forests, while soil thickness and soil pH had significant effects (P<0.05) on biomass of coniferous forests. Phylogenetic diversity was negatively correlated with biomass due to environmental factors.  Conclusion  Environmental factors and biodiversity jointly affect the biomass of public welfare forest in Zhejiang Province. In the future management of public welfare forest, measures should be taken to increase soil fertility of coniferous and broad-leaved mixed forest, and improve the species structure of broad-leaved forest, so as to better maintain and enhance the ecosystem function of public welfare forest.[Ch, 2 fig. 2 tab. 44 ref.]
Effects of different fertilizer types on nitrogen and phosphorus nutrient absorption and runoff loss in rice-vegetable rotation system
ZHANG Kun, XU Jian, LU Changgen, SHAO Jianjun, CAI Guangyue, ZHANG Yan, WU Jiasen
doi: 10.11833/j.issn.2095-0756.20200593
[Abstract](12) [PDF](139)
  Obejective  To explore the effect of different fertilization on nitrogen and phosphorus content in farmland in Xianju County, Zhejiang Province.  Method  A rice/Chinese cabbage rotation experiment was conducted to study the change of four fertilization treatments to crop yield, fertilizer absorption, runoff-driven N and P loss. The four treatments were no fertilizer application (ck), pure chemical fertilizer application (FP), 50% organic fertilizer replacement (CM) and carbon-based fertilizer application (CC).  Result  Compared with ck, the yield of rice and Chinese cabbage under three fertilization increased significantly by 33.5%−42.5% and 26.0%−31.8%, respectively. But there was no significant difference among three fertilizer treatments. Compared with ck, nitrogen absorption in Chinese cabbage increased by 33.8%−53.6%, whereas those of CM treatment were significant higher than others. Phosphorus absorption increased by 163.5%−267.8%, and the increase between different treatments was CM>FP>CC>ck. However, there was no significant difference among each treatment (P<0.05). For rice, runoff volume of nitrogen and phosphorus under three fertilization treatments was 13.5−15.3, 2.2−2.6 kg· hm−2, and runoff rate was 3.5%−4.2%, 2.0%−2.4%, respectively. For Chinese cabbage, nitrogen and phosphorus loss was 6.3−6.8, and 0.35−0.44 kg·hm−2, runoff rate was 1.3%−1.6%, 0.1%−0.4%, respectively. However, there was no significant difference among three fertilization treatments.While maintaining the same nutrient equivalent. There was no significant difference betweenpure chemical fertilizer application, 50% organic fertilizer replacement and carbon-based fertilizer application. [Ch, 3 fig. 4 tab. 25 ref.]
Pollution characteristics of heavy metals in PM2.5 in four kinds of green space in Lin’an District of Hangzhou City
ZHANG Tianran, ZHENG Wenge, ZHANG Yinke, HUANG Fang, LI Xiaolu, YUAN Chuyang, YU Hui, YAN Hai, SHAO Feng
doi: 10.11833/j.issn.2095-0756.20200558
[Abstract](22) [HTML](3) [PDF](141)
  Objective  This study aims to analyze the spatio-temporal variation of heavy metal concentration in PM2.5 in urban green space and probe into its influencing factors, so as to provide reference for scientific planning of urban green space and improvement of the quality of human settlement environment.  Method  Four kinds of green space in Lin’an District of Hangzhou were taken as the research objects, including residential green space, commercial green space, square green space and public green space. The intelligent medium volume TSP sampler was used to collect the airborne PM2.5. The component and mass concentration of heavy metals in the samples were detected by the inductively coupled plasma mass spectrometer (ICP-MS), and their sources were analyzed.  Result  The average concentrations of heavy metals in four kinds of green space were higher in winter [(950.13±90.15) ng·m−3] than those in spring [(843.55±80.70) ng·m-3]. The average concentrations of heavy metals ranging from large to small in these two seasons were commercial green space [(1 023.18±94.10) ng·m−3], residential green space [(942.20±89.20) ng·m−3], square green space [(861.85±84.05) ng·m−3] and public green space [(760.18±80.48) ng·m−3]. The heavy metals in green space mainly came from complex pollution sources (natural sources, road dust, vehicle exhaust and industrial pollution), coal-based industrial sources and traffic sources, etc.  Conclusion  Reasonable increase of green space area can effectively reduce the heavy metal pollution in cities. Controlling traffic flow around commercial green space and promoting new energy vehicles can significantly lower the heavy metal concentration. [Ch, 6 fig. 2 tab. 41 ref.]
Effects of pH on the dynamic migration of nutrient salts in the sediment of ditches in mountain rural areas
GONG Yunhui, LIU Yungen, YANG Silin, WANG Yan, WANG Yuying, DU Pengrui
doi: 10.11833/j.issn.2095-0756.20200709
[Abstract](26) [HTML](10) [PDF](140)
  Objective  As pH is a key factor affecting the migration and release of nutrients in the ditch sediment, this study, with an investigation of the dynamic changes of nutrient release and migration in the bottom mud of mountainous rural ditches under different pH conditions, is aimed to provide a theoretical basis for rural ecological environment management.  Method  With the bottom mud of typical mountainous rural ditches in the Dianchi Lake Basin collected, indoor simulation experiments were conducted to determine the nutrient salt content of the bottom mud and the overlying water under different pH (pH 5.5, 7.5, 9.5, 11.5) conditions under non-sterilized and sterilized treatments after which the nutrient release flux at the sediment-water interface was estimated.  Result  The mass fraction of total nitrogen (TN) in the bottom sludge decreased with the increase of pH. The total nitrogen release flux under the strong alkaline (pH 11.5) and acidic (pH 5.5) conditions of the non-sterilized group was 8 and 4 times of the control (pH 7.5), and its release flux in the sterilization group was 2 times of that in the control. The mass concentration and release flux of soluble total phosphorus (DTP) in the overlying water increased with the increase of pH. The release of DTP under the conditions of strong alkaline (pH 11.5) and weak alkaline (pH 9.5) in the non-sterilized group was 12 and 4 times of that in the control, respectively, and its release flux in the sterilized group was 30 and 15 times of that in the control while the non-sterilized group had higher DTP release flux than the sterilized group. RDA shows that acidic conditions promote the release of calcium-bound phosphorus (Ca-P) in sediments, and alkaline (pH≥9.5) conditions promote the release of total nitrogen, total phosphorus and iron-aluminum-bound phosphorus (Fe/Al-P). Neutral (pH 7.5) conditions have little effect on the release of nitrogen or phosphorus in the sediments.  Conclusion  Alkalinity (pH≥9.5) and acidity significantly promote the release of nitrogen and phosphorus nutrients in the bottom mud of mountain rural ditches, and the release amount is the smallest under neutral conditions. Also, the sterilization of the bottom sludge reduces the microbial activity at different pH levels, and prevents the migration and release of nitrogen and phosphorus in the bottom sludge of mountain and rural ditches to the overlying water. [Ch, 6 fig. 1 tab. 40 ref.]
Interspecific association dynamics of Nanmu natural forest in Jiande, Zhejiang Province
WU Danting, WU Chuping, SHENG Weixing, JIAO Jiejie, JIANG Bo, ZHU Jinru, YUAN Weigao
doi: 10.11833/j.issn.2095-0756.20200565
[Abstract](16) [HTML](7) [PDF](0)
  Objective  This study aims to investigate the interspecific relationship of natural forest of Nanmu with different dominant degrees in Shouchang Forest Farm of Jiande City, Zhejiang Province, so as to reveal the dynamic change rules of the interspecific association in the process of community development and succession.  Method  In 2015 and 2019, two natural forest plots with different dominance of Nanmu were investigated. Based on the 2×2 contingency table, the interspecific association of tree layer, shrub layer and herb layer of Nanmu under different stand conditions was studied by χ2 test, association coefficient (\begin{document}$ \mathrm{A}\mathrm{C} $\end{document}), and percentage of co-occurrence (\begin{document}$ \mathrm{P}\mathrm{C} $\end{document}).  Result  In 2015 and 2019, the overall interspecific association of tree layer was significantly positive, while that of shrub layer and herb layer tended to be negative. In the natural stands with Nanmu as associated tree, the correlation among tree layer, shrub layer and herb layer tended to be negative. In both stands, Nanmu showed stand fault phenomenon in vertical direction. In the tree layer, the association between Nanmu and other species was relatively independent, while the interspecific competition between Nanmu and other species in shrub layer and herb layer was intense.  Conclusion  In natural forests, thinning, selective cutting and other tending methods can be adopted when Nanmu is taken as the target tree species for management and protection. The tree species with significant positive correlation with Nanmu are retained and the tree species with negative correlation are cut down to ease the interspecific contradiction. Thinning tall trees in the upper layer and increasing the forest gap can meet the needs of illumination for renewal layer. Protecting the renewal layer is conducive to the formation of a complete vertical structure. [Ch, 7 fig. 4 tab. 22 ref.]
Spatial distribution patterns and interspecific relationship of dominant tree species in the tree layer of typical natural secondary forest communities in Jiande, Zhejiang Province
ZHAN Xiaohao, WANG Xuhang, YE Nuonan, WU Chuping, YUAN Weigao, YI Lita
doi: 10.11833/j.issn.2095-0756.20200586
[Abstract](25) [HTML](3) [PDF](0)
  Objective  To investigate the spatial distribution pattern and interspecific relationship of dominant tree species in the tree layer of natural secondary forest communities, and to provide a scientific basis for the restoration, rehabilitation and reforestation management of the secondary forest community in the region.  Method  This paper set up 100 m×100 m (1 hm2) sample plot in each type of typical natural secondary forest communities(evergreen braod-leaved secondary forest, mason pine and broad-leaved mixed secondary forest and secondary forest of mason pine) in Jiande, Zhejiang Province. Based on the tally, the Pianka niche overlap index, point pattern analysis method, variance ratio method (VR), χ2-test and Spearman rank correlation coefficient were used to analyze the spatial distribution pattern and interspecific relationship of the dominant tree species in each community.  Result  (1) The dominant tree species in each type of secondary forest community showed an aggregate distribution on all scales; (2) In the 0−25 m scale, the spatial correlation of each community is dominated by insignificant correlations, and the number of species pairs showing negative correlation is more than the number of species pairs showing positive correlation; (3) The overall correlations between the dominant tree species of each community and the interspecific associations obtained by the χ2-test were mainly non-significant positive associations. Spearman rank correlation analysis results showed that the non-significant correlations were mainly among the species pairs in each community. The results of spatial correlation analysis and niche overlap of the dominant tree species in each community are in good agreement.   Conclusion  The above results show that the dominant tree species of each community are relatively independent in their respective distribution patterns. Although there are similar environmental resource requirements between species, the inter-species linkages are basically loose, and the community succession has not yet entered the mature stage.[Ch, 7 fig. 4 tab. 37 ref.]
Genome identification and expression analysis of GRF gene family in Phyllostachys edulis
RUAN Shiyu, ZHANG Zhijun, CHEN Jialu, MA Ruifang, ZHU Fengxiao, LIU Xiaoyu
doi: 10.11833/j.issn.2095-0756.20200544
[Abstract](24) [HTML](8) [PDF](1)
  Objective  This study aims to explore the nature and structural features of general regulatory factor(GRF) gene family in moso bamboo(Phyllostachys edulis) and its expression levels in different tissues, so as to lay the foundation for further study on the molecular mechanism of GRF in growth and development of Ph.edulis.  Method  Bioinformatics approach was used to analyze the whole genome and transcriptome information of Ph.edulis, and 13 members of GRF gene family were selected and analyzed for their physicochemical properties, evolution, gene structure, conserved domains, promoters, gene family expression patterns, and tertiary structure.  Result  Members of the GRF gene family in Ph.edulis were named PeGRF01~PeGRF13 according to their distribution on the scaffold. PeGRF04 and PeGRF12 with 3 introns were classified as ε group, and the rest were non-ε group. The physicochemical properties of the members of each GRF gene family differed, but their domains were relatively conservative, all containing 14/3/3 domains. The promoter region of GRF family in Ph. edulis contained a large number of cis-acting elements related to light response, low temperature response, and hormone regulation. The gene duplication and amplification in PeGRF was significantly higher in collinearity with Oryza sativa than with Arabidopsis thaliana. PeGRFs were expressed in different tissues and organs, and the expression levels of each family member were different. The expression levels in panicle and root tissues of Ph.edulis were slightly higher than those in leaf and rhizome, and there were some differences among family members. The GRF protein was composed of 2 monomers, each of which was composed of 9 α-helices, and the overall structure was W-shaped.  Conclusion  The GRF gene family of Ph.edulis has a typical 14/3/3 domain, which may be involved in the development of roots, rhizomes, leaves, panicles and shoots. [Ch, 6 fig. 1 tab. 39 ref.]
Effects of combined application of bamboo charcoal and organic fertilizer on soil fertility and growth of Brassica oleracea var. capitata f. rubra
CHEN Limei, LI Xiaoying, LI Junlong, LIANG Zhi, SHI Liangtao
doi: 10.11833/j.issn.2095-0756.20200723
[Abstract](12) [HTML](4) [PDF](0)
  Objective  This objective is to investigate the effects of combined application of bamboo charcoal and organic fertilizer on soil fertility and growth of Brassica oleracea var. capitata f. rubra in dry red soil of Yuanmou area, Yunnan Province.  Method  Three levels of bamboo charcoal mass fraction (4%, 6%, 8%) and three levels of organic fertilizer (5, 10, 20 t·hm−2) were set up in the experiment. A total of 10 treatments were designed with 3×3 complete scheme and blank treatment (ck) as control. The photosynthetic characteristics of leaves were measured once a month from September to December. After the B. oleracea var. capitata f. rubra was harvested at the end of December, soil samples were collected from 0−20 cm soil layer to determine the soil nutrient contents, as well as the yield and quality of B. oleracea var. capitata f. rubra.  Result  Combined application of bamboo charcoal and organic fertilizer increased soil pH, organic matter, total phosphorus, available phosphorus, total potassium and available potassium, and improved the net photosynthetic rate, yield and quality of B. oleracea var. capitata f. rubra, with significant differences among treatments (P<0.05). Compared with the control, the pH value in B8F10 treatment was the highest, which increased by 0.9 units. The contents of organic matter and total potassium were the highest in B4F10 treatment, with an increase of 107.93% and 46.06%, respectively. Total phosphorus content was the highest in B8F5 treatment, with an increase of 58.67%. Available phosphorus content was the highest in B6F20 treatment, with an increase of 157.44%, and available potassium content was the highest in B8F20 treatment, with an increase of 226.60%. Compared with the control, except for B8F5 treatment, the average net photosynthetic rate in leaves of B. oleracea var. capitata f. rubra at each stage increased by 1.14%−23.54%, and the average transpiration rate and intercellular CO2 concentration in leaves of B. oleracea var. capitata f. rubra increased by 3.01%−43.52% and 2.33%−9.11%, respectively. Except for B4F5 treatment, the mean value of stomatal conductance of leaves increased by 2.33%−39.54%. B6F10 treatment had the highest yield-increasing effects, soluble protein and anthocyanin contents.  Conclusion  Combined application of bamboo charcoal and organic fertilizer can continuously supply nutrients for B. oleracea var. capitata f. rubra, also promote its growth, yield and quality. Appropriate amount of organic fertilizer (10 t·hm−2) with bamboo charcoal (6%) has better effect on growth promotion, yield increase and quality improvement.[Ch, 4 fig. 2 tab. 34 ref.]
Effects of swine manure hydrochar on soil organic carbon mineralization and soil properties
ZHANG Zeng, SONG Chengfang, SHAN Shengdao, ZHENG Huabao, ZHANG Cheng
doi: 10.11833/j.issn.2095-0756.20200651
[Abstract](21) [HTML](7) [PDF](0)
  Objective  The purpose of this study is to evaluate the effects of swine manure hydrochar on soil organic carbon mineralization, pH, conductivity and nutrients, in order to provide a theoretical basis for the practical application of swine manure hydrochar.  Method  The hydrochar was prepared by swine manure under 180 ℃ for 1 h, and mixed with soil at the mass fraction of 0(ck), 1%, 2%, and 4% for cultivation experiments.  Result  Swine manure hydrochar could improve soil mineralization rate, soil mineralization potential, and soil organic carbon turnover rate. When the mixing ratio was 4%, the cumulative mineralization of soil increased by 1.52 times. The pH value of soil decreased from 7.17 to 6.67−6.98 during the cultivation process, and the overall trend of change was first down and then up. The mass fraction of soil available nitrogen and available phosphorus decreased to the lowest level on the 10th and 15th day and then increased. The soil electrical conductivity and nutrient composition increased with the addition of hydrochar. When the mixing ratio was 4%, the soil electrical conductivity, total organic carbon, water-soluble organic carbon, available nitrogen, available phosphorus and available potassium increased by 58.9%, 54.3%, 146.4%, 27.4%, 591.2% and 88.6%, respectively.  Conclusion  Swine manure hydrochar can accelerate the mineralization of soil organic carbon and significantly improve soil nutrient content, and is a suitable soil amendment. [Ch, 6 fig. 3 tab. 40 ref.]
Correlation between non-spatial structure distribution characteristics and productivity of natural coniferous and broad-leaved mixed forests in Zhejiang
GUO Jianhui, WEI Xinliang, ZHU Jindi, YANG Jingjing, ZHANG Jiyan
doi: 10.11833/j.issn.2095-0756.20200442
[Abstract](21) [HTML](3) [PDF](0)
  Objective  The objective of this study is to explore the distribution characteristics of non-spatial structure and the correlation between non-spatial structure and productivity of coniferous and broad-leaved mixed forests in Zhejiang Province, so as to provide theoretical basis and technical support for improving forest quality.  Method   Based on the data of natural coniferous and broad-leaved mixed forest sample plots and sample wood from the consecutive forest resource inventory in 1999, 2004, and 2009, the diameter at breast height(DBH), tree height, volume, and non-spatial structure factors and accumulation per unit area of conifer species were extracted. Patterns of non-spatial structure distribution in each period was modeled to explore characteristics of change. The continuous function method of biomass conversion factor was used to estimate biomass and productivity, and then the partial correlation analysis between non-spatial structure and productivity was performed.  Result  There existed regular distribution characteristics of forest non-spatial structure factors in different periods. The non-spatial structure factors and productivity showed a positive correlation. From 1999 to 2009, the proportion of coniferous species in the coniferous and broad-leaved mixed forest in Zhejiang Province increased gradually, and the productivity in the first period (1.39 t·hm−2·a−1) was higher than that in the second period (1.15 t·hm−2·a−1). The mean value of DBH, tree height and volume per plant were approximately normal.  Conclusion  In the management of coniferous and broad-leaved mixed forests, priority should be given to the proportion of coniferous and broad-leaved mixed forest in order to maintain the high productivity of the forest stand. The proportion of species should be kept above 50% and the mixed forests with a low proportion of coniferous species should be artificially intervened. If DBH is lower than 10.00 cm, tending should be strengthened, and if DBH is higher than 12.00 cm, cutting should be carried out in time. The average volume and tree height of per plant should be maintained at 0.040−0.070 m3·plant−1 and 7.00−10.00 m respectively. [Ch, 6 fig. 5 tab. 34 ref.]
Transcriptome analysis and PsHSP gene expression of Paeonia suffruticosa in response to high temperature stress
HAO Lihui, DONG Bin, ZHU Shaohua, MA Jin
doi: 10.11833/j.issn.2095-0756.20200529
[Abstract](25) [HTML](4) [PDF](4)
  Objective  High temperature in summer can lead to growth restriction, shorter flowering period and lower ornamental quality of Paeonia suffruticosa. This study aims to explore the molecular mechanism of heat stress induced by heat tolerance genes in P. suffruticosa.  Method  Using P. suffruticosa ‘Yuhong’ as material, transcriptome sequencing of leaves treated with high temperature (40 ℃) and room temperature (25 ℃) was conducted to analyze the differentially expressed genes in response to high temperature. Meanwhile, the differential genes were verified by real-time fluorescence quantitative PCR (qRT-PCR), and the spatio-temporal expression of heat shock protein gene HSPs was analyzed.  Result  A total of 45.97 Gb data were obtained by sequencing. Compared with the control group (25 ℃), 4 220 genes were up-regulated and 3 453 genes were down-regulated after high temperature treatment. Through gene ontology (GO) analysis, it was found that these differential genes were mainly concentrated in biological processes such as metabolism, cellular components such as cell and membrane structure, and molecular functional items such as binding and catalytic activity. In addition, genome-wide and metabolic pathway database (KEGG) analysis showed that the number of differential genes in carbon metabolic pathway was the largest. Quantitative analysis of heat shock protein PsHSP gene showed that the expression of PsHSP gene increased with the time of high temperature treatment, reached the peak at 24 h, and then showed a downward trend.  Conclusion  High temperature significantly affects the metabolism and synthesis of P. suffruticosa, and further affects its growth and development. PsHSP gene can rapidly respond to high temperature stress in a short time and participate in heat tolerance regulation in P. suffruticosa. [Ch, 4 fig. 6 tab. 34 ref.]
Soil-microbial stoichiometry of Eucalyptus urophylla × E. grandis plantation at different growth stages
ZHU Wankuan, XU Yuxing, WANG Zhichao, DU Apeng
doi: 10.11833/j.issn.2095-0756.20200536
[Abstract](21) [HTML](6) [PDF](1)
  Objective  The present study aims to investigate the soil-microbial stoichiometry of Eucalyptus. urophylla × E. grandis plantation at young, mature, and overmature stages in order to enrich the basic research in the field of ecological stoichiometry of Eucalyptus plantation ecosystem.  Method  Three E. urophylla × E. grandis plantations at different growth stages in Leizhou Peninsula were selected as the research objects. Soil samples were collected from 0−20, 20−40, 40−60 cm soil layers respectively for measuring soil organic carbon (Csoil), total nitrogen (Nsoil), total phosphorus (Psoil), soil microbial biomass carbon (Cmic), nitrogen (Nmic), and phosphorus (Pmic), and the ratio among them was estimated to analyze the relationship between soil and microbial biomass.  Result  The mean values of soil organic carbon, total nitrogen, total phosphorus and soil microbial carbon, nitrogen and phosphorus were the highest in overmature forest, which were 20.15, 1.47, 0.88 g·kg−1 and 583.09, 55.20, and 28.03 mg·kg−1, respectively. The differences in different stages were not consistent. The vertical changes of soil organic carbon, total nitrogen, total phosphorus and microbial biomass carbon, nitrogen and phosphorus showed the characteristics of “surface aggregation”, and the differences among soil layers in different growth stages were different due to different element types. The average values of Csoil/Nsoil and Csoil/Psoil in mature forest were 10.52 and 19.25, respectively, which were significantly lower than those in young and overmature forests (P<0.05). The mean value of N/Psoil in overmature forest was 1.67, which was significantly lower than that in young and mature forests (P<0.05). The average values of Cmic/Nmic, Cmic/Pmic, and Nmic/Pmic were 8.81 (overmature stage), 28.36 (young stage), and 2.72 (young stage) respectively, which were significantly lower than those in other two stages (P<0.05). The ratio of soil microbial biomass carbon to soil organic carbon (Cmic/Csoil) had no significant difference at three stages. The ratio of soil microbial biomass nitrogen to soil total nitrogen (Nmic/Nsoil) and the ratio of microbial biomass phosphorus to soil total phosphorus (Pmic/Psoil) in overmature forest were significantly lower than those in other two stages (P<0.05). Redundancy analysis showed that Csoil, Csoil/Psoil and Nsoil were the primary influencing factors of soil microbe in young forest, mature forest and overmature forest, respectively.  Conclusion  The soil microbial biomass of E. urophylla × E. grandis plantation is the highest in the overmature forest stage, and is closely related to the soil chemical properties. The index and degree of soil microbes affected by the soil are different at different growth stages of the stand. The effect of nutrient availability on the growth and reproduction of soil microbe should be paid attention to at the later growth stage. [Ch, 4 fig. 2 tab. 54 ref.]
Genome-wide identification and bioinformatics analysis of LBD family of transcription factors in Carya illinoensis
HUANG Yuancheng, GUO Wenlei, WANG Zhengjia
doi: 10.11833/j.issn.2095-0756.20200454
[Abstract](28) [HTML](3) [PDF](2)
  Objective  This study is aimed to investigate the structural features and the evolutionary patterns of the LBD transcription factor family as well as their expression patterns throughout the embryonic development in Carya illinoensis.  Method  With bioinformatic software employed, efforts were made to identify the LBD gene and analyze its gene structure characteristics, phylogeny relationships and evolutionary history in flower plants, as well as their expression patterns at the three key stages througout the embryonic development.  Result  Results showed that a) within the whole genome in Carya illinoensis there were a total of 52 candidate LBD genes which, in terms of gene structure, maximum likelihood phylogenetic tree and motif analysis, could be classified into 3 categories: Group Ⅰ, Group Ⅱ and Group Ⅲ; b) after the multiple sequences alignment analysis three important structures in the LOB domains of 52 LBD genes were identified, namely the CX2CX6CX3C zinc finger structure, the highly conserved glycine GAS structure and the leucine zipper-like structure with the occurrence of specific mutations or deletions in each of them; c) according to the LBD gene family phylogenetic analysis of representative flowering plants, Group Ⅰ and Group Ⅱ are relatively conservative, while all LBD genes in Group Ⅲ share a longer branch which indicates that they have undergone greater variation and new functions have been differentiated; d) the expression analysis showed that the LBD gene family participates in the function of regulating the development of embryos, usually with control over the development and morphogenesis of cotyledons and e) there is a cluster of genes in the LBD gene of hickory pecans that are highly expressed during the entire embryo development process playing a highly significant role.  Conclusion  In conclusion, a total of 52 LBD genes were obtained in the whole genome of Carya illinoensis, which can be divided into three different subfamilies with different gene structures, protein structures, evolutionary patterns, and expression patterns, and these subfamilies, according to the transcriptome expression analysis, are differentially expressed at different stages of embryonic development, and involved in the regulation of Carya illinoensis embryo development collectively. [Ch, 5 fig. 2 tab. 47 ref.]
Cloning and expression analysis under adversity stress of 2 PmWRKY2 in Prunus mume
WANG Nannan, DONG Bin, YANG Liyuan, ZHAO Hongbo
doi: 10.11833/j.issn.2095-0756.20200706
[Abstract](16) [HTML](2) [PDF](0)
  Objective  Low temperature is a main environmental factor that influences the cultivation and application of Prunus mume whereas WRKY gene is a plant-specific transcription factor which participates in the response to abiotic stress process. This study, with an investigation of how WRKY gene responds to low temperature and drought stress, is aimed to provide guidance for the directional breeding of P. mume.  Method  With the P. mume ‘Guhong Zhusha’ cDNA template selected as the substance, two WRKY2 genes were cloned by means of RT-PCR, named as PmWRKY2-1and PmWRKY2-2 before their expression patterns were under low temperature and in the condition of drought employing real-time quantitative PCR (qRT-PCR).   Result  a) PmWRKY2-1 and PmWRKY2-2, with respective coding area lengths of 2 223 and 2 220 bp, encode 740 and 739 amino acids respectively, both including 2 WRKY domains and a C2H2 zinc finger structure; b) though with a distant genetic relationshp with each other, both PmWRKY2-1 and PmWRKY2-2 had a close relationship with P. avium, P. persica and P. dulcis; c) according to the results of the real-time quantitative PCR (qRT-PCR), both PmWRKY2-1 and PmWRKY2-2 could be induced by low temperature and drought treatment And d) the expressions of PmWRKY2-1 and PmWRKY2-2 were significantly reduced after abscisic acid (ABA) treatment.  Conclusion  PmWRKY2-1 and PmWRKY2-2 are likely to participate in the regulation of low temperature and drought response of P. mume, yet might be subject to the regulation by ABA. [Ch, 6 fig. 1 tab. 28 ref.]
Application of low-alkali and low-salt reactive red dyes in Xylosma japonicum veneer dyeing
WANG Jingxian, SHEN Jun, WANG Jianjun, HE Liang, WANG Yuechan
doi: 10.11833/j.issn.2095-0756.20200391
[Abstract](27) [PDF](0)
  Objective  This study is to analyze the applicability of low-alkali and low-salt reactive red dyes in veneer dyeing, with the purpose of reducing the pollution of dyeing wastewater and the cost of production.  Method  A new low-salt reactive red dye(SNE) and low-alkali reactive red dye(LA) were selected to dye Xylosma japonicum veneers with poor permeability. The widely used reactive red dye (M-3BE) was used as control. The substantivity, reactivity, fixation rate and dyeing effects were tested. Fourier transform infrared spectroscopy(FTIR), thermal gravimetric(TG) analyzer and scanning electron microscopy(SEM) were used to analyze the changes of functional groups, wood components and microstructure of specimens.  Result  Compared with M-3BE, when the dosages of Na2SO4 and Na2CO3 were reduced to 1/2 and 1/8 respectively, the fixation rate of SNE increased by 15.33% and color difference decreased by 1.35%, while the fixation rate of LA decreased by 3.37% and color difference increased by 2.03%. After dyeing, the hydroxyl content on the wood surface decreased, and the lowest hydroxyl content was detected on the X. japonicum wood surface dyed with SNE dyes. No new absorption peak was observed on the dyed X. japonicum veneers except weak sulfate S=O absorption peak. The mechanism and the functional group structure between three reactive dyes and wood were similar. The thermal decomposition curves were slightly different due to differences in the parent structures of the three reactive dyes. All dye molecules could diffuse to the wood interior from the wood surface, and the order of diffusion degree from large to small was SNE, M-3BE, and LA.  Conclusion  SNE has high dye uptake and LA has excellent color effect, which can greatly reduce the discharge of electrolyte salt and alkali. [Ch, 3 fig. 3 tab. 28 ref.]
Ecological effects of microplastics contamination in soils
ZHOU Yumiao, HE Ganghui, MA Shaofeng, SHAO Fanglei, FEI Yufan, HUANG Shunyin, ZHANG Haibo
doi: 10.11833/j.issn.2095-0756.20200729
[Abstract](33) [HTML](8) [PDF](1)
Large amounts of microplastics have been accumulated in soils and their degradation is relatively slow. The residual time of microplastics in soils could be extended to decades or even over a hundred years. Therefore, the ecological effects of long-term residual of the microplastics in soils has been of concerned widely in recent years. Published papers related to the microplastics and their effects in soils were collected and introduced in order to make a full review in the field. The research advances were presented based on the different ecological receptors, which included change of soil physical environment due to the accumulation of microplastics, ingestion of microplastics by invertebrates from soils and their effects on the enteric microorganism, response of soil microbial community and soil enzyme to microplastics pollution, plant uptake of microplastics and their effects. The studies of effects on soil physical environment in the present of microplastics mainly focus on soil density, soil aggregate composition and water hold capacity. Such effects were supposed to have further impacts on soil enzyme activity, microbial community composition and even plant growth based on current limited studies. Many other studies at present were also concentrated on the migration of microplastics induced by soil invertebrates e.g. earthworm, springtail. Meanwhile, microplastics in the soil might be ingested by soil invertebrates and subsequently caused some negative effects and influence on the gut microorganism community of the soil invertebrates. There were also some studies focusing on the microplastics accumulation through food chain regarding the effects of microplastics on soil animals. For example, microplastics might be accumulated in chicken through the predation of earthworm by chicken. After the introduction of current studies, several research proposal were put forward based on the complication of microplastic’s properties and the shortage of current researches. These proposal contained four aspects: (1) development of standard protocols for the study of ecotoxicology of soil microplastics pollution, (2) studying the interaction mechanism between microplastics and microorganisms, plants and invertebrates, (3) revealing microbiological mechanisms that regulation of the transformation of materials and microplastics in soils, (4) exploring plastishere in soils of different ecosystems. All these researches are expected to be supportive to assessment of the ecological effects of soil microplastics pollution. [Ch, 80 ref.]
Preparation and antibacterial effect of yak bone protein peptide-calcium chelate embedded with cinnamon essential oil
NI Yunqi, TANG Jingyi, HONG Hui
doi: 10.11833/j.issn.2095-0756.20200503
[Abstract](27) [HTML](8) [PDF](0)
  Objective  This study aims to explore the formation mechanism and antibacterial effect of yak bone protein peptide-calcium chelate embedded with cinnamon essential oil, so as to make full use of the bone resource and improve its utilization rate and avoid serious waste.  Method  The yak bone was autoclaved at high temperature to separate protein and bone residue. Yak bone collagen peptide was obtained from enzymatic hydrolysis of protein, and soluble yak bone calcium was obtained from acid-dissolved bone residue. The cinnamon essential oil and the yak bone collagen peptide were mixed and homogenized to form a cinnamon essential oil-yak bone peptide emulsion, and the calcium chelate of yak bone protein peptide encapsulated in cinnamon essential oil was obtained by high speed shear method. The turbidity, particle size, polydispersity index, antibacterial activity of the chelated calcium were determined and organoleptic evaluation was conducted.  Result  The yak bone peptides were mostly small molecule peptides (less than 1.0 kDa), and were suitable for the preparation of chelated calcium. When pH value was less than 7, many yak bone peptides were negatively charged and were affected by hydrophobicity to form yak bone protein peptide-calcium chelates. The yak bone peptide was composed of a large number of proline (P) and glycine (G), which could easily form the β-turn, one of the polypeptide secondary structures, and facilitate the release of substances. The yak bone protein peptide-calcium chelate embedded with cinnamon essential oil had good stability, with an average particle size of 780.2 nm. The dispersibility was good and the polydispersity index was less than 0.200. The 12 h antibacterial rates of yak bone protein peptide, cinnamon essential oil and chelate against Aeromonas veronii were −13.70%, 70.24% and 77.33%, respectively. The inhibition rate of chelate to Aeromonas was higher than that of cinnamon essential oil after 6 hours. The organoleptic evaluation revealed that the aroma scores of chelate and cinnamon essential oil were 7.15 and 4.35 respectively, and the cinnamon flavor of chelate was significantly stronger than that of cinnamon essential oil (P<0.05), indicating that the chelate had a certain sustained-release effect.  Conclusion  Yak bone protein peptide and yak bone calcium are suitable for the development of complex amino acid mineral chelated calcium products, and the yak bone protein peptide-calcium chelate encapsulated with cinnamon essential oil can be used for the development of new antibacterial agents. [Ch, 4 fig. 4 tab. 32 ref.]
Codon usage bias analysis of rbcL genes of 20 Lythraceae species
ZHENG Gang, GU Cuihua, LIN Lin, WANG Jie
doi: 10.11833/j.issn.2095-0756.20200390
[Abstract](40) [HTML](10) [PDF](3)
  Objective  With an analysis of the codon usage characteristics of the rbcL genes in Lythraceae species, this study is aimed to clarify the influencing factors of codon bias, and screen the optimal receptor for heterologous expression and genetic transformation.  Method  After rbcL gene CDS of 20 Lythraceae species were obtained from NCBI, CodonW, EMBOSS, and DAMBE software were utilized to compute relevant parameters of gene base composition and codon usage bias before an analysis is conducted of the usage bias of such genes and its incluencing factors using SPSS and Origin software.  Result  The GC content of the rbcL gene from Lythraceae species ranged from 0.425 to 0.437, with GC3s being 0.275 to 0.300 and there was a significant correlation between GC3s, GC, and ENC(P<0.01). As was shown in the analysis of ENC-GC3s plot, the neutral plot and PR2, natural selection pressure affected the codon usage bias of the rbcL gene from Lythraceae species more heavily than mutation pressure. The result of clustering analysis based on RSCU is partially consistent with that of the neighbor-joining tree based on CDS. Compared with the average codon usage frequency of the rbcL gene from the 20 Lythraceae species, Escherichia coli, Saccharomyces cerevisiae, Arabidopsis thaliana, Nicotiana tabacum, and Solanum lycopersicum possessed 28, 26, 20, 19 and 17 codons, respectively, with significant differences in usage frequency.  Conclusion  In terms of the base composition of the rbcL gene from 20 Lythraceae species, there was a tendency towards A/T bases and codons with A/T base at ther termonal were generally preferred. Also, of all the factors having an influence on codon bias, natural selection pressure was the most important one. Systematic clustering is a good complement for phylogenetic analysis. S. cerevisiae is more suitable as a heterologous expression receptor, while S. lycopersicum is more suitable to act as a receptor material for genetic transformation and function research of rbcL gene. [Ch, 6 fig. 3 tab. 32 ref.]
Effects of thinning on the functional traits of understory Vitex negundo var. heterophylla in Quercus variabilis plantation
MA Ruiting, DONG Xiaoming, JIN Shanshan, HU Linpo, YAN Dongfeng
doi: 10.11833/j.issn.2095-0756.20200551
[Abstract](26) [HTML](8) [PDF](2)
  Objective  The objective of this study is to explore the effect of thinning on the functional traits of roots, stems and leaves of Vitex negundo var. heterophylla under Quercus variabilis plantation in order to provide theoretical basis for the optimization of plantation structure and the regeneration and protection of understory seedlings.  Method  The V. negundo var. heterophylla in the shrub layer of Q. variabilis plantation 3 years after thinning was taken as the research object, and the differences of leaf area, specific leaf area, leaf dry matter content, stem dry matter content, total root length, specific root length and other structural traits, as well as total nitrogen, total phosphorus, total potassium and total organic carbon content in various plant organs were compared. The relationship between plant functional traits and the understory light environment and soil physical and chemical characteristics was studied.  Result  After thinning, the aboveground functional traits of plants of V. negundo var. heterophylla such as total leaf organic carbon, leaf area, specific leaf area, leaf organic nitrogen, stem total organic carbon, and the underground functional traits of plants such as root length, root volume, root biomass, the total organic carbon content of roots were significantly higher than those of the control plot (P<0.05). Correlation and stepwise regression analysis results showed that scattered radiation was the main factor affecting the structural properties of V. negundo var. heterophylla leaves. Direct radiation flux, photosynthetically active radiation and total solar radiation time were the key factors affecting leaf chemical properties, while stem functional properties were mainly affected by the direct radiation and scattered radiation under the forest. Total root length, specific root length and root organic carbon content were significantly correlated with soil non-capillary porosity, soil total porosity, soil organic carbon and soil total nitrogen (P<0.05), among which soil organic matter content was the key factor affecting functional traits.  Conclusion  Thinning can significantly promote the development of the functional traits of leaves and roots of Q. variabilis plantation, and has a weak effect on stem functional traits. [Ch, 1 fig. 6 tab. 31 ref.]
Bioinformatics analysis of PIF transcription factors in Magnolia sinostellata and expression pattern analysis under extreme shading condition
LU Danying, CHENG Shaoyu, ZHANG Yingjia, LIU Zhigao, JIN Mengting, DONG Bin, ZHANG Shouzhou, PENG Hao, DAI Mengyi, WANG Zhuowei, ZHAO Hongbo, SHEN Yamei
doi: 10.11833/j.issn.2095-0756.20200488
[Abstract](34) [HTML](8) [PDF](0)
  Objective  The shading caused by the community is one of the important factors that lead to the endangerment of Magnolia sinostellata. Therefore, it is important to conduct a systematic analysis and research of PIF family transcription factors which play an important role in light signal transduction and plant growth. Also, such analysis will help lay a foundation for the exploration of its role in the light signal transduction mechanism of M. sinostellata.  Method  With the transcriptome data of M. sinostellata collected, transcription factors of PIF family were identified and analyzed by bioinformatic while the expression patterns were analyzed employing the qRT-PCR technology.  Result  The nine MsPIFs transcription factor genes screened from the M. sinostellata enjoyed a length of 188~735 aa, a protein size of 20314.56~78957.02 Da, and a theoretical isoelectric point range of 5.18~8.22. The proteins encoded by MsPIFs gene were unstable proteins, and all proteins were hydrophilic proteins localized in the nucleus as was demonstrated in the subcellular localization prediction. All nine proteins have Ser, Thr and Try phosphorylation sites. As was shown in the qRT-PCR results, under extreme shading conditions, there was the occurrence of changes of different degrees in the gene expression of 9 MsPIFs families of which MSBHLH23 has an expression level that was 52.77 and 20.03 times higher than that of the control at 5 d and 10 d after shading treatment.  Conclusion  The PIF transcription factor family of M. sinostellata can respond to shading and this study has laid a foundation for the identification of MsPIFs biological function. [Ch, 7 fig. 3 tab. 32 ref. ]
Effects of simulated nitrogen deposition and phosphorus addition on soil respiration in Chinese fir forest
LIN Yuxuan, AI Jianguo, SONG Xinzhang, LI Quan, ZHANG Junbo
doi: 10.11833/j.issn.2095-0756.20200326
[Abstract](37) [HTML](4) [PDF](1)
  Objective  With an examination of the effects of simulated nitrogen deposition and phosphorus addition on the soil respiration in Chinese fir(Cunninghamia lanceolata) forest, this study is aimed to provide scientific basis for the regulation of the soil carbon cycle in Chinese fir forest.  Method  In an attempt to investigate the changes in soil respiration in Chinese fir forest under atmospheric nitrogen deposition and phosphorus addition, a 10-year-old Chinese fir forest was selected as the research object with a total of 9 treatment levels, namely the control treatment group (ck), low nitrogen (N30: 30 kg·hm−2·a−1), high nitrogen (N60: 60 kg·hm−2·a−1), low phosphorus (P20: 20 mg·kg−1), high phosphorus (P40: 40 mg·kg−1), low nitrogen and low phosphorus (N30+P20), low nitrogen and high phosphorus (N30+P40), high nitrogen and low phosphorus (N60+P20), high high nitrogen and high phosphorus (N60+P40).  Result  The application of nitrogen and phosphorus had a significant effect on the respiration of Chinese fir soil. Nitrogen applied alone promoted the respiration of Chinese fir soil, to the largest degree (P<0.05) when the nitrogen level reached N60: 60 kg·hm−2·a−1. When the phosphorus level reached P40: 40 mg·kg−1, the soil respiration was most significantly promoted(P<0.05). With both nitrogen and phosphorus applied, the low nitrogen and high phosphorus treatment level (N30+P40) promoted the respiration most significantly. The soil respiration rate was extremely significantly positively correlated with soil temperature(P<0.01), and extremely significantly negatively correlated with the soil moisture(P<0.01). And at low nitrogen and low phosphorus treatment level (N30+P20), the soil temperature sensitivity coefficient(Q10) value was higher than the control.  Conclusion  Both nitrogen deposition and phosphorus addition can promote the soil respiration of Chinese fir and the combined application of nitrogen and phosphorus can promote the soil respiration of Chinese fir more significantly. Among all the treatment levels, the effect of high nitrogen and low phosphorus is the most significant. [Ch, 1 fig. 2 tab. 46 ref.]
Effects of water stress on chloroplast ultrastructure and key enzymes of flavonoid synthesis in Tetrastigma hemsleyanum
TU Lingyan, WU Xueqian, XU Haishun
doi: 10.11833/j.issn.2095-0756.20200358
[Abstract](14) [HTML](4) [PDF](0)
  Objective  This study aims to investigate the effects of water stress on the ultrastructure of chloroplast and the activity and content of key enzymes in the flavonoid synthesis pathway of Tetrastigma hemsleyanum, so as to improve the quality of T. hemsleyanum.  Method  With two-year-old seedlings of T. hemsleyanum as materials, and through water control pot experiments (setting waterlogging, drought, and the control), the effects of water stress on chloroplast ultrastructure, root flavonoid content and the activities of three key enzymes [phenylalanine ammonia lyase(PAL), chalcone synthase(CHS) and chalcone isomerase(CHI)] in flavonoid synthesis pathway were analyzed.  Result  Drought and waterlogging both caused the decrease of chloroplast number in the leaves, and they moved toward the center of the cell instead of clinging to the cell wall. Besides, the number of plastid globules in the chloroplast increased and the volume became larger, the color became lighter, and the lamella structure of chloroplast was no longer neat and compact. The total flavonoid content of T. hemsleyanum reached the peak on the 12th day under drought stress, and reached the peak on the 16th day under waterlogging stress. Analysis of key enzyme activities in the biosynthetic pathway of flavonoids showed that the activities of PAL, CHS and CHI increased successively in the early stage of the maximum flavonoid content or during the same period, but with the extension of stress time, the total flavonoid content and key enzyme activities decreased in varying degrees. There was a significant correlation between the content of flavonoids and the activities of PAL, CHS, and CHI (P<0.05).  Conclusion  Moderate water stress can increase the content of flavonoids in the roots of T. hemsleyanum and enhance the activity of related enzymes. [Ch, 7 fig. 1 tab. 36 ref.]
Risk assessment of Bursaphelenchus xylophilus in Hubei Province based on ecological niche factor analysis model
SHEN Peng, LI Gongquan
doi: 10.11833/j.issn.2095-0756.20200365
[Abstract](49) [HTML](21) [PDF](0)
  Objective   The epidemic situation of Bursaphelenchus xylophilus in Hubei Province is severe. The objective of this study is to investigate the invasion risk and the damage degree of B. xylophilus disease in Hubei Province, so as to provide suggestions and reference for current epidemic prevention and control.   Method   Combined with 3S technology, the ecological niche factor analysis (ENFA) model was used, and 4 factors affecting the colonization and spread of B. xylophilus (climate, vegetation, terrain, human disturbance) were selected to predict and evaluate the invasion risk of the disease.   Result   The high risk area of B. xylophilus disease in Hubei Province covered an area of 38 884.62 km2, accounting for 20.92% of the total area of Hubei Province, mainly concentrated in the central and eastern regions with low altitude and frequent human activities. The moderate risk area was 66 501.84 km2, representing 35.77% of the total area. The low risk area was 80 513.54 km2, representing 43.31% of the total area. These areas were mainly distributed in Jianghan Plain and high-altitude mountains in the west. B. xylophilus preferred to be distributed in coniferous forest areas with high temperature, abundant precipitation, low altitude, close to human settlements and frequent human activities. Through cross-validation to test the prediction of the model, the P/E curve was obtained. The curve was monotonically increasing and the Boyce index was very high, indicating that the model had high accuracy.   Conclusion   The ENFA model can simulate the risk areas of B. xylophilus. The results of the model can provide reference for the prevention and control of B. xylophilus in Hubei Province. [Ch, 2 fig. 3 tab. 25 ref.]
Natural regeneration factors of Abies georgei var. smithii seedlings in Sejila Mountain
WANG Ruihong, PAN Gang, ZHANG Xinjun, LI Jiangrong, ZHANG Xinjian
doi: 10.11833/j.issn.2095-0756.20200302
[Abstract](28) [HTML](7) [PDF](0)
  Objective  This paper with an analysis of the influencing factors of natural regeneration of Abies georgei var. smithii in Sejila Mountain, is aimed to provide theoretical guidance for the effective promotion of its natural regeneration.   Method  Based on a field sample survey as well as an analysis of the correlation between the seedlings density and the five influencing factors on shady and sunny slopes of A. georgei var. smithii in Sejila Mountain, the path analysis was carried out to find out the key factors affecting its natural regeneration.   Result  On both sunny and shady slopes, there was a significant positive correlation between the natural regeneration seedlings and the length of seed wing, 1000-seed weight, moss thickness, litter thickness, canopy density of sunny slope. Litter thickness was the most important factor affecting the growth of natural regeneration seedlings of A. georgei var. smithii on sunny slope and the order of contribution to seedlings density was litter thickness, 1 000-seed weight, moss thickness, winged seed length and canopy density. Moss thickness was the most important factor affecting the growth of natural regeneration seedlings of A. georgei var. smithii on shady slope and the order of contribution to seedlings density was moss thickness, litter thickness, 1000-seed weight, canopy density and winged seed length.  Conclusion  Litter thickness was the largest factor affecting the density seedlings of A. georgei var.smithii on sunny slope, while moss thickness on shady slope was the most critical factor. [Ch, 3 tab. 27 ref.]
Response of rainfall runoff to forest quality in Shicheng County, Jiangxi Province
ZHOU Yong, XU Tongxin, LUO Shuwen, YANG Hao, CHANG Meng, ZHUANG Jiayao
doi: 10.11833/j.issn.2095-0756.20200505
[Abstract](53) [HTML](10) [PDF](10)
  Objective  The study aims to explore the characteristics and laws of the chronological change of rainfall runoff and forest quality in Shicheng County of Jiangxi Province, and the relationship between rainfall, runoff and forest, so as to provide basis for quantitative monitoring and scientific evaluation of soil erosion and ecological environment in the red soil hilly area in southern China.  Method  Based on the natural rainfall and runoff sequence data of Shicheng County from 1989 to 2018 and remote sensing image maps in different years, the methods of wavelet analysis, remote sensing supervision and interpretation, and forest quality grade determination were employed.  Result  (1) Rainfall and runoff showed a slow downward trend with inter-annual changes, but the decreasing trend was not significant. (2) The forest quality index showed an upward-downward-upward trend with the increase of resolution years. (3) The improvement of forest quality had a significant role in flood detention. (4)The wavelet model of Shicheng County showed the runoff depth was positively correlated with precipitation and negatively correlated with forest quality index.  Conclusion  The improvement of forest quality can strengthen the ability of forest water conservation and forest flood detention.[Ch, 4 fig. 5 tab. 27 ref.]
Prediction of future changes in suitable distribution area for rare tree species of Dalbergia
CHEN Yuheng, LU Shuangfei, MAO Lingfeng
doi: 10.11833/j.issn.2095-0756.20200522
[Abstract](66) [HTML](9) [PDF](1)
  Objective  Dalbergia has high economic value and its wild population has been seriously damaged. With the aggravation of climate change, the population distribution of Dalbergia is highly uncertain. Therefore, it is urgent to understand the future development trend of the species for better protection.   Method  Based on the current climate and environment factors, the suitable distribution areas of 7 rare tree species of Dalbergia listed in the China biodiversity red list were predicted by using the MaxEnt model, and the changes of distribution areas under different climate scenarios in the future were analyzed.   Result  The annual mean temperature, isothermal property, seasonal variation coefficient of air temperature, precipitation in the hottest season, precipitation in the driest month, precipitation in the driest season, soil calcium carbonate content and slope were the key environmental factors affecting the distribution simulation of 7 species of Dalbergia rare trees. Except D. hupeana, the rare trees of Dalbergia would obtain more suitable distribution area in the future. The suitable distribution area and optimum distribution area of D. hupeana decreased by 30.8% and 49.3% respectively.  Conclusion  The future distribution of different species of the same genus has different responses to climate change due to the differences in distribution areas, so the future conservation efforts should focus on species such as D. hupeana, which are suitable for reduced distribution area. [Ch, 3 tab. 39 ref.]
Sequence and expression analysis of hexokinase gene family members in Osmanthus fragrans
PANG Tianhong, QIAN Jieyu, FU Jianxin, GU Cuihua, ZHANG Chao
2021, 38(2): 225-234.   doi: 10.11833/j.issn.2095-0756.20200370
[Abstract](175) [HTML](34) [PDF](41)
  Objective  This study aims to analyze the sequence characteristics and expression changes of hexokinase family members of Osmanthus fragrans.  Method  Based on the transcriptome data of O. fragrans cultivars ‘Yanhong Gui’, ‘Yulinglong’ and ‘Jinqiu Gui’, HXK homologous genes were selected for sequence analysis and phylogenetic tree analysis, and real-time fluorescence quantitative PCR was used to detect the expression of OfHXKs genes in different tissues and development stages of O. fragrans.  Result  Four HXK homologous genes OfHXK1−OfHXK4 were screened, and sequence identity of OfHXK1, OfHXK3 and OfHXK4 from different cultivars is more than 99%. OfHXKs encode 461−510 amino acid residues, including two conserved phosphorylation motifs phosphate 1 and phosphate 2, and one sugar binding motif. Sequence analysis and phylogenetic tree analysis showed that OfHXK1 and OfHXK2 have N-terminal membrane anchoring structures, which are grouped together with AtHXK1 and AtHXK2 from Arabidopsis thaliana. OfHXK3 without transmembrane region is closely related to AtHXK3, so it was speculated that OfHXK3 has catalytic effect but without sugar signaling function. OfHXK4 protein with 11 amino acid insertions at the adenosine binding domain, is closely related to AtHKL1 and AtHKL2. Four HXK gene members from O. fragrans are all expressed in the annual stem, biennial stem, tender leaves, mature leaves and inflorescence. With the development of flower, the expression levels of OfHXK1, OfHXK3 and OfHXK4 genes increase first and then decrease, while the expression patterns of OfHXK2 genes during flower development are different in the three cultivars.  Conclusion  According to sequence analysis and evolutionary tree analysis, it is speculated that OfHXK1−OfHXK4 all have the function of catalysing hexose phosphorylation, and OfHXK1 and OfHXK2 have the function of sugar sensing and signaling. The expression patterns of OfHXK1, OfHXK3, and OfHXK4 genes during the inflorescence development of the three varieties showed a regular increase and decrease with the process of flower opening, which may be associated with their functions in sugar metabolism. [Ch, 6 fig. 4 tab. 30 ref.]
On the diversity and stability of forest communities in Wudalianchi Volcanoes
XIE Lihong, CAO Hongjie, HUANG Qingyang, YANG Fan, WANG Jifeng, WANG Jianbo, NI Hongwei
2021, 38(2): 235-245.   doi: 10.11833/j.issn.2095-0756.20200255
[Abstract](122) [HTML](32) [PDF](40)
  Objective   Wudalianchi Volcanoes, with its intact inland monogenetic volcanic landform and a complete vegetation succession process, is an ideal place to research matters like vegetation succession and the development of biodiversity system development. With a survey conducted of the species diversity and stability of forest community as well as the relationship between species diversity and stability, this study is an attempt to provide scientific basis for the succession, restoration and sustainable development of forest vegetation in Wudalianchi Volcanoes.   Method   Targeting at four old volcanic forest communities, the study has mainly investigated the quantitative characteristics of community structure, the species diversity of the tree, shrub and herb layer, the age structure of community and the age structure of Tilia amurensis and Quercus mongolica populations.   Result   (1) The number of species in the tree and shrub layer of each mountain forest community was bigger on the north slope than that on the south slope: with only one species with an important value≥1 found on the south slope, the composition species of the whole community showed little complexity. (2) On the north slope, the Margalef index and the Shannon-Wiener index of the tree and herb layer are larger than those of the shrub layer while the Simpson index and the Pielou index of the tree and shrub layer are larger than those of the herb layer yet on the south slope, all species diversity indexes of the herb and tree layer are larger than those of the shrub layer. (3) The age structure of forest community was stable on both north and south slopes, so was the age structure of T. amurensis and Q. mongolica populations, which indicated the stability of the communities. (4) On the north slope, the species diversity of the tree and shrub layer are bigger than that of the south slope, while that of the herb layer is smaller than that of the south slope. Moreover, the species diversity of the communities on the north and south slopes show either extremely significant or significant differences, with a large coefficient of variation.   Conclusion   The community structure of the old volcanic forest in the Wudalianchi Volcanoes was simple and the north slope enjoyed a bigger species diversity and higher community stability when compared with the south slope. [Ch, 6 fig. 4 tab. 31 ref.]
Effects of biodiversity on biomass of Pinus massoniana plantation under different succession degrees
HAN Zemin, LI Yuan, WANG Xiong, JIAN Yongfeng, ZHOU Jingjing, DIAN Yuanyong, HUANG Guangti
2021, 38(2): 246-252.   doi: 10.11833/j.issn.2095-0756.20200334
[Abstract](88) [HTML](17) [PDF](31)
  Objective  The purpose of this study is to explore the change law of biomass and biodiversity of Pinus massoniana plantations under natural succession degree and the relationship between them, so as to solve the problems of fertility decline, biodiversity reduction, and biomass decline of P. massoniana forest under the long-term pure forest management mode.  Method  Taking 3 P. massoniana plantations with different degrees of natural succession in Taizi Mountain, Jingshan County, Jingmen City of Hubei Province as the research object, the typical plot method was used to explore the relationship between biomass, biodiversity and stand density.  Result  (1) The biomass of 40-year-old and 50-year-old stands was significantly different from that of 30-year-old stand (P<0.05), and the average biomass of 40-year-old stand was the highest. (2) The diversity index increased with the succession, but it was different in different succession stages. Among them, Shannon-Wiener index and Simpson index had significant differences among different succession stages(P<0.05). There was no significant difference in Pielou index between 40-year-old and 50-year-old stands (P>0.05), but both were different from 30-year-old stands. The changes of functional richness and diversity were consistent with Pielou index. There was no significant difference in functional dispersion between 40-year-old stands and stands of other succession stages (P>0.05), but significant difference between 30-year-old stands and 50-year-old stands (P<0.05). There was significant difference in functional evenness among different succession stages (P<0.05). (3) There was no significant difference in stand density between 40-year-old stand and the stands of other succession stages (P>0.05), but significant difference between 30-year-old stand and 50-year-old stand (P<0.05), and the change trend increased with the succession degree. (4) In the best explanation model, the explanatory variables included functional dispersion, Shannon-Wiener index, Simpson index and Pielou index, among which functional dispersion was more effective than other species diversity indexes in explaining biomass changes.  Conclusion  Biodiversity factors can explain the changes of biomass to some degree, and the functional dispersion of functional parameters has the greatest impact on biomass. [Ch, 1 fig. 4 tab. 34 ref.]
Effects of human interference on species diversity and biomass of Eucalyptus grandis plantation in Cangping Mountain Park in Ya’an
ZENG Hong, CHEN Conglin, YU Jing, XIANG Lin, SUN Yimiao, HU Mingyue, HAO Jianfeng
2021, 38(2): 253-261.   doi: 10.11833/j.issn.20950756.20200312
[Abstract](151) [HTML](43) [PDF](52)
  Objective  This study aims to reveal the effects of human interference on species diversity and biomass in E. grandis plantations.  Method  12 sample plots of E. grandis plantations (20 m×20 m) with different interference intensities were set up by typical plot method in Cangping Mountain Park in Ya’an City of Sichuan Province, to investigate the species composition, species diversity(richness index D, Shannon-Wiener index H, Simpson dominance index H', Pielou evenness index Jsw), and plant layer biomass.  Result  There were 87 species of vascular plants belonging to 55 families and 82 genera. The number of species in E. grandis plantation decreased with increasing interference. The D, H and H' indices of tree layer and herb layer decreased with the increase of interference intensity. The D, H and H' indices of shrub layer reached the maximum under moderate disturbance. The difference of D and H indices in tree layer was significant (P<0.05). With the increase of disturbance intensity, the biomass of each plant layer showed different changing trends. The tree layer had the highest volume (12.01 m3·hm−2) under moderate disturbance, while the biomass of shrub layer (394.533 kg·m−2) and herb layer (359.680 g·m−2) was the highest under light disturbance. The D index of tree layer and H' index of herb layer were significantly positively correlated with aboveground biomass and total biomass of herb layer (P<0.05). The Jsw index of herb layer was significantly positively correlated with total biomass of herb layer (P<0.05).  Conclusion  Moderate disturbance will increase species diversity and biomass in E. grandis plantation. The relationship between species diversity and biomass is subject to human interference and natural conditions, and there is no fixed relationship. [Ch, 2 fig. 3 tab. 25 ref.]
Community characteristics of Sinocalycanthus chinensis in Dalei Mountains of Tiantai County
ZHANG Zhongzhao, XIE Wenyuan, ZHANG Peilin
2021, 38(2): 262-270.   doi: 10.11833/j.issn.2095-0756.20200349
[Abstract](84) [HTML](12) [PDF](18)
  Objective  This study aims to explore the species composition, population structure and interspecific association of wild Sinocalycanthus chinensis community, and to supplement the distribution of wild S. chinensis resources in Tiantai County, Zhejiang Province.  Method  On the basis of field survey and previous research data, five 20 m × 20 m sample plots of S. chinensis were established for community investigation.  Result  (1) The community types of S. chinensis were diverse, mainly including deciduous broad-leaved forest, coniferous forest and bamboo forest, with obvious stratification. The dominant species of tree layer were Platycarya strobilacea, Lindera glauca, Botrocarpyum contoversum, Cunninghamia lanceolata, and Phyllostachys edulis. The dominant species of shrub layer were Hydrangea chinensis, S. chinensis, and Boehmeria tricuspis. The dominant species of herb layer were Parathylyperis glandulgera, Viola rossii, and Pilea pumila. (2)The population structure of S. chinensis was “Pyramid” type, with the highest proportion of individuals in gradeⅠ, accounting for 56.51%, indicating that the population was in the growth stage. (3) The analysis of interspecific association and correlation of species pairs in tree layer and shrub layer showed that the positive and negative correlation ratios were both greater than 1, and there was no correlation between S. chinensis and most tree species.  Conclusion  The species of S. chinensis community are closely related, and the structure and function of the community tend to be perfect, but S. chinensis may be relatively independent in the community. In view of its negative correlation and competitive relationship with Lindera erythrocarpa, Rubus corchorifolius, Cerasus schneideriana, Platycarya strobilacea and other tree species, it is suggested that in the later stage of S. chinensis field conservation, appropriate artificial selective cutting and tending measures should be taken to create a good growth environment. [Ch, 10 fig. 5 tab. 24 ref.]
Reflection spectrum and photochemical characteristics of different colors’ leaves in Pseudosasa japonica
WANG Jie, CHEN Keyi, JIN Hai, LI Zhaona, CHENG Minmin, YANG Haiyun
2021, 38(2): 271-279.   doi: 10.11833/j.issn.2095-0756.20200360
[Abstract](103) [HTML](27) [PDF](17)
  Objective  This study is aimed to explore the differences in photosynthetic capacity of different colors’leaves of Pseudosasa japonica, analyze the leaf color variation from a physiological point of view and lay the foundation for the further exploration of the mechanism of leaf color variation.  Method  With the strong bamboo leaves of Pseudosasa japonica(GL), regreened leaves of P. japonica f. akebonosuji(AL), striped leaves of P. japonica f. akebonosuj(SL), including the white part(SA) and the green part(SG), and the leaves of P. japonica f. akebono(VL) selected as the subjects, an investigation was conducted of the photosynthetic pigment content, ChlNDI, PRI, fast fluorescence kinetic parameters and 820 nm relative absorption.  Result   a) The relative content of chlorophyll in leaves was as follows: GL>SL>VL>AL and the change trend of chlorophyll normalized difference index (ChlNDI) and photochemical reflectance index(PRI) in different leaves of Pseudosasa japonica is the same, which is GL>SG>VL>SA>AL; b) The maximum redox capacity of Photosystem Ⅰ(PSⅠ) of three bamboo species was GL>VL>SG>AL; the regreened leaves and the striped green leaves of P. japonica f. akebonosuji and the P. japonica f. akebono demonstrate chlorophyll fluorescence curve kinetic activity, but the PhotosystemⅡ(PSⅡ) reaction center had a significantly lower degree of openness than that of the Pseudosasa japonica, and the share of energy used for electron transfer becomes smaller; c) The lack of chlorophyll makes the light energy absorbed by the unit reaction centers increase continuously, probably because it requires more reaction centers to cope with its lower conversion efficiency, however, the maximum photochemical efficiency (Fv/Fm) and the leaf performance index on absorption basis (PIABS) are gradually reduced, possibly due to the fact that the PSⅡ reaction center is reversibly deactivated, able to absorb light energy yet unable to promote electron transfer.  Conclusion  The variation of leaf color will lead to the difference of photosynthetic pigment content in different kinds of Pseudosasa japonica, and then affect the chlorophyll normalization index and photochemical reflectance index characteristic parameters. Chlorophyll deficiency will affect the active reaction center of PSⅡ, causing reversible inactivation. There are fewer reaction centers in the striped leaves of P. japonica f. akebonosuji, but it still demonstrates good PSⅡ activity, chlorophyll level, and maintains good photosynthetic capacity, usually subject to the uniqueness of flowers and features of leaves. [Ch, 8 fig. 2 tab. 31 ref.]
Effects of different dissolved oxygen concentration on growth, physiology and biochemistry of hydroponic Phyllostachys violascens seedlings
YANG Wangting, SHAO Xiangjun, ZHOU Jumin, GUI Renyi
2021, 38(2): 280-288.   doi: 10.11833/j.issn.2095-0756.20200286
[Abstract](84) [HTML](20) [PDF](13)
  Objective   This study aims to investigate the effects of dissolved oxygen concentration on growth, physiological indexes and root structure of hydroponic Phyllostachys violascens seedlings, and to explore the adaptive mechanism of hydroponic P. violascens seedlings to hypoxia.   Method   The hydroponic P. violascens seedlings were used as materials, and the effects of different dissolved oxygen concentrations (0, 2, 4, 6, 8 mg·L−1) on biomass accumulation, leaf area, root activity, antioxidant enzyme activity, photosynthetic pigment content and root structure were analyzed.   Result   The biomass accumulation, leaf area, root activity, leaf antioxidant enzyme activity and photosynthetic pigment content of hydroponic seedlings significantly increased with the increase of dissolved oxygen concentration(P<0.05). The activities of SOD, CAT, POD and APX of hydroponic seedling leaves treated with 8 mg·L−1 dissolved oxygen reached the peak, which were 746.13×16.67 nkat·g−1, 63.13×16.67 nkat·g−1·min−1, 59 395.45×16.67 nkat·g−1·min−1 and 407.46×16.67 nkat·g−1·min−1 respectively. Under hydroponic conditions, lysigenous aerenchyma was formed in the roots of hydroponic seedlings, and its percentage of root cross-sectional area significantly increased with the decrease of dissolved oxygen concentration (up to 7.1%), while the number of lysigenous aerenchyma changed in the opposite direction (P<0.05).   Conclusion   Under hydroponic conditions, the higher the dissolved oxygen concentration is, the better the growth of hydroponic seedlings can be. The oxygen requirement for the growth of hydroponic seedlings is greater than 8 mg·L−1 . Hypoxia can induce the formation of lysigenous aerenchyma in the root of hydroponic seedlings, but it is not enough to make it highly resistant to flooding.[Ch, 5 fig. 50 ref.]
Effect of NaCl stress on the morphology and related physiological indexes of Magnolia biondii seedlings
SHEN Xuyue, ZHANG Lang, CHEN Rongrong, SHEN Yamei, JIN Hexian
2021, 38(2): 289-295.   doi: 10.11833/j.issn.2095-0756.20200449
[Abstract](103) [HTML](22) [PDF](7)
  Objective  With an investigation conducted of the effects of NaCl stress on the morphology and related physiological indexes of Magnolia biondii seedlings and the physiological indexes indicating the NaCl stress screened, this paper is aimed to provide a theoretical basis for the evaluation of the salt tolerance of Magnoliaceae and the selection of high-quality germplasm resources.  Method  Firstly, the hydroponic culture experiment was done with M. biondii 1-year-old seedlings with the effects of NaCl stress under 200 mmol·L−1 on relative electrical conductivity, MDA contents, chlorophyll contents, osmotic substances and antioxidant enzyme activities in leaves tested, after which the principal component analysis was conducted to screen key physiological indexes.  Result  With the increase of treatment time, the soluble sugar content, relative electric conductivity, MDA content and SOD activity increased. The soluble protein content, Pro content, chlorophyll content and POD activity first increased and then decreased. The three indicative physiological indexes screened by principal component analysis were MDA content, soluble sugar content and SOD activity.  Conclusion  The MDA content, soluble sugar content and SOD activity underwent significant changes under NaCl stress, and they could be used as key physiological indexes in the evaluation of the salt tolerance of Magnoliaceae such as M. biondii. [Ch, 4 fig. 2 tab. 19 ref.]
Cutting test of Catalpa bungei and change analysis of cutting contents
WANG Gaiping, WANG Xiaocong, ZHANG Lei, ZHANG Chen, LIU Bin
2021, 38(2): 296-303.   doi: 10.11833/j.issn.2095-0756.20200313
[Abstract](74) [HTML](18) [PDF](8)
  Objective  The objective of this study is to explore the rooting mechanism of Catalpa bungei, as well as the morphological characteristics and physiological and biochemical characteristics of cuttings during rooting process.  Method  The cuttings of C. bungei were treated with dissolved GGR-6 to promote rooting, and the enzyme activities, nutrients and rooting inhibitors in different rooting stages were measured.  Result  GGR-6 treatment significantly promoted the rooting of cuttings, and the rooting rate reached 82.04%, higher than that of the control treatment (P<0.01). During the rooting process, the activities of superoxide dismutase (SOD), peroxidase (POD) and polyphenol oxidase (PPO) increased during the formation of a large number of callus, and the maximum values of SOD and PPO were 623.33×16.67 and 57.44×16.67 nkat·g−1, respectively. POD activity decreased during the formation of adventitious roots, and the three enzymes were positively correlated with the rooting rate. The soluble sugar and C/N ratio in cuttings decreased sharply at the callus stage, only about 40% of the initial value, and reached the maximum at 20 days of cutting. The soluble protein and total nitrogen showed a decreasing trend, and reached the minimum at 25−30 days. Under GGR-6 treatment, the change range of nutrients in cuttings was large, and the maximum values were higher than those of the control. Total nitrogen content was negatively correlated with rooting rate (P<0.05), while soluble sugar, soluble protein and C/N were significantly positively correlated with rooting rate (P<0.05). GC-MS analysis identified four rooting related substances, three of which might inhibit rooting and one might promote rooting.  Conclusion  The increase of antioxidant enzyme activities of cuttings can promote the occurrence of adventitious roots of C. bungei. Soluble sugar and soluble protein are the main nutrients of cuttings. Quercetin, linoleic acid and palmitic acid may inhibit the rooting of cuttings and phytosterol may promote the rooting of cuttings. [Ch, 2 fig. 4 tab. 32 ref.]
Effects of mechanical damage and deep soil treatment on sprouting and antioxidant enzyme activities of Cunninghamia lanceolata
ZHANG Jiling, CHEN Gang, CAO Guangqiu, LIN Sizu, ZHENG Hong, LI Yong
2021, 38(2): 304-310.   doi: 10.11833/j.issn.2095-0756.20200323
[Abstract](78) [HTML](11) [PDF](5)
  Objective  With an analysis conducted of the relationship between the sprouting ability of Cunninghamia lanceolata (Chinese fir) clones and the activity of antioxidant enzymes under the treatment of mechanical injure as well as an elaboration on the sprouting mechanism of C. lanceolata from the metabolic physiology of enzyme activity, this study is aimed to provide theoretical basis for solving the sprouting problem of C. lanceolata clones.  Method  Using the 1-year-old cuttings of Chinese fir Clone Yang 020 as experimental materials, with pot experiment and treatments of topping removal and no topping set at depths of 0, 3 and 6 centimeters, the enzyme activity absorbance test was carried out to measure and analyze the activities of superoxide dismutase (SOD), catalase (CAT) and peroxidase (POD) in different organs, such as branches and leaves, basal phloem and root tip.  Result  (1) With the increase of soil depth, the tillering capacity of seedlings of Chinese fir clones with and without mechanical damage at different soil depths decreased, and treatments of different soil depths could affect the activity of antioxidant enzymes. (2) With the increase of soil depth, SOD activity of branches and leaves of Chinses fir seedlings increased, while CAT activity decreased. (3) The soil depth of 6 centimeters was conducive to pod accumulation of branches and leaves and root tips.  Conclusion  In conclusion, the mechanical damage and treatments of different soil depths had impact on the clonal tillering of Chinese fir. Of the same soil depth, the tillering of Chinese fir with the removal of topping is higher than the one without the removal. Also, the antioxidant enzyme activity of different organs plants was one of the main factors that affect the mechanical damage of C. lanceolata clones and the tillering of treatments of different soil depths. [Ch, 3 fig. 3 tab. 18 ref.]
Response of growth and physiological indicators of Lycopersicone sculentum to water stress relieved by rock wool
GU Jiayue, SHAO Shuai, DENG Yujuan, YU Chengbo, CHEN Junhui, QIN Hua, LIANG Chenfei, XU Qiufang
2021, 38(2): 311-319.   doi: 10.11833/j.issn.2095-0756.20200221
[Abstract](76) [HTML](11) [PDF](5)
  Objective  The purpose of this study is to explore the effects of rock wool and its different burying methods on improving soil water retention capacity as well as plant growth under pot culture mode.   Method  Lycopersicone sculentum seedlings were selected as the experimental objects. Three treatments were set up to simulate the plant growth under water stress, including burying block rock wool (BR) under the root, sheet rock wool (FR) around the root and inert nonabsorbent material (ck). The dynamic changes of soil water content at 5 cm below the soil surface, the growth and physiological indicators of L. sculentum were monitored.  Result  Under the condition of equal irrigation, the order of soil volume moisture content from large to small was BR, FR and ck, and the soil volume moisture content of rock wool treatment was significantly higher than that of ck (P<0.05), indicating that rock wool treatment could improve water retention and water storage capacity of potted soil. During the same growth period, the growth index such as plant height, base diameter, leaf number, maximum leaf area, root length and dry weight of L. sculentum treated with rock wool (BR and FR) were higher than those of ck, but there was no significant difference between two rock wool treatments, except that the root length of BR treatment was significantly higher than that of FR treatment (P<0.05). The order of the chlorophyll a content, total chlorophyll content and relative water content of L. sculentum leaf from large to small in the same period were BR, FR, and ck, while the contents of malondialdehyde (MDA), proline (Pro) and peroxidase (POD) were in the opposite order, indicating that BR was more beneficial to plant root elongation and capable of alleviating plants damage caused by soil water stress.  Conclusion  Rock wool materials can effectively improve water retention and storage capacity of potted soil, and alleviate adverse effects of water stress on the growth and physiological characteristics of potted plants. Burying block rock wool (BR) under the root is more effective in alleviating water stress and promoting plant root colonization. [Ch, 3 fig. 1 tab. 31 ref.]
Effects of thinning and stand types on litter stock and soil water-holding capacity
JIAN Yongqi, WU Jiasen, SHENG Weixing, NIE Guohui, ZHENG Cheng, JIANG Peikun
2021, 38(2): 320-328.   doi: 10.11833/j.issn.2095-0756.20200355
[Abstract](84) [HTML](17) [PDF](6)
  Objective  This study aims to explore the effects of thinning and stand types on forest litter stock and soil water-holding capacity, and to provide scientific basis for evaluating water conservation function of different forest stands.  Method  Two forest types (Cunninghamia lanceolata forest and broad-leaved forest) and two types of thinning (thinning C. lanceolata forest and thinning broad-leaved forest) in three small river basins in Jiande City, Zhejiang Province were taken as the research objects. Litter and soil (0−10, 10−30, 30−60 cm) were collected in the field, and the water immersion method was used to analyze the influence of thinning on the forest litter stock and water-holding capacity of different forest stands. Three standard plots (20 m×20 m) were selected in each forest stand for litter collection and soil sampling. The litter stock, water-holding capacity and water absorption rate, as well as the soil bulk density, porosity and water-holding capacity were determined. The statistic data of litter and soil characteristics were analyzed using one-way ANOVA and Duncan.  Result  The litter stock of thinning C. lanceolata forest decreased by 25.2% (P<0.05), while the maximum water-holding rate and effective retention rate of litter increased by 24.4% and 47.1%, respectively (P<0.05). Thinning had no significant effect on litter stock in broad-leaved forests, but the maximum water-holding capacity and effective retention capacity of litter increased by 42.5% and 42.2% (P<0.05) respectively, compared with those without thinning. The overall water-holding capacity of litter in thinning forest was higher than that in normal forest. Thinning significantly increased non-capillary pores porosity and water-holding capacity of non-capillary pores in 10−60 cm soil layer of C. lanceolata forest (P<0.05). Thinning significantly increased soil non-capillary pores porosity and non-capillary water-holding capacity in 30−60 cm soil layer, as well as those in 0−10 and 30−60 cm soil layer of broad-leaved forest (P<0.05). The maximal water-holding capacity of each soil layer in the thinning C. lanceolata forest was significantly higher than that in the thinning broad-leaved forest, and the maximal water-holding capacity of 0−60 cm (3 775.19 t·hm−2) of the thinning C. lanceolata forest was higher than that of other forest stands.  Conclusion  Thinning significantly improves the water-holding capacity of forest litter and soil, and the water conservation function of litter and soil in the thinning C. lanceolata forest is the strongest among the four treatments for two stands. [Ch, 3 fig. 5 tab. 24 ref.]
Effects of single/mixed sowing of three medicinal plants on the contents of carbon, nitrogen and enzymes activities of sandy soil
WU Yuchen, LIN Fang, ZHANG Jiayang, ZHANG Lulu
2021, 38(2): 329-335.   doi: 10.11833/j.issn.2095-0756.20200486
[Abstract](63) [HTML](19) [PDF](4)
  Objective  This study aims to explore the effects of single and mixed sowing of three medicinal plants on soil quality.  Method  Taking Lonicera japonica (LJT), Chrysanthemum morifolium (CMR) and Astragalus membranaceus var. mongholicus (AMB) as experimental materials and sandy bare land as control(ck), the effects of single and mixed sowing patterns on organic carbon, alkaline hydrolyzable nitrogen and soil enzyme activity in different soil layers (0−40 cm) were studied in the location test conducted in northern Henan Province for 4 consecutive years, and their correlation was analyzed.  Result  The content of soil organic carbon, alkali hydrolyzable nitrogen and soil enzyme activity of urease, sucrase and alkaline phosphatase under the mixed sowing patterns of CMR/AMB and LJT/AMB were significantly higher than those under the single patten of CMR or LJT (P<0.05). Soil organic carbon content in CMR/AMB pattern increased by 29.32%, 20.16% and 10.25% respectively, compared with ck, CMR and AMB. Alkaline hydrolyzable nitrogen content increased by 28.02% and 13.24% respectively, compared with ck and CMR. Soil organic carbon content of LJT/AMB pattern increased by 25.46%, 18.09% and 6.96%, respectively, compared with ck, LJT and AMB. Alkaline hydrolyzable nitrogen content increased by 25.56% and 11.80% respectively, compared with ck and LJT. Soil organic carbon, alkali hydrolyzable nitrogen, and four soil enzymes were all significantly correlated with each other (P<0.01). From the view of soil profile, the soil organic carbon, alkali hydrolyzable nitrogen and the activities of 4 species of soil enzymes showed the characteristics of surface aggregation under different planting patterns.  Conclusion  CMR/AMB and LJT/AMB mixed patterns can improve the effectiveness of soil nutrients through the biological nitrogen fixation of A. membranaceus var. mongholicus. They are sustainable ecological patterns suitable for local promotion. [Ch, 2 fig. 3 tab. 28 ref.]
Survey and risk assessment of soil heavy metals in the main rice producing areas in Hangjiahu Plain
MA Jiayan, MA Jiawei, LIU Dan, FU Weijun, YE Zhengqian
2021, 38(2): 336-345.   doi: 10.11833/j.issn.20950756.20200309
[Abstract](159) [HTML](51) [PDF](92)
  Objective  This study aims to investigate the status of heavy metal pollution in soil and rice safety in Jiaxing, the main paddy field of Oryza sativa in Hangjiahu Plain.  Method  In 2018, Jiaxing City was selected as the main rice producing area for investigation and analysis. Soil and rice were sampled during rice harvest period to determine the contents of four heavy metal elements (Cd, Pb, Cr, and As) in soil and rice samples. The pollution level and risk of heavy metals in paddy soil were evaluated by single factor pollution index method, Nemero comprehensive pollution index method, potential ecological risk index method and ecological risk early warning index method.  Result  Contents of Cd, Pb, Cr, and As in soil were 0.01−1.92, 17.60−34.80, 47.00−123.00 and 3.97−9.89 mg·kg−1, with an average of 0.36, 25.78, 72.73, and 7.55 mg·kg−1 respectively. The proportion of soil samples whose Cd content exceeded the soil safety threshold for rice production (Safety Threshold Values of Cadmium, Lead, Chromium, Mercury and Arsenic in Soil For Rice Production, GB/T 36869−2018) reached 31.82%. The potential ecological risks of the four heavy metals from strong to weak were Cd, As, Pb, and Cr, and the region as a whole presented slight potential ecological risks. Cd content in rice grain was safe according to the national criterion, although Cd content exceeded the national standard (GB/T 36869−2018) in some soil.  Conclusion  All indexes of rice in the study area are in line with National Food Safety Standard Limits of Contaminants in Food (GB 2762−2017) and the soil is generally at a safe level for rice production. In the future it’s necessary to monitor changes of heavy metals in soil, especially transformation and availability of Cd, in order to guarantee safe rice production. [Ch, 1 fig. 8 tab. 29 ref.]
Effect of raw and iron-modified biochar on the sorption of As (Ⅴ) by soils
DAI Zhinan, WEN Ergang, CHEN Hanbo, YANG Xing, CHEN Junhui, GUO Jia, WANG Hailong
2021, 38(2): 346-354.   doi: 10.11833/j.issn.2095-0756.20200392
[Abstract](116) [HTML](12) [PDF](14)
  Objective  This study is aimed to investigate the effect of raw biochar and Fe-modified biochar on the soil adsorption of As(Ⅴ).  Method  First, the raw biochar was produced from the branches of Platanus orientalis by means of pyrolysis at 650 ℃ in an oxygen-limited condition, while its Fe-modified biochar (weight ratio of Fe∶biochar=1∶20) was obtained from the impregnation with FeCl3 solutions and re-pyrolysis beofe the physiochemical properties and surface functional groups of two biochars were examined for changes. Then with the employment of a batch equilibration method, an investigation was conducted of the impacts of initial As (Ⅴ) concentration and sorption time on As (Ⅴ) sorption by soils treated with raw and Fe-modified biochars. At last, The characteristics of the sorption isotherms and kinetics were analyzed.  Result  a) The Fe-modified biochar had higher ash content and electrical conductivity, but lower pH, specific surface area and abundance of surface functional groups than those of the raw biochar; b) Langmuir isothermal models could well describe the sorption process of As (Ⅴ) by biochar-amended soils, indicating that the monolayer sorption was the predominant process: with an initial As (Ⅴ) concentration higher than 25 mg·L−1 in the solution, the sorption capacity of the Fe-modified biochar to As (Ⅴ) (up to 0.36 mg·g−1) was greater than that of the raw biochar; c) The kinetic sorption of As (Ⅴ) could be described by the pseudo-second-order kinetics and the sorption process could be divided into two stages from the critical point of reaction at 4th hour, i.e., rapid sorption and slow sorption, respectively; d) The sorption equilibrium was achieved around 24 hours of reaction, and the maximum sorption capacity of the Fe-modified biochar treatment was 11% higher than that of the raw biochar treatment.  Conclusion  Both biochars could enhance the As (Ⅴ) sorption capacity of the soil, and the addition of the Fe-modified biochar was more effective than that of the raw biochar. Therefore, the Fe-modified biochar is recommended in the reduction of the bioavailability of As (Ⅴ) in contaminated soils by enhancing its adsorption capacity. [Ch, 6 fig. 3 tab. 39 ref.]
Adsorption of cadmium on multi-walled carbon nanotubes with different functional groups and their bacterial toxicity
LI Siyan, LIU Junfan, LI Mei
2021, 38(2): 355-361.   doi: 10.11833/j.issn.2095-0756.20200297
[Abstract](150) [HTML](21) [PDF](5)
  Objective  This study attempted to explore the adsorption properties of multi-walled carbon nanotubes (MWCNTs) with different functional groups for cadmium, and to reveal the influence mechanism on the bacterial toxicity of cadmium.  Method  The adsorption abilities of Cd2+ on MWCNTs with different functional groups (hydroxylated, carboxylated, aminated and unmodified) were studied by batch adsorption equilibrium test. The effects of MWCNTs with different functional groups on the toxicity of Cd2+ to Escherichia coli (E. coli) were evaluated by the bacterial toxicity test.  Result  The order of Cd2+ adsorption capacity on the four MWCNTs were carboxylated MWCNTs, hydroxylated MWCNTs, MWCNTs, finally aminated MWCNTs, which was related to the oxygen content. The combined bacterial toxicity of MWCNTs and Cd2+ was lower than that of free Cd2+, and the bacterial survival rate increased from 67% to 81% with the increasing carboxylated MWCNTs concentration (0−200 mg·L−1).  Conclusion  The adsorption of Cd2+ by MWCNTs with different functional groups was positively correlated with their oxygen content. The combined bacterial toxicity of MWCNTs and Cd2+ was lower than that of free Cd2+, and it was concluded that MWCNTs could reduce the bacterial toxicity of free Cd2+. [Ch, 4 fig. 2 tab. 26 ref.]
Influence of algal derived dissolved organic matter on mercury methylation in water
LI Yutong, HE Xinlong, PENG Yifan, HU Xieke, WANG Yuhang, ZHAO Ting, WU Shengchun, LIANG Peng
2021, 38(2): 362-368.   doi: 10.11833/j.issn.2095-0756.20200146
[Abstract](119) [HTML](20) [PDF](23)
  Objective  To determine the effects of subcomponents of algae dissolved organic matter (DOM) on mercury methylation at different decomposition intervals and different Hg2+ concentrations.  Method  Six subcomponents of the DOM derived from the algae through a tandem connection of resin, and then conducted simulation experiments separately.  Result  Algae DOM was mainly composed of hydroxyl group, alkyl group and C=C of aromatic hydrocarbon, etc. Different subcomponents of DOM before decomposition, the influence of hydrophobic component on mercury methylation was significantly stronger than that of hydrophilic component. With the progress of algal decomposition, the relative content of functional groups was gradually decreasing while the influence of hydrophobic components on Hg methylation first weakened and then enhanced during the decomposition process and hydrophilic component can inhibit Hg methylation.  Conclusion  The increase in relative content of DOM results in the inhibition of Hg methylation. After the decomposition of DOM, the Hg2+ released got methylated by bacteria again, which helped promote the degree of methylation. [Ch, 3 fig. 24 ref.]
A pest collection method based on global contrast
LIU Yixiang, WANG Hangjun, XU Tieping
2021, 38(2): 369-376.   doi: 10.11833/j.issn.2095-0756.20200318
[Abstract](67) [HTML](13) [PDF](1)
  Objective  The real-time and accurate forecast of field pests has gradually become an important method of pest forecasting to trap insects by light, and to collect, count and identify insect images by computer. This study aims to explore the method of collecting insects in the sampling plate based on insect image and insect density, so as to improve the collection efficiency and accuracy, and reduce the counting and identification errors caused by the overlapping of insects on the sampling plate.  Method  According to the characteristics of insects’ posture on the sampling plate, an image segmentation method based on global contrast was proposed. Combined with threshold iterative segmentation, the insect area was obtained, the insect proportion was calculated, and the collection of insects was completed by controlling the flip of the sampling plate.  Result  Experiments on the actual images of 5 pest species showed that compared with the 4 algorithms, namely level set, OTSU, threshold iteration and saliency detection based on histogram contrast(HC), the accuracy and recall rate of this method were improved by more than 10%, and good results were obtained. At the same time, the segmentation speed was 3 times faster than that of the level set, which was basically the same as the threshold and HC algorithm.  Conclusion  Due to its simplicity and high efficiency, the segmentation method based on global contrast has high practical application value in automatic pest detection and reporting. [Ch, 7 fig. 1 tab. 17 ref.]
Spatial measurement and classification of forest carbon sink demand based on industry emission reduction
ZHU Meiyu, LONG Fei, QI Huibo, ZHANG Zhe
2021, 38(2): 377-386.   doi: 10.11833/j.issn.2095-0756.20200386
[Abstract](90) [HTML](33) [PDF](15)
  Objective   This paper classifies the forest carbon sink demand space of 28 provincial administrative regions and Shenzhen City in China, and puts forward some suggestions for improving the future forest carbon sink demand space of various regions, so as to provide an objective basis for scientific design of carbon sink policy and targeted development of forest carbon sink demand space.   Method   Taking the above 29 areas as sample units, the input and output data of the industrial industries in 2008−2017 statistical yearbook were collected. The directional distance function model was used to calculate the carbon marginal emission reduction cost of the industrial industries in each region, and the demand space model was used to measure the forest carbon sink demand space of 29 areas in the past 10 years. Then cluster analysis and discriminant analysis were carried out on the obtained demand space data.   Result   There were some regional fluctuations in the marginal carbon emission reduction cost and the spatial data of forest carbon sink demand in each sample area. The Pearson correlation coefficient between marginal carbon emission reduction cost and forest carbon sink demand space was 0.999, showing a significant positive correlation. The clustering results showed that the average marginal carbon emission reduction cost in regions of Category 1, 2 and 3 was 15.9, 11.8 and 5.1 thousand yuan·t−1 respectively. The average spatial value of forest carbon sink demand in Category 1, 2 and 3 was 5 719.1, 3 749.3 and 1 741.5 thousand t·a−1, respectively. Through the final discriminant equation, it was found that the demand spatial data of 2011 and 2014 had the most significant impact on regional classification.   Conclusion   On the whole, the classification results are roughly consistent with the economic development level of the eastern, central and western regions of China. The policy scenario simulation shows that the penalty rate of over emission should be taken as an important entry point for the regions of Category 1 and 2, and the quota distribution mode should be optimized. The 3rd category should be encouraged and guided. [Ch, 6 tab. 16 ref.]
Urban park layout in the main urban area of Fuzhou in the light of service ability
LIU Yanfen, YU Kunyong, ZHAO Qiuyue, GAO Yangchi, AI Jingwen, CHEN Fengfei, LIU Jian
2021, 38(2): 387-395.   doi: 10.11833/j.issn.20950756.20200314
[Abstract](139) [HTML](36) [PDF](19)
  Objective  With an analysis conducted of the service capacity of urban parks in the main urban area of Fuzhou, this study is aimed to optimize the layout of urban parks, which is reflective of the construction of urban human settlements.  Method  Firstly, using the GIS spatial statistical method, the current status of urban parks was analyzed with the two indicators of recreational accessibility and disaster avoidance coverage employed. Then the city service pressure was calculated before an analysis was made of the potential service demand of city parks by means of city POI (point of interest) data.  Result  (1) The current service capacity of Taijiang District and Gulou District is good, as is shown in the large disaster avoidance coverage a well-built transport network and the easy access with Gulouqian Park demonstrating the best service ability; (2) The current service ability of Jinan District and Cangshan District is poor, shown in the small disaster avoidance coverage, the inadequate transport network and the poor accessibility with Feifengshan Park demonstrating the worst service capacity; (3) In terms of potential demand for urban parks, with the urban parks mainly distributed in Gulou District and Cangshan District, Gulou District has the highest service pressure while Cangshan District has the least service pressure.  Conclusion  In conclusion, the layout of city parks is generally favorable with a distribution featured with spacial aggregation: the city parks with a good layout are mainly distributed in the north of Gulou District and the south of Taijiang District while the ones with poor layout rationality are mainly distributed in the southern and southeastern regions of Cangshan District as well as the eastern and northern regions of Jin’an District. The lack of parkland, small avoidance coverage and poor access in such areas are the main reasons behind the low rationality. As a result, it is of vital importance to optimize the urban spatial layout of the 12 optimized urban parks: 4 are located in Taijiang District, 3 are located in Gulou District, 2 are located in Jin’an District with the rest 3 in Cangshan District. On the other hand, with the current land use circumstances taken into consideration, potential urban parks should be built: 45 in Cangshan District, 7 in Gulou District, and 19 in Jin’an District. [Ch, 10 fig. 3 tab. 25 ref.]
Preparation and performance evaluation of bamboo scrimber/glass fiber/PET foam multilayer structural insulated panel
XU Bin, WANG Hengxu, LU Jie, FU Shenyuan, DAI Jinfeng
2021, 38(2): 396-402.   doi: 10.11833/j.issn.2095-0756.20200330
[Abstract](65) [HTML](20) [PDF](8)
  Objective  The purpose of this study is to introduce renewable bamboo scrimber with excellent mechanical properties and decorative effect, combined with environment-friendly powdery epoxy resin adhesive, to prepare bamboo scrimber/structural insulated panel, so as to promote the sustainable development of woody structural insulated panel(SIP).  Method  The curing characteristics of powdery epoxy resin adhesive and bonding strength, flexure strength, thermal conductivity as well as hot-water resistance were investigated by differential scanning calorimetry (DSC), mechanical property test and thermal conductivity tester.  Result  (1) The optimal curing condition of powdery epoxy resin adhesive was that the curing reaction began at 84 ℃, curing thoroughly at 116 ℃, and curing completely at 180 ℃. (2) When the amount of glue was 150 g·m−2 and the hot pressing time was 15 min, the tensile bonding strength and flexure strength of the composite reached 0.83 MPa and 19.8 MPa respectively, and the thermal conductivity was 0.054 2 W·m−1·K−1 (25 ℃). After being soaked in hot water at 80 ℃ for 3 h, the bonding strength of the composite still reached 0.15 MPa.  Conclusion  The bamboo scrimber/structural insulated panel composite with excellent comprehensive properties and good hot-water resistance is obtained. [Ch, 6 fig. 2 tab. 21 ref.]
Review on the formation of bamboo shoot palatability and its main influencing factors
XU Sen, YANG Liting, CHEN Shuanglin, GUO Ziwu, GU Rui, ZHANG Chao
2021, 38(2): 403-411.   doi: 10.11833/j.issn.2095-0756.20200400
[Abstract](101) [HTML](34) [PDF](18)
Bamboo shoots are traditional forest vegetables in China and also large export agricultural products. Palatability is an important index to reflect the economic value, market potential, and quality of bamboo shoots. However, the basic research on the formation of bamboo shoot palatability and development of upgrading technology are relatively weak, which limits the development and application of bamboo shoot quality improvement technology to a certain extent. This paper reviews the main evaluation indicators for bamboo shoot palatability, summarizes the main research results, and puts forward prospects for future research. Current studies on bamboo shoot palatability mainly focus on the following aspects: the interspecific differences in bamboo shoot palatability, the effects of environmental factors on palatability, and the impact of management measures on palatability. The main conclusions are as follows: Sugar, acids, phenols, fibers and amino acids are the chief indicators for evaluating the palatability of bamboo shoots. The formation of palatability depends not only on genetic factors of bamboo species, but also on climate factors and soil texture. Bamboo shoot palatability can be improved by mulching cultivation, fertilization, regulation and control of stand structure, and selection of appropriate shooting time, but there are obvious differences among species in their effects. Future studies on bamboo shoot palatability should focus on such aspects as constructing comprehensive evaluation indicators and methods, exploring the effects of multi-factor interaction on the palatability, revealing the formation mechanism of palatability from the ecological, physiological, biochemical, and molecular aspects, selecting high-quality shoots with good palatability, high yield and strong ecological adaptability for large-scale cultivation, as well as developing the palatability improvement techniques from selection of cultivation environment, precise supplement of soil nutrients, environmental control of shoot bud germination, and treatment of bamboo shoot organs. [Ch, 66 ref.]
Research progress on the characteristics and molecular mechanism of yellowing mutation in Brassicaceae
WU Yannong, ZHENG Weiwei, LU Weijie, ZANG Yunxiang
2021, 38(2): 412-419.   doi: 10.11833/j.issn.2095-0756.20200132
[Abstract](254) [HTML](149) [PDF](157)
During their short growth period, most Brassicaceae plants have some light-green or golden-colored mutants, named as yellow mutants, either naturally grown or induced physically or chemically. Such mutants, with intuitive phenotypes, such as shortness, low chlorophyll content and suppressed photosynthesis usually result in the reduction of yield, thus considered as harmful. In the past two decades, the phenomenon of yellowing mutation has attracted an increasing amount of attention from scholors with the research results applied in the study of plant chloroplast structure and chlorophyll metabolism. This review, with a brief introduction to the common types, phenotype characteristics, chloroplast ultrastructure, photosynthetic pigments and photosynthetic properties of yellowing mutants in Brassicaceae plants, is aimed at a discussion of the genetic characteristics and molecular mechanism of the yellowing mutation in the hope of providing a theoretical basis for the study of leaf color mutations and selection of new varieties in Brassicaceae plants. [Ch, 52 ref.]
Agrobacterium-mediated transformation of CP4 gene into indica rice
HU Huan, LI Yuan, DING Yun, CAO Hanzhang, LÜ Zunfu, LI Feifei
2021, 38(2): 420-425.   doi: 10.11833/j.issn.2095-0756.20200436
[Abstract](90) [HTML](20) [PDF](12)
  Objective  The objective was to establish the Agrobacterium-mediated transformation system of Oryza sativa subsp. indica ‘Zhonghui 161’.  Method  5 groups of glyphosate concentrations (100, 200, 300, 400 and 500 mg·L−1) were used to test the sensitivity of embryogenic callus to glyphosate. The glyphosate-resistant gene (CP4-EPSPS) was introduced into the embryogenic callus of ‘Zhonghui 161’ by Agrobacterium-mediated method. The transformed embryogenic callus was screened for glyphosate resistance on the selective medium containing 300, 350 and 400 mg·L−1 glyphosate. The resistant callus was further differentiated and seeded.  Result  When the concentration of glyphosate was 300−400 mg·L−1, the browning rate of callus was about 50%, showing a good selection effect. The positive rates of callus on 300, 350 and 400 mg·L−1 glyphosate were 40.16%, 61.72% and 84.04%, respectively. The further differentiation rate was 46.43%, and the seedling rate was 32.84%. A total of 67 regenerated plantlets were obtained, and 43 of them were successfully transformed into CP4 gene by PCR detection. The positive rate of regenerated plantlets was 64.18%.  Conclusion  Agrobacterium-mediated transformation system of ‘Zhonghui 161’ was established. [Ch, 5 fig. 20 ref.]
Ecological stoichiometric characteristics of nitrogen, phosphorus and potassium in different organs of Ostrya rehderiana and O. multinervis
YE Zihao, WU Weifeng, PENG Jianjian, ZHANG Kun, CAI Guangyue, LI Yun, ZHAN Jiejia, WU Jiasen
2021, 38(2): 426-432.   doi: 10.11833/j.issn.2095-0756.20200470
[Abstract](82) [HTML](24) [PDF](6)
  Object   This study aims to explore the stoichiometric characteristics of different organs of two minimal population plants, Ostrya rehderiana and O. multinervis, and to predict the limiting elements of the growth of the two plants, so as to provide scientific basis and suggestions for forest soil management.   Method   The mass fractions of total nitrogen, total phosphorus and total potassium in roots, branches, leaves and bark of plants as well as the basic physical and chemical properties of soil were determined. SPSS software was used to test the significance of differences and analyze the differences among different organs of the two plants.   Result   The N and K fractions of O. rehderiana in order from large to small were leaf, branch, bark and root, and the P fraction was branch, root, leaf and bark. The N and K fractions of O. multinervis in order from large to small were leaf, branch, root and bark, and the P mass was root, branch, leaf and bark. The mean values of N∶P, N∶K and K∶P in O. rehderiana were 3.18−19.22, 1.60−2.56, and 1.97−11.80, respectively.The mean values of N∶P, N∶K and K∶P in O. multinervis were 3.57−28.43, 1.14−4.59, and 2.77−11.77, respectively. The ecological stoichiometric features of N, P and K among different organs of the two species were similar, and only N in roots and K in leaves and branches of O. multinervis were significantly higher than those in the corresponding organs of O. rehderiana(P<0.05).   Conclusion   The limiting elements affecting the growth of O. rehderiana are N and P, and the one affecting the growth of O. multinervis is P. Therefore, in woodland soil management, N and P fertilizer should be properly applied to O. rehderiana, while P fertilizer should be properly applied to O. multinervis.[Ch, 2 fig. 1 tab. 33 ref.]

Bimonthly, Start in 1984

Supervisor:Department of Education of Zhejiang Province

Sponsor:Zhejiang A&F University

Editor-in-Chief:SHEN Xi

Editor:Editorial Department of Journal of Zhejiang A&F University


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