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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).
On the application of flow cytometry in the genomic size determination of bamboo plants
CHEN Rongfen, HUANG Jianqin, CHEN Rong, XU Chuanmei
, Available online  doi: 10.11833/j.issn.2095-0756.20200212
  Objective  This research is aimed to study the effects of material tissue and the treatment method on the genome size of bamboo plants with the ultimate purpose to improve the genome size determination accuracy of bamboo plants.  Method  With the leaves and shoots of different bamboo species selected as materials, and the rice used as the reference standard while the nuclear staining time set for 9 different gradients, that is 1, 3, 5, 7, 9, 12, 18, 24 and 30 minutes, an investigation was carried out of the tissue sites and staining materials of different bamboo plants with the employment of flow cytometry.  Result  (1) With the same bamboo species, the leaves and shoots were similar in the fluorescence peak and genome size with the genome size difference range as narrow as 0.04~0.20 pg. (2) The 12 bamboo species are different in their nuclear staining time, with the fluorescence intensity of Sinobambusa tootsik, Sinobambusa tootisik f. albo-striata, Pseudosasa japonica var. tsutsumiana, Pseudosasa japonica f. akebono, Indocalamus decorus, Sasaella glabra f. albo-striata and Chimonobambusa mamorea f. variegata reaching the maximum within 1 minute, that of Bambusa multiplex and Phyllostachys sulphurea reaching the maximum within 3 minutes, that of Pseudosasa amabilis var. amabilis and Thyrsostachy ssiamensis reaching the maximum within 5 minutes, while that of Phyllostachys sulphurea(leaf) reaching the maximum within 7 minutes. (3) The fluorescence intensity of the 12 bamboos varies greatly from 1 to 30 minutes, all exceeding 5% except for the leaf of P. amabilis var. amabilis, T. ssiamensis, B. multiplex and the shoot of S. tootsik. In fact, the fluorescence intensity of P. japonica var. tsutsumiana and S. glabra f. albo-striata have reached 12.93% and 12.88% respectively. (4) As for the genome size of 12 bamboo species, 2 tropical woody bamboo species of B. multiplex and T. ssiamensis changed from (2.64±0.54) pg to (2.69±1.01) pg, however, that of the 10 temperate woody bamboo species changed from (3.76±1.51) pg to (5.73±1.85) pg; of the 10 temperate bamboo species, the genome size of Phyllostachys changed from (3.76±1.51) pg to (3.91±0.95) pg, yet that of the other bamboo genus changed from (4.82±0.54) pg to (5.73±1.85) pg, which is obviously larger than Phyllostachys.  Conclusion  (1) Both leaves and shoots of bamboo can be used as experimental materials to determine their genome sizes by flow cytometry. The nuclear staining time has a certain effect on the determination of the bamboo genome size with 3 to 5 minutes as the optimal staining time. (2)The genome size of tropical woody bamboo species is obviously smaller than that of temperate woody bamboo species while among the temperate woody bamboo species, the genome size of Phyllostachys is obviously smaller than that of the other genus bamboo species. [Ch, 1 fig. 5 tab. 29 ref.]
Dissolution and regeneration of rice straws with LiCl/DMSO
WU Wenjuan, LIU Huijun, LI Bowen, YAN Xueqing, XU Lu, XIE Dongjia
, Available online  doi: 10.11833/j.issn.2095-0756.20200163
  Objective  With the straw of Oryza sativa selected as raw materials, this study is aimed at an investigation of the dissolution behavior and regeneration characteristics of straw samples dealt with the LiCl/DMSO solvent system.  Method  With the national standard method employed, the four samples of straw (internode with knot, stem without knot, leaf and whole straw)were treated with the LiC1/DMSO system before an analysis was conducted of the general chemical composition of cellulose, hemicellulose, lignin and ash. On top of this, the effect of dissolution and regeneration of bamboo on the cellulose crystallization zone was investigated with the crystallinity calculated employing X-ray diffraction after the yield of lignin structural units produced by alkaline nitrobenzene oxidation was measured and the condensed degree of lignin was analyzed.  Result  (1) Both of stem and leaf with 1.0 h ball milling could be completely dissolved in LiCl/DMSO solvent system with a dissolution rate up to 10% even in the 8% LiCl/DMSO solvent system; (2) After water regeneration, more than 80% of the lignin could be retained with that of the stem reaching 87.5%; (3) The cellulose crystallinity was decreased from 37.8% to 27.5% for the leaf and from 43.1% to 26.5% for the stem; (4) The uncondensed units of lignin of all four samples were increased, as observed in the results of alkaline nitrobenzene oxidation.  Conclusion  (1) Both ball milling time and LiCl concentration affect the dissolution of rice straw in LiCl/DMSO solvent system; (2) In terms of regeneration, the chemical content displays high capacity and in comparison, that of the cellulose and lignin was the lowest in leaf sample while with a different ash distribution, the regeneration capacity of the leaf was higher than that of the stem; (3) After ball milling, the condensation degree of lignin decreases while the oxidation environment of nitrobenzene and homogeneous reaction was improved; (4) After regeneration, it was showed in the X-ray diffraction analysis that the crystalline region of cellulose was damaged to a certain extent and the crystallinity decreased. [Ch, 6 fig. 4 tab. 36 ref.]
Natural regeneration of Alcimandra cathcartii in south section of Gaoligong Mountain
LI Guixiang, CHAI Yong, HE Liping, ZHAO Xinfeng, BI Bo, MA Saiyu, CHEN Jianhong
, Available online  doi: 10.11833/j.issn.2095-0756.20200268
  Objective  This study aims to explore the natural regeneration status of Alcimandra cathcartii, a National GradeⅠProtection plant, in order to better protect this species.  Method  By setting sample circles to investigate the natural regeneration of A. cathcartii, the spatial pattern and regeneration of this species were studied.  Result  (1) The ratio of index variance (S2) to mean of the distribution pattern (m) was 4.14, which was significantly greater than “1.00”, indicating that the distribution of individuals was uneven, and the distribution of saplings in the survey circle was cluster type. (2) 67 regenerated plants were recorded in 8 sampling circles. According to the diameter class distribution of the seedlings, the regeneration proportion of young, small and medium trees was 46.27%, 32.83% and 20.90%, respectively. The regeneration number showed a pyramid structure, indicating that the structure was relatively stable although the regeneration number was small. (3) The proportion of regenerated plants at 0°−90°, 90°−180°, 180°−270° and 270°−360° was 26.86%, 19.40%, 20.90% and 32.84%, respectively. There were some differences in the number of regenerated plants in each angle range, but the variance analysis of the number of trees showed there was no significant difference in the number of regenerated plants in different azimuth angles. (4) The regeneration of A. cathcartii was correlated with the distance between mother trees. Within the distance of 0−5, 5−10, 10−15, 15−20, 20−25 and 25−30 m from mother trees, the proportion of regenerated plants was 11.94%, 34.33%, 23.88%, 22.39%, 5.97% and 1.49% respectively. The regeneration was mainly distributed in the range of 5−20 m from the mother tree, accounting for 80.60% of the total number of regenerated plants. The variance analysis showed there were significant differences between the distance from the mother tree and the regeneration distribution of A. cathcartii.  Conclusion  The regeneration number of A. cathcarti is small and the distribution scope is narrow, so it is difficult to expand the population. Artificial promotion is suggested for its population generation and expansion. [Ch, 7 tab. 17 ref.]
Soil PhytOC sequestration in Quercus acutissima forest in northern subtropics
WANG Xia, HU Haibo, CHENG Can, ZHANG Shuai, CHEN Jianyu, LU Honglin
, Available online  doi: 10.11833/j.issn.2095-0756.20200283
  Objective  The purpose is to investigate the content and profile distribution of soil PhytOC in northern subtropical Quercus acutissima forest, and discuss the difference of PhytOC sequestration in Q. acutissima forest at different ages.  Method  Taking soil samples from Q. acutissima forest of different ages in Jurong City, Jiangsu Province as the research object, the soil samples were collected in layers of 0−10, 10−20, 20−40 and 40−60 cm to determine the content of phytolith, PhytOC, and the PhytOC sequestration in soil of Q. acutissima forest.  Result  The available silicon content of soil ranged from 45.74 to 153.32 mg·kg−1, which increased with the increase of soil depth. There was no significant difference in the content of soil available silicon among different layers, but there existed significant difference in soil available silicon content among different forest ages(P<0.05). The content of soil phytolith, PhytoOC and organic carbon in phytolith in young forest and mature forest increased first and then decreased with the increase of soil depth, whereas that in half-mature forest decreased with the increase of soil depth. The content of organic carbon in soil phytoliths, PhytoOC and phytoliths was significantly different among different forest ages (P<0.05), but difference was not significant among layers. In addition, the ratio of PhytOC/TOC ranged from 0.36% to 1.49%, which increased with the increase of soil depth. There was no significant difference in the ratio of phytoc/TOC among different soil layers, but there was significant difference among different forest ages (P<0.05). There was an extremely significant positive correlation between soil phytolith content and PhytOC content (P<0.01), but there was no correlation between PhytOC content and available silicon content. The PhytOC sequestrations in the soil of Q. acutissima forest ranged from 1.15 to 1.47 t·hm−2, and the proportions of PhytOC sequestrations to organic carbon storage in young forest, middle-aged forest and mature forest soil accounted for 0.80%−1.50%, 0.73%−1.10% and 0.36%−0.67%, respectively.  Conclusion  Affected by soil physical and chemical properties, and leaching, etc., the distribution of phytolith and PhytOC in soil profiles of Q. acutissima forest at different ages is different to some extent. The proportion of PhytOC sequestration to organic carbon storage was small, but it increased with the increase of soil depth, indicating that PhytOC is more stable than other forms of carbon. In terms of time scale, PhytOC sink is an important component of long-term carbon sinks in forests. [Ch, 3 fig. 4 tab. 40 ref.]
Impact of scenic area environment and sports experience satisfaction on tourists’ perception of environmental restoration
ZHANG Jianguo, LIU Yuxiao
, Available online  doi: 10.11833/j.issn.2095-0756.20200243
  Objective  This study aims to investigate the relationship between environmental perception, sports experience and health efficacy of scenic spots.  Method  Using random sampling, the tourists in Lingjiu mountain forest sports town in Quzhou City of Zhejiang were investigated by questionnaire to obtain the relevant data. The structural equation was used to analyze the impact of environmental perception and leisure sports experience satisfaction of forest sports scenic spots on tourists’ environmental restoration perception.  Result  (1) The environmental perception satisfaction had a significant positive impact on tourists’ perception of environmental restoration. The mean value of standardized path coefficient was 0.26. The influence of the four dimensions on environmental restoration perception from large to small was ductility (0.29), charisma (0.27), compatibility (0.25), distance (0.23). Among the elements of environmental perception in forest scenic spots, the load of ecological environment quality on tourists’ satisfaction of forest environmental perception was the largest, which was 0.74. (2) Leisure sports experience satisfaction had a significant positive impact on tourists’ perception of environmental restoration (P<0.05). The average value of standardized path coefficient was 0.86, and the degree of influence on the four dimensions of environmental restoration perception from large to small was distance (0.90), compatibility (0.88), charisma (0.84), ductility (0.82), which showed little difference between the four dimensions. In the satisfaction of leisure sports experience, the load of sports facilities and sports interest was the largest, both were 0.59. (3) From the difference of path coefficient, the effect of leisure sports experience satisfaction on environmental restoration sensitivity (0.86) was significantly higher than that of environmental perception satisfaction of scenic area (0.26).  Conclusion  Both the environmental quality of forest scenic spots and forest leisure sports experience have a significant positive impact on tourists’ perception of environmental restoration, but the impact of forest leisure sports experience is greater than that of scenic spots. The most important factor affecting the satisfaction of forest scenic spot environmental perception is the quality of ecological environment, and the biggest factor affecting the satisfaction of leisure sports experience is the richness of sports facilities and the interest of forest sports. For forest sports tourist attractions, more attention should be paid to how to improve the richness and interest of forest leisure sports. [Ch, 2 fig. 1 tab. 24 ref.]
Twig and leaf traits of Michelia wilsonii at different developmental stages in Zhougong Mountain, Ya’an
PENG Xi, ZHAO Anjiu, CHEN Zhichao, LÜ Jiayao, LI Yaoxi
, Available online  doi: 10.11833/j.issn.2095-0756.20200209
  Objective  This study, with an examination of the twig and leaf traits of Michelia wilsonii at different developmental stages, is aimed to research the balanced utilization of such resources so as to better predict the spatial distribution of the branch and leaf traits.  Method  With the M. wilsonii of Zhougong Mountain in Ya’an selected as the research object, the standardized major axis regression (SMA), principal component analysis (PCA) and geostatistical methods were employed to study the correlation and spatial characteristics of twig and leaf traits at different developmental stages.  Result  (1) The fresh leaf weight, dry leaf weight, dry matter content, leaf area, specific leaf area, leaf thickness, annual twig density, biennial twig density and biennial twig dry matter content were significantly different among developmental stages (P<0.05), while the annual twig dry matter content was not significantly different among developmental stages (P>0.05); (2) There was a significant correlation between leaf traits among developmental stages (P<0.05) and a significant correlation between twig traits (P<0.05) while the correlation among leaf and twig traits was weak(P>0.05); (3) The optimal model of the semi-variogram function was linear model for the twig and leaf traits among the whole population, with a distribution of randomness while the big tree stage, with a distribution of aggregation, mainly followed the exponential and spherical model; the spatial correlation of small and medium tree stage is weak.  Conclusion  As developmental stages advance, the yielding of profits by M. wilsonii slows down and the distribution of twig and the employment of the semivariance function can help predict leaf traits. [Ch, 2 fig.7 tab. 30 ref.]
Effects of light and nitrogen on clonal reproduction characteristics and biomass allocation of Dicranopteris dichotoma
WANG Jiajia, ZHANG Mingru, YI Lita, ZHANG Rumin, HE Yunhe
, Available online  doi: 10.11833/j.issn.2095-0756.20200199
  Objective  To study the effect of different light and nitrogen application on the clonal propagation characteristics and biomass distribution of Dicranopteris dichotoma, aiming to provide a theoretical basis for the development of monolayers of D. dichotoma.  Method  Three light intensities[light transmittance 35.96%(L1), 13.00%(L2) and 4.75% (L3)], and two nitrogen levels[nitrogen application (N1) and no nitrogen application(N0)]were set up in pot experiments. The effects of light intensity and nitrogen on clonal reproduction characteristics and biomass allocation were analyzed.  Result  (1) Under the two nitrogen levels, the number of rhizome buds in L2 treatment was the highest. The number of clonal ramets of L3 treatment was significantly lower than that of L1 and L2 (P<0.05). Nitrogen application significantly increased the number of clonal ramets and buds of D. dichotoma under different shading conditions (P<0.05), with an increase rate of 124.7%(L1), 82.8%(L2) and 53.8%(L3) and 70.0%(L1), 125.7%(L2), 122.5%(L3), respectively. (2) Under the two nitrogen levels, the height of clonal ramets increased significantly (P<0.05) with the increase of shading degree, and the length of leaves in L3 shading condition was significantly higher than that in L1 and L2 (P<0.05), but there was no significant difference in leaf width (P>0.05). Under nitrogen application level, the clonal ramet height of L1 and L3 treatments increased significantly (P<0.05), the leaf length in the L1 treatment increased significantly (P<0.05), and the leaf length in L3 treatment decreased significantly (P<0.05). Both plant height and leaf length in L2 treatment did not increase significantly (P>0.05). (3) Under the two nitrogen levels, the aboveground and underground biomass (dry weight) ratio and biomass allocation ratio of clonal ramets in L3 treatment were significantly higher than those in L1 and L2 shading treatments (P<0.05). The rhizome distribution ratio was significantly lower than that of L1 and L2 (P<0.05). The percentage of biomass and leaf allocation of each shading treatment was significantly higher than that of rhizomes (P<0.05), and rhizomes were significantly higher than stems and fine roots (P<0.05).  Conclusion  L2 treatment is more conducive to the formation of clonal ramets, and nitrogen application is conducive to the enhancement of clonal reproduction capacity. Clonal ramets of L3 treatment can adapt to low-light habitat by increasing plant height, leaf length and biomass leaf allocation ratio. Regardless of the light intensity and nitrogen level, D. dichotoma gives priority to ensuring the growth of feather leaves, followed by rhizomes. [Ch, 2 fig. 5 tab. 38 ref.]
Research review on features and the molecular mechanism of wax formation in Brassicaceae
LU Weijie, ZHENG Weiwei, WU Yannong, ZANG Yunxiang
, Available online  doi: 10.11833/j.issn.2095-0756.20200138
Mainly composed of vegetables, oil crops, medicinal plants, ornamental plants and dyewood, Brassicaceae is a plant that can be annual, biennial or perennial, also as the most important family of vegetable and oil crops in China. Wax, comprised with very long chain fatty acids and corresponding derivatives, a layer of protective structure formed on plant surface to adapt different environmental conditions, plays an important role in resistance to biotic and abiotic stresses. It helps maintain water balance, reflect ultraviolet rays, reduce external mechanical damage, decrease low temperature damage, resist invasion of bacteria and fungi, prevent fruit cracking and fight off insect invasion. This paper, with a brief review of the type, physiological function, genetic characteristics, biosynthetic and transport pathways of wax, is intended to provide reference for the study of wax metabolism in Brassicaceae plants. [Ch, 2 fig. 2 tab. 61 ref.]
Relationship between spatial structure and terrain factors of evergreen broad-leaved forest in Mount Tianmu
LONG Junsong, TANG Mengping
, Available online  doi: 10.11833/j.issn.2095-0756.20200267
  Objective  The objective of this study is to explore the relationship between spatial structure and terrain factors of evergreen broad-leaved forest in Mount Tianmu, so as to provide scientific reference for the management of evergreen broad-leaved forest.  Method  Taking the evergreen broad-leaved forest in Mount Tianmu National Nature Reserve of Zhejiang Province as the research object, a large sample of 100 m×100 m was set up and divided into 100 grids of 10 m×10 m investigation units using the method of adjacent grid survey. The trees in the sample plot were measured. The aggregation index, competition index and mingling degree of tree species diversity were used to describe the spatial structure characteristics. Slope, aspect, altitude and roughness were used as terrain factors. The relationship between spatial structure and terrain factors was analyzed by analysis of variance.  Result  (1) If the slope was too large or too small, the competition index increased significantly (P<0.05). The mingling degree of tree species diversity on the semi-sunny slope was significantly higher than that on the sunny slope (P<0.05), and that in class Ⅰ roughness was significantly lower than that in class Ⅲ roughness (P<0.05). With the increase of the altitude in the plot, the mingling degree of tree species diversity increased significantly (P<0.05), but the aggregation index decreased significantly (P<0.05) when the altitude was too high or too low. (2) In roughness of class Ⅲ, the competition index of classⅠslope was significantly higher than that of classⅡand class Ⅲ (P<0.05), the mingling degree of tree species diversity of classⅡslope was significantly higher than that of classⅠand class Ⅲ (P<0.05), and the aggregation index and the mingling degree of tree species diversity on the semi-sunny slope was significantly higher than those on the sunny slope (P<0.05). In the high altitude area of the plot, the competition index of classⅠslope was higher than that of class Ⅱ and class Ⅲ slope (P<0.05), while in the middle altitude area of the plot, the aggregation index and the mingling degree of tree species diversity of class Ⅲ roughness were significantly higher than those of class Ⅰ and class Ⅱ roughness (P<0.05).  Conclusion  In evergreen broad-leaved forest community, different terrain factors have different effects on its spatial structure. It is an important management strategy to regulate the spatial structure of evergreen broad-leaved forest under certain terrain conditions. [Ch, 10 fig. 2 tab. 31 ref.]
Spatial structure of Larix principis-rupprechtii-Picea spp. secondary forests on shady slope of Luyashan National Nature Reserve
WU Xiujuan, AO Xiaoping, ZHAO Yupeng, CUI Xueqing
, Available online  doi: 10.11833/j.issn.2095-0756.20200261
  Objective  The objective is to analyze the spatial structure of typical secondary forests on shady slope of Luyashan National Nature Reserve, and provide reference for scientific management of natural secondary forest and artificial forest in similar habitats.  Method  Based on the survey data of Larix principis-rupprechtii-Picea spp. secondary forest communities at five different altitudes on the shady slope of Luyashan National Nature Reserve, the spatial structures of the communities at different altitudes were analyzed by calculating the angle scale, size ratio, mingling degree and forest spatial structure index.  Result  The average angular scale was 0.51−0.53. The spatial distribution pattern of the forests was dominated by aggregation distributions, but the degree of aggregation was low. The dominant tree species were randomly distributed in the stand. The size differentiation degree of the trees at all altitudes was close to the mean state, and the size differentiation degree of L. principis-rupprechtii was smaller than that of Picea spp., indicating that L. principis-rupprechtii was more competitive. With the increase of altitude, the spatial isolation degree and the spatial structure index decreased. The overall structure of lower altitude stand was better than that of other altitudes.  Conclusion  The communities of L. principis-rupprechtii-Picea spp. secondary forests in the study area are in late state of succession. The stand at 1 950 m above sea level has the best spatial structure and stability. [Ch, 1 fig. 4 tab. 20 ref.]
Cloning and functional analysis of early light induced protein genes of Phyllostachys edulis
LOU Yongfeng, GAO Zhimin
, Available online  doi: 10.11833/j.issn.2095-0756.20200237
  Objective  With an exploration of the role of early light induced proteins (ELIPs) in photoprotection of bamboo, this study is aimed at providing reference for the further elucidation of the photoprotective mechanism in bamboo.  Method  The ELIP genes were isolated from moso bamboo (Phyllostachys edulis) leaves using qRT-PCR before an analysis was conducted of their expression profiles under different light conditions employing qRT-PCR and the function of one ELIP gene was initially validated by ectopic expression in Arabidopsis thaliana.  Result  All the three ELIP genes (PeELIP1, PeELIP2 and PeELIP3) isolated from moso bamboo, with 165, 179 and 182 amino acids encoded respectively have the light-harvesting chlorophyll a/b binding protein domain that consists of three α-helices transmembrane domains, indicating that they belonged with the chlorophyll a/b binding protein superfamily. As was shown in the phylogenetic analysis, PeELIPs were closely related to the ELIPs from monocotyledonous plants including Oryza sativa and Zea mays, which had a high homology of more than 72% and clustered in a same branch. With the employment of qRT-PCR, it was found that the three PeELIPs were weakly expressed in etiolated bamboo seedlings, but their expression was dramatically increased upon light treatment. Meanwhile, with the increase of light intensity and the duration of treatment with strong light stress, they were all upregulated significantly in the normal bamboo leaves. In addition, the over-expression of PeELIP3 in Arabidopsis thaliana inhibited the decline of Fv/Fm under strong light treatment, but it had no effect on non-photochemical quenching coefficient(NPQ).  Conclusion  In conclusion, at least three homologous genes of ELIPs can be identified from moso bamboo, all with light-inducible expression. On the other hand, the over-expression of PeELIP3 could alleviate the photoinhibition in transgenic Arabidopsis thaliana, implying that PeELIP3 might play a positive role in photoprotection. [Ch, 8 fig. 1 tab. 40 ref.]
Effects of biochar application on soil nitrogen transformation and N2O emissions: a review
QU Tianhua, LI Yongfu, ZHANG Shaobo, LI Linlin, LI Yongchun, LIU Juan
, Available online  doi: 10.11833/j.issn.2095-0756.20200549
The sustainability and uncertainty of global climate warming have a profound impact on the sustainable development of human society. The continuous increase of atmospheric N2O concentration is one of the major contributions to the global climate warming. Soil is an important site of nitrogen transformation and a biochemical reaction reservoir of the nitrogen cycle, and also an important source of N2O emissions. Therefore, changes in soil N2O emission rate will significantly affect atmospheric N2O concentration. Biochar refers to the aromatic chemicals prepared by pyrolysis of biomass under the condition of complete or partial hypoxia. Biochar has the characteristics of porosity, strong adsorption, chemical stability, high pH and large cation exchange capacity. After it is applied to soils, biochar will directly or indirectly affect the transformation process of soil nitrogen and significantly affect the soil N2O emissions. This article reviewed the research progress of biochar effects on nitrogen transformation and N2O emission in the soil ecosystem, elaborated the effects of biochar input on the dynamic changes of soil inorganic nitrogen, nitrification, denitrification and N2O emission. Futher, in terms of biochar’s absorption and reduction of nitrogen leaching, effects on soil physicochemical properties, abundance and diversity of soil ammonia oxidizing bacterial, along with functional genes of denitrifying bacteria, the machamnisms influencing the processes above-mentioned are specifically elucidated in details. The future research of biochar in increasing soil sinks, reducing emissions and mitigating the greenhouse effect, as well as the related technology promotion, have been prospected. [Ch, 109 ref.]
Effects of the mole fraction of elevated atmospheric CO2 on soil organic carbon stability
HAN Mixue, YU Hongyan, LIU Panyang, RAO Dean, TENG Yue, ZOU Luyi
, Available online  doi: 10.11833/j.issn.2095-0756.20200502
The fast development of the industry has been accompanied with a significant increase of the global atmospheric CO2, which will affect the transformation and renewal of soil organic carbon (SOC), and then its stability. Therefore, an exploration of the effects of elevated atmospheric CO2 on SOC stability is not only an important attempt to evaluate the feedback effect of terrestrial ecosystem on climate change, but also of great significance to the effective storage of element C in soil and the sustainability of soil fertility. With an overview of previous researches, this study is aimed at a summary of the effects of elevated atmospheric CO2 on SOC stability and its stability indexes (biological index, chemical index, other index, etc.), the interaction between exogenous N and elevated atmospheric CO2 on SOC stability as well as the variation trend of SOC stability over time. The results showed that elevated atmospheric CO2 resulted in an increase in the proportion of labile organic carbon (readily oxidized carbon, particulate organic carbon, dissolved organic carbon, etc.), and a decrease in SOC stability, especially in nitrogen limitation environment. It was also found, with a summary of the research findings in recent decades, that there was a gradual decrease in the SOC stability reduction rate with the increase of high CO2 treatment time, indicating that the soil itself is equipped with the capacity to adapt and recover on its own. In conclusion, given the the feedback effect of SOC stability variation on plant physiology and growth, future researches on the effects of elevated atmospheric CO2 on SOC stability should be focused on promoting the sustainability of soil fertility in farmland ecosystem and increasing crop production and productivity. [Ch, 1 fig. 74 ref.]
Characteristics of soil moisture and its main influencing factors in different hydrological years in western Shanxi loess region
SUN Zhanwei, MA Lan, MEI Xuemei, LIU Jingjing, WANG Fuxing, ZHANG Jinge, YAN Lin
, Available online  doi: 10.11833/j.issn.2095-0756.20200260
  Objective   This study aims to investigate soil moisture variation of different vegetation types during the growing season in the loess region of western Shanxi Province, where the eco-environment is fragile and soil moisture is an important factor restricting the vegetation restoration.   Method   The soil moisture content of 0−400 cm soil layer in the growing season (May to October) in artificial forestland (Robinia pseudoacacia), natural forestland (Acer buergerianum) and grassland (Artemisia lavandulaefolia) was monitored by location observation method. On this basis, the soil active layer was divided according to the standard deviation of moisture content, and the annual soil water storage profit and loss were explored by comparing the water storage before and after the growing season. The soil properties of typical sample plots were measured, and the redundancy analysis of the factors affecting soil water storage capacity was carried out in combination with topography and characteristics of drought and flood in different hydrological years.   Result   (1)The soil moisture of the artificial forestland, the natural forestland, and the grassland ranged from 8.36% to 9.63%, 10.01% to 3.19% and 15.43% to 19.17%, respectively, and the surface soil moisture content of the grassland was significantly higher than that of the forestlands (P<0.05). (2)The depth of soil water active layer in the natural forestland reached 180 cm, deeper than that of the artificial forestland and the grassland. The soil water active layer was the deepest in moderate humid years, shallower in severe drought years, and the shallowest in normal years. (3)In severe drought years, the depth of soil water deficit of the three types was 100−300, 0−200 and 0−100 cm, respectively. The input and output of soil moisture could keep balance in normal years. In moderate humid years, the moisture content in 0−200 cm soil layer was replenished to different degrees, while the moisture content in 200−400 cm soil layer was close to 0. (4)The soil moisture storage of different soil layers was affected by different environmental factors among which vegetation types and bulk density were the dominant factors of soil moisture in 0−100 cm soil layer, and the water content of 100−200 cm soil layer was mainly controlled by bulk density and slope aspect, while the degree of drought and flood in different hydrological years, the content of soil clay and silt were the dominant factors of soil moisture in 200−400 cm soil layer.   Conclusion   The soil water deficit is severe in drought years, and is alleviated in normal or wet years. Vegetation types have the greatest impact on soil moisture storage. In the future restoration of vegetation in the Loess Plateau, we should not only consider the drought tolerance of tree species, but also the impact of topography, soil properties, and precipitation distribution during the growing season. [Ch, 5 fig. 5 tab. 33 ref.]
Effects of long-term combined application of fungus residue and chemical fertilizer on soil enzyme activities in paddy field
CHEN Wenbo, WANG Xudong, SHI Sibo, JI Shiyu, YE Zhengqian, REN Zetao, LIU Zhang
, Available online  doi: 10.11833/j.issn.2095-0756.20200139
  Objective   The purpose of this study is to explore the effects of different proportions of fungus residue and chemical fertilizer on soil enzyme activities during the rice growth period over a long-term scale.   Method   A long-term location experiment in paddy field was carried out in which the fertilizer levels were set as 0% (C0), 50% (C50) and 100% (C100) of conventional fertilization amount, and the relative amount of edible fungus residue was set as 0% (F0), 50% (F50) and 100% (F100), respectively. There were 9 treatments in total. The changes of catalase, sucrase and urease activities in different treatments at the main growth stages of rice and the interaction effect of fungus residue and chemical fertilizer on soil enzyme activities were analyzed.   Result   The soil enzyme activities showed obvious regularity with the change of rice growth period. The catalase, sucrase, and urease activities were 3.01−10.02 mL·g−1, 0.20−2.04 mg·g−1, and 0.54−4.80 mg·g−1 respectively. There were significant differences (P<0.05) in soil catalase, sucrase and urease among the treatments in different growth stages of rice. The results showed that the combined application of fungus residue and chemical fertilizer promoted the soil urease activity in the early stage of rice transplanting, and enhanced the activities of catalase and sucrase in the filling stage and harvest stage. The activities of catalase and urease were the highest in C100F50 treatment, while the sucrase activity was the highest in C50F100 treatment. Path analysis showed that available phosphorus, alkali hydrolyzed nitrogen and total nitrogen had the greatest impact on catalase, sucrase and urease respectively, with path coefficients of 0.69, 1.80, 0.69 respectively. The combined application of fungus residue and chemical fertilizer promoted soil enzyme activity mainly by increasing the mass fraction of alkali hydrolyzed nitrogen. Interaction analysis showed that the effect of combined application of fungus residue and chemical fertilizer was higher than that of chemical fertilizer and fungal residue alone, and the activities of catalase, sucrase and urease in soil were significantly affected(P<0.05).   Conclusion   The combined application of fungus residue and chemical fertilizer can significantly increase the activities of soil catalase, sucrase and urease, but with the increase of application amount, the activity of soil catalase, sucrase and urease increases first and then decreases. C100F50 treatment is the optimal choice to improve soil enzyme activity and promote carbon and nitrogen cycle under the experimental condition. [Ch, 1 fig. 4 tab. 38 ref.]
A comparative study of three determination methods for seed vigor of Cunninghamia lanceolata
XU Zhenfei, GUO Shengpeng, QIAN Wang, BAO Miaoqing, LIN Erpei, HUANG Huahong, TONG Zaikang
, Available online  doi: 10.11833/j.issn.2095-0756.20190615
  Objective  This study is aimed to establish a quick and simple method for the determination of the seed vigor of Cunninghamia lanceolata.  Method  With the seeds selected from three different cultivars of C. lanceolata, a comparison was conducted of the accuracy and efficiency of triphenyltetrazolium chloride (TTC) and ultraviolet spectrophotometer (UVS) methods with the standard germination test for reference.  Result  The standard germination test was the most accurate but most time-consuming method, which could not be performed on a large scale. TTC method was unstable and inaccurate with cumbersome operation for C. lanceolata seeds. UVS method displayed an estimated value quite close to the real germination rate and enjoyed advantages such as high reliability and simple operation.  Conclusion  UVS method could be taken as an efficient method for the rapid determination of seed vigor in C. lanceolata. [Ch, 2 fig. 5 tab. 21 ref.]
Relationship between stand growth and impact factors in karst area
WANG Lei, CUI Ming, LIU Yuguo, ZHOU Mengling, WU Jianhong, ZHOU Taolong
, Available online  doi: 10.11833/j.issn.2095-0756.20190762
  Objective  This study aims to explore the dominant factors affecting the growth of different stands in the karst area at the headwaters of South-to-North Water Diversion Project, so as to provide scientific evidence for vegetation restoration, forest management and forest rehabilitation in such area.  Method  The karst area of Xichuan County, where the head of the middle channel of South-to-North Water Diversion Project is located, was taken as the research object. The models of tree layer biomass, bedrock exposure, soil thickness, tree species diversity and stand density were built, based on the structural equation model to carry out relational coupling.  Result  There existed a positive correlation between bedrock exposure and stand density (P<0.01), a very significant positive correlation with tree species diversity (P<0.01), and a very significant negative correlation with the biomass of constructive species (P<0.01). The direct impact coefficient of bedrock exposure on stand density was 0.198, the direct impact coefficient on tree species diversity was 0.519, the total, direct and indirect impact coefficients on biomass of constructive species were −0.659, −0.722 and 0.063, respectively, and the indirect impact coefficient on stand biomass was −0.604. There existed a significant positive correlation between soil thickness and constructive species biomass (P<0.05), and a positive correlation between tree species diversity, stand density and constructive species biomass. The direct and indirect impact coefficients of soil thickness on the biomass of constructive species were 0.258 and 0.262 respectively. The direct impact coefficient of tree species diversity on constructive species was 0.084, and the total, direct and indirect impact coefficients on total biomass of stand were 0.211, 0.126 and 0.085 respectively. The direct impact coefficient of stand density on constructive species was 0.096, and the indirect impact coefficient on total biomass was 0.098. There was a significant positive correlation between the biomass of constructive species and the total biomass of stands(P<0.01), and the total impact coefficient of constructive species biomass on the total biomass of stands was 1.014.  Conclusion  There are complex relationships between bedrock exposure degree, soil thickness, tree species diversity, stand density, and constructive species biomass and total stand biomass. Reducing bedrock exposure in karst area and increasing soil thickness (i.e. improving site conditions) can improve the stand structure, as well as the constructive species biomass and stand biomass. Biomass is positively correlated with site conditions, stand density, and tree species diversity. Improving site conditions, tending and changing stand structure can promote individual growth, increase the biomass accumulation, and improve the ecological environment in karst area. [Ch, 1 fig. 3 tab. 34 ref.]
Landscape performance assessment of phase I of greenway around Qingshan Lake National Forest Park, Zhejiang Province
TANG Huichao, HONG Quan, XU Bin
, Available online  doi: 10.11833/j.issn.2095-0756.20200167
  Objective  Taking phaseⅠof the greenway around Qingshan Lake National Forest Park in Zhejiang Province as an example, this study aims to evaluate quantitatively and qualitatively the landscape performance from such aspects as environment, economy and society, so as to objectively reflect the comprehensive benefits of greenway construction.  Method  Corresponding evaluation index system was established. Ecological and economic methods were used for environmental performance evaluation. Market value method was used for economic performance evaluation, and post occupancy evaluation and questionnaire survey were used for social performance evaluation.  Result  The economic value of the environmental performance of the greenway was about 3 984 400 Yuan·a−1, of which the value of regulating the temperature and water conservation accounted for 74% and 18% respectively. In terms of economic performance, about 900 800 Yuan construction cost was saved. After the completion of the greenway, it provided new jobs, stimulated the development of tourism, and had a positive impact on the value of nearby real estate. In terms of social performance, the construction of the greenway improved the image of the city, reflected the history and culture of Lin’an District of Hangzhou City, enhanced people’s participation in outdoor activities, and changed people’s lifestyle to a certain extent. Most people visited the greenway because of the beautiful natural environment. More than half of the respondents said they had a deeper understanding of sustainable design.  Conclusion  Through quantitative and qualitative analysis and evaluation of the comprehensive value of waterfront greenway landscape performance, the comprehensive benefits of greenway construction can be presented objectively and clearly. [Ch, 9 tab. 35 ref.]
Evolution characterization of P gene of peste des petits ruminants virus in China from 2013 to 2017
SHENG Yanxiang, LIU Chunju, WANG Qinghua, CHI Tianying, MA Hongchao, WANG Zhiliang, WU Xiaodong, BAO Jingyue
, Available online  doi: 10.11833/j.issn.2095-0756.20190742
  Objective  The objective of this study is to explore the molecular evolution characteristics of P gene of peste des petits ruminants virus (PPRV) during an epidemic in China.  Method  Bioinformatics analysis on the sequences of P gene of PPRV strains from 37 epidemic sites in 21 provinces of China from 2013 to 2017 was carried out.  Result  The genetic distances among the nucleotide sequences of P gene of 37 strains was 0-0.0092, and the variation sites were distributed in 47 sites. The genetic distances among the amino acid sequences of P gene of these strains ranged from 0-0.0079, and the variation sites were distributed in 26 sites. Sequence comparison with 15 representative strains showed that nucleotide sequence mutations occurred at 10 sites of P gene of 37 PPRV epidemic strains in China since 2013, and 3 of them led to the change of amino acid sequence. Phylogenetic analysis of P gene using maximum likelihood method revealed that all the 37 PPRV strains prevalent in China from 2013 to 2017 could be grouped into an independent clade in lineageⅣ, different from the strain introduced into Tibet in 2007.  Conclusion  From 2013 to 2017, the P gene mutation of peste des petits ruminants virus in China was relatively large. With the increase of epidemic time, the mutation sites of P gene increased, but the mutation sites of different strains were different, showing a relatively random mutation. [Ch, 3 fig. 4 tab. 12 ref.]
Evaluation on the effect of National Key Soil and Water Conservation Project based on fine management of map spots
LUO Mengqi, DUAN Qian, JIANG Yaqiong, LIU Xia, LI Xiang, WU Zhenyu, HU Xuli
, Available online  doi: 10.11833/j.issn.2095-0756.20200168
  Objective  This study aims to discuss the governance effect of the National Key Soil and Water Conservation Project after implementation.  Method  Taking the small watershed of Zhangjia Village in Mengyin County of Shandong Province as an example, and soil and water conservation in basic spot and effect spot as the unit, the changes of land use, forest and grass vegetation coverage, soil and water conservation measures, and soil and water loss before and after the implementation of the National Key Soil and Water Conservation Project were compared and analyzed through investigation, measurement and field review, based on high-resolution remote sensing, UAV, mobile terminal and other technologies.  Result  (1)After the implementation of the project, there were 339 plot changes, covering an area of 870.60 hm2. The change direction was mainly from slope farmland/dry terrace into orchards, followed by slope farmland into dry terrace. (2)The basic annual forest and grass coverage rate was 31.13%, and the assessed annual forest and grass coverage rate was 45.69%. The coverage rate was mainly medium and high (60%–75%), and the improvement rate of forest and grass coverage was 14.56%. (3) The conservation rate of soil and water conservation measures was the highest in reservoir (100.00%), the lowest in millet workshop (55.56%), and the conservation rate of other soil and water conservation measures was above 80.00%. (4) The area of soil and water loss reduced by 400.39 hm2 in the evaluation year compared with the base year, the reduction rate of soil and water loss was 23.21%, and the degree of soil and water loss control was 76.78%.  Conclusion  Through implementation of the National Key Soil and Water Conservation Project, the ecological environment in the small watershed of Zhangjia Village in Mengyin County has been significantly improved, which is mainly reflected in the reduction of soil and water loss and the increase of forest and grass vegetation coverage. [Ch, 5 fig. 5 tab. 11 ref.]
Analysis of avian composition characteristics in Jiulongshan National Nature Reserve
ZHENG Yingmao, LIU Juan, PAN Chengchun, LI Chenghui, HUANG Bangwen, DING Ping, LIU Julian
, Available online  doi: 10.11833/j.issn.2095-0756.20190737
  Objective  The investigation of biological resources is the basis of the management and protection in nature reserve. The objective of this study is to investigate and analyze bird resources in Jiulongshan National Nature Reserve and provide scientific basis for the protection and restoration of birds.  Method  The bird community in the research area was investigated and analyzed by integrating historical data, special bird survey and infrared camera survey.  Result  A total of 165 species were recorded, belonging to 15 orders and 49 families, among which resident birds had the highest proportion(56.36%). The dominant species were Alcippe morrisonia and Aegithalos concinnus. There were 37 species in need of special protection, among which there were 2 species of national class Ⅰ protection birds (Syrmaticus ellioti and Tragopan caboti), 26 species of national class Ⅱ key protected birds, 10 species listed in IUCN Red List, and 18 species listed in the red list of vertebrates in China. There were both Palaearctic and Oriental elements in the composition of avifauna, but the Oriental realm was dominant (89 species, 53.94%). Among 121 breeding birds (i.e. the sum of resident and summer birds), the most species were Oriental (69.42%). Palaearctic species occupied the highest proportion (84.62% and 100.00% respectively) of migratory and winter birds.  Conclusion  Jiulongshan National Nature Reserve is rich in bird resources, accounting for more than 30.00% of bird species in Zhejiang Province. The faunal composition is dominated by the Oriental fauna, and has the characteristic of transition to the Palaearctic fauna. [Ch, 4 tab. 13 ref.]
Metabolism of the cutin and wax of plants and their disease resistance mechanisms
ZHANG Qihui, LI Xiaoman, LONG Xiyang, HU Baoyu, XIAO Xinli, ZHANG Xiaowen, TAKPAH Dennis, YANG Caiqiong, YANG Wenyu, LIU Jiang
, Available online  doi: 10.11833/j.issn.2095-0756.20190745
As a type of secondary metabolites produced by plants during long-term ecological adaptation, cutin and wax are widely involved in many resistance physiological processes including stress defense and resistance to pests and diseases, playing critical roles in the plant-pathogen interaction, thus becoming an important part of plant disease resistance mechanism. With the development of molecular biology, there is an increasing understanding on the cutin and wax metabolism and their mechanisms against fungal disease in plant. With prior researches mainly focused on the constitutive resistance and inducible resistance of plant cutin and wax, the present study, with a review of the research progress achieved on the plant cutin and wax biosynthesis and its disease resistance mechanism, is aimed to put forward prospects for future research. It was concluded that 1) as the main components of the cuticle, the first line of defense for plants against pathogen infection, cutin and wax play a critical role in physical resistance (physical barrier) and chemical resistance (bacteriostasis) as constitutive resistance components, 2) They can also play the role of inducible resistance components and 3) in addition to being the main component of the cuticle to exert physical resistance, the inducible cutin and wax component can also act as a signal molecule or inducer to activate downstream resistance reactions and exert its chemical resistance function. In the future, the research concerning cutin and wax can be focused on an in-depth explanation of the mechanism of cutin and wax inducible resistance, so as to further enrich the theoretical system of plant chemical ecology. In addition, cutin and wax biopesticides (plant immunity inducers) can be developed based on the inducible resistance of cutin and wax to provide new insight for the plant diseases control. [Ch, 1 fig. 71 ref.]
Effects of three different host plants on the feeding preference and developmental status of Ceracris kiangsu
JIN Jing, XIE Rong, LI Xia, ZHOU Liujiang, DU Yongbin, GU Yutong, FAN Jianting
, Available online  doi: 10.11833/j.issn.2095-0756.20190723
  Objective  To further the relationship of Ceracris kiangsu with their host plants, an investigation was conducted of its feeding preferences and developmental status when living on three different host plants.  Method  The grid area calculation method was employed to determine the feeding selectivity of bamboo locust of different ages and observation was made of the effects of three different host plants on the body weight, body length, pre-laying period, spawning volume and survival rate of C. kiangsu.  Result  The feeding preference of host plants of C. kiangsu changes as its age accumulates; the average feeding area of first-instar nymphs was Zea mays (474.67 mm2±66.03 mm2)>Phyllostachys edulis (179.33 mm2±41.38 mm2)>Miscanthus sinensis (76.00 mm2±42.11 mm2) while the feeding area of the nymphs from the second to the fifth instar on M. sinensis was significantly larger than that on the other two host plants(P<0.05). The weight growth of different host plants was Z. mays (0.301 g±0.015 g)>M. sinensis (0.295 g±0.022 g)>Ph. edulis(0.229 g±0.027 g) whereas the length growth of different host plants was M. sinensis (25.120 mm±0.682 mm)>Z. mays (24.860 mm±1.436 mm)>Ph. edulis (22.910 mm±2.914 mm). When breeding on different host plants, C. kiangsu demonstrates significant differences in the pre-spawing period of the adults(P<0.05) and the average pre-spawning period of the three populations was M. sinensis (55.4 d± 6.9 d)>Ph. edulis (41.7 d±2.2 d)>Z. mays (41.2 d±3.7 d), and the pre-spawning period of the population feeding on M. sinensis was significantly longer than that of those feeding on the other two plants(P<0.05). The population of spawn per female was significantly different after feeding on different host plants, and the result was Ph. edulis (122.00 seeds±6.08 seeds)>Z. mays (121.00 seeds±12.70 seeds)>M. sinensis (21.00 seeds±2.89 seeds), yet there was no significant difference in the survival rate of C. kiangsu feeding on different host plants(P>0.05) with the survival rates as follows: Ph. edulis(88.33%±1.70%)>M. sinensis (86.67%±1.66%)>Z. mays (83.33%±1.60%).  Conclusion  With the difficulty of obtaining the host plants and the weight growth, body length calculation and reproductive capacity of C. kiangsu taken into consideration, corn leaves, compared with other two host plants which are not easy to obtain in large quantities, can be planted in large quantities, thus making the most suitable food source for artificial breeding of C. kiangsu. [Ch, 4 fig. 1 tab. 17 ref.]
Effects of light quality on biomass and triterpenoid accumulation in leaves of Cyclocarya paliurus from different families
LIU Yang, CHEN Pei, ZHOU Mingming, LI Na, FANG Shengzuo
, Available online  doi: 10.11833/j.issn.2095-0756.20200117
  Objective  As a factor affecting photosynthesis, light quality can influence the accumulation of secondary metabolites in plants. Cyclocarya paliurus is a medicinal and edible multifunctional plant unique to China, and the active substances (such as triterpenoids) in its leaves can promote and improve human health. The objective of this study is to investigate the effects of light quality on biomass and the accumulation of triterpenoids in C. paliurus leaves from different families to provide reference for environmental selection during the seedling stages and further development of health care products.  Method  Taking 1-year-old seedlings of C. paliurus as materials, four families (Muchuan 31, Anji 1, Jinzhongshan 6, Jinzhongshan 7) and four different light qualities (white light, blue light, green light and red light) were selected to examine the effects of different treatments on biomass, leaf triterpenoid content and yield per plant.  Result  Light quality and genetic factors had significant effects on biomass, triterpenoid content and yield in C. paliurus leaves (P<0.05). Compared with white light treatment, other light quality treatments significantly reduced total biomass accumulation of C. paliurus (P<0.05), but there was no significant difference between blue light treatment and white light treatment in Anji 1 family(P>0.05). The total triterpenoid content in C. paliurus leaves was the highest under white light treatment in Anji 1 and Muchuan 31 families, followed by blue light. Red light treatment significantly increased the content of unique triterpenoid individuals in C. paliurus leaves(P<0.05). Under white light treatment, the plants with higher level of leaf biomass accumulated more triterpenoids than those under blue and green light treatments.  Conclusion  Proper light quality treatment can be used to increase the contents of target compounds (e.g. triterpenoids) in medicinal plants. [Ch, 1 fig. 8 tab. 27 ref.]
Dynamic analysis of mineral elements across the growth cycle of Paeonia ostii ‘Feng Dan’
XU Ya’ nan, SONG Chengwei, ZHANG Lixia, GUO Lili, DUAN Xiangguang, LIU Shuguang, HOU Xiaogai
, Available online  doi: 10.11833/j.issn.2095-0756.20200303
  Objective  With the changes of main mineral element contents in the annual growth cycle of the Paeonia ostii ‘Feng Dan’ measured, the current study is aimed at an analysis of the fertilizer requirement of and nutrient diagnosis for the oil peony.  Method  With ‘Feng Dan’ (eight years old), an oil peony cultivar selected as the study subjects, the mineral elements content of roots, stems and leaves were measured across the annual growth cycle of the oil peony.  Result  The content of P in roots, stems and leaves, and the content of N in roots and leaves decreased gradually as the growth cycle of the peony proceeds, while the changes of K and Mg vary from part to part. The content of Fe was significantly more than any other trace elements in the roots, stems and leaves, and increased first and then decreased across the growth cycle. All of the trace elements, except for Cu, have showed first an increase and then a decrease in content in the roots. As the process of fruit development advanced, the content of N increased, with the content of K in fruit pods and P in seeds displaying a trend of decrease, increase and decrease. The changes of mineral elements in roots, stems and leaves of the peony showed different degrees of correlation across the peony’ s growth cycle, with N、P、K、Fe and Mn closely related to most of the other mineral elements. The same mineral elements displayed different correlations with vegetative organs and reproductive organs.  Conclusion  Throughout one growth cycle, the oil peony ‘Feng Dan’ has a large demand for N and P from the leaf-growth stage to the current bud stage, and N and P fertilizers should be applied before the leaf-growth stage; and there is a large demand for N, P and K during the fruiting period, and it is recommended to apply N, P and K fertilizer after the flowering of the peony. Fe fertilizer should be applied before the budding stage (early March) while B and Zn fertilizers should be applied during the seed development stage from May to July to meet the demand of ‘Feng Dan’ plants for these three microelements. [Ch, 7 tab. 36 ref.]
Image recognition of poplar leaf diseases with feature segmentation and lesion enhancement
MING Hao, SU Xiyou
, Available online  doi: 10.11833/j.issn.2095-0756.20190752
  Objective  In view of the inconspicuous characteristics of poplar(Populus) scab and mosaic disease, this paper is aimed to propose a method to improve the disease recognition accuracy by means of the pre-treatment of the original image set.  Method  Firstly, the contour of the blade was extracted employing the improved Canny operator edge detection method combined with Hoss Transformation so as to remove the disturbance of the image background. After that, the contrast limited adaptive histogram equalization was adopted to reduce the impact of local illumination unevenness. Thirdly, the OTSU segmentation algorithm with adaptive threshold was used to extract leaf lesion images. At last, the binarized images with lesion and the leaf lesion images were fed into the Alexnet which consists of 5 convolutional layers, 3 full-connection layers, 650 000 neurons and over 60 million learning parameters.  Result  Both groups came back with a significantly higher recognition accuracy rate than that of the the original image experiment group (93.56% and 98.05% VS 88.77%). The hybrid method proposed in this paper could help completely extract the images of the main body of the blade with different backgrounds and effectively avoid the background interference of the target blade. And the adaptive histogram equalization algorithm with limited contrast helped in dealing with the uneven light produced by natural environment and reducing the interference of reflective factors like reflected light.  Conclusion  The pre-treatment of the images of the above-mentioned diseases has significantly improved the recognition accuracy, and is highly recommended in future tasks. [Ch, 8 fig. 1 tab. 22 ref.]
Research progress on the characteristics and molecular mechanism of yellowing mutation in Brassicaceae
WU Yannong, ZHENG Weiwei, LU Weijie, ZANG Yunxiang
, Available online  doi: 10.11833/j.issn.2095-0756.20200132
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.]
Monitoring of vegetation coverage change in hilly and gully regions on the Loess Plateau
ZHANG Shuting, WANG Xiaohui, PENG Daoli, JI Ping, LIU Hua, LING Chengxing, HOU Ruixia
, Available online  doi: 10.11833/j.issn.2095-0756.20200136
  Objective  The present study is to analyze the vegetation changes in areas with severe soil erosion on the Loess Plateau since the implementation of forestry ecological projects such as the Three-north (northwest, north and northeast) Shelterbelts and Conversion of Farmland to Forests, so as to provide basis for formulating reasonable ecological restoration and management countermeasures.  Method  Taking Ansai District of Yan’an City in Shaanxi Province as an example, the vegetation coverage in 2000 and 2017 was estimated by pixel dichotomy based on Landsat TM/OLI image, and topographic differentiation characteristics were analyzed in combination with altitude, slope and slope direction.  Result  (1)Vegetation coverage significantly increased from 24.98% in 2000 to 53.34% in 2017. (2)The proportion of vegetation coverage with extremely significant increase in the study area accounted for 44.70%, which was concentrated along rivers. (3)In 2000, the vegetation coverage gradually decreased with the increase of altitude. In 2017, the vegetation coverage increased first and then decreased with the increase of altitude. In 2000 and 2017, the vegetation coverage increased first and then decreased as the slope increased, and reached its maximum value at the slope of 25°−35°. The order of vegetation coverage from large to small with the change of slope direction was shady slope, semi shady slope, semi sunny slope, and sunny slope. (4)When the altitude was less than 1 300 m and the slope was 15°−35°, flat land, shady and semi shady slopes had good water and heat conditions, with easy vegetation recovery and the largest proportion of high vegetation coverage area.  Conclusion  The vegetation in Ansai District showed a trend of improvement from 2000 to 2017, with differences under terrain conditions such as altitude, slope, and slope aspects. Ecological restoration countermeasures should be formulated based on local conditions. [Ch, 2 fig. 6 tab. 27 ref.]
Effect of immobilized lignin-degrading bacteria on green waste composting
MENG Tongyao, LI Suyan, ZOU Rongsong, YU Kefei, FU Bingyan, JIE Yang
, Available online  doi: 10.11833/j.issn.2095-0756.20200219
  Objective  The purpose of this research is to prepare a kind of solid microbial inoculant to promote green waste composting by immobilizing lignin-degrading bacteria No.11, with biochar-rice bran as a carrier.  Method  Through single factor experiment, the optimal range of inoculation amount (5%, 10%, 15%, 20%, 25%), volume fraction of protective agent (0, 4%, 8%, 12%, 16%, 20%) and water content (5%, 10%, 15%, 20%, 25%) were explored, and the best preparation conditions of solid microbial inoculant were found by orthogonal test. Taking a common commercially available microbial inoculant (EM) as an example, the microbial agent was added to the composting process of green waste to explore its effects on lignin and cellulose degradation and related enzyme activities.  Result  The optimal immobilization conditions of lignin-degrading bacteria No.11 were as follows: 10% inoculation amount, 8% protectant volume fraction and 15% water content. The amount of the effective living bacteria in the prepared fungus reached 1.26×1011 CFU·g−1. Enzyme activities related to lignin degradation(laccase, manganese peroxidase, and lignin peroxidase) were promoted after adding self-made microbial inoculant. Lignin degradation rate increased by 8.69% compared with the addition of EM bacteria. Compared with the control (without inoculant), the degradation rate of lignin and cellulose increased by 23.91% and 8.34%, respectively, and the compost products reached the maturity standard.  Conclusion  The number of effective viable bacteria of the solid microbial inoculant prepared by immobilizing lignin-degrading bacteria complies with the requirements in Microbial Inoculants in Agriculture (GB 20287−2006). Adding the inoculant to green waste compost can improve the degradation rate of lignin and cellulose and promote the maturity of compost products. [Ch, 3 fig. 3 tab. 36 ref.]
Effects of exogenous BR on physiological characteristics of Phyllostachys edulis seedlings
LI Qicheng, YU Xuejun
, Available online  doi: 10.11833/j.issn.2095-0756.20200161
  Objective  This research aims to study the effects of exogenous brassinolide (BR) on physiological characteristics of Phyllostachys edulis, and to provide theoretical basis and technical reference for future cultivation and management of Ph. edulis.  Method  The seedlings of Ph. edulis were used as test materials, and 6 kinds of brassinolide solutions with different concentrations[0(ck), 0.050 0, 0.010 0, 0.005 0, 0.001 0, 0.000 5 mg·L−1] were set up through hydroponic culture experiment to compare the differences in the growth characteristics, photosynthetic pigment, photosynthetic characteristics and antioxidant system of the seedlings.   Result  On the whole, compared with ck, brassinolide with different mass concentrations could promote the growth and development of Ph. edulis seedlings to varying degrees, improve the quality of photosynthetic pigments and photosynthetic capacity, and promote the synthesis of osmotic adjustment substances. Compared with ck, when the mass concentration of brassinolide was 0.005 0 and 0.001 0 mg·L−1, the superoxide dismutase activity of bamboo seedlings increased by 6.7% and 6.1%, respectively, oxidase activity increased by 14.6% and 13.7%, and catalase activity increased by 8.2% and 14.6%, respectively. The mass fraction of soluble protein increased by 31.5% and 31.2%, and the mass fraction of starch increased by 17.3% and 16.9%, respectively. However, compared with 0.005 0 and 0.001 0 mg·L−1 treatment, brassinolide treated with mass concentration of 0.050 0, 0.010 0 and 0.000 5 mg·L−1 had no significant effect on antioxidant capacity and osmotic adjustment ability of Ph. edulis seedlings.  Conclusion  Brassinolide can improve the photosynthetic capacity and stress resistance of Ph. edulis seedlings, and promote nutrient growth. The best concentration of brassinolide is 0.005 0−0.001 0 mg·L−1.[Ch, 5 tab. 42 ref.]
Indoor prevention and toxicity test of three chemical insecticides against Melanotus ribricollis
JIN Jing, XIE Rong, DU Yongbin, WU Jiahao, ZHOU Liujing, FAN Jianting
, Available online  doi: 10.11833/j.issn.2095-0756.20190731
  Objective   In order to clarify the control effect of different chemical insecticides on the larvae of the Melanotus cribricollis, a virulence test was carried out on the larvae stage for the present study.   Method   With 5.0% phoxim granules, 0.5% fipronil powder and 20.0% chlorantraniliprole suspension selected and mixed into sand and bamboo forest soil in a 1∶2 ratio with 5 concentration gradients, to observe the mortality rate of M. cribricollis after 24 hours in contrast with a control group where water was sprayed without any insecticides.   Result   The three selected chemical insecticides all have certain control effects on M. cribricollis, with the control effect from strong to weak: 5.0% phoxim>0.5% fipronil>20.0% chloranthrene Benzoamide. It was found that the 5.0% phoxim has the best control effect, with an LC50 of 0.190 0 g·kg−1, followed by 0.5% fipronil, with an LC50 of 0.950 0 g·kg−1, and 20.0% chlorantraniliprole which has the weakest control effect with a LC50 of 1.820 0 g·kg−1.   Conclusion   With control effectiveness, toxicity and control costs taken into consideration, 5.0% phoxim Phosphorus granules and 0.5% fipronil are suitable for the control of bamboo forest pests M. cribricollis, yet with the need to further explore the application methods and relevant technologies of forest chemicals. [Ch, 2 tab. 27 ref.]
Inhibitory effect of succinic acid, cinnamic acid and vanillic acid from Pontederia cordata on Microcystis aeruginosa
ZHAO Chu, QIAN Yanping, TIAN Runan
, Available online  doi: 10.11833/j.issn.2095-0756.20190722
  Objective  With succinic acid of fatty acids, cinnamic acid and vanillic acid sdanders of phenolic acids, three allelochemicals extracted from Pontederia cordata rhizomes used both alone and jointly.  Method  This paper is aimed at an investigation of the effects of organic acids on the growth of Microcystis aeruginosa.  Result   (1) The growth of M. aeruginosa could be inhibited by succinic acid, cinnamic acid and vanillic acid either solely or jointly, with 92.78% as the inhibition rate achieved with the employment of 100 mg·L−1 succinic acid and cinnamic acid for seven days; (2) when used alone, cinnamic acid demonstrates the strongest inhibition ability with succinic acid and vanillic acid following behind, yet when used jointly, the inhibition ability weakens in the following order: succinic acid + cinnamic acid > cinnamic acid + vanillic acid > succinic acid + cinnamic acid + vanillic acid with vanillic acid weakening the inhibition effect of succinic acid and cinnamic acid on the growth of M. aeruginosa to a certain degree; (3) when succinic acid was combined with phenolic acid (cinnamic acid or vanillic acid), cinnamic acid was combined with vanillic acid or the three organic acids combined, their inhibition effect on M. aeruginosa was enhanced; (4) the combination of fatty acid and phenol acidification either in the same kind or among different kinds can enhance the effect of algal inhibition.  Conclusion  The three allelochemicals extracted from the rhizome of P. cordata might have good algae inhibition effect and the combined action of various allelochemicals might be the main mechanism of P. cordata inhibiting cyanobacteria bloom. Therefore, succinic acid, cinnamic acid and vanillic acid have the potential to be developed as algal inhibitors. [Ch, 2 fig. 2 tab. 26 ref.]
Application of Bos grunniens waste on nutrient leaching reduction for the desertified soil
OU Shengye, DING Li, YU Ninger, WU Shengchun, LIANG Peng
, Available online  doi: 10.11833/j.issn.2095-0756.20190703
  Objective   This study aimed to determine the effects of different proportions of biochar and compost from Bos grunniens waste as well as the polyacrylamide (PAM) on nutrient leaching in desertified soil. [ Method ] Experiment were conducted in the laboratory by using soil column leaching method. All of treatments were divided into two groups, with and without PAM. Additionally, each group include four treatments, Bos grunniens biochar only, Bos grunniens biochar: Bos grunniens compost equal to 1∶1, bos grunniens compost only and the control treatment.   Result   1) In general, the application of biochar or compost can enhance soil nutrients, and the effect of combined application of biochar fertilizer is significantly better than that of single application of biochar or compost. 2) Compared with the control group, the mixed application of biochar and compost (1∶1, w/w) with a rate of 3% of soil weight can significantly increase the soil pH and make the soil become weak alkalescent: the organic matter content increased by 530% with the addition of biochar and compost, the total nitrogen concentration increased by 255%, with the nitrate nitrogen concentration improved by 24.1% and the total and available phosphorus contents increased by 120% and 78% respectively, with no significant impact on the ammonium nitrogen content, though. 3) The addition of PAM can effectively reduce the leaching loss of exogenous nutrients with the total nitrogen leaching rate decreased by 9.6% in the presence of biochar and compost and the total phosphorus decreased by 7.1%.   Conclusion   The application of biochar and compost products with the addition of PAM can effectively increase the soil nutrient content while reducing nutrient seepage. [Ch, 8 fig. 1 tab. 38 ref.]
Water purification efficiency and resource utilization of three tuberous emergent aquatic plants
CHU Shuyi, LAI Zhenggang, LI E, SHAO Jianlei, HUANG Zhida, XIAO Jibo
, Available online  doi: 10.11833/j.issn.2095-0756.20200124
  Objective  This study aims to investigate the purification capacity for nutrients in polluted water and the yield of tuber starch of three common tuberous aquatic plants, and estimate the feasibility and potential risk of starch resource utilization.  Method  Purification efficiency of Iris pseudacorus, Canna indica and Calla palustris for polluted water body was compared using hydroponic experiment, and three replicates were set for each group. No plant treatment was used as control group. Removal efficiency of ammonium nitrogen, total nitrogen and total phosphorus in water was investigated. The contents of nitrogen and phosphorus in plant roots, stems, leaves and tubers were analyzed. The content of starch and heavy metals including Cu, Zn, Cr and Pb in plant tubers were measured.  Result  When initial concentrations of ammonium nitrogen and total phosphorus were 7.37−7.53 and 0.41−0.45 mg·L−1, concentrations of ammonium nitrogen, total nitrogen and total phosphorus in plant treatment groups decreased to 0.01−0.07, 0.61−0.91, and 0.025−0.031 mg·L−1 respectively after 20 days of treatment, which met the Class Ⅲ standard for surface water environmental quality (GB 3838−2002). The starch extracted from tubers of I. pseudacorus, C. indica and C. palustris was 61.3, 14.1 and 64.0 g·kg−1, respectively. Starch yields of these plant species were 14.3, 1.2 and 2.6 kg·m−2 respectively in the 100 m2 trial plot. The tuber could accumulate heavy metals. As initial concentrations of Cu2+, Zn2+, Cr3+ and Pb2+ in water were 2.01−2.08, 2.56−2.87, 0.22−0.26, and 0.24−0.26 mg·L−1, the contents of Cu, Zn, Cr and Pb in tuber starch of I. pseudacorus were 10.30, 46.7, 12.03, and 1.74 mg·kg−1, respectively and those of C. indica were 12.68, 44.67, 8.15 and 1.32 mg·kg−1, respectively, while those of C. palustris were 19.28, 66.91, 9.63 and 3.97 mg·kg−1, respectively.  Conclusion  The three tuberous aquatic plants can effectively purify nutrients such as nitrogen and phosphorus, and recover a considerable amount of starch. However if heavy metals coexist in the polluted water, plant tubers are not recommended for resource utilization. [Ch, 4 fig. 17 ref.]
Effect of aluminum stress on growth and physiological characteristics of Hydrangea tissue culture seedlings
LI Yehua, CHEN Shuang, ZHAO Bing
, Available online  doi: 10.11833/j.issn.2095-0756.20200121
  Objective  The aim is to explore the aluminum tolerance of Hydrogena strigosa and H. longipes tissue culture seedlings, so as to lay a foundation for the application of aluminum resistant plants and the utilization of special acid soil resources.  Method  The effects of different concentrations of AlCl3 (0, 25, 50, 100, 200 mg·L−1) on the growth and physiological characteristics of H. strigosa and H. longipes tissue culture seedlings were studied.  Result  Under low concentration of aluminum stress (25, 50 mg·L−1), the growth of H. strigosa was normal and similar to that of the control group, while the growth of H. longipes was inferior to that of the control group. Under the medium and high concentration of aluminum stress (100, 200 mg·L−1), the growth of tissue culture seedlings was significantly reduced, and the average root length and root volume were lower than those of the control group, indicating that aluminum stress inhibited both the aboveground and underground parts of Hydrangea. With the increase of aluminum stress concentration, the chlorophyll mass fraction of H. strigosa increased at 50 mg·L−1, while the chlorophyll mass fraction of H. longipes decreased, which indicated that H. strigosa promoted chlorophyll synthesis under low aluminum stress, and H. longipes inhibited chlorophyll synthesis under aluminum stress. The content of malondialdehyde in H. strigosa and H.longipes decreased first and then increased. The catalase and peroxid activities increased continuously. The activities of superoxide dismutase were lower than those of the control group, but the difference was not significant. The proline mass fraction of H. strigosa was lower than that of the control group under the treatment of 25 mg·L−1, and higher than that of the control group under other aluminum concentration treatment. The proline mass fraction of H. longipes under aluminum stress was higher than that of the control group.  Conclusion  Hydrangea can make positive growth and physiological responses under aluminum stress, and different species of Hydrangea have different aluminum tolerance. In sum, H. strigosa and H. longipes are resistant to low concentration of aluminum.[Ch, 2 fig. 3 tab. 24 ref.]
Effects of nitrogen addition on decomposition and nutrient release of Cinnamomum migao litter leaves
CHEN Meng, LIU Jiming, CHEN Jinzhong, LI Jia, HUANG Luting
, Available online  doi: 10.11833/j.issn.2095-0756.20200106
  Objective  This research aims to examine the effects of different nitrogen application levels on nutrient decomposition of Cinnamomum migao litter leaves.  Method  In January 2017, the litter leaves of the medicinal plant C. migao were taken as the research object. The leaves were washed, air dried and put into decomposition bags, 10.00 g each. Nitrogen treatments were designed as ck(0 g·m−2·a−1), N1(5 g·m−2·a−1), N2(15 g·m−2·a−1), and N3(30 g·m−2·a−1), and there were three repetitions for each treatment. The samples of litter leaves were collected in March, May, July, September and November, respectively. The quality and nutrient contents of the leaves were measured, and the dynamic effects of nitrogen deposition on nutrient release from the leaves were analyzed.  Result  At the end of litter decomposition experiment, the mass loss rate of litter leaves in all nitrogen application groups was lower than that of ck, the residue rate of litter was higher than that of ck. The difference between N2 and ck was not significant, but the difference between N2 and N3 was significant (P<0.05). The time needed for 95% decomposition of ck, N1, N2 and N3 was 2.973, 3.626, 3.285 and 3.671 a, respectively. In the leaves of all treatments, the content of C decreased and the content of total N increased first and then decreased, while the content of total P and total K was similar, which decreased at the initial stage of decomposition, then increased as a whole, and finally stabilized. The residual rates of C, total P, total K in the leaves decreased, while the residue rates of total N increased first and then decreased. The residual rate of C in each nitrogen treatment was significantly higher than that of ck (P<0.05). With the passage of time, the residue rate of N, which increased first and then decreased in ck treatment, showed an overall upward and then downward trend in each nitrogen application treatment. C/N ratio of each nitrogen application group was lower than that of ck in the whole decomposition process, and there was a significant difference between the early decomposition stage and ck (P<0.05).  Conclusion  Nitrogen addition is not conducive to the decomposition and nutrient release of litter leaves. The more nitrogen is applied, the more obvious the inhibition of decomposition is.[Ch, 4 fig. 1 tab. 33 ref.]
Preparation of magnetic sodium alginate composite gel balls and their adsorption properties for Pb2+
WANG Jue, GUO Ming, SUN Liping
, Available online  doi: 10.11833/j.issn.2095-0756.20190751
  Objective   Magnetic gel balls are new adsorbents which can efficiently remove pollutants and can be reused. Therefore, it is necessary to prepare a new type of magnetic gel ball.   Method   Magnetic particles (MNP) prepared by the ion co-precipitation method were used as carries for silanization reaction to synthesize magnetic nanoparticles (AM) with amino terminals. A novel magnetic composite gel ball (SA@AM) containing amino, hydroxyl and carboxyl multifunctional groups was prepared by coating sodium alginate (SA) on the surface of magnetic particles with electrostatic effect. Fourier transform infrared spectroscopy (FTIR), elemental analyzer, X-ray diffractometer (XRD), scanning/transmission electron microscope (SEM/TEM), and vibrating sample magnetometer (VSM) were used to characterize the product, and the adsorption properties of the products for heavy metal ions were studied.   Result   The target functional composite gel ball (SA@AM) successfully prepared was of paramagnetic magnetite crystal type, and the size of the SA@AM gel ball was 1.5−2.0 mm. The magnetization values of MNP, AM, SA@AM were 13.8, 13.4, and 6.85 A·m2·kg−1, respectively. Adsorption experiments showed that the maximum adsorption capacity of heavy metal Pb2+ by SA@AM was 105.82 mg·g−1, and the adsorption mechanism was more in line with the Langmuir isothermal adsorption model. Repeated adsorption-desorption experiments showed that the removal rate of Pb2+ by SA@AM was more than 76%.   Conclusion   The new sodium alginate magnetic composite gel ball has excellent adsorption capacity for heavy metal ions Pb2+, and the magnetic gel ball has good regeneration properties. [Ch, 10 fig. 1 tab. 25 ref.]
Phenotypic diversity of male cones and the selection of superior plants among male populations in Torreya grandis
ZHAN Liyun, LIU Lian, ZENG Yanru, YU Weiwu, DAI Wensheng
, Available online  doi: 10.11833/j.issn.2095-0756.20190676
  Objective  With the phenotypic diversity of male Torreya grandis populations explored and superior male individuals initially screened, this paper is aimed to provide a reference for the scientific configuration of superior pollinator trees so as to improve the actual yield and quality of T. grandis ‘Merrillii’.  Method  With 121 single plants selected from 5 natural male populations in T. grandis, an analysis was conducted of 10 phenotypic traits including single leaf weight, leaf shape index, weight of single male cone, cone shape index, percentage of pollen yield and pollen vitality, etc to study variation in phenotype, based on which superior male individuals were selected.  Result  (1) There were no significant differences (P>0.05) between populations in all the traits except leaf length and percentage of pollen yield (P<0.05), but there were significant differences in all 10 traits among individuals within each population, indicating that variation within a population is the main sources of phenotypic variation in male T. grandis and larger than that among populations, which means that artificial selection should be based on the selection of individuals. (2) Among the 10 phenotypic traits, coefficients of variation for male cones were larger than those for leaves with 42.36% and 34.13% as the coefficient of variation for the pollen vitality and pollen yield respectively, which indicates that the selection of superior male individuals should be based on the traits of male cones. (3) 36 superior early, interim and late flowering individuals were screened out according to traits of male cones, which could be used as reference for breeding and plantation in the future.  Conclusion  The phenotypic traits of male T. grandis demonstrate more significant genetic diversity within the populations, and the focus should be laid on the choice of superior individuals within populations in the attempt at the establishment of later genetic improvement strategy of T. grandis while cone shape index, percentage of pollen yield, pollen vitality are important phenotypic indexes for the primary selection of superior individual. [Ch, 1 fig. 7 tab. 26 ref.]
Evaluation of foliar spraying of zinc in Carya illinoensis
SHANG Yangjuan, TAN Pengpeng, FAN Pinghua, KONG Deyi, PENG Fangren, LI Yongrong
, Available online  doi: 10.11833/j.issn.2095-0756.20190687
  Objective  With the effect of foliar spraying of zinc (Zn) on leaves growth and mineral elements of pecans (Carya illinoensis) explored, the study is aimed to provide scientific basis for the fertilizer control of fruit trees.  Method  Using 6-year-old ‘Pawnee’ pecans as the research material under field conditions, a field experiment was conducted with 3 types of zinc fertilizers, such as EDTA-Zn, zinc sulfate (ZnSO4·7H2O), zinc nitrate [Zn (NO3)2·6H2O)] sprayed at 3 levels of concentrations (50, 100, 150 mg·L−1Zn) in terms of 10 treatments (with 0 mg·L−1Zn as control). Treatments were replicated three times in a randomized complete block design to measure the growth parameters (leaf length and width and area, rate of water content, specific leaf weight, tree height and diameter) and leaf mineral elements [nitrogen (N), phosphorus (P), potassium (K), calcium (Ca), magnesium (Mg), zinc (Zn), iron (Fe), manganese (Mn), copper (Cu)]. These parameters were initially evaluated with the employment of principal component analysis (PCA) and weight subordinate function (WSF).  Result  The leaf growth parameters and tree height and diameter increased to a certain extent with the increased concentration. The leaf length, width, area, specific leaf weight increased by 26%, 37%, 25%, 17% with the 150 mg·L−1 of zinc nitrate treatment respectively, which was significantly higher than that with other treatments (P<0.05). With the increased concentration, the N, K, Zn, Mn contents of pecan leaves increased and the P, Fe content decreased while the Ca and Mg contents first increased and then decreased. As was shown in the correlation analysis, the length, width, N, K were significantly and positively correlated (P<0.05) to Zn in leaves while the coverage, Ca, Mn were significantly and positively correlated (P<0.01) to Zn in leaves.  Conclusion  Foliar spraying of zinc has significantly improved the leaf growth of pecans (P<0.05) and increased the accumulation of mineral elements in leaves. Thus, it was suggested that 150 mg·L−1 of zinc nitrate or 100 mg·L−1 of zinc sulfate or 50 mg·L−1of Zn-EDTA could be used for foliar spraying of zinc fertilizers in pecans. [Ch, 2 fig. 4 tab. 30 ref.]
Application of convolutional neural network in rosewood species identification
HUANG Penggui, ZHAO Fan, LI Xiaoping, WU Zhangkang, TANG Zhengjie, ZHANG Yanfeng
, Available online  doi: 10.11833/j.issn.2095-0756.20190672
[Abstract](110) [HTML] (13) [PDF](5)
  Objective  Due to the differences in growth cycles and wood characteristics, the market price of rosewood species including some nationally protected species varies sharply. To prevent fraud and better protect tree tree species, this paper is aimed at the accurate identification of redwood specie.  Method  With 376 samples of 7 species of rosewood collected in the actual test by the National Forestry and Grassland Administration Center for Quality Supervision and Testing of Wood and Bamboo Products (Kunming) selected as the research subject, a convolutional neural network model for automatic recognition of redwood is proposed using the computer algorithm to expand the number of samples.  Result  This method can automatically identify features that fit with the model of classification and recognition, making it more convenient to utilize. Compared with traditional methods, it secures a more accurate identification with an average identification accuracy of 99.4%.  Conclusion  The self-built convolutional neural network can effectively identify redwood species. Although it takes a long time to achieve the parameter adjustment and train than VGG16 and other transfer learning methods, it shows stronger competence of generalization. It is proved that the self-built model is superior to the transfer learning model when applied in redwood recognition. [Ch, 7 fig. 4 tab. 23 ref.]
Research progress on tendril formation in Cucurbitaceae horticultural crops
ZENG Kang, WANG Shuwen, ZHOU Binying, WANG Huasen, XU Yunmin
, Available online  doi: 10.11833/j.issn.2095-0756.20190756
Cucurbitaceae is one of the important plant families in agricultural production, most of which are annual vines. The key morphological marker of Cucurbitaceae plants is tendril. This paper summarizes and analyzes the main research results on tendrils of Cucurbitaceae plants, and puts forward a prospect for future research. The present researches on tendrils of Cucurbitaceae horticultural crops mainly focus on the following aspects: (1) the origin of tendril; (2) the key gene regulating tendril development; (3) the genes specifically or highly expressed in tendrils; (4) the endogenous hormones regulating tendril development; (5) the influence of external environment on tendril development. The main conclusions are as follows: tendrils of Cucurbitaceae horticultural crops are identified as abnormal organs of lateral branches, and the key gene regulating tendril is TCP1. Tendril tissue-specific or high-level genes are mainly involved in morphological development, tropism, auxin polar transport, calcium ion transport, glutamate metabolism, lignin metabolism, which are closely related to tendril generation, development and coiling. Hormone (auxin, gibberellin) and environment factors (light, temperature and water) have been reported to affect tendril development, but the specific molecular mechanism remains unknown. Future research on tendrils of Cucurbitaceae horticultural crops should focus on the analysis of the upstream and downstream gene network of TCP1 to improve the regulatory effect of hormones and external environment on tendrils. Based on the mature gene editing technology, it will be beneficial to explore the molecular regulatory network of tendrils of Cucurbitaceae horticultural crops and develop tendril-less breeding design. [Ch, 2 fig. 32 ref.]
Electroantennogram and behavioral responses of Agrilus mali to the volatiles from Malus sieversii trees induced by pest and disease
LIU Aihua, KONG Tingting, ZHANG Jingwen, WEN Junbao, JIAO Shuping
, Available online  doi: 10.11833/j.issn.2095-0756.20190738
  Objective  This study aims to explore the electroantennogram and behavioral responses of Agrilus mali to the volatiles from Malus sieversii trees in different damaged states to provide reference for the research and development of highly effective attractants.  Method  The volatiles were collected by using dynamic headspace adsorption from branches and limbs of M. sieversii trees.  Result  There are total of 46 volatile compounds in 9 categories has been obtained, including alcohols, lipids, aldehydes, alkanes, alkenes, ketones, terpenes, ethers and others. Compared with healthy branches, the relative contents of eicosane and pentadecane increased in A. mali damaged branches, while the relative contents of 8 volatiles such as butenol, 2-methylacrolein, heptadecane, heneicosane, cycloheptatriene, cyclohexanone, α-pinene and chamomile decreased. Fourteen compounds were added such as cis-3-hexenol, hexanal, decanal, nonanal, (+)-limonene etc. In Valsa mali damaged branches, pentadecane, heptadecane, 3,7-dimethyldecane, eicosane and α-pinene increased, and heneicosane, cyclohexanone, cycloheptatriene, azulene decreased. Twelve compounds were added such as cis-3-hexenol, butyl butyrate, hexanal, (+)-α-pinene, (+)-limonene, etc. Compared with the volatilides released from healthy limbs, the relative contents of cis-3-hexenol, α-pinene, (−)-α-pinene and camphene were increased in A. mali damaged limbs, and hexanal, cycloheptane, β-pinene, cycloheptatriene, azulene contents decreased. Seventeen compounds were added such as 3-octene-2-alcohol, butyl butyrate, decanal pentadecane, (+)-aromadendrene, etc. In Valsa mali damaged limbs, hexanal increased, and cis-3-hexenol, acrolein, cyclohexanone, α-pinene, (−)-α-pinene, β-pinene and azulene decreased. Eleven compounds were added such as benzaldehyde, pentadecane, dipentene, etc. EAG responses and behaviour of A. mali towards volatiles released by host were tested. The results showed that strong EAG reactants could be produced in the antennae of male and female adults of A. mali, these compounds were (−)-α-pinene, nonanal, (+)-α-pinene, benzaldehyde, decanal, butyl acrylate. A. mali were attracted by (−)-α-pinene, α-pinene, (+)-β-pinene, β-pinene, decanal, nonanal in the behavior bioassay.  Conclusion  According to the results of EAG responses and behavioral orientation, the (−)-a-pinene, nonanal and decanal had good attraction to the adult of Agrilus mali.[Ch, 1 fig. 3 tab. 27 ref.]
Genetic variation of wood basic density and fiber morphology and selection of Pinus massoniana
YIN Huanhuan, LIU Qinghua, ZHOU Zhichun, WAN Xueqin, YU Qixin, FENG Zhongping
, Available online  doi: 10.11833/j.issn.2095-0756.20190720
  Objective  With an analysis of the genetic variation of wood basic density and fiber morphology of Pinus massoniana among seed sources and clones within seed sources, this paper is aimed to provide high quality genetic material for the breeding and improvement of P. massoniana.  Method  Fifty clones from five seed sources of P. massoniana clones selected from 34-year-old experimental forests of different seed sources in Laoshan Forest Farm, Chun’an County, Zhejiang Province, were investigated to determine the wood basic density, fiber length, fiber width and fiber length-width ratio. Then variance analysis, correlation analysis and genetic parameter estimation were conducted to reveal the genetic variation while superior individuals were selected from the 50 P. massoniana with the employment of Independent Selection Standard Method.  Result  The results of ANOVA revealed that there were significant or extremely significant differences in the basic density and fiber morphology of the wood among seed sources and clones within seed sources. The variation of clones within seed sources with the variance components ranging from 19.37% to 28.26% was the main source of wood basic density, fiber length and fiber length-width ratio. The variation of seed sources with the variance components (45.57%) was the main source of fiber width. There is a significant phenotypic and genetic negative correlation between basic densities of wood and fiber length and fiber length/width, but the correlation coefficient is not high and the basic densities of wood is not related to fiber width. The fiber morphological indexes showed significant positive genetic correlation in the juvenile age and mature age, while the wood basic density showed no significant correlation in the juvenile age and mature age. A total of 12 clones of P. massoniana with excellent wood properties were selected.  Conclusion  More attention should be paid to the selection of superior trees within seed sources in the attempt to improve the three traits of wood basic density, fiber length and fiber length-width ratio. On the other hand, the fiber width can be better improved through the choice of seed sources. In view of the significant correlation of fiber morphology indexes between juvenile and mature timber, they can be selected as reference indexes in the early stage. [Ch, 4 tab. 25 ref.]
Age structure and spatial point pattern of Phoebe sheareri population in Tianmu Mountain
FAN Yi, LOU Yikai, KU Weipeng, DAI Qilin, WANG Zhengyi, ZHAO Mingshui, YU Shuquan
, Available online  doi: 10.11833/j.issn.2095-0756.20190631
  Objective  This research aims to study the age structure and spatial pattern of Phoebe sheareri population in Tianmu Mountain, so as to better protect the population and provide basis for forest management.  Method  Based on the survey data of 1 hm2 (100 m×100 m) of evergreen broad-leaved forests in Tianmu Mountain of Zhejiang Province, the age structure of dominant species P. sheareri population was analyzed. According to the diameter at breast height(DBH), the population was divided into five diameter classes: diameter class 1 (1.0 cm≤DBH<2.5 cm), diameter class 2 (2.5 cm≤DBH<10.0 cm), diameter class 3 (10.0 cm≤DBH<20.0 cm), diameter class 4 (20.0 cm≤DBH<30.0 cm), diameter class 5 (DBH≥30.0 cm). The point pattern method was used to analyze the spatial distribution pattern of P. sheareri and spatial correlation of individuals of different diameter classes.  Result  (1) 68.95% were young individuals in diameter class 1 and diameter class 2, 23.71% in diameter class 3, 7.34% in diameter class 4 and diameter class 5. The survival curve of the population was close to Deevey type I, belonging to the growth-oriented development model. (2) The individuals of diameter class 1, diameter class 2, diameter class 3 and diameter class 4 were mainly distributed in clusters, and with the increase of research scale, the aggregation was more significant, and diameter class 5 was mainly of random distribution. (3) There existed a close relationship between diameter classes, displaying a dominant positive correlation. In small scale observation, diameter class 1 and diameter class 4 were negatively correlated in the scale of 0−5 m, diameter class 3 and diameter class 4 were negatively correlated in the scale of 0−8 m, and diameter class 3 and diameter class 5 were negatively correlated in the scale of 0−4 m. All other diameter individuals were positively correlated. From the large-scale observation, there was a significant positive correlation between individuals of different sizes in P. sheareri population.  Conclusion  The population of P. sheareri in Tianmu Mountain belongs to the growth-oriented development model, and each diameter class is distributed in clusters. The relationship between different diameter classes is close, displaying a dominant positive correlation. [Ch, 5 fig. 2 tab. 24 ref.]
Gene expression of starch decomposing enzymes in Phyllostachys edulis stems during the rapid growth period
LI Qingli, WANG Lingjie, GAO Peijun, WEI Saijun, LÜ Jiaxin, GAO Yan, ZHANG Rumin
, Available online  doi: 10.11833/j.issn.2095-0756.20190661
[Abstract](183) [HTML] (10) [PDF](3)
  Objective  The aim of this study is to reveal the regulating mechanism alpha amylase (AMY) and beta amylase (BAM) and related gene expression of Phyllostachys edulis in the rapid growth period.  Method  The stems of Ph. edulis shoots were used as materials, and the content of non-structural carbohydrates (NSC), AMY and BAM activity, and gene expression of PeAMY and PeBAM were measured at different time (10:00, 14:00, 18:00, 22:00, 2:00, 6:00) and different internodes (7, 10, 13, 16).  Result  The NSC content of bamboo stems was higher in the daytime, and gradually decreased after 18:00. At 2:00, the glucose content in the 7th and 10th internodes decreased by 25.4% and 27.2% (P<0.01), fructose by 50.0% and 34.1%, respectively (P<0.01), sucrose by 49.8% and 27.4%, respectively (P<0.01). Starch content at 6:00 decreased by 27.3% and 23.2%, respectively (P<0.01). The activity and gene expression of BAM were stable in the daytime, increased significantly after 18:00, and gradually decreased before dawn. BAM activity of the 7th, 10th and 13th internodes was 90.5%, 76.7% and 50.5% higher at 22:00 than at 18:00 (P<0.01). The PeBAM gene expression was 1.8, 1.8 and 1.7 times higher at 2:00 than at 18:00 (P<0.01).  Conclusion  During the period of rapid growth, the stem of Ph. edulis grows slowly in the daytime and quickly at night. The development and maturation of stems are promoted from bottom to top. The rapid growth of Ph. edulis is closely related to the expression of PeBAM gene. BAM may play a key role in starch degradation. [Ch, 4 fig. 1 tab. 38 ref.]
Calculation and correction of wood internal cavity area based on radar detection
CHEN Yongping, GUO Wenjing, TANG Qiheng
, Available online  doi: 10.11833/j.issn.2095-0756.20190709
  Objective  The objective of this study is to realize the rapid recognition and quantitative characterization of the internal cavities in wood by evaluating the accuracy and precision of the cavity imaging under radar detection method.  Method  Pinus massoniana and Cunninghamia lanceolata, commonly used in ancient building timber structure, were taken as the research object. Artificial simulation was used to make special-shaped cavities at the end of the logs to simulate the internal damages, and then the radar scanner was used to detect the cavities. The differences between the visual imaging technology and the processing methods such as the Hilbert integral method, single path data extraction and synthesis, and the multi-parameter correction of the image contour were compared and analyzed. The calculation and feasible correction method of wood internal cavity area based on radar detection was proposed.  Result  The internal cavity of P. massoniana and C. lanceolata wood could be recognized rapidly by the radar nondestructive testing technology, but the visual imaging technology had a large error in quantitative evaluation, which required further relevant data processing and correction. The estimated cavity area of the unmodified radar image was smaller than that of the actual one. There was still a certain error between the actual cavity area and the estimated cavity area of the radar image calculated by Hilbert integral method or modified by dielectric constant. The distance between the wood edge and the cavity edge should be corrected according to the formula s3c=(sra)k1k2, that was to say, the dielectric constant obtained by tree species and moisture content in practical application was only one factor in the multi-parameter correction. Therefore, it was difficult for radar scanner to accurately recognize the specific shape of the cavity, regardless of data processing and correction, and further research should be carried out.  Conclusion  The radar detection and correction technology can be applied to the detection of cavities in wood and the error of cavity area identification can be less than 30% by integrating tree species and moisture content values. [Ch, 6 fig. 2 tab. 17 ref.]