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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).
Anti-WSSV effect of inactivated preparation of white spot syndrome virus (WSSV) on Procambarus clarkii
QIU Jieke, LAI Yongyong, XU Yinglei, ZHU Fei
, Available online  doi: 10.11833/j.issn.2095-0756.20220459
  Objective  This study is to explore the protective effect of white spot syndrome virus (WSSV) preparation inactivated by binary ethyleneimine (BEI) on Procambarus clarkii against WSSV infection, so as to provide an effective immune method for the prevention of WSSV.   Method  Starting with the preparation of WSSV inactivation preparations, BEI was applied to inactivate WSSV, immunize P. clarkii by oral and injection methods, and then conduct anti-WSSV infection test.   Result  WSSV could be completely inactivated under BEI treatment for 24 hours. After 7 days of oral immunization with inactivated WSSV, the mortality rate of P. clarkii was significantly decreased. The effect of oral immunization was better than that of injection immunization.   Conclusion  The inactivated WSSV preparation inactivated by BEI for 24 hours is safe for P. clarkii and can significantly reduce its mortality infected with WSSV. [Ch, 2 fig. 3 tab. 19 ref.]
Characteristics of fire behavior in prescribed burning under Pinus yunnanensis forest
WANG Jin, ZHANG Wenwen, WANG Qiuhua, CAO Hengmao, ZHANG Xiyan, BAI Wanhui, LI Xiaona, GAO Guiqing
, Available online  doi: 10.11833/j.issn.2095-0756.20220560
  Objective  Prescribed burning is the most widely used and effective management measure for forest fuels. This study aims to reveal the behavior characteristics of prescribed burning in Pinus yunnanensis forest, so as to effectively clean up the forest land combustibles, reduce the possibility of forest fire, and realize the goal that forest fire management should focus on prevention.   Method  Downhill fire technology was employed as prescribed burning in P. yunnanensis forest. In the early stage of the fire prevention period, field investigation was conducted in the continuous distribution area of P. yunnanensis in Zhaobi Hill, Xinping County in central Yunnan Province, including sample plot setting and prescribed burning test to investigate the characteristics of fuels and record dynamic changes of fire behavior during the burning process, such as fire spreading rate, fireline intensity, flame temperature and height.   Result  In the early stage of fire prevention, the moisture content of surface fuels in the forest was 11.99%−12.06%, which was dry and flammable. The burning test showed that the fire spreading speed was 0.14−0.29 m·min−1, the fireline intensity was 147−332 kW·m−1, the flame temperature was 386−578 ℃, and the maximum flame height was 0.9 m. The parameters of fire behavior differed significantly among different surface fuels (P<0.05), but they were all low-intensity fires. The average under-branch height of P. yunnanensis forest was more than 7 m, and the vertical continuity of surface fuels was poor, so it was difficult for the understory burning flame to spread to the canopy. The unburned land rate accounted for 5% and the overall burning rate was 59.00%−75.00%, which achieved the expected effect and could effectively control combustibles.   Conclusion  The burning and fire spreading speed in P. yunnanensis forest is slow, belonging to stable surface fire, with spreading speed less than 4 km·h−1, and the surface combustibles burn thoroughly. Fireline intensity is less than 750 kW·m−1, which is a low-intensity fire and manually controllable. The average burning rate is 63.05% and the burning effect is good, and the load of flammable and combustible materials can be regulated to prevent forest fires. [Ch, 2 fig. 5 tab. 33 ref.]
Effects of fertilization at different growth stages on yield and quality of Fritillaria thunbergii
ZHOU Shuideng, SUN Jian, JIANG Jianming, SHAO Jiangwei, DENG Huimin, SHAO Qingsong, WANG Zhian
, Available online  doi: 10.11833/j.issn.2095-0756.20220613
  Objective  This study explores the impact of fertilization at different growth stages on yield and quality of Fritillaria thunbergii, a traditional herb from Zhejiang Province, in order to provide scientific guidance in fertilizer application.   Method  The cultivar ‘Zhebei 3’ was used as the material in Hangzhou, Zhejiang Province in October 2021. Experimental groups were set up, including full fertilizer control group, no fertilizer control group and treatment groups without basal fertilizer, seed fertilizer, winter fertilizer, seedling fertilizer or flower fertilizer. The morphological and physiological indexes of ‘Zhebei 3’ at different growth stages were measured, such as plant height, fresh weight, leaf size, soluble sugar, malondialdehyde and antioxidant enzymes. In harvesting period in May 2022, the yield of bulbs was counted and the quality indexes were measured. The changes of nitrogen, phosphorus and potassium in bulbs before and after cultivation were measured.   Result  There were no significant differences in yield and quality indexes among treatment groups without basal fertilizer, seed fertilizer or winter fertilizer. The yield of ‘Zhebei 3’ in the groups without seedling fertilizer or flower fertilizer decreased by 19.15% and 21.58% (P<0.05), and the total content of Peimine and Peiminine decreased by 30.76% and 15.38% (P<0.05). Compared with seed bulbs, the content of nitrogen and potassium in the new bulbs of the treatment groups without basal fertilizer, seed fertilizer or winter fertilizer significantly increased (P<0.05) and phosphorus content significantly decreased (P<0.05). The lack of seed fertilizer or winter fertilizer significantly reduced the phosphorus content of new bulbs (P<0.05), but did not affect the content of nitrogen and potassium. The lack of seedling fertilizer or flower fertilizer significantly reduced the contents of nitrogen and phosphorus in the new bulb (P<0.05), but did not affect the content of potassium.   Conclusion  The deficiency of basal fertilizer, seed fertilizer or winter fertilizer has no significant effect on yield and quality of ‘Zhebei 3’. Under the condition of sufficient basal fertilizer, fertilization before seedling emergence can be appropriately reduced. The lack of seedling fertilizer or flower fertilizer will significantly decrease yield and quality of ‘Zhebei 3’, so the supply of appropriate types of fertilizer should be timely and sufficient at the seedling and flowering stages. [Ch, 1 fig. 6 tab. 24 ref.]
Habitat community characteristics and species diversity of Chimonanthus nitens in Wuxi River Basin, Suichang
ZHANG Chuanying, LI Tingting, GONG Xiaofei, PAN Jiangyan, GONG Zhengyu, PAN Jun, JIAO Jiejie, WU Chuping
, Available online  doi: 10.11833/j.issn.2095-0756.20220570
  Objective  Chimonanthus nitens is a rare wild plant unique to China both for tea and medicine. The wild resources have been seriously damaged with the development of its medicinal function and the increase of market demand. This study aims to explore the structure characteristics and species diversity of the habitat community of C. nitens population, as well as its suitable living environment, so as to provide a scientific basis for the protection, development and utilization of C. nitens population.   Method  Based on the field survey, the typical community of C. nitens was selected in Wuxi River Basin of Suichang, and five 400 m2 plots were set up to investigate and analyze the flora, species composition, community structure and species diversity of the community.   Result  (1) The flora of C. nitens community was dominated by pantropical distributions, disjuncted distribution in East Asia and North America, and northern temperate distribution. The proportions of tropical and temperate genera were 50.70% and 40.85%, respectively, with typical characteristics of mid-subtropical flora. (2) There were 105 species in the 2000 m2 sample plots, belonging to 80 genera and 47 families. The families and genera were rich in species and dispersed in composition. The dominant families were Lauraceae, Rosaceae, Fagaceae, Fabaceae and Rubiaceae. (3) The diameter class structure of C. nitens population and habitat community was an inverted “J” type, indicating a growth type. The top 5 tree species with important values of the arbor layer were Cunninghamia lanceolata (11.67%), C. nitens (11.63%), Castanopsis sclerophylla (9.05%), Loropetalum chinense (7.28%) and Lithocarpus glaber (7.08%). The vertical structure of the community was rich. K-means clustering showed that individuals with DBH≥1 cm in the tree layer could be divided into five forest layers according to the tree height. The main location of the community was in the tree layer Ⅰ [1.0, 4.5) m and tree layer Ⅱ [4.5, 7.0) m. (4) The species diversity index varied greatly in different regions. Margalef index, Shannon-Wiener index, Simpson index, Pielou index and Dominance index were 1.98−3.84, 1.56−2.37, 0.72−0.87, 0.69−0.86 and 1.98−3.85, respectively.   Conclusion  The community of wild C. nitens in Wuxi River Basin of Suichang has rich species composition and complex vertical structure. Small and medium diameter trees account for the vast majority, which is an increasing community with high species diversity as a whole. Under the premise of protecting the existing community habitat, it is suggested to carry out experiments imitating wild cultivation to rationally develop and utilize the wild resources of C. nitens. [Ch, 2 fig. 7 tab. 26 ref.]
Cloning and expression analysis of bHLH6 gene from Phyllostachys edulis
ZHUO Juan, HOU Dan, LIN Xinchun
, Available online  doi: 10.11833/j.issn.2095-0756.20220553
  Objective  The objective is to study the role of PhebHLH6 transcription factor in stress response of Phyllostachys edulis; so as to explore the molecular mechanism of resistance to stress in Ph. edulis.   Methods  Seedlings of Ph. edulis were treated with abiotic stress, including treatments of drought stress, salt stress, salicylic acid (SA) and abscisic acid (ABA). A differentially expressed gene named PhebHLH6 was screened using transcriptome data, and its gene cloning and bioinformatic analysis were performed. Real-time fluorescent quantitative PCR was used to analyze the expression patterns of PhebHLH6 under drought, salt stress and SA and ABA treatments.   Result  The coding region of PhebHLH6 gene had a base of 801 bp, encoding 266 amino acids, including bHLH domain, which was a typical bHLH transcription factor. Tissue-specific expression analysis showed that PhebHLH6 was expressed in nearly all the tissues of Ph. edulis, with the highest abundance at the top of 1.5 m and 3 m shoots. Under drought and high salt stress, the expression levels of PhebHLH6 were strongly induced after 3 h of treatment but significantly down-regulated after 24 h of treatment. Under SA and ABA hormone treatment, the expression levels of PhebHLH6 increased first and then decreased when induced by SA and ABA, with strong SA induction and weak ABA induction.   Conclusion  PhebHLH6 may be involved in the early response pathway to drought and salt stress of Ph. edulis and may play a regulatory role in SA and ABA hormone signaling pathways. [Ch, 4 fig. 2 tab. 32 ref.]
Prediction of the potential distribution pattern of Pinus sylvestris var. mongolica in China under climate change
ZHANG Shilin, GAO Runhong, GAO Minglong, HAN Shumin, ZHANG Wenying, ZHAO Jing
, Available online  doi: 10.11833/j.issn.2095-0756.20220451
  Objective  This study aims to predict the potential distribution and migration of Pinus sylvestris var. mongolica under different climate conditions in China and to determine the main environmental variables affecting its distribution, so as to provide theoretical basis for rational introduction and protection of P. sylvestris var. mongolica.  Method  Based on 200 distribution points and 20 environmental variables, the potential distribution of P. sylvestris var. mongolica under current climate conditions was simulated by using ENMeval packet optimization maximum entropy model (MaxEnt) in R language and ArcGIS spatial analysis technology. Through Person correlation analysis and variance inflation factor (VIF) analysis combined with the screening of environmental factors based on pre-modeling results, Jackknife test and correlation coefficient were integrated to analyze the dominant limiting factors of P. sylvestris var. mongolica, and predict the change trend of suitable habitat under three climate scenarios (SSP126, SSP245 and SSP585) from the current to the future (2050s and 2100s).  Result  The area under ROC curve (AUC) of the MaxEnt model was greater than 0.94, indicating that the model had high accuracy and could better predict the potential distribution of P. sylvestris var. mongolica. The main factors affecting the distribution were the average temperature in the coldest quarter, seasonal variation of precipitation, minimum temperature in the coldest month, seasonal variation coefficient of temperature, average temperature in the driest quarter and maximum temperature in the hottest month, with a cumulative contribution rate of 92.9%. Under the current climate conditions, the suitable distribution area of P. sylvestris var. mongolica was mainly located in the Greater Hinggan Mountains of China, and the total suitable area accounted for 6.72% of the total area of China. In the future, the potential distribution area of P. sylvestris var. mongolica would decrease under different climatic conditions, and the centroid would migrate to the northwest area at high latitude and southwest area with abundant precipitation.  Conclusion  The annual temperature and precipitation are the main factors affecting the distribution of P. sylvestris var. mongolica. At present, the suitable growing areas are mainly concentrated in the Greater Hinggan Mountains of China, and its distribution will migrate to the northwest and southwest of the existing distribution area in the future. [Ch, 1 fig. 7 tab. 29 ref.]
Soil quality assessment of different land use types in Qingshui River Basin of western Shanxi Province
ZUO Qilin, YU Yang, ZHA Tonggang, ZHANG Hengshuo, LIANG Yipeng, OUYANG Jiahuan
, Available online  doi: 10.11833/j.issn.2095-0756.20220498
  Objective  This study aims to explore and evaluate the soil quality under different land use types in Qingshui River Basin in gully regions of the Loess Plateau, and quantify its relationship with environmental factors.   Method  Taking 4 typical site types (agricultural land, forest land, orchard, and irrigated grassland) in the basin as the study site, and based on 9 soil physical and chemical property indicators including soil bulk density, soil mechanical composition, soil nutrient content (organic matter, total nitrogen, total phosphorus, total potassium, and available potassium), principal component analysis and correlation were used to establish a minimum data set (MDS), and the soil quality of different land use types was calculated according to the weighted summation index method.   Result  (1) The contents of organic matter and total nitrogen of each soil layer in the forest land were the highest among the 4 site types. In 0−20 cm soil layer, the bulk density and total phosphorus content of agricultural land were significantly higher than those of other land types (P<0.05). In 0−20 cm soil layer, the available potassium content in forest land was significantly higher than that in other 3 land use types (P<0.05). There was no significant difference in pH among different land use types. The content of organic matter decreased gradually with the increase of soil depth and showed a significant positive correlation with total nitrogen (P<0.05). (2) MDS for soil quality index evaluation included bulk density, sand percentage and available potassium content. The soil quality of the 4 land use types from high to low was forest land, irrigated grassland, agricultural land, and orchard. The soil quality index increased with the increase of altitude.   Conclusion  The overall soil quality of Qingshui River Basin is good, and the soil quality of forest land and irrigated grassland is high, while the soil quality of agricultural land and orchard is relatively low. [Ch, 4 fig. 2 tab. 34 ref.]
Growth variation of Michelia chapensis provenance in different ages and its early selection
WEI Ruping, YAN Shu, ZHENG Huiquan, WANG Runhui, HU Dehuo
, Available online  doi: 10.11833/j.issn.2095-0756.20220357
  Objective  This study, with an investigation of the genetic variation of Michelia chapensis and the correlation between the main growth traits of juvenile trees and those of the adult trees, is aimed to determine the suitable age for the early selection of M. chapensis provenances.   Method  First, two testing forests of M. chapensis provenances with an age range of 3 to 14 planted in Qujiang forest farm and Jiuqushui forest farm, Shaoguan, Guangdong Province were selected for measuring growth traits. Then, an analysis was conducted of the genetic variation of growth traits at different ages with the employment of variance analysis, genetic parameter estimation, correlation analysis and cluster analysis before the suitable age of early selection was determined.   Result  The preservation rate of testing forest had significantly decreased in 11−14 years with significant differences (P<0.01) in tree height, diameter at breast height (DBH) and individual volume among tested provenances at different ages. The provenance effect had a significant impact on growth traits, which was gradually enhanced or tended to stabilize with the increase of age. The range of the provenance heritability for tree height, DBH and individual volume at different forest ages were 0.69−0.90 displaying significant phenotypic and genetic correlations between the early tree height, early DBH or early individual volume and the individual volume at the age of 14. As was shown in the classification and evaluation of provenances using comprehensive index and single index methods, the consistency of high-yield type Ⅰ provenances obtained by the two evaluation methods was very high, but the single index method was relatively easier to operate. Taking the high-yield type Ⅰ provenances selected in 14 years old as a reference, the early selection risk of single index method was lower than that of comprehensive index method. Using the single index method to carry out early selection at the age of 3 and 6 years, the correct selection rate of the two experimental forests was 83%−100% and the missed selection rates of both was 0.   Conclusion  The main growth traits of M. chapensis had rich variation among different provenances and the provenance effect had significant and stable influence on growth traits. The provenance heritability of tree height, DBH and individual volume was medium to high. As a result, for the sake of high-yield provenances, it was feasible to carry out early selection of individual volume during the age of 3−6 years. [Ch, 1 fig. 7 tab. 20 ref.]
Screening and validation of reference genes in Heimia myrtifolia in different tissues and under drought stress
ZHAO Yu, LIN Lin, WANG Qun, ZHANG Guozhe, WANG Jie, SHANG Linxue, HONG Sidan, MA Qingqing, GU Cuihua
, Available online  doi: 10.11833/j.issn.2095-0756.20220342
  Objective  The objective is to study the gene expression of Heimia myrtifolia in different tissues and under different drought stress.   Method  The root, stem, leaf, and flower of H. myrtifolia at full flowering stage and 5 leaves under different drought treatments were selected as experimental materials, and 9 candidate internal reference genes screened from the transcriptome data were analyzed by RT-qPCR. The software geNorm, BestKeeper, NormFinder, and RefFinder were used to comprehensively evaluate the expression stability of candidate reference genes. Finally, 2 stress-related genes CSLD and SOD were selected to verify the selected internal reference genes.   Result  GeNorm, BestKeeper, and NormFinder showed some differences in the ranking of candidate internal parameters. By using the online software RefFinder to comprehensively analyze the results of the above 3 software, it was concluded that GAPDH was the most stable internal reference gene and TUA was the most unstable in different tissues. In drought stress, GAPDH was the most stable internal reference gene and TUB was the least stable. In all samples, the most stable reference gene was GAPDH, and the most unstable one was 18S RNA. The expression patterns of CSLD and SOD genes in different tissues and under drought stress were verified, which showed that the expression levels and change trends of the above 2 genes were consistent with those of the selected internal reference genes.   Conclusion  GAPDH is the best internal reference gene for gene expression of H. myrtifolia in different tissues and under drought treatment. [Ch, 4 fig. 4 tab. 33 ref.]
Effects of soil nutrient heterogeneity on competition between Aegilops tauschii and Triticum aestivum
WANG Ning, FU Yajun, SHAO Jing, XUE Yunyun
, Available online  doi: 10.11833/j.issn.2095-0756.20220370
  Objective   Soil nutrient heterogeneity widely exists in nature, and affects competition among different plant species. This study aims to explore the effects of soil nutrient heterogeneity on competitiveness of invasive plants, so as to provide reference for the study of invasion hazards.   Method   The invasive plant Aegilops tauschii and its main endangered cropTriticum aestivum were used as test materials. Under the conditions of homogenous and heterogeneous nutrients, de Wit substitution experiment was carried out to investigate the impact of soil nutrient heterogeneity on the growth and development of A. tauschii and its competition with T. aestivum, based on plant height, leaf area and biomass.   Result   (1) Soil nutrient heterogeneity promoted the increase of plant height, leaf area and tiller number per plant of A. tauschii andT. aestivum seedlings. In particular, the total biomass of the two plants increased significantly (P<0.05). (2) Under the condition of interspecific competition, the root-shoot ratio of A. tauschii in heterogeneous soil decreased the most, indicating that A. tauschii increased its inhibition on T. aestivum competition by allocating more biomass to the ground surface. (3) Competition balance index showed that the competitiveness of A. tauschii in heterogeneous soil was above 0, and slightly increased compared with that in homogeneous soil, indicating that soil nutrient heterogeneity enhanced the competition of A. tauschii on T. aestivum.   Conclusion   Soil nutrient heterogeneity promotes the growth of A. tauschii seedling, and enhances its competitive inhibition on T. aestivum. [Ch, 5 fig. 1 tab. 46 ref.]
Effects of different ages and positions on fiber morphology and crystallinity of Phyllostachys edulis
NIU Sijie, WANG Na, CUI Baixiang, WANG Chuangui, WU Heng, ZHANG Shuangyan
, Available online  doi: 10.11833/j.issn.2095-0756.20220749
  Objective   This study, with an investigation of the influence of bamboo age and position on the morphology and crystallinity of Phyllostachys edulis fiber, is aimed to provide basic data for the the reasonable selection and efficient utilization of Ph. edulis in the production of pulp, paper, bamboo textile and other industrial products.   Method   With fiber segregation method and common optical microscope measurement method employed, the fiber morphology was determined whereas the relative crystallinity was calculated by Segal method.   Result   Bamboo age was postively correlated with the fiber length of bamboo, 80% of which was between 1 000 and 2 500 µm, belonging with long fiber. The shape of bamboo fiber was less affected by the axial height of bamboo, and the fiber wall cavity ratio and length width ratio had significant differences among the three sampling positions (P<0.05), but there was no obvious change rule, and the fiber length had no significant difference. In radial direction, the fiber length displayed a significant change rule, which was generally reflected as bamboo medium>bamboo green>bamboo yellow. There was no significant relationship between crystallinity and bamboo age, and there was an increasing trend from near yellow to near green in radial direction. Among the factors affecting bamboo fiber morphology, bamboo age had the largest contribution rate and the most obvious influence.   Conclusion   The fiber morphology of Ph. edulis was most affected by the bamboo age, significantly affected by the radial sampling position, and less affected by the axial height. All samples could be used in industrial production, and it is recommended to take the bamboo age as the priority index for raw material screening. [Ch. 6 fig. 6 tab. 22 ref.]
Effect of green waste compost combined decomposed peanut shells and humic acid on seedling emergence of Perilla frutescens
, Available online  doi: 10.11833/j.issn.2095-0756.20220292
  Objective   The objective is to study the effect of decomposed peanut shells and humic acid with different proportions on the improvement of green waste compost products, as well as the impact of the improved green waste compost products as nursery substrate on Perilla frutescen seedling emergence, so as to explore the best proportion of the substrate conducive to P. frutescen seedling.   Method   Using orthogonal design, different mass fractions of the decomposed peanut shells (0, 1.5%, 3.0%) and humic acid (0, 0.3%, 0.6%) were added to the green waste compost products, and the composite effect was observed by measuring physical and chemical properties of the substrate. Based on redundancy analysis (RDA) and membership function method, the effects of improved green waste compost products on seedling emergence were observed through the measurement of germination rate, germination speed and number of seedling leaves per plant, mortality rate, leaf infestation rate and plant infestation rate of P. frutescen.   Result   Adding decomposed peanut shells and humic acid could significantly (P<0.05) reduce the bulk density, pH and EC values, improve the water content and porosity, and increase the mass fractions of total N, total P, NH4+-N , NO3-N, available P, available K and organic matter of green waste compost products. And the composite green waste compost products could significantly (P<0.05) increase the germination rate, germination speed and the number of leaves per seedling, reduce the mortality rate, the percentage of insect damaged plants and damaged leaves of P. frutescen. RDA showed that the percentage of seedling emergence, the percentage of damaged leaves and damaged plants of P. frutescen seedlings were positively correlated with the total porosity, mass fractions of total N, total P, total K and available K of the substrate, but negatively correlated with pH, EC and bulk density of the substrate. The number of leaves per plant of P. frutescen seedlings was positively correlated with mass fractions of total N, total P, total K and total porosity of the substrate, but negatively correlated with pH and bulk density of the substrate. The mortality rate of seedlings was positively correlated with pH, EC and bulk density of the substrate, but negatively correlated with mass fractions of total porosity, total N, total P, total K and available K of the substrate.   Conclusion   The decomposed peanut shells and humic acid can effectively improve the physical and chemical properties of green waste compost products and optimize their quality. The optimized green waste compost products can reduce the death rate of seedlings, and facilitate the rapid emergence and survival of P. frutescen. At the same time, the optimized green waste compost products can significantly reduce the incidence of insect pests, improve insect resistance, and achieve a certain biological control effect. The optimal combination is 3.0% decomposed peanut shells + 0.3% humic acid. [Ch, 2 fig. 5 tab. 27 ref.]
Responses of soil enzyme activities to different defoliation intensities in alpine meadow
ZHANG Zhen, LIANG Haibin, CHEN Youchao, WU Xiaofen, CAI Yanjiang
, Available online  doi: 10.11833/j.issn.2095-0756.20220281
  Objective   This study aims to investigate the effects of livestock defoliation on soil enzyme activities of alpine meadow, so as to provide evidence for revealing the degradation mechanisms of alpine meadow under human disturbance.   Method   Livestock defoliation behaviors, including light-intensity defoliation (LD) and heavy-intensity defoliation (HD) were simulated by cutting plants, and the non-grazed meadow was taken as the control (ck). The activity of enzymes obtained by carbon, nitrogen, and phosphorus, as well as the change characteristics of soil physical and chemical properties were measured.   Result   Generally, the activities of Invertase, β-1,4-glucosidase (BG), and Urease did not show any significant differences under different defoliation intensities, but there was significant time variation. The activity of cellobiohydrolase (CBH) increased in LD treatment (P<0.05), while it decreased in HD treatment. LD treatment also enhanced the activities of leucine aminopeptidase (LAP), β-1,4-N-acetyl-glucosaminnidase (NAG) and acid phosphatase (AP). Defoliation behavior of livestock might affect soil enzyme activity by changing soil nutrients. The temporal variation of soil enzyme activity in alpine meadow was controlled by the changes of soil temperature and soil nutrients.   Conclusion   Mild defoliation behavior may increase soil hydrolase activities, which helps maintain soil quality. [Ch, 3 fig. 4 tab. 44 ref.]
Purification effects of different combinations of ornamental aquatic plants on eutrophic water
CHI Minghong, LIU Min, XU Yingchun, JIN Qijiang, WANG Xiaowen, WANG Yanjie
, Available online  doi: 10.11833/j.issn.2095-0756.20220446
  Objective  The objective is to study the purification effects of aquatic ornamental plants on eutrophic water bodies.   Method  From late April 2020, different planting combinations were carried out with the water-holding plants Lythrum salicaria, Iris pseudacorus and Scirpus validus, the floating plants Nymphoides peltatum and Nymphaea tetragon, and the submerged plant Ceratophyllum demersum to compare their growth in water with 3 different levels of eutrophication: low, medium and high, and the water purification effects of removing total phosphorus(TP), total nitrogen(TN), ammonia nitrogen(NH3-N) and reducing chemical oxygen demand (COD ). TP, TN, NH3-N and COD of the 3 experimental water bodies were 2.00, 0.20, 0.67, 20.00 mg·L−1, 10.00, 1.00, 3.34, 50.00 mg·L−1, and 20.00, 2.00, 6.67, 100.00 mg·L−1).   Result  (1) S. validus grew well in the eutrophic water body with low mass concentration, while L. salicaria and I. pseudacorus grew better in the treatment of medium and high mass concentration than in the treatment of low mass concentration. N. peltatum grew faster and better than N. tetragon , but it might affect the growth of combined plants. C. demersum grew weaker in combination with N. peltatum than with N. tetragon. (2) In the low concentration treatment, the S. validus, N. tetragon and C. demersum algae group had a better ability to remove TP from eutrophic water body in the early stage, with a removal rate of 47.57%. The combination of I. pseudacorus, N. tetragon and C. demersum algae had the best purification effect in the late stage, with a TP removal rate of 74.59%. In the medium and high concentration treatment, both the I. pseudacorus, N. tetragon and C. demersum algae group and S. validus, N. tetragon and C. demersum algae group had good TP removal effects. (3) In the low concentration treatment, the two planting combinations with S. validus had better removal effects, reaching 30.00% or more. In the medium concentration treatment, the TN removal effect of S. validus, N. tetragon and C. demersum algae group was better. I. pseudacorus, N. tetragon and C. demersum algae had good purification effect in the treatment of low, medium and high concentrations. (4) In the low concentration treatment, the group of S. validus, N. peltatum and C. demersum algae had the best effect of removing NH3-N, with a removal rate of 14.03%. In the medium concentration treatment, the group of L. salicaria, N. tetragon and C. demersum algae had the best purification effect, reaching 4.09%. In the high concentration treatment, both I.pseudacorus, N. tetragon and C. demersum algae group and S. validus, N. tetragon and C. demersum algae group had the best purification effect. (5) In the low concentration treatment, the effect of S. validus, N. tetragon and C. demersum algae group on COD removal was the best, up to 108.33%. The group of I. pseudacorus, N. tetragon and C. demersum algae had good purification effect in the treatment of low, medium and high concentrations, and the removal rates were 115.00%, 46.00% and 41.50% respectively.   Conclusion  The group of I. pseudacorus, N. tetragon and C. demersum has good purification effects in eutrophic water bodies of different concentrations and has high landscape application value. It proves to be the best planting combination. [Ch, 4 fig. 6 tab. 25 ref.]
Stoichiometric characteristics and influencing factors of soil C, N and P in Pinus yunnanensis forests under different restoration modes on rocky desertification slope land in eastern Yunnan
LIANG Chuxin, FAN Tao, CHEN Peiyun
, Available online  doi: 10.11833/j.issn.2095-0756.20220417
  Objective  The objective is to study the stoichiometric characteristics of soil carbon (C), nitrogen (N) and phosphorus (P) of Pinus yunnanensis under different vegetation restoration modes, so as to provide the basis for vegetation restoration and fertility improvement in karst rocky desertification areas.  Method  Pure forest, artificial mixed forest and natural secondary forest of P. yunnanensis were selected as research objects in the rocky desertification area of eastern Yunnan. The contents of C, N and P in 0−10, 10−20, 20−40 and 40−60 cm soil layers of various plots were measured , the stoichiometric ratio was calculated and the influencing factors of soil stoichiometric characteristics were analyzed with redundancy analysis tools.  Result  The average contents of soil C, N and P of P. yunnanensis vegetation were 2.94, 0.26 and 0.46 g·kg−1, showing a pattern of low C and low N. The soil organic C content in natural secondary forest was significantly higher than that in artificial mixed forest and pure forest (P<0.05), and the artificial mixed forest had the richest soil N and P contents. There was no significant difference in soil P content (P>0.05). Soil organic C content in natural secondary forest increased with soil deepening, while soil C and N contents in artificial mixed forest and pure forest reached the maximum in 0−10 cm soil layer, showing a surface aggregation. The soil P content had little variation in different soil layers of P. yunnanensis. The mean values of soil C/N, N/P and C/P in P. yunnanensis vegetation were 11.43, 0.59 and 4.53, and the values of soil C/N and C/P in natural secondary forest were significantly higher than those in pure forest and artificial mixed forest (P<0.05). The soil N/P ratio in pure forest was the greatest. In the 3 P. yunnanensis vegetation types, the soil N/P ratio was less than 14 and the litter N/P ratio was less than 25, so soil N was deficient and litter decomposition was also limited by N. The natural secondary forest was the most deficient in soil N. With the deepening of soil, the soil C/N ratio in artificial mixed forest and pure forest decreased, so did the soil N/P ratio and C/P ratio of the 3 P. yunnanensis vegetation. The stoichiometric characteristics of soil C, N and P in the study area were affected by the litter C/N ratio, soil macroaggregates, bulk density, porosity, root length density and other environmental factors.   Conclusion  The vegetation soil of P. yunnanensis in eastern Yunnan presents a pattern of low C and low N, which is mainly limited by N elements. It is suggested that mixed forest should be used instead of pure forest in vegetation restoration of P. yunnanensis, and fertilization should be applied to vegetation with limited elements. [Ch, 4 fig. 3 tab. 33 ref.]
Research progress on the role of reactive oxygen species in seed germination
LI Min, HE Yong
, Available online  doi: 10.11833/j.issn.2095-0756.20220681
Seed is the most basic resource for agricultural production. The germination of seeds is essential for plant growth and development, and affect crop yield and quality. Reactive oxygen species (ROS) are multifunctional compounds that play a key role in seed germination. In this study, the species, production site and“oxidation window”effect of ROS on seed germination were introduced, the mechanism of ROS regulation on seed germination was summarized. Current studies on ROS regulation of seed germination mainly focus on: (1) When these conditions are permissive for germination, ROS levels are maintained at a level which triggers cellular events associated with germination, such as inducing of GA signaling and inhibition of ABA signaling. (2) However, when seeds are exposed to abiotic stresses, the over accumulation of ROS induces ABA signaling, promotes oxidative damage and thus inhibits seed germination. Moreover, the release of seed dormancy by ROS would be related to oxidation of biomacromolecule, the weakening of seed coat and recession of endosperm. The present review would shed a new light on the signalling roles of ROS in seed physiology. The scope of “oxidation window”which plays a positive role in seed germination should be further explored in future research, and transcriptomics and metabolomics techniques should be combined to screen genes related to the regulation of ROS content in seed germination, so as to better understand the mechanism of ROS promoting seed germination. [Ch, 3 fig. 1 tab. 94 ref.]
Screening and physiological characteristics of storable Oryza sativa germplasm resources
DING Yunqian, ZHU Qingxiang, TANG Zhenghao, JIN Peng, LI Xinze, WANG Xiaomin, ZHAO Guangwu
, Available online  doi: 10.11833/j.issn.2095-0756.20220594
  Objective  This study, with an investigation of the seed storability, an important trait closely related to seed value, provenance and food security, of rice (Oryza sativa), is aimed to survey the storability characteristics of rice seeds so as to promote the conservation of rice germplasm resources and the protection of national food security.  Method  Based on 220 rice cultivars, after 5−6 years of natural aging, rice varieties with good storage tolerance were selected employing laboratory standard germination experiment before the physiological characteristics of different cultivars were determined.  Result   (1) With the prolongation of natural aging time, the germination rate and germination potential of different rice cultivars showed a trend of gradual decrease. (2) Compared with the initial seed quality, the germination rates of conventional japonica rice, conventional indica rice and hybrid indica rice decreased by 62.2%, 23.4% and 45.3% on average, respectively whereas the germination potential decreased by 55.0%, 38.1% and 50.7% on average. (3) Based on the evaluation criteria (varies with a decrease in germination rate <5% and a decrease in germination potential <15% are regarded as storable cultivars), storable conventional japonica rice represented by ‘Nanjing 44’ ‘Shendao 18’ and ‘Tiandaofeng’ were screened out along with storable conventional indica rice represented by ‘Wanxian 35’ ‘Ganwannuo 7’ and ‘Yongxian 69’; the storable hybrid rice represented by ‘Liangyoupeijiu’ ‘Zhongzheyou 1’ and ‘Jingliangyou Huazhan’. (4) It was further found that ‘Nanjing 44’ ‘Shendao 18’ ‘Tiandaofeng’ ‘Ganwanxian 35’ ‘Ganwanuo 7’ ‘Yongxian 69’ ‘Liangyou Peijiu’ ‘Zhongzhenyou 1’ and ‘Jingliangyou Huazhan’ had the characteristics of high amylase activity, high antioxidant enzyme activity, high proline content and low MDA content.   Conclusion  In terms of the storability and physiological characteristics, ‘Nanjing 44’ ‘Shendao 18’ ‘Tiandaofeng’ ‘Ganwanxian 35’ ‘Ganwannuo 7’ ‘Yongxian 69’ ‘Liangyoupeijiu’ ‘Zhongzheyou 1’ ‘Jingliangyou Huazhan’ are recommended and storable germplasms, providing new resources for the future selection of rice cultivars with storage tolerance. [Ch, 2 fig. 6 tab. 40 ref.]
Effects of mineral conditioner on the yield of sweet potato and ecoenzymatic stoichiometry in a hilly red soil
YU Jinzhu, WU Chenchen, JI Haonan, LI Songhao, WU Qifeng, QIN Hua, CHEN Junhui
, Available online  doi: 10.11833/j.issn.2095-0756.20220487
  Objective  With a field survey, this study is aimed to investigate the responses of sweet potato (Ipomoea batatas) yield, soil microbial biomass, enzyme activity and stoichiometry to mineral conditioner application and determine the main factors affecting the status of soil microbial nutrient limitation so as to provide a theoretical basis for improving the fertility of hilly red soil in Southern China.   Method  With a non-amended control (ck), a mineral conditioner amendment which was prepared from a mixture of dolomite and potassium feldspar, was applied at 3 t·hm−2 (W1) and 6 t·hm−2 (W2), respectively.   Result  Compared with ck, the application of mineral conditioner significantly decreased soil exchangeable acid content(P<0.05); The W2 treatment significantly increased soil pH, available nitrogen (N) and available phosphorus (P) contents(P<0.05), but had no significant effect on the yield of sweet potato; Compared with ck, W1 and W2 significantly increased soil microbial biomass nitrogen (MBN) and carbon (MBC) (91.1% and 67.1%, respectively, P<0.05), while both of them increased the ratio of microbial biomass nitrogen/phosphorus ratio (MBN/MBP) (148.2% and 131.8%, respectively, P<0.05); Compared with ck, W1 and W2 significantly reduced the activity of acid phosphatase (by 31.9% and 45.4%, respectively, P<0.05), and W2 treatment significantly reduced the activity of leucine aminopeptidase (by 52.4%, P<0.05), but they had no significant effect on the activities of β-glucosidase, cellobiohydrolase and β-1,4-N-acetylglucosaminidase; Soil enzymatic stoichiometry showed that W2 significantly increased the vector length (by 19.7%, P<0.05) and reduced the vector angle (by 10.5%, P<0.05), indicating that the high amendment rate of mineral conditioner increased microbial C limitation and alleviated their P limitation. As was shown by redundant analysis, soil pH, available N, MBC and MBN were the main factors affecting soil enzyme activity and its stoichiometry.   Conclusion   The application of mineral conditioner can effectively reduce soil acidity, increase the available nutrient content, and alleviate soil microbial P limitation, thereby helping to potentially reduce the P limitation to crop growth in hilly red soils from Southern China. [Ch, 3 fig. 2 tab. 32 ref.]
Growth regulation characteristics of current-year shoots of Fraxinus sogdiana in Yili River Valley
LI Dongyu, YU Yu, XU Shun, WEN Bingxia, SHI Rukang, HAN Dayong
, Available online  doi: 10.11833/j.issn.2095-0756.20220243
  Objective  The current-year shoots, as the main parts of woody plants for population spatial expansion, fruiting and photosynthesis, are the most vigorous modulars and reflect the important ecological characteristics of population evolution and adaptive regulation. Therefore, this study, with an investigation into the growth regulation characteristics of current year branches, is aimed to reveal the adaptive mechanism of plant population.   Method  An analysis was conducted of the allometric growth relationships among the modulars of three types of shoots (long shoot, medium shoot and short shoot) of Fraxinus sogdiana, a plant of second-class protection in China, so as to explore the functional differences of different types of branches and their roles in population adaptation and regulation.   Result  Leaves and stems of different types of shoots are featured with different growth rules with allometric growth on long shoot and medium shoot (slope was 1.170 and 1.135 respectively), and isokinetic growth on short shoot (slope was 0.657) in terms of total leaf area and stem biomass. Isokinetic, allometric and isokinetic growth rules apply on long shoot, medium shoot and short shoot when it comes to the relationship between leaf biomass and stem biomass with the slope of regression equation being 1.460, 0.908 and 0.840 respectively. The long shoot and the medium shoot had higher leaf growth ability and mainly functioned in the expansion of space and photosynthetic production whereas the short shoot was more involved in the sexual reproduction process. Leaf rachis can also regulate leaf growth, making up for the lack of stem support efficiency for leaf area on medium shoot and short shoots, yet with no obvious effect on long shoots.   Conclusion  The long and medium shoots of F. sogdiana have higher leaf support efficiency, and their functions are not only reflected in expanding the population growth space, but also in higher photosynthetic production capacity. The current year shoots of F. sogdiana demonstrate more complex functional differentiation, with their roles in population adaptation regulation being more diverse, implying that shoot types should be considered in future studies dealing with the characteristics of plant growth regulation with dimorphic shoots. [Ch, 3 fig. 3 tab. 37 ref.]
Spatial pattern and correlation of Malus sieversii population in Emin County
CAO Ling, JIN Shengkang, Yeerjiang Baiketuerhan, Nuersiya Abuduresuli, CHE Chang
, Available online  doi: 10.11833/j.issn.2095-0756.20220267
  Objective  This study, with an investigation of the spatial distribution pattern and correlation of Malus sieversii population in Emin County, Tacheng Prefecture of Xinjiang, is aimed to explore its biological characteristics so as to provide a scientific basis for the restoration and sustainable management of M. sieversii population in this area.   Method  First, employing the typical sample plot investigation method, an investigation was conducted of the individuals of M. sieversii in 20 blocks (30 m×30 m) with diameter class structure used instead of age structure and univariate function and bivariate function analysis methods adopted in point pattern analysis. Then, a study was carried out of the spatial distribution pattern and its correlation of M. sieversii individuals with different age classes.   Result  (1) The age structure of M. sieversii population presented an atypical pyramid like a spindle, with poor regeneration and unstable population structure. (2) The individual parts of M. sieversii with younger age showed aggregation distribution with the tendency to become random with the increase of age. (3) The spatial relevance of individuals with similar age is positively correlated or not significantly correlated whereas with the increase of the gap between individuals’ ages, the spatial relevance was mostly non-correlated.   Conclusion  The population structure of M. sieversii in Emin County is unstable, and the spatial correlation between individuals of different age classes is not strong. Therefore, efforts should be focused on the enhancement of tending management and the change of their existing random distribution state through artificial planting and other methods, so as to make them aggregate and grow and promote the stable growth of local M. sieversii population and resource recovery. [Ch, 3 fig. 1 tab. 35 ref.]
Research progress on application effect of orchard waste biochar in orchard
ZHANG Bi, FANG Xianzhi, MA Jiawei, WU Yuping, PAN Xian, YE Liting, LIU Dan, YE Zhengqian
, Available online  doi: 10.11833/j.issn.2095-0756.20220535
Treatment of orchard waste is an important link in orchard production. The carbonization of orchard waste is a green, environmentally friendly and low-carbon mode of production, which can improve orchard soil, as well as yield and quality of fruits. Therefore, it’s of great scientific significance and application value to carry out research on orchard waste biochar for its rational application and evolution in orchard. The current research on biochar from orchard wastes was reviewed, which mainly focused on the preparation principle and properties of biochar from different types of orchard wastes and the effects on soil improvement, and the impact of its application combined with organic fertilizer on orchard production. The future research directions are proposed: (1) To further classify the orchard wastes to prepare more biochar to meet the differentiated needs. (2) To compare the production benefits of different types of orchard waste biochar application. (3) To prepare biochar-based organic fertilizer for orchard. (4) To explore the effect of orchard waste biochar on orchard environment and ecology. [Ch, 1 fig. 2 tab. 94 ref.]
Spatial and temporal evolution of Nanjing’s urban green space pattern and its influencing factors
XU Hao, LI Wei, LIU Wei, WANG Chengkang
, Available online  doi: 10.11833/j.issn.2095-0756.20220332
  Objective   The urban green space is not only an important part of the regional ecological environment, but also an important bearing space for suburban recreation and a structural space that restricts the infinite spread of the city. Therefore, this study, with an investigation of the dynamic landscape changes of green space in Nanjing, a mega city in the Yangtze River Delta and its influencing factors, is aimed to help further optimize the spatial structure of green space and regional sustainable development. In Nanjing so as to promote the sustainable development of the Yangtze River Delta region.   Method   With the land cover data of Nanjing City in five time nodes in 2000, 2005, 2010, 2015 and 2020 selected, an analysis was conducted of the spatio-temporal evolution pattern of the green space in Nanjing City employing dynamic degree calculation and landscape pattern index. Then, the partial least squares regression equation (PLSR) model was adioted to explore the impact of socioeconomic factors and natural factors on the evolution of green space pattern.   Result   From 2000 to 2020, there was first a decrease and then an increase in the green space in Nanjing. From 2000 to 2005, the green space patches in Nanjing City tended to be integrated, with the fragmentation of green space landscapes easing up. After 2005, the scale of urban green space has increased, with an obvious fragmentation trend and a steady decrease in the overall landscape connectivity, The regression model showed that among the socioeconomic factors, the proportion of the industrial structure, the green area of the built-up area and the changes in the urban green space pattern had a greater correlation, and there were differences in the force of natural factors.   Conclusion   The overall scale of green space in Nanjing has increased with an obvious trend of pattern fragmentation and the socioeconomic factor being the direct influencing factor in the evolution of urban green space spatial pattern which is subject to the restriction of many natural factors. There is an urgent need to strengthen systematic planning for regional green spaces. [Ch, 5 fig. 6 tab. 29 ref.]
Spatial-temporal evolution process of rocky desertification in Yunnan Province from 2000 to 2020
CHEN Qi, ZHANG Chao, TIAN Xiangyun, SHI Xiaorong, ZHANG Yuwei, WANG Yan
, Available online  doi: 10.11833/j.issn.2095-0756.20210806
  Objective  This study aims to identify and extract information of rocky desertification patches at macroscopic scale by remote sensing tools and quantitatively analyze the spatial distribution characteristics and temporal evolution process of rocky desertification, so as to provide technical means and data support for the study of the occurrence process and development of rocky desertification in southwest China.   Method  Information of rocky desertification patches in Yunnan Province in 2000, 2010 and 2020 was extracted quantitatively by decision tree classification method based on Google Earth Engine platform. The spatial-temporal evolution model was used to analyze the spatial-temporal evolution process and characteristics of rocky desertification.   Result  (1) The overall rocky desertification situation in Yunnan Province was improved during the study period but still deteriorated in some areas. The ratio of rocky desertification to land area decreased from 9.65% to 6.48%. (2) The spatial distribution of rocky desertification in Yunnan Province was characterized by more in the east and less in the west, and the major distribution areas were Zhaotong, Qujing, Wenshan, Honghe and Kunming, accounting for 65.42%−72.14% of the occurrence area of rocky desertification in the whole province. (3) The evolution of rocky desertification tended to be complex, which shifted to both high grade and low grade of rocky desertification, and the phenomenon of destruction while treatment was not curbed. (4) Most of the extremely severe rocky desertification has shifted to severe rocky desertification in the past 20 years, indicating that it would take a long time for the extremely severe rocky desertification to be restored. (5) The internal evolution process of rocky desertification was intense, and the comprehensive change rate of light rocky desertification and moderate rocky desertification was fast. It was easy to improve but also had a higher risk of deterioration.   Conclusion  The relevant protocols are used as criteria for determining the grade of rocky desertification, and the macro-scale information of rocky desertification patches can be accurately extracted by decision tree classification method. The area of rocky desertification in Yunnan Province is decreasing, with uneven spatial distribution and mutual transformation among different grades of rocky desertification. [Ch, 3 fig. 4 tab. 25 ref.]
Callus induction and morphological and cytological observation of unpollinated ovules of Camellia oleifera
JIN Haoran, YANG Shanwei, YUAN Leihuizi, PAN Qian, HOU Silu, FAN Xiaoming, YUAN Deyi
, Available online  doi: 10.11833/j.issn.2095-0756.20220507
  Objective  The objective is to screen the optimal medium suitable for callus induction from unpollinated ovules of Camellia oleifera, and explore the origin and developmental process of callus by cytological observation, so as to provide data reference for haploid breeding of C. oleifera.   Method  C. oleifera ‘huajin’ was used as the test material to screen the optimal medium formula for inducing callus from unpollinated ovule, and to study the basic medium types MS, WPM, MT, 1/2MS, and B5, as well as effects of plant growth regulator concentration such as auxins NAA, IAA, IBA, and 2,4-D, and cytokinins 6-BA, KT, and TDZ on callus induction. Calluses with different external morphology were selected for paraffin section, and their origin and development process were studied according to the ploidy identification results of flow cytometry.   Result  MS was used as the basic medium, and the highest induction rate was 92.97% when 1.0 mg·L−1NAA+2.0 mg·L−1 TDZ+40 g·L−1 sucrose was added. NAA and TDZ had significant effects on the induction rate(P<0.05), and the impact of TDZ was greater than that of NAA. The embryogenic callus was light green granular, with cytological characteristics of close arrangement, large nucleus, and ploidy identification of hexaploid.  Conclusion  The optimal medium for inducing embrygenic callus from unpollinated ovules of C. oleifera is MS+40 g·L−1sucrose +7 g·L−1 AGAR +1.0 mg·L−1 NAA+2.0 mg·L−1 TDZ. The callus is formed by dedifferentiation of outer integument cells. A relatively stable and efficient technical system for inducing embryogenic callus from unpollinated ovules of C. oleifera is obtained, providing a reference for further establishing a complete and efficient system for somatic embryogenesis and haploid breeding of C. oleifera. [Ch, 4 fig. 3 tab. 33 ref.]
Spatiotemporal evolution of ecological security pattern and its influencing factors in Tianshan-Pamir region
DENG Zhuo, LI Wenjing, ZHANG Yufang, DONG Ye
, Available online  doi: 10.11833/j.issn.2095-0756.20220458
  Objective  Tianshan-Pamir region, with its unique geographical location and rich and diverse ecosystems, plays an important role as a barrier to China’s ecological security. However, great changes had taken place in the regional economy and ecological environment in the past 30 years, and it is urgent to carry out research on the spatiotemporal evolution of ecological security pattern and its influencing factors in Tianshan-Pamir region under natural and human pressure.   Method  Taking Tianshan-Pamir region as the study area, 20 key indicators were selected to analyze the ecological security and its influencing factors in the region from 1990 to 2018 by using the pressure-state-response (PSR) model and geographical detector method.   Result  The distribution pattern of regional ecological security in this region did not change significantly, but the ecological security levels of different cities and counties varied greatly. From 1990 to 2018, the area with ecological security of level Ⅲ or above accounted for 60% or more and reached 80% in 2010, indicating significant improvement of regional ecological environment. 5 factors among them had a relatively stable impact on the ecological security of the region, while other factors had different impacts. The influence of the 3 subsystems from large to small was response, pressure and state, and the change trend of state index and pressure index was similar.   Conclusion  The ecological security in Tianshan-Pamir region is gradually improving, but there are still some damage phenomena. Among them, Bole City, Jinghe County, Wenquan County, and Tashkurgan Tajik Autonomous County have significantly improved their ecological security status, and the improvement of response capacity has a great contribution to alleviating ecological pressure. [Ch, 4 fig. 4 tab. 32 ref.]
Difference in water use sources of Eucalyptus urophylla×E. grandis plantation in the Leizhou Peninsula during dry and rainy seasons
WANG Zhichao, XU Yuxing, ZHU Wankuan, DU Apeng
, Available online  doi: 10.11833/j.issn.2095-0756.20220481
  Objective  The objective is to explore the water use strategies of eucalyptus plantations to adapt to seasonal drought, so as to provide data support for assessing the impact of future rainfall patterns on eucalyptus industry and accurately guiding the sustainable management of eucalyptus industry and efficient use of water resources.   Method  Eucalyptus urophylla × E. grandis, the most widespread eucalyptus species in the Leizhou Peninsula, was taken as the research object. The differences in water use sources during dry and rainy seasons were discussed in depth by measuring the δD and δ18O values of xylem water, soil water in each soil layer and groundwater during typical dry and rainy seasons, and the MixSIAR model was used to quantify the utilization proportion of soil water and groundwater in each soil layer by E. urophylla × E. grandis in dry and rainy seasons.   Result  There was an obvious evaporative enrichment in local atmospheric precipitation, and the δ18O value showed a clear seasonal pattern of negative in rainy season and positive in dry season. Soil moisture content in each month increased with the depth and eventually became stable. Soil moisture content was significantly lower in dry season than in rainy season (P<0.05), and the difference was even greater close to the surface. E. urophylla × E. grandis mainly used 0−40 and 40−100 cm soil water in rainy season, with the utilization ratio of 28.0% and 24.3% respectively. In dry season it mainly used 50−200 cm soil water and groundwater, with the utilization ratio of 29.9% and 22.6% respectively. After a large amount of precipitation in dry season, soil water, especially shallow soil water, was greatly replenished, and the proportion of surface soil water used by E. urophylla × E. grandis in the 0−40 and 40−100 cm layers increased by 111.4% and 10.3% respectively, while the utilization proportion of 100−150 and 150−200 cm soil water and groundwater decreased by 3.1%, 40.1% and 15.9%, respectively.   Conclusion  E. urophylla × E. grandis has a flexible water use source strategy in the face of changes in environmental available water resources, indicating that it has strong adaptability to seasonal drought. [Ch, 5 fig. 1 tab. 44 ref.]
Effects of light intensity on growth, chemical composition and antioxidant activity of Isatis indigotica
LI Xinyao, HUANG Jiabin, GUO Qiaosheng, LIU Lijun, GONG Min, SU Yong, LU Lixian, ZHAO Kun
, Available online  doi: 10.11833/j.issn.2095-0756.20220263
  Objective  The present study, with an exploration of the effects of light intensity on growth of Isatis indigotica, and chemical composition, antioxidant activity of isatidis folium, is aimed to provide reference for the artificial cultivation of I. indigotica.   Method  With seedlings of I. indigotica planted under 100%, 60% and 20% of full sunlight, their growth indexes were measured at the vigorous growth period, whereas chemical compounds such as indigo, indirubin, total flavonoids, total polysaccharides and total free amino acid, as well as antioxidant activity were determined after harvest.   Result  The growth of leaves was positively correlated with the light intensity, and the plant height, leaf length, leaf width, number of leaves, and the single leaf area in 100% of full sunlight treatment were the largest. Indigo, total flavonoids and total polysaccharides of isatidis folium were decreased with the decrease of light intensity, and there were significant differences among three groups (P<0.05). Indirubin showed a trend of increasing first and then decreasing, with that of the 60% of full sunlight treatment being the highest (P<0.05), yet no significant differences between the ones of 100% and 20% of full sunlight treatment. The total free amino acid was negatively correlated with light intensity and increased with the decrease of light intensity. The antioxidant activity was positively correlated with the light intensity and the IC50 (half maximal inhibitory concentration) for DPPH of 20% of full sunlight treatment was significantly higher than that in 60% and 100% of full sunlight treatment (P<0.05).   Conclusion  The 100% of full sunlight treatment was the optimum light intensity condition to achieve high yield and intrinsic quality of isatidis folium, which is more conducive to the cultivation of isatidis folium than the 60% and 20% full sunlight treatment. [Ch, 8 tab. 39 ref.]
Cloning and expression characteristics of LiCMB1 gene in Lagerstroemia indica
SHANG Linxue, WANG Qun, ZHANG Guozhe, ZHAO Yu, GU Cuihua
, Available online  doi: 10.11833/j.issn.2095-0756.20220333
  Objective  The LiCMB1 gene of Lagerstroemia indica was cloned, and its expressions in different stages of flower bud differentiation and different tissues and organs were analyzed, so as to explore the expression characteristics of LiCMB1 gene.   Method  The gene sequence of LiCMB1 was cloned from L. indica by simple cloning technology. Physical and chemical properties of the protein were analyzed by online tools including ExPasy, and phylogenetic tree was constructed by MEGA 6.0 software. Combined with the phenotypic observation and paraffin section of L.indica flower bud differentiation, the expressions of LiCMB1 gene in different stages of flower bud differentiation and different tissues and organs were analyzed by real-time quantitative PCR (RT-qPCR).   Result  LiCMB1 gene belongs to SEP gene of MADS-box family, except for typical MADS_ MEF2_ like and K-box structure domain, there is also a SEP motif conserved motif near the C-end. The results of RT-qPCR showed that the expression trend of LiCMB1 increased first and then decreased in the process of flower bud differentiation of L. indica. It is expressed in different tissues and organs, and the expression levels of LiCMB1 from high to low were in the order of pistil, sepal, bud, long stamen, short stamen, petal, leaf, stem, root, indicating that LiCMB1 may play an important role in flower bud differentiation and participate in the regulation of flower organ development.   Conclusion  LiCMB1 gene belongs to the SEP gene of MADS-box family. It plays an important role in the early stage of flower bud differentiation of L. indica, especially in the calyx differentiation period. Tissue specificity analysis indicated that it was likely involved in the regulation of floral organ development. [Ch, 7 fig. 28 ref.]
Changes of soil organic carbon storage and carbon components in typical meadow communities in Napahai
LIU Pan, LU Mei, LI Cong, LÜ Jinghua, YANG Zhidong, ZHAO Xuyan, CHEN Zhiming
, Available online  doi: 10.11833/j.issn.2095-0756.20220377
[Abstract](51) [HTML] (1) [PDF](779)
  Objective  This study aims to explore the change characteristics of soil organic carbon(SOC) components in typical meadow wetlands of Napahai caused by different groundwater levels and their coupling relationship with environmental factors, so as to provide data support for understanding the process of soil carbon cycle in plateau wetlands.   Method  3 typical meadow communities of different underground water levels were selected as the research objects in Napahai Wetland in November 2020. The concentration of soil microbial biomass carbon(MBC) and total organic carbon(TOC), easily oxidized carbon(EOC), and particle organic carbon(POC) as well as the distribution pattern of carbon pool along soil profile were compared. The relationship between carbon components, plant diversity and soil physicochemical factors was analyzed.   Result  The total soil carbon stocks of different meadow communities (0−40 cm soil layer) ranking from high to low were Poa pratensis community (47.55 t ·hm−2), Carex nubigena community (42.28 t ·hm−2), and Gnaphalium affine community (32.14 t ·hm−2), which decreased along the deepening of soil layers. Soil TOC storage decreased the most in G. affine community. Soil TOC, MBC, EOC and POC decreased with the decrease of groundwater depth, ranging from1.8 to 3.4 times. SOC component decreased by 1.0−3.4 times along the deepening of soil layer in the communities of P. pratensis, C. nubigena and G. affine. Plant biomass, Shannon-Wiener diversity index of plant community, Pielou evenness index, Margalef richness index and Simpson dominance index all decreased by 1.5−2.8 times along the decrease of groundwater depth. Soil water content (SWC), pH and total phosphorus (TP) contents also significantly decreased with decreasing depth of groundwater. RDA redundancy and Pearson correlation analysis showed that aboveground biomass, SWC, soil bulk density(SBD), total nitrogen(TN), and TP had the strongest response to the change in groundwater depth, and were the controlling factors affecting changes of SOC components in typical meadow communities in Napahai.   Conclusion  The mass fraction and vertical distribution of SOC components in typical meadows of Napahai wetland mainly depend on the change of plant aboveground biomass and soil physicochemical properties caused by different groundwater depths. Therefore, in the process of protecting typical meadow wetlands in Napahai, it is recommended to monitor the groundwater level to prevent the impact of low groundwater level from affecting the stability of wetland carbon pool. [Ch, 3 fig. 4 tab. 42 ref.]
Identification of Ph-TElncRNA1 in Phyllostachys edulis and its regulation of target genes
ZHAO Jiamin, YU Lu, DING Yiqian, ZHOU Mingbing
, Available online  doi: 10.11833/j.issn.2095-0756.20220396
  Objective   The purpose of this study is to explore the expression patterns of Ph-TElncRNA1 and target genes in Phyllostachys edulis, and to preliminarily analyze the function of lncRNA.   Method   Based on the whole transcriptome sequencing data of Ph. edulis seedlings under high temperature, low temperature, ultraviolet and high salt stress, lncRNAs differentially expressed under stress were screened. The coding characteristics of lncRNA were analyzed by four kinds of software(CNCI, Pfam, CPC2 and PLEK), and the target genes of lncRNA were identified by LncTar software. The expression patterns of lncRNA and target genes under UV stress and leaf coloration were analyzed by real-time fluorescent quantitative PCR.   Result   One differentially expressed lncRNA under UV stress was screened, which was derived from the lncRNA of the Large retrotransposons derivatives and named Ph-TElncRNA1(Ph. edulis transposable element derived lncRNA1). Ph-TElncRNA1 was a typical non-coding RNA with a total length of 342 bp, 185 bases from exons and 157 bases from introns. The target gene of Ph-TElncRNA1 was psbA, encoding photosystem Ⅱ protein D1. Real time fluorescence quantitative results showed that the relative expression of Ph-TElncRNA1 and psbA was the same, indicating that Ph-TElncRNA1 was positively correlated with psbA under UV stress. Through the analysis of the relative expression of Ph-TElncRNA1 and psbA in Ph. edulis leavesat different coloring stages, it was found that the expression of psbA and Ph-TElncRNA1 reached the peak during chloroplast formation stage.   Conclusion   Ph-TElncRNA1 and psbA are co-expressed under UV stress, andPh-TElncRNA1 can participate in the leaf development of Ph. edulis by regulating the target gene psbA.[Ch, 7 fig. 33 ref.]
Adsorption-degradation of oil in catering wastewater by the microorganism immobilized on sponge pyrolytic carbon
MA Shuwen, LIU Xin, ZHOU Xiaoqin, FANG Xiaobo, ZHENG Huabao, MAO Haonan, YANG Yu, MENG Qishen, ZHANG Cheng
, Available online  doi: 10.11833/j.issn.2095-0756.20220338
  Objective  The objective of this study is to explore the effective treatment of catering wastewater, which has become increasingly harmful to the environment with the rapid development of catering industry.  Method  Sponge pyrolytic carbon (SPCx) with good adsorption performance was prepared from waste sponge by pyrolysis and carbonization. The physical and chemical properties such as the morphology and structure of the materials were characterized by cold field emission scanning electron microscopy, Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy. Through the adsorption of soybean oil in wastewater by SPCx, the effects of pyrolysis temperature, wastewater pH and temperature on the adsorption performance were studied. The adsorption kinetics and adsorption isotherm of SPC600 adsorbent were analyzed, and the Langmuir and Freundlich models were used to analyze the data. Based on this, the oil adsorption-degradation law of SPC600 immobilized microorganisms in simulated wastewater and actual wastewater was explored.   Result  Sponge pyrolytic carbon (SPC600) had abundant “network” structure and fracture branches, and contained a large number of hydroxyl, carbonyl, ether bonds, and other oxygen-containing functional groups on its surface, which improved its ability to adsorb oil and immobilize microoganism. The optimized SPC600 had an adsorption capacity of 8 093.1 mg·g−1 at pH 7 and adsorption temperature of 30 ℃. The adsorption process of oil conformed to the pseudo-second-order kinetic equation, and was an exothermic process dominated by chemical adsorption. The screened oil-degrading strains and SPC600 were made into immobilized microbial adsorbents, and the degradation rate of actual oil wastewater reached 67.6%, which was 11.0% and 14.4% higher than that of free strain and free strain+SPC600 respectively.   Conclusion  The sponge pyrolytic carbon immobilized microbial technology can stabilize the degrading strain and improve the oil degradation rate, so as to achieve the effect of “treating waste with waste” and avoid secondary pollution, which has a good application prospect. [Ch, 8 fig. 3 tab. 42 ref.]
Effects of intercropping patterns on physiological characteristics and Pb uptake of edible plants in community gardens
YAN Yue, JIN Hexian, WANG Ying, CHEN Chaoyi, FAN Yingjia, LIU Dan
, Available online  doi: 10.11833/j.issn.2095-0756.20220365
  Objective  The objective is to study the physiological characteristics of plants in Pb contaminated soil and uptake characteristics of Pb in community gardens intercropped with Sedum alfredi, in order to screen out the best planting mode to reduce the uptake of Pb by edible plants.  Method  S. alfredii, Apium graveolens, Brassica chinensis, Capsicum annuum and Raphanus sativus were used as research materials. A pot experiment was carried out in Pingshan Nursery of Lin’an District of Hangzhou City, Zhejiang Province. The effects of intercropping S. alfredii on physiological and biochemical indexes of edible plants, uptake and transfer characteristics of Pb, the pH of rhizosphere soil and distribution characteristics of Pb were analyzed.  Result  (1) Intercropping significantly improved the biomass of S. alfredii, A. graveolens and C. annuum, and reduced the biomass of B. chinensis and R. sativus (P<0.05). (2) The content of MDA in leaves of S. alfredii and edible plants showed a consistent pattern, and intercropping was lower than monoculture. In the intercropping system, CAT activities in leaves of A. graveolens, C. annuum and R. sativus significantly increased by 33.92%, 41.94% and 53.80%, compared with the monoculture system (P<0.05). (3) Intercropping S. alfredii significantly reduced Pb accumulation in edible parts of A. graveolens, C. annuum and R. sativus, which decreased by 24.37%, 162.50% and 39.82%, respectively (P<0.05), compared with monoculture. (4) Intercropping decreased the pH of rhizosphere soil and changed the distribution of Pb in soil. Intercropping S. alfredii decreased the form proportion of weak acid extracted and oxidized Pb in the rhizosphere soil of edible plants, but increased the form proportion of reducible Pb in soil.   Conclusion  The intercropping mode can promote the enrichment and migration of Pb in S. alfredii and reduce the toxic effect of Pb on edible plants. Intercropping S. alfredii significantly reduces Pb content in edible parts of A. graveolens and C. annuum, reaching the safe edible standard. The Pb content in edible parts of R. sativus tends to decrease, which is an ideal combination mode for intercropping restoration. [Ch, 6 fig. 3 tab. 31 ref.]
Allelopathic effects of Phyllostachys edulis extracts on Fritillaria thunbergii
WU Haiping, YE Genhua, LI Weicheng
, Available online  doi: 10.11833/j.issn.2095-0756.20220471
  Objective  The purpose is to explore the allelopathic effects of forest extract of Phyllostachys edulis on Fritillaria thunbergii, so as to screen the suitable economic species for compound management of Ph. edulis and medicinal plants.   Method  F. thunbergii was selected as the target plant to carry out the allelopathy experiments of different extracts of Ph. edulis forest (roots, fresh branches and leaves, litter and 0~20 cm soil) at different concentrations (0.005, 0.010, 0.020, 0.050 and 0.100 kg·L−1).   Result  (1) The effects of root extract on the growth characters (plant height, biomass and leaf area), photosynthetic pigments (chlorophyll a, chlorophyll b and chlorophyll a+b) and active medicinal components (Fritillarin A and Fritillarin B) of F. thunbergii showed promotion at lower extract concentration while inhabitation at higher concentration. (2) Fresh branches and leaves, litter and soil extracts promoted the growth traits, photosynthetic pigments and active components, increased the leaf area and absorption capacity of direct and diffuse light, which was conducive to the growth of F. thunbergii under low light condition. The maximum net photosynthetic rate and light saturation point also increased under the treatment of these three extracts, which first increased and then decreased with the increase of the extract concentration. At the same time, the apparent quantum efficiency increased and the light compensation point decreased, indicating that Ph. edulis extracts changed the utilization rate of light energy and the absorption range of light intensity. (3) The comprehensive allelopathic effect of root extract on F. thunbergii was the strongest, while that of the soil extract was the weakest. (4) The MDA content increased when the root extract was in high concentration, indicating that F. thunbergii was under certain environmental stress.   Conclusion  F. thunbergii can adapt to the irrigation of other extracts except root extract of high concentration, and can improve biomass and active medicinal components. Land preparation and cleaning up the dead root of Ph. edulis forest is conducive to the high-quality growth of F. thunbergii. [Ch, 1 fig. 5 tab. 20 ref.]
Preparation and algae inhibition of garlic oil microemulsion
HUANG Yang, GUO Ming, WANG Yiping, YE Bihuan, CHEN Youwu, WANG Weiyu
, Available online  doi: 10.11833/j.issn.2095-0756.20220336
  Objective  This study aims to prepare microemulsion from garlic oil in order to improve the stability of garlic oil and develop a new type of plant-derived algaecide.  Method  The effects of surfactant and co-surfactant types and mass ratio (Km) on the formation of garlic oil microemulsion system were investigated by phase transition method and pseudo-ternary diagram, and orthogonal experiments were carried out. The stability of garlic oil microemulsion prepared under the optimal conditions under different temperature, pH and centrifugation conditions of 5 000 and 10 000 r·min−1 was investigated, and the algae inhibition of garlic oil microemulsion experiment was carried out.  Result  The optimum preparation conditions were 25 ℃, Tween 80 as surfactant, ethanol and n-butanol as co-surfactants. The mass ratio of the three was 1∶1∶1, and the mass ratio of mixed surfactant and garlic oil was 4∶6. The obtained microemulsion was yellow clear transparent liquid with light blue luster. The average particle size was 20.1 nm and the polydispersity coefficient was 0.144. The algae inhibition rate of 320 mg·L−1 garlic oil microemulsion was 82.54%.  Conclusion  The successfully prepared oil-in-water type garlic oil microemulsion has good stability, suitable particle size, and obvious algae inhibitory effect. It is expected to be a new algaecide. [Ch, 9 fig. 3 tab. 31 ref.]
Analysis of genetic diversity of Bletilla striata germplasm by ISSR and SRAP markers
WANG Jie, ZHU Xipeng, WANG Tengfei, ZHU Jianjun, LI Wenjun, XING Bingcong, ZHENG Ying
, Available online  doi: 10.11833/j.issn.2095-0756.20210690
[Abstract](157) [HTML] (46) [PDF](2)
  Objective  The objective is to analyze the genetic diversity and genetic relationship of 32 Bletilla striata samples from different provenances by ISSR and SRAP markers, so as to provide theoretical basis for identification, classification, conservation and development of B. striata germplasm.   Method  Primers with high polymorphism, clear amplification bands and good repeatability were selected from 100 ISSR primers and 238 pairs of SRAP primers for polymerase chain reaction (PCR) amplification. Genetic diversity parameters and genetic distance of B. striata from 32 different provenances in Zhejiang, Yunnan, Guizhou and Sichuan were calculated by Popgene 32.0, and cluster analysis was performed by NTSYS-PC 2.10e.   Result  11 highly polymorphic primers were screened from 100 ISSR primers, and a total of 188 bands were amplified, with an average of 17.09 bands per primer, among which 174 were polymorphic loci, accounting for 92.20% of the total amplified fragments. 11 pairs of highly polymorphic primer pairs were screened from 238 pairs of SRAP primer pairs, and a total of 216 bands were amplified, with an average of 19.64 bands per primer, including 202 polymorphic loci, accounting for 93.52% of the total amplified fragments. Based on ISSR and SRAP markers, the genetic diversity level of B. striata population in Sichuan Province was the highest, while that in Guizhou Province was the lowest. UPGMA and PCoA analysis showed that the clustered B. striata samples were mostly from the same province. The genetic distance of B. striata population between Yunnan Province and Sichuan Province was relatively close, and that between Zhejiang Province and Guizhou Province was relatively close, indicating that there was a certain overlap between genetic distance and geographical distance, but there was no positive correlation.   Conclusion  B. striata provenances selected in this study have high genetic diversity. Both ISSR and SRAP markers can effectively reveal the genetic diversity and genetic relationship of B. striata. [Ch, 4 fig. 4 tab. 25 ref.]