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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).
Cloning and expression of phosphorus efficient gene GhMGD3 in Gossypium hirsutum
MENG Chaomin, GENG Feifei, QING Guixia, ZHOU Jiamin, ZHANG Fuhou, LIU Fengju
doi: 10.11833/j.issn.2095-0756.20220145
[Abstract](9) [HTML](4) [PDF](0)
Abstract:
  Objective  Based on the genome-wide expression profile of cotton seedlings under low phosphorus stress in the early stage of our research group, related genes were excavated and their preliminary expression analysis was conducted.   Method  Genomic DNA and cDNA sequence of the gene were cloned and analyzed by bioinformatics method. Semi-quantitative RT-PCR and fluorescence quantitative PCR (qRT-PCR) were used to detect the changes of gene expression in root, stem, leaf and flower tissues. The expression patterns of GhMGD3 under low phosphorus stress were analyzed by qRT-PCR technology.  Result  GhMGD3 gene was cloned. The coding sequence of GhMGD3 was 681 bp, encoding 226 amino acids and containing 3 introns. The molecular weight is 26 610.54 Da, isoelectric point is 8.74, it is a stable hydrophilic alkaline protein. The secondary structure is dominated by α-helix and random crimp. The protein does not have signal peptide, transmembrane domain and N-glycosylation site, but contains multiple acidification sites. Subcellular localization showed that the gene encoded a protein in chloroplast. GhMGD3 protein and Hibiscus syriacus protein amino acid sequence similarity is high, the most recent genetic relationship. The results of semi-quantitative RT-PCR and qRT-PCR showed that GhMGD3 gene was mainly expressed in root, medium expression in stem, and trace expression in leaf and flower, and its expression level reached the highest value at 72 h of low phosphorus stress.   Conclusion  The GhMGD3 gene was preliminarily obtained. The expression patterns of GhMGD3 in different tissues and under low phosphorus stress were analyzed. GhMGD3 gene has an important function in regulation of the efficient utilization of phosphorus in cotton. [Ch, 7 fig. 1 tab. 27 ref.]
Research progress on the causes of spatial heterogeneity of soil salinity and its effects on plants’ growth
WANG Lu, LI Lele, LAI Mengxia, DU Changxia, FAN Huaifu
doi: 10.11833/j.issn.2095-0756.20220155
[Abstract](12) [HTML](4) [PDF](0)
Abstract:
Since salinity is one of the major restraints for agricultural production, and plants are sensitive to the general heterogeneous variability in salt over time and space, it is of great importance to investigate the response patterns of plants to heterogeneous salt stresses which can shed some light on the improvement of plant resistance under nonuniform salt stress. However, studies conducted on plant salt stress so far have mainly focused on homogeneous salt stress, which is very different from the heterogeneous salt stress phenomenon in soils in actual agricultural production. In view of this, this paper is aimed at a review of the causes of soil salinity heterogeneity distribution and recent research progress on plants under salinity spatial heterogeneity, including: (1) the causes and distribution of soil salinity spatial heterogeneity; (2) effects of soil salinity spatial heterogeneity on plant above-ground growth; (3) plant root system response to soil salinity spatial heterogeneity and (4) the relationship between plant growth and root zone salt concentration under soil salinity spatial heterogeneity. This paper provides an insight into the feasibility study of the effects of spatial heterogeneity of soil salinity on plant growth for the subsequent research on heterogeneous salt stress. [Ch, 65 ref.]
Response of soil respiration to understory vegetation management in Eucalyptus urophylla × E. grandis plantation
ZHU Wankuan, XU Yuxing, WANG Zhichao, DU Apeng
doi: 10.11833/j.issn.2095-0756.20220138
[Abstract](16) [HTML](4) [PDF](0)
Abstract:
  Objective  This study aims to investigate the impact of different understory vegetation management measures on soil respiration and its components in Eucalyptus urophylla × E. grandis plantation on Leizhou Peninsula, so as to provide a reference for accurate evaluation of soil carbon cycle in Eucalyptus plantation.   Method  Understory vegetation removal was conducted in 2 ways (physical removal and herbicide treatment) in E. urophylla × E. grandis plantation, and the non-removal group was used as the control. The LI-8100A automatic soil carbon flux measurement system was used to continuously monitor total soil respiration and its component rates, soil temperature and humidity (5 cm deep) for 1 year.   Result  Physical and chemical removal of understory vegetation significantly reduced total soil respiration and its components (except chemical removal of root respiration) (P<0.01). In addition, the total soil respiration rate of physical removal (3.45 μmol·m−2·s−1) was significantly lower than that of chemical removal (4.15 μmol·m−2·s−1) (P<0.01). There was no significant difference between the two approaches in mineral soil respiration rate and litter layer respiration rate. The root respiration rate showed physical removal (1.02 μmol·m−2·s−1) was significantly lower than that of chemical removal (1.37 μmol·m−2·s−1)(P<0.05). The contribution rates of litter layer respiration, mineral soil respiration, and root respiration to total soil respiration were 36.45%−39.40%, 26.34%−31.29%, and 30.10%−39.40%, respectively. The highest value of total soil respiration rate and its components occurred in the rainy season (April-October) and the lowest value of root respiration rate occurred in July and August. The fitting model of soil total respiration rate with soil temperature and humidity was the best, which could explain 75.1% (physical removal), 60.9% (chemical removal) and 57.1% (control) of the variation of soil total respiration rate. The temporal variation of litter respiration rate was mainly controlled by soil moisture; There was no significant correlation between root respiration rate and soil temperature, but a significant negative correlation with soil moisture (P<0.05). The temperature sensitivity (Q10) of total soil respiration was 2.12 for physical removal, 1.95 for chemical removal, and 1.93 for control.   Conclusion  The removal of understory vegetation affects soil respiration by changing biological and abiotic factors in the forest. Compared with chemical removal, physical removal of understory vegetation can reduce the total soil respiration rate and carbon emission of forest soil to a greater extent. [Ch, 4 fig. 3 tab. 49 ref.]
Applicability of land use classification method in Dali City based on Sentinel-2A image
JIA Yujie, LIU Yungen, YANG Silin, WANG Yan, ZHANG Chao, XU Hongfeng, ZHENG Shujun
doi: 10.11833/j.issn.2095-0756.20220134
[Abstract](17) [HTML](6) [PDF](125)
Abstract:
  Objective  The purpose of this study is to obtain more efficient and accurate automatic land use classification methods, so as to provide theoretical support for the follow-up study of land use classification in plateau mountainous areas.   Method  Taking Dali City, a typical plateau mountainous area of Yunnan Province in China, as the research area and Sentinel-2A image as the object, an object-oriented decision tree classification method was proposed and compared with traditional ISODATA classification method and maximum likelihood method.  Result  (1) The classification results of object-oriented decision tree method were better than those of ISODATA classification method and maximum likelihood classification method in terms of spatial distribution and area statistics of various classes, and were closer to the actual land use area data of the study area. (2) In Dali, the maximum likelihood classification method had better applicability in the extraction of water body and forest land, while the object-oriented decision tree classification method had stronger applicability in the extraction of farmland, grassland, construction land and other land types, and had better extraction effect in the extraction of glacier snow. (3) Compared with the traditional ISODATA method and maximum likelihood method, the object-oriented decision tree classification method could further improve the classification accuracy. The overall classification accuracy could reach 90.20% and the Kappa coefficient was 87.95%.   Conclusion  Compared with the traditional classification methods, the idea of coarse classification before fine classification can avoid the confusion between regions. The combination of object-oriented features and decision tree has better applicability in plateau mountainous areas, and can effectively improve the classification accuracy. [Ch, 3 fig. 8 tab. 26 ref.]
Effect of prescribed burning on soil anti-erodibility and anti-scourability of Pinus yunnanensis forest
YANG Fuyu, CHEN Qibo, LI Jianqiang, GONG Shunqing, FU Yishan
doi: 10.11833/j.issn.2095-0756.20220321
[Abstract](10) [HTML](3) [PDF](1)
Abstract:
  Objective  Prescribed burning is an essential measure for forest fire prevention. The purpose of this study is to explore the impact of prescribed burning on soil anti-erodibility and anti-scourability of Pinus yunnanensis forest, so as to provide scientific basis for sustainable forest management and optimization of prescribed burning in forest areas.  Method  The sample plots of P. yunnanensis forest in central Yunnan Plateau were selected as the research objects. The effects of prescribed burning on soil anti-erodibility and anti-scourability of P. yunnanensis forest were systematically studied by combining field investigation and sampling with indoor experimental analysis.   Result  (1) After prescribed burning, the content of mechanically stable aggregates(>2.00 mm) in 0−40 cm soil layer increased and the content of waterstable aggregates (>2.00 mm) decreased. The mean mass diameter and mean geometric diameter of the water stable aggregates decreased. The damage rate of soil aggregate structure increased, and the erosion resistance index decreased. The soil erosion resistance index of 40−60 cm soil layer did not change significantly. (2)After the prescribed burning, the litter accumulation decreased and the water holding capacity and storage capacity of the litter weakened, and the plant root system was burned. The decrease of litter and root system after periodic burning was the main reason for the decrease of soil erosion resistance coefficient in forest land.   Conclusion  Prescribed burning reduces water erosion resistance of soil surface. With the increase of soil depth, the impact of planned burning on soil erosion resistance gradually decreases. After prescribed burning, the surface litter and vegetation roots decrease and the erosion resistance weakens. [Ch, 1 fig. 6 tab. 37 ref.]
Advances in plant phylogeny in the genome era
WANG Jie, HE Wenchuang, XIANG Kunli, WU Zhiqiang, GU Cuihua
doi: 10.11833/j.issn.2095-0756.20220313
[Abstract](22) [HTML](14) [PDF](2)
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Phylogeny is a basic issue in evolutionary biology and an important topic in other branches of biology as well, which focuses on the genetic relationship and evolutionary fate among various taxa. Using molecular data to investigate the evolutionary relationship between organism is an important means of phylogenetic research. Along with the development of sequencing technology and its decreasing cost, phylogenetic research has gradually developed from the early stage based on single gene or combined minority fragments to the present stage using massive genome data to study the evolutionary relationship among individuals, populations, and species. In this paper, the representative achievements of three sets of genomes (chloroplast genome, mitochondrial genome, and nuclear genome) in plant phylogenetic research are discussed. The characteristics of different plant genomes and their advantages and limitations in phylogenetic studies are summarized. The main methods of phylogenetic tree construction are explored and the future research is prospected. At present, the three sets of genomes in plants are suitable for phylogenetic studies of different order elements and taxa. The differences in genetic characteristics between different genomes have different advantages and applications in phylogenetic studies: (1) Chloroplast genome is relatively simple in structure, conservative in sequence, difficult to recombine, and uniparentally inherited. It is an ideal molecular data resource widely used in the fields of phylogeny and evolutionary biology. (2) The evolutionary rate of plant mitochondrial genome sequence is relatively slow, so it is only suitable for early plant and large-scale phylogenetic research. (3) The nuclear genome is biparental inheritance, which can comprehensively reveal the parental lineage and phylogenetic network evolutionary relationship, and has great application potential in phylogenetic research. Different tree construction methods are suitable for datasets with different characteristics, and reasonable methods should be adopted in the process of tree construction to avoid the effects of long-branch attraction and incomplete lineage sorting. In the future, nuclear genome will become the mainstream of phylogenetic research, and its biparental genetic characteristics can provide sufficient insights into hybridization and genomic introgression during speciation. With more taxon phylogenetic positions determined, biparental inheritance such as hybridization, backcross, nucleocytoplasmic interaction, polyploidy, functional adaptation, and convergent evolution during speciation and evolution will become the focus of phylogenetic research. [1 tab. 78 ref.]
Spatial heterogeneity of soil nutrients and the influencing factors in Zhejiang subtropical nature reserve
DU Fangfang, TONG Genping, GUO Rui, JIANG Niwen, YE Zhengqian, FU Weijun
doi: 10.11833/j.issn.2095-0756.20220213
[Abstract](17) [HTML](11) [PDF](1)
Abstract:
  Objective  This study aims to reveal the spatial variability of soil nutrients and the influencing factors in subtropical national nature reserves of China, so as to provide a theoretical basis for protecting rare vegetation and natural ecosystems in China’s subtropical hilly regions.   Method  Soil samples were collected from Longtangshan-Shunxiwu in Qingliangfeng Nature Reserve of Zhejiang Province. Classical statistics and geostatistical method were used to systematically analyze the soil variables such as pH, soil organic matter (SOM), total nitrogen (TN), total phosphorus (TP) and total potassium (TK), and the main influencing factors were explored.   Result  The soil in the study area was acidic as a whole. The average contents of SOM, TP, TN and TK were 65.04, 0.67, 1.63 and 18.45 g·kg−1, respectively, which belonged to moderate variation. Semi variance analysis showed that SOM, TN and TK displayed strong spatial autocorrelation while pH and TP displayed moderate spatial autocorrelation, indicating that the soil nutrients were mainly affected by structural factors. The global Moran’s I index revealed that the spatial autocorrelation of SOM reached a significant level and its spatial distribution was aggregated, while the distribution of soil pH tended to be random. Kriging interpolation results showed that the spatial distribution of various nutrients was fragmented and the patch characteristics were significant. Correlation analysis showed that SOM and TN were significantly correlated with altitude, bulk density, and slope (P<0.05), and there was a significant positive correlation between SOM and TN (P<0.01).   Conclusion  All the soil nutrients show an obvious spatial heterogeneity. Altitude and bulk density are strongly correlated with the spatial variation of SOM and TN in the study area. [Ch, 6 fig. 4 tab. 38 ref.]
Effects of acid rain type change on soil nutrient characteristics and microbial C and N in the Cunninghamia lanceolata plantation
CHEN Meiling, LIU Xin, CHEN Xinfeng, MENG Miaojing, ZHANG Jinchi, NIE Hui, ZENG Jingyi, XIE Dejin
doi: 10.11833/j.issn.2095-0756.20220132
[Abstract](22) [HTML](11) [PDF](1)
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  Objective  The purpose of this study is to investigate the effects of acid rain type change on soil nutrients and microbial C and N of the Cunninghamia lanceolata plantation, with a view to providing a theoretical basis for sustainable management of the C. lanceolata plantation in areas with different types of acid rain.   Method  Taking C. lanceolata plantation in Dongshanqiao Forest Farm in Nanjing as the research object, a control treatment (ck, mountain fire pool water, pH 6.6) was set. After 1 year of stress of different types of acid rain (sulfuric acid type, nitric acid type and mixed type) and acid rain acidity (simulated solution pH 4.5, 3.5 and 2.5), the effects of acid rain type change on soil nutrients and microorganisms in the C. lanceolata plantation were explored.   Result  With the increase of acid rain acidity, soil pH value of different types of acid rain treatment decreased significantly (P<0.05), while soil exchangeable hydrogen ions (H+) and aluminum ions (Al3+) increased significantly (P<0.05). Compared with the control (ck), when the pH value of acid rain was 2.5, the mean values of soil exchangeable H+ and Al3+ increased by 275% and 240% under sulfuric acid rain treatment, 254% and 246% under mixed acid rain treatment, and 246% and 249% under nitric acid rain treatment, respectively. In addition, the time of acid rain stress significantly affected the contents of soil total carbon, total nitrogen, total sulfur, available phosphorus and microbial C and N (P<0.05), but the type of acid rain had no significant effect on soil microbial C and N. After acid rain stress for 1 year, soil microbial C and N contents were the lowest under the treatment of pH 2.5 nitric acid rain, which were (378.89±60.69) and (38.67±4.10) mg·kg−1 respectively. According to the structural equation model, the effect of acid rain acidity on soil microbial C and N in the C. lanceolata plantation was stronger than that of acid rain type, which indirectly influenced microbial C and N mainly by affecting soil pH, available phosphorus and total carbon.   Conclusion  After 1 year of short-term acid rain stress, acid rain acidity is still the main factor affecting soil characteristics of C. lanceolata, and the change of acid rain type will intensify the inhibition effect of acid rain acidity on soil characteristics of C. lanceolata plantation. [Ch, 6 fig. 3 tab. 29 ref.]
Effects of biochar-based urea and common urea on soil N2O flux in Phyllostachys edulis forest soil
CAO Shanzhi, ZHOU Jiashu, ZHANG Shaobo, YAO Yihan, LIU Juan, LI Yongfu
doi: 10.11833/j.issn.2095-0756.20220254
[Abstract](22) [HTML](13) [PDF](1)
Abstract:
  Objective  The aim of this study is to explore the effect and mechanism of the application of biochar-based urea and common urea on soil N2O flux and environmental factors in Phyllostachys edulis forest, so as to provide scientific basis for the development of fertilization technology to reduce soil N2O emissions.   Method  A field control experiment was carried out in a typical subtropical Ph. edulis forest in Qingshan Town, Lin’an District of Hangzhou from September 2018 to September 2019. 5 treatments were set up: control (ck), low-level urea (100 kg·hm−2), high-level urea (300 kg·hm−2), low-level biochar-based urea (100 kg·hm−2) and high-level biochar-based urea (300 kg·hm−2). Soil N2O flux of Ph. edulis forest was determined by static chamber-gas chromatography, and the dynamic changes of soil N2O flux, temperature and water content, nitrogen forms and related enzyme activities were analyzed under the above fertilization treatments.   Result  Low-level urea and high-level urea treatments increased the annual cumulative N2O emission by 17.3% and 36.0%, while low-level biochar-based urea and high-level biochar-based urea treatments reduced it by 3.1% and 16.9%, respectively. Both urea and biochar-based urea treatments significantly increased soil NH4 +-N and NO3 -N concentrations (P<0.05). Urea treatment significantly increased the concentration of soil water-soluble organic nitrogen and activities of urease and protease, while biochar-based urea treatment significantly decreased the values of these 3 indicators (P<0.05). In addition, under the above 5 treatments, there was a significant correlation between soil N2O emission rate and soil temperature, NH4 +-N, water-soluble organic nitrogen, urease and protease activities.   Conclusion  Compared with urea, biochar-based urea has a significant reduction effect on soil N2O flux in Ph. edulis forest, and the key mechanism lies in that biochar-based urea reduces concentration of soil water-soluble organic nitrogen and activities of N-cycling enzymes. [Ch, 5 fig. 3 tab. 55 ref.]
Ecological risk assessment of alien landscaping plants in wetland parks on the west bank of Dianchi Lake
PENG Lindi, WANG Qiong, ZHANG Hongli, ZHENG Chengjie, WANG Nanyuan, PAN Qubo
doi: 10.11833/j.issn.2095-0756.20220301
[Abstract](30) [HTML](17) [PDF](842)
Abstract:
  Objective  This study aims to evaluate the ecological risk of alien species of landscaping plants in 3 wetland parks on the west bank of Dianchi Lake, and explore their potential ecological risk, risk characteristics and hazard status.   Method  By route inspection method and key regional reconnaissance method, 3 wetland parks on the west bank of Dianchi Lake were investigated. Data on the growth characteristics, ecological characteristics, geographical flora, diffusion and escape of alien species of landscaping plants were collected. Combined with expert consultation method, analytic hierarchy process and cluster analysis, the ecological risk assessment system was established to evaluate alien species of landscaping plants in small areas.   Result  There were 93 species of alien landscaping plants in the 3 wetland parks, belonging to 48 families and 77 genera, and geographical flora was dominated by world widespread and tropical widespread varieties. The proportions of trees (including bamboo), shrubs (including vine) and herbs were 39.78%, 30.11% and 30.11%, respectively. Among the 58 alien species evaluated, Pharbitis purpurea, Eichhornia crassipes, and Solidago canadensis were high risk plants, while Cortaderia selloana, Cosmos bipinnatus, and Trifolium pratense were medium risk plants. Hierarchical clustering analysis showed that the risk genetic characteristics of the medium and high risk plants were similar, and the distance to the cluster center was closer than that of the low risk plants. Under the same risk, trees and shrubs were closer to the cluster center than herbs because of their similar growth characteristics.   Conclusion  Among the 58 alien species evaluated, herbaceous plants account for the majority of the high and medium risk species, and most of them are widely distributed in the world. The application of alien species of landscaping plants in this area should be selected and controlled strictly. High risk plants need to be cleared in time especially S. canadensis. [Ch, 2 fig. 7 tab. 26 ref.]
Spatiotemporal differentiation of organic carbon in upland soils converted from paddy field under the leisure agriculture tourism background in Zhejiang Province
YANG Dongwei, ZHANG Jianqiang, HUANG Xuebin, ZHANG Mingkui
doi: 10.11833/j.issn.2095-0756.20210607
[Abstract](42) [HTML](17) [PDF](6)
Abstract:
  Objective  This paper, with an exploration of the spatiotemporal differentiation of soil organic carbon (SOC) in such upland as nurseries of flowers and trees as well as orchards, which have been converted from paddy field in Zhejiang Province under the background of leisure agriculture, is aimed to better understand the carbon sequestration in soils after the land-use conversions.   Method  With soil samples selected from paddy field and the converted upland as the research objects, combined methods of field investigation and laboratory analysis were employed, on the basis of “trading space for time”, to investigate the spatiotemporal changes in the density and storage of SOC in 1 meter depth soil before a comparison was conducted of the differences of SOC among different types of upland converted from paddy fields and an estimation was made of the storage changes of SOC after the land-use conversions in Zhejiang Province.   Result  Soil organic carbon on four types of stagnic anthrosols (hap-stagnic, Fe-leachi-stagn, iFe-accumuli-stagnic and hapli-stagnic anthrosols) in 1 meter depth upland soils decreased by 13.9%, 34.9%, 18.9% and 23.9% respectively after 15 to 20 years with the loss of SOC density being 2.06, 2.92, 1.14 and 1.54 t·hm−2·a−1, respectively. There was a significant positive correlation (P<0.01) between the decline rate of SOC and the decline depth of groundwater level in the upland soils.   Conclusion  Paddy field is a better choice for the storage of SOC whereas the conversion from paddy field to upland decreases the storage of SOC and affects regional carbon balance. [Ch, 3 fig. 4 tab. 16 ref.]
Effects of stand spatial structure on understory plant diversity in Pinus taiwanensis plantation
LÜ Kangting, ZHANG Ershan, LI Siying, JIN Shanshan, ZHOU Mengli, YAN Dongfeng
doi: 10.11833/j.issn.2095-0756.20220139
[Abstract](42) [HTML](16) [PDF](6)
Abstract:
  Objective  The objective is to explore the key stand spatial structure factors that influence the understory plant diversity in Pinus taiwanensis plantations and provide a scientific basis for constructing healthy and stable P. taiwanensis plantations.   Method  Three analysis methods were used (grey correlation analysis, Pearson correlation analysis, and canonical correlation analysis) to discuss the effects of stand spatial structure on understory plant diversity in a 40-year-old P. taiwanensis plantation. We selected uniform angle index, mingling degree, spatial density index, storey index, opening degree index, Hegyi competition index as stand spatial structure parameters, and Simpson dominance index, Shannon diversity index, Pielou uniformity index, Margalef richness index as plant diversity indexes.   Result  Grey correlation analysis showed uniform angle index had the highest grey correlation with herb plant diversity; while mingling degree had the highest grey correlation with shrub and regeneration plant diversity. Pearson’s correlation analysis indicated that uniform angle index was extremely significant positively correlated with herb Shannon diversity index, herb Margalef richness index, and shrub Simpson dominance index (P<0.01); mingling degree was significantly positively correlated with herb Pielou uniformity index, shrub Shannon diversity index and shrub Margalef richness index significantly (P<0.05); while spatial density index was extremely significant positively correlated with the Margalef richness index of understory regeneration tree species (P<0.01). Canonical correlation analysis suggested that the six stand spatial structure parameters had a strong overall canonical correlation with herb and shrub plant diversity with corresponding coefficients of 0.998 5, and 0.999 5, respectively. Especially, uniform angle index and mingling degree had a greater impact.   Conclusion  Stand spatial structure significantly impacted understory plant diversity in P. taiwanensis plantations. Therefore, it’s a feasible way to improve understory plant diversity by adjusting stand horizontal spatial structure, optimizing stand competitive condition, and regulating stand vertical spatial structure. [Ch, 6 tab. 34 ref.]
Soil heavy metal pollution and its ecological risk analysis in the main Diospyros kaki producing areas of Henan Province
JIN Yu, YE Lingshuai, LI Huawei, HUANG Lin, LI Zhenyuan, FAN Xiongfei, ZHANG Chunling, FU Jianmin, DIAO Songfeng
doi: 10.11833/j.issn.2095-0756.20210721
[Abstract](18) [HTML](18) [PDF](6)
Abstract:
  Objective  The objective is to investigate the soil heavy metal pollution and its ecological risk in Diospyros kaki main producing areas in Henan Province, so as to provide scientific basis for evaluation of soil environmental safety and heavy metal prevention in the main producing areas.   Method  450 soil samples were collected from 90 D. kaki plantations in 3 major producing areas, including Anyang, Jiyuan and Sanmenxia, and the contents of 6 heavy metal elements such as As, Hg, Pb, Cd, Cr, and Cu were determined. Pollution load index(IPL), potential ecological risk index(IR) and ecological risk warning index (IER) were used to evaluate the heavy metal pollution and ecological risk in D. kaki orchard.   Result  The average contents of As, Hg, Pb and Cu in soil were 1.26, 2.01, 1.86, and 1.64 times of the background values, respectively. The soil in D. kaki orchard was moderately polluted by Hg, slightly polluted by As, Pb and Cu. Cd and Cr were pollution-free. Soil As, Hg, Pb and Cu in the main producing areas were greatly affected by human activities, among which As was mainly affected by agricultural activities, while Hg, Pb and Cu were greatly affected by industrial activities. The average values of IPL, IR and IER were 1.08, 136.95 and 2.33, respectively, showing mild pollution, slight risk and mild warning grade. Jiyuan producing area had the most serious pollution, and the highest IR and IER level, with IPL, IR and IER reaching 1.32, 154.10 and 3.79, respectively. 13.33% of the orchards were moderately or severely polluted, and 33.33% were in moderate or strong IR level. 66.67% and 26.67% of orchards showed moderate and severe warnings respectively. Among the 6 heavy metals, Hg had the highest single factor pollution index (CF), IR and IER, which were 2.01, 80.31 and 1.01, respectively.  Conclusion  Hg is the heavy metal element with the highest IR and IER level in the soil of the main D. kaki producing areas. Jiyuan has the highest IPL, IR and IER among the 3 producing areas, all reaching the medium level. [Ch, 2 fig. 8 tab. 30 ref.]
Effects of biochar from Procambarus clarkii shells and Ficus microcarpa branches on soil nutrients and bioavailability of Cd and Pb
GU Shaoru, YANG Xing, CHEN Hanbo, YANG Bingshuang, DAI Zhinan, CHEN Junhui, FANG Zheng, WANG Hailong
doi: 10.11833/j.issn.2095-0756.20220182
[Abstract](33) [HTML](14) [PDF](3)
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  Objective  This study aims to investigate the effects of biochar derived from Procambarus clarkii shells (CSB) and Ficus microcarpa (FMB) on physicochemical properties of contaminated soil and plant growth.   Method  The biochar was prepared by pyrolysis of both typical kitchen and garden wastes at 650 ℃ with limited oxygen supply. A pot trial was conducted using Raphanus sativus with different mass ratios (0, 1%, 3%) to investigate the effects of different doses of CSB and FMB on cadmium (Cd) and lead (Pb) bioavailability in soil, nutrient transformation, soil enzyme activity, and R. sativus growth.   Result  3% FMB treatment had the most significant effect on improving contents of soil organic carbon, available phosphorus and available potassium (P<0.05), which increased by 135.8%, 35.4%, and 173.7% respectively compared with the control. Except 1% CSB treatment, other biochar treatments significantly (P<0.05) decreased the concentrations of available Cd by 60.7%−91.1% and Pb by 21.0%−26.1%. 3% CSB treatment showed significant increase in soil enzyme activities such as β-glucosidase, leucine aminopeptidase and β-N-acetylglucosamine (P<0.05), which were 79.7%, 30.3% and 1668.5% higher than that of the control, respectively. All biochar treatments significantly (P<0.05) increased the biomass of the edible part of R. sativus. 3% CSB treatment had the most significant improvement effect (P<0.05), which increased by 171.5% compared with the control.   Conclusion  The CSB is more effective than the FMB in improving soil enzyme activity, reducing Cd and Pb bioavailability in soil, and improving crop quality and yield. It is more suitable as a potential material for the remediation of soils co-contaminated with Cd and Pb. [Ch, 7 fig. 1 tab. 46 ref.]
Stoichiometric characteristics of leaf litter at different decomposition stages in 4 forest types
WU Renjie, XING Wei, GE Zhiwei, MAO Lingfeng, PENG Sili
doi: 10.11833/j.issn.2095-0756.20220289
[Abstract](51) [HTML](24) [PDF](3)
Abstract:
  Objective  This research aims to study the stoichiometric characteristics of leaf litter at different decomposition stages in different stands in southwest Guizhou Province, so as to better understand the nutrient cycling law of different forest ecosystems in karst areas.   Method  4 typical forest types were selected in southwest Guizhou, including Pinus massoniana forest, Phyllostachys edulis forest, Cunninghamia lanceolata forest, and natural forest dominated by Quercus acutissima, Machilus cavaleriei and Cyclobalanopsis glaucoides. Leaf litter at different decomposition stages was collected and stoichiometric characteristics of C, N and P were measured.   Result  (1) The total C content of leaf litter in each decomposition stage of P. edulis forest was significantly lower than that in other stands (P<0.05), and the total C content of leaf litter at decomposed stage of P. massoniana and C. lanceolata forests was significantly lower than that at undecomposed and semi-decomposed stages (P<0.05). The total N content of leaf litter in C. lanceolata forest at undecomposed stage was significantly lower than that at semi-decomposed and decomposed stages (P<0.05). The total P content of leaf litter at decomposed stage of natural forest was significantly higher than that in other stands (P< 0.05), and the total P content at semi-decomposed stage of natural forest was significantly lower than that at undecomposed and decomposed stages (P< 0.05). (2) The C/N ratio of C. lanceolata forest at decomposed stage was significantly higher than that of Ph. edulis forest (P<0.05), and the C/N ratio at undecomposed stage was significantly higher than that at semi-decomposed and decomposed stages (P<0.05). The N/P ratio at undecomposed and decomposed stages of Ph. edulis forest was significantly higher than that of natural forest (P<0.05). The C/P ratio of leaf litter at semi-decomposed stage of C. lanceolata and natural forests was significantly lower than that of P. massoniana forest (P< 0.05), and the C/P ratio at decomposed stage of natural forest was significantly lower than that of other stands (P<0.05).   Conclusion  Both forest type and decomposition stage have significant effects on contents of total C, N and P, as well as stoichiometric characteristics of leaf litter. [Ch, 2 fig. 2 tab. 36 ref.]
Response of Eucalyptus grandis EgrCIN1 to abiotic stress
LI Fangyan, XIA Xiaoxue, WU Mengjie, HONG Jiadu, CHENG Longjun
doi: 10.11833/j.issn.2095-0756.20220348
[Abstract](31) [HTML](17) [PDF](2)
Abstract:
  Objective  The objective is to analyze the sequence and expression characteristics of EgrCIN1 (Eucgr.B02882), a unique low temperature response gene in Eucalyptus grandis, and to explore its function in plant low temperature response, so as to enrich gene resources to cold resistance.   Method  Bioinformatics methods were used to analyze the characteristics of EgrCIN1 gene, protein sequence and cis-acting elements on the promoter. The expression pattern of EgrCIN1 in different tissues, at 4 ℃ in different time, under drought condition, under treatment of 300 mmol·L−1 NaCl, 100 μmol·L−1 ABA and 100 μmol·L−1 MeJA were analyzed by qRT-PCR method. Subcellular localization of EgrCIN1 was completed by transient transformation of Nicotiana tabacum with EgrCIN1::GFP vector. Besides, an overexpression vector driven by CaMV35S promoter was constructed and transformed into Arabidopsis thaliana. Three transgenic lines were obtained and treated with low temperature(−6 ℃) and ABA(0.5 μmol·L−1) to analyze the function of EgrCIN1 in response to low temperature stress.   Result  EgrCIN1 was a unique gene induced by low temperature in E. grandis. It did not contain introns and had no transmembrane structure. The promoter contained multiple cis acting elements related to stress response. The gene was mainly expressed in leaves and stems, but not in roots. Moreover, its expression in leaves was strongly induced by low temperature treatment. Meanwhile, abiotic stress factors such as drought, high salt and ABA could also induce EgrCIN1 expression in leaves. The encoded protein of EgrCIN1 was localized in chloroplasts. In Arabidopsis, EgrCIN1 overexpression transgenic lines were more tolerant to low temperature and more sensitive to exogenous ABA.   Conclusion  EgrCIN1 is expressed in chloroplasts and may participate in plant cold stress response possibly through ABA-dependent pathway to improve plant cold resistance.[Ch, 8 fig. 2 tab. 27 ref.]
Identification and expression analysis of AP2/ERF gene family in Betula luminifera
HUANG Yizi, QIAN Wang, QIU Shan, WANG Wenxin, HUANG Huahong, LIN Erpei
doi: 10.11833/j.issn.2095-0756.20220331
[Abstract](36) [HTML](16) [PDF](4)
Abstract:
  Objective  This study aims to explore biological roles of AP2/ERF gene family in growth and development of Betula luminifera, and its responses to environmental stress.   Method  Based on the genome data of B. luminifera, AP2/ERF gene family were identified through bioinformatics method, and their gene features, phylogeny, gene structure, conserved motifs, cis-acting elements, protein interactions and expression pattern were analyzed.   Result  A total of 77 AP2/ERF genes were identified in the genome of B. luminifera. The physical and chemical properties of the encoded proteins were different, and the isoelectric points of most proteins (60) were less than 7.0. Phylogenetic analysis showed that these 77 AP2/ERF transcription factors belonged to 5 subfamilies, among which ERF subfamily was the largest, including 34 members. The gene structures of AP2/ERF subfamilies were quite different. The members of AP2 subfamily had 6-9 introns, while DREB subfamily gene had no introns. However, similar conserved motif types and distributions were observed in different members of AP2/ERF subfamilies. At the same time, there were a large number of cis acting elements related to hormone, regulation, stress responses, and growth and development in promoter of AP2/ERF genes. Protein interaction network analysis predicted that there were extensive interactions among different AP2/ERF subfamily proteins. Further expressions analysis showed that the expression of most AP2/ERF genes (71) had strong tissue specificity, and the expressions of most ERF or DREB genes changed significantly under heat stress, indicating that ERF and DREB genes might play an important role in the response to heat stress.   Conclusion  Through bioinformatics analysis, 77 AP2/ERF genes are identified in B. luminifera, which belong to 5 subfamilies. Different subfamily genes have similar gene structure and conserved motifs. The promoter region of the gene contains hormone, stress response and other related elements. Gene expression has strong tissue specificity, and most ERF and DREB genes have obvious response to heat stress. [Ch, 6 fig. 1 tab. 39 ref.]
Establishment and application of comprehensive evaluation system for ornamental quality of Clematis cultivars
SHAO Weili, LIAO Dihua, LIU Zhigao, SHEN Yamei, DONG Bin, YANG Liyuan
doi: 10.11833/j.issn.2095-0756.20220164
[Abstract](60) [HTML](33) [PDF](403)
Abstract:
  Objective  The objective is to establish a comprehensive evaluation system for ornamental quality of Clematis cultivars, so as to provide a theoretical basis for the rational introduction and utilization of Clematis cultivars.  Method  The growth phenological periods of plant, leaf, flower and fruit traits of 20 Clematis varieties were investigated. The ornamental value was evaluated using analytic hierarchy process and grey correlation analysis.   Result  (1) The 20 Clematis cultivars could be divided into 2 ecotypes: evergreen and deciduous. (2)The budding stage, branching and leaf spreading stage of plants in Hangzhou were mostly in early and mid-February to mid-March and late March. The flowering period was usually from April to June, and 7 cultivars including ‘Bagatelle’ and ‘Blue Light’ could bloom twice from July to December. (3) Sepals were mostly purplish red, blue purple or polychromatic with more than 2 colors.   Conclusion  Through ornamental evaluation and cluster analysis, ‘Bagatelle’and ‘Madame Julia Correvon’ have the highest comprehensive evaluation scores(Grade Ⅰ). Grade Ⅱ includes 4 cultivars such as ‘Innocent Blush’. Grade Ⅲ contains 3 cultivars including ‘Utopia’, and Grade Ⅳ contains 9 cultivars including ‘Julka’ and Grade Ⅴ includes ‘Blue Light’ and ‘Daniel Deronda’. 6 varieties of Grade Ⅰ and Ⅱ can be preferentially popularized and applied in Hangzhou. [Ch, 12 tab. 17 ref.]
Effects of clear-cutting and harvest residue of Phyllostachys edulis forests on soil quality
LIU Zongyue, LÜ Shixin, XU Junjie, CHEN Xu, LOU Yikai, QI Xiangbin, YU Shuquan
doi: 10.11833/j.issn.2095-0756.20220122
[Abstract](67) [HTML](34) [PDF](4)
Abstract:
  Objective  Ecological restoration of Phyllostachys edulis forest is a challenge in subtropical regions of China. This study aims to understand the natural restoration status of the soil after clear-cutting and residue retention of Ph. edulis forest, so as to provide guidance for ecological restoration of forest.   Method  In the clear-cutting sites, 3 treatments were set up, i.e. cutting residue reserved (UR), cutting residue removed (CR), and uncut Ph. edulis forest as the control (ck). The changes of soil indexes under different treatments were analyzed and compared through soil survey and measurement 5 years later, and fuzzy mathematical discrimination and principal component analysis were used to quantitatively evaluate the natural restoration effect of Ph. edulis forest after clear-cutting.   Result  (1) The soil bulk density of CR and UR decreased by 31% and 14% respectively compared with ck (P<0.05). Soil total porosity, capillary water holding capacity, field water holding capacity and saturated water holding capacity were higher than those of ck. The water holding capacity of UR soil was better than that of CR. (2) The contents of soil organic carbon, total nitrogen, total phosphorus, alkali-hydrolyzed nitrogen and available potassium in CR and UR were higher than those in ck, and each index increased by 17%−123%. Available phosphorus showed that CR was significantly lower than UR and ck (P<0.01). Due to the retention of cutting residues of Ph. edulis forest after clear-cutting, the soil organic carbon, total nitrogen, total phosphorus, alkali-hydrolyzed nitrogen and available phosphorus in UR were significantly higher than those in CR treatment by 33%−99% (P<0.05). (3)The activities of urease, β-glucosidase and peroxidase in CR, UR soil were higher than those in ck. The activities of 3 extracellular enzymes in UR soil were 46%−98% higher than those in CR treatment. (4) The comprehensive evaluation results showed that the soil quality had been well restored, and the comprehensive scores ranging from high to low in the restored site soil of Ph. edulis forest after clear-cutting was sample area with cutting residue reserved, sample area with cutting residue removed, Ph. edulis forest sample area.   Conclusion  After 5 years of natural recovery, the soil of Ph. edulis forest after clear-cutting can be restored faster than that in Ph. edulis forest land, and the retention of the cutting residues after clear-cutting of Ph. edulis forest is more conducive to soil restoration. [Ch, 1 fig. 4 tab. 23 ref.]
Diurnal and nocturnal changes in stem sap flow of Robinia pseudoacacia during growing season and its response to meteorological factors
ZHANG Rong, BI Huaxing, JIAO Zhenhuan, WANG Ning, ZHAO Danyang, YUN Huiya, HUANG Jinghan
doi: 10.11833/j.issn.2095-0756.20220159
[Abstract](55) [HTML](24) [PDF](3)
Abstract:
  Objective  The objective is to analyze the diurnal and nocturnal changes in stem sap flow of Robinia pseudoacacia in the growing season and explore the impact of meteorological factors on transpiration of R. pseudoacacia , so as to provide theoretical basis for estimating forest water consumption and forest water resource management.   Method  Eight sample trees were selected from R. pseudoacacia sample plots in Caijiachuan watershed, Ji County of Shanxi Province. From May to September 2021, thermal diffusion probe (TDP) was used to continuously observe stem sap flow of sample trees, and meteorological factors such as solar radiation, air temperature, soil temperature, wind speed and relative humidity were monitored simultaneously. Random forest and stepwise linear regression were used to analyze the influence of meteorological factors on stem sap flow.   Result  (1) The order of diurnal sap flow rate from small to large in the growing season was September, May, June, August and July, and the contribution rate of diurnal sap flow to full-day sap flow was 88%−93%. The nocturnal sap flow rate ranging from small to large was September, May, August, July and June, and the contribution rate of nocturnal sap flow to full-day sap flow was 7%−12%. (2) The main meteorological factors affecting the diurnal sap flow rate were basically the same, mainly solar radiation and air temperature. The dominant meteorological factors affecting nocturnal sap flow were different in each month. The main factors were soil temperature and water vapor pressure deficit in May and June, air temperature in July, water vapor pressure deficit and relative humidity in August, and wind speed and water vapor pressure deficit in September. (3)The fitting degree of the monthly day-night flow rate model constructed by random forest regression method was better than that by stepwise regression method.  Conclusion  There are obvious differences in diurnal and nocturnal sap flow rate in each month. The effect of nocturnal sap flow on water consumption of R. pseudoacacia should not be ignored, and the effect of meteorological factors on diurnal and nocturnal sap flow rate is different. Daytime and nighttime should be distinguished when simulating water consumption of tree transpiration according to meteorological factors. [Ch, 5 fig. 6 tab. 24 ref.]
Health assessment and influencing factors of Fraxinus pennsylvanica in Beijing core area
WANG Yan, YU Yun, LIU Yong, WANG Kaiyong, ZHOU Xiaojie, WANG Yang
doi: 10.11833/j.issn.2095-0756.20220109
[Abstract](57) [HTML](29) [PDF](2)
Abstract:
  Objective  For the rapid, accurate, and productive assessment of urban tree health, this study aims to investigate and analyze the growth, health, and management status of Fraxinus pennsylvanica in Beijing core functional area, so as to provide a scientific basis for comprehensive health assessment and technical measures for management and protection.  Method  Taking street trees of 11 main streets in the core area of Beijing as the research object, the health assessment model of F. pennsylvanica was constructed by principal component analysis and K-means clustering. The results were verified by discriminant analysis, and the BP neural network health prediction model was established by combining the assessment results with the assessment indexes. Meanwhile, the effects of DBH, tree height, the number of pruning stubble, anti-trampling pavement etc. on the health status of F. pennsylvanica were analyzed.  Result  The results indicated that healthy, sub-healthy, unhealthy, and dying plants accounted for 39.20%, 41.26%, 16.78%, and 2.76%, respectively. In the BP neural network health prediction model, the correlation coefficients between expected value and predicted value of the training set, verification set, test set, and total set were 0.9997, 0.9720, 0.9976 and 0.9953 respectively, all greater than 0.9500, indicating that the model could accurately reflect the relationship between 12 evaluation indexes and health assessment categories of F. pennsylvanica and could be used to predict the health status of other F. pennsylvanica in the same area. Variance analysis and multiple comparisons showed that DBH, pruning stubble, anti-trampling pavement, plant spacing, tree pool area, number of lanes and lane direction all had significant effects on the health status of F. pennsylvanica (P<0.05), but tree height had little effect. The health condition of F. pennsylvanica was the best under the following conditions: 60−70 cm DBH, tree body without pruning stubble, tree pool pavement with good water permeability, 5−10 m tree spacing, 1−2 m2 tree pool area, suitable road width, and north-south direction.  Conclusion  F. pennsylvanica street trees in the study area are in a sub-health state on the whole, with good conservation and maintenance potential. However, some of them are seriously damaged and need to be dealt with urgently. In planting and management process, important measures should be taken to ensure the good status of F. pennsylvanica, such as standard pruning, strong water permeability of pavement materials, 5−10 m plant spacing, 1−2 m2 tree pool area, and suitable road conditions . [Ch, 3 fig. 13 tab. 26 ref.]
Metabolome of nematicidal fungus Esteya vermicola in carbon and nitrogen culture
LI Xingpeng, ZHANG Yang, WANG Ruizhen, DONG Leiming
doi: 10.11833/j.issn.2095-0756.20210828
[Abstract](55) [HTML](33) [PDF](105)
Abstract:
  Objective  The objective is to compare the metabolic differences of the nematode-killing fungus Esteya vermicola (EV) cultured in carbon and nitrogen nutrient sources and to identify key metabolites or signal molecules.   Method  The carbon medium (mainly composed of PDB) for culturing fungi and the nitrogen medium (mainly composed of yeast powder) for culturing bacteria were selected. EV bacteria were cultured on two kinds of culture media at 25 ℃ for 7 days. The mycelia were harvested and the metabolites were extracted. Non-target high performance liquid chromatography-mass spectrometry(HPLC-MS) was used to analyze and identify metabolite components in both positive and negative ion modes. The metabolic pathways of metabolites with significant differences were analyzed.   Result  A total of 498 metabolites were identified, including 176 negative and 362 positive ion modes and 40 metabolites in both modes. There were 444 metabolites with significant differences, accounting for 89.2% of the total, among which 162 were negative and 310 were positive, and 28 were common to the two modes. Both principal component analysis and partial least square discriminant analysis could cluster the metabolites into different clusters and separate them significantly in carbon and nitrogen culture. In nitrogen culture, guanidine phosphate acetate and p-cresol sulfate were abundant and unique metabolites, and the yield of allantoin, photopigment, indole, and trehalose were significantly up-regulated. Pathway analysis enriched the significantly up-regulated and down-regulated metabolites into the metabolic pathways related to amino acid and carbohydrate metabolism, respectively.   Conclusion  EV bacteria showed significant metabolic differences in carbon and nitrogen culture. The metabolic pathway mainly involves carbohydrate and amino acid metabolism. The important metabolites will provide a theoretical basis for efficient culture and application of EV. [Ch, 3 fig. 2 tab. 31 ref.]
Soil microbial characteristics of evergreen broad-leaved forest at different altitudes in Fengyang Mountain, Zhejiang Province
HE Liu, CAO Minmin, LU Jianbing, ZHENG Xiang, LIU Shenglong, JIANG Jiang
doi: 10.11833/j.issn.2095-0756.20210820
[Abstract](58) [HTML](38) [PDF](0)
Abstract:
  Objective  The objective is to explore the characteristics of soil microbial community of zonal vegetation in evergreen broad-leaved forest in Fengyang Mountain, Zhejiang Province, and to clarify the changes of soil microbial community along the elevation gradient and the main factors affecting structure and diversity of microbial community.   Method  Soil samples were collected at 343, 765, 1364 and 1611 m above sea level. High-throughput sequencing technology was used to explore the relationship between soil microbial community and altitude.   Result  The number of OTU of bacteria was more than that of fungi, and middle and low altitudes (343 and 765 m) displayed more OTUs. Chao 1 index decreased with the increase of altitude, while Shannon index had no obvious trend. The dominant taxa of bacteria at the phylum level were Acidobacteria (43.77%−51.55%), Proteobacteria (31.18%−35.77%) and Actinobacteria, (5.24%−7.99%), while the dominant groups of fungal community were Basidiomycota (33.16%−67.35%) and Ascomycota (22.98%−46.78%). Among the top 10 bacterial phyla in relative abundance, Gemmatimonadetes, Nitrospirae and Verrucomicrobia were significantly negatively correlated with altitude (P<0.01). There were no altitudinal taxa in the fungal community at the phylum level. LefSe (LDA Effect Size) analysis exhibited more different taxa in the fungal community. In addition, PCoA showed that the soil microbial community had the characteristics of altitudinal differentiation bounded by 765 m, and the first axis of this PcoA(PC1) was significantly correlated with temperature, total phosphorus, total kalium and pH(P<0.05).   Conclusion  The change of altitude leads to the change of soil microbial community characteristics in Fengyang Mountain, and temperature is the main driving factor. [Ch, 5 fig. 6 tab. 41 ref.]
Taxonomic study of Cayratia s.l. from Zhejiang, China
XIE Wenyuan, LU Yifei, CHEN Zhenghai, JIN Xiaofeng
doi: 10.11833/j.issn.2095-0756.20210751
[Abstract](95) [HTML](44) [PDF](2)
Abstract:
  Objective  Molecular systematics have aroused a series of disputes on the classification of Cayratia s.l. (Vitaceae). Taking the species of Cayratia s.l. from Zhejiang Province as the research object, the present study aims to conduct a comprehensive classification research based on different evidences.   Method  The seed morphology and characteristics of stem and leaf indumentum were compared. Based on the phylogenetic analysis of four chloroplast gene fragments such as atpB-rbcL, trnC-petN, trnH-psbA and trnL-F, the classification of Cayratia s.l. from Zhejiang Province was discussed.   Result  The stem and leaf indumentum of Cayratia s.l. were different, and the type (glabrous, pubescent or multicellular-pilose) and density of the indumentum were different among species. There existed significant difference in the cross-sectional morphology and dorsal ventral infold morphology of endosperm between Causonis (M-shape in cross section, and ventral infolds narrowly obovate or obovate-elliptic, deeply concave) and Pseudocayratia (T-shape in cross section, and ventral infolds elliptic, shallowly concave). The phylogenetic tree supported the evidence that Cayratia s.l. in Zhejiang could be clearly divided into two genera: Causonis and Pseudocayratia.  Conclusion  Cayratia tenuifolia and C. japonica var. pseudotrifolia are treated as subspecies of C. japonica, and Pseudocayratia pengiana is treated as a subspecies of P. speciosa. [Ch, 3 fig. 3 tab. 16 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
doi: 10.11833/j.issn.2095-0756.20210690
[Abstract](93) [HTML](39) [PDF](1)
Abstract:
  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.]
Effects of light intensity and nitrogen treatments on photosynthetic characteristics of Stewartia sinensis seedlings
ZHANG Tingyu, ZHANG Mingru, LI Qingxiang, ZHAO Nannan, WAN Qi, CAI Yihang
doi: 10.11833/j.issn.2095-0756.20210771
[Abstract](52) [HTML](26) [PDF](1)
Abstract:
  Objective  This study, with an investigation of the differences in the hotosynthetic hysiological and ecological adaptation of Stewartia sinensis seedlings to different light intensity and soil nitrogen content, is aimed to select combinations of light intensity and nitrogen treatment that are conducive to the cultivation of S. sinensis seedlings.   Method  With S. sinensis seedlings used as test materials, efforts were made to set four light intensity gradients, namely full light (L0), light light (44.79±0.51)% (L1), moderate light (19.60±0.23)% (L2), high light (7.25±0.10)% (L3), and three nitrogen application rates, i.e, low nitrogen 0.2 g·kg−1 (N1), high nitrogen 0.6 g·kg−1 (N2) and no nitrogen application (N0) before the light response process, photosynthetic pigment mass fraction and chlorophyll fluorescence parameters were recorded and measured upon 90d treatment.   Result   Light intensity, nitrogen and their interaction displayed significant effects on photosynthetic pigment and chlorophyll fluorescence of S. sinensis seedlings (P<0.05). Chl a/Chl b values of S. sinensis seedlings varied from 2.0 to 2.5, the LSP of S. sinensis seedlings varied from 571.3 to 931.4 μmol·m−2·s−1 whereas LCP varied from 4.8 to 26.0 μmol·m−2·s−1. With the increase of shading degree, the Chl, Car, Fo, Fm, AQY of S. sinensis seedlings tended to increase, the Chl a/Chl b and Car/Chl tended to decrease while the Pmax, Fv/Fo, Fv/Fm and PIABS increased first and then decreased. With the increase of nitrogen application rate, the PIABS of S. sinensis seedlings tended to increase, the Chl a/Chl b, Fo and Fm tended to decrease and the Chl, Car, Pmax and AQY increased first and then decreased; With L1 and L2 light intensity, Pn, Gs and Tr of S. sinensis seedlings were higher and Ci was lower and the application of low nitrogen significantly promoted Pn, Gs and Tr. The Pmax of L1N1 increased by 45.21% compared with L1N0 with the Pn and Pmax of L2N1 being the highest.   Conclusion  S. sinensis seedlings had the best photosynthetic capacity when grown with moderate shading and low nitrogen treatment whereas photosynthetic inhibition occurred with full light or high nitrogen treatment. [Ch, 1 fig. 6 tab. 34 ref.]
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Diversity and endangered status of Chinese key protected wild plants in Zhejiang Province
CHEN Feng, XIE Wenyuan, ZHANG Fenyao, ZHANG Peilin, CHEN Zhenghai
2022, 39(5): 923-930.   doi: 10.11833/j.issn.2095-0756.20220328
[Abstract](113) [HTML](26) [PDF](31)
Abstract:
  Objective  This study, with an investigation of the diversity and endangered status of Chinese key protected wild plants (published in 2021) in Zhejiang Province and an evaluation of their respective endangerment categories, is aimed to provide reference for the design of scientific protection strategies in Zhejiang Province.   Method  On the basis of the second survey of protected wild plant resources in Zhejiang from 2013 to 2018, Flora of Zhejiang (New Edition) and other related investigations in recent years, an exploration was made of the species diversity along with an assessment of the endangered status of these threatened species in light of IUCN, China Biodiversity Red List—Higher Plants and others.   Result  (1) There are 116 Chinese key protected plants in Zhejiang and compared with the 1999 list, 3 first-class protected plants and 61 second-class protected plants were newly added, 3 species were downgraded whereas 4 species were removed. (2) They could be divided into 6 categories, among which 19 belong with the Critically Endangered (CR) species, accounting for 16.38%, 36 belong with the Endangered (EN) species, accounting for 31.03%, 30 belong with the Vulnerable (VU) species, accounting for 25.86%, 17 belong with Near Threatened species (NT) species, accounting for 14.66%, 12 belong with the Least Concern (LC) species, accounting for 10.34%, whereas 2 belong with the Data Deficiency (DD) species which accounts for 1.73%. (3) With 85 species falling into threatened species(CR, EN and VU) accounting for 73.28%, a high degree of threat was shown among the threatened plants.   Conclusion  Of the large number of Chinese key protected plants in Zhejiang Province, about 70 species have received great attention with plenty of research resources granted and favorable protection achieved and to better promote preservation of threatened species the following recommendations are made: (1) efforts should be devoted to the protection of the original habitat, the prevention of excessive interference, and the promotion of nature reserves and other types of nature reserves; (2) scientific researches should be conducted with improved field investigation methods, better collected habitat information of species with close attention paid to species genetic diversity; (3) multidisciplinary cooperation should be encouraged so as to establish and improve the protection network and form a complete breeding system. [Ch, 2 tab. 35 ref.]
Species composition and niche of Sinojackia microcarpa, a rare and endangered plant
FANG Qing, TAN Jurong, XU Huichun, LI Tingting, WU Chuping, WU Zhengzhu, YUAN Weigao, YAO Liangjin
2022, 39(5): 931-939.   doi: 10.11833/j.issn.2095-0756.20220197
[Abstract](49) [HTML](22) [PDF](16)
Abstract:
  Objective  The purpose is to study the habitat adaptability and interspecific relationship of the endangered plant Sinojackia microcarpa based on population ecology, which is beneficial to its effective protection and propagation.   Method  Based on the community survey and habitat data of typical population of S. microcarpa in Jiande, Zhejiang Province, the species composition, niche characteristics, and the linkage between dominant species were analyzed.   Result  (1) A total of 401 woody plants with diameter at breast height (DBH)≥1 cm were recorded, belonging to 51 species, 50 genera, and 35 families. There were 16 species with an important value≥1% in the upper wood of the sample site, and the top 4 species with an important value ranging from large to small were Phyllostachys edulis, Cupressus funebris, Castanea mollissima, and S. microcarpa. The sum of the important values of these 4 species was 49.85%. (2) S. microcarpa had the highest niche similarity with the upper wood species such as Cinnamomum cmphora, as well as the lower wood species such as Loropetalum chinensis. The ecological overlap value was greater than 0.5. The negative interspecific association between S. microcarpa, Camellia sinensis, Loropetalum chinensis and Camellia fraterna suggested that there was significant competition between them.   Conclusion  Rare individuals, poor habitat conditions, and fierce interspecific competition when resources are limited are the key reasons for the extinction of S. microcarpa. [Ch, 8 tab. 33 ref.]
Microsporogenesis, megasporogensis and development of male and female gametophytes of Torreya jiulongshanensis, a critically endangered plant
RAN Yucen, HE Fang, LIU Julian, ZHENG Zihong, ZHENG Weicheng, HU Jiangqin, JIN Xiaofeng
2022, 39(5): 940-949.   doi: 10.11833/j.issn.2095-0756.20220181
[Abstract](96) [HTML](38) [PDF](17)
Abstract:
  Objective  Torreya jiulongshanensis, an ancient relict plant endemic to Zhejiang Province, is a national Class Ⅱ key protected wild plant and also listed as a protected plant of extremely small population in Zhejiang Province. The purpose of this study is to systematically observe the occurrence of megaspores and microspores of T. jiulongshanensis, as well as the development of male and female gametophytes , so as to find out whether the gametes are abnormal and the reasons for low seed-setting rate.  Method  The male and female individuals of T. jiulongshanensis from the type locality were collected as the research objects. Through regular observation and sampling, the occurrence of megaspores and microspores and the development of female and male gametophytes were sectioned, stained and observed by paraffin sectioning method.  Result  (1) The microsporophyll differentiated in mid-August, differentiated into secondary sporogenesis cells in late August and formed microspore mother cells in mid-November. In late February of the next year, it entered the meiosis stage, formed free microspore cells in mid-March, and gradually matured at the end of March. The mature pollen grains were binucleate without air sacs. The development type of microsporangium was basic type, and the spore division model was simultaneous type. The tetrad had tetrahedral and zygomorphic forms. (2) Male gametophytes began to develop in mid-to-late March, and formed sperm at the end of July. The whole process lasted about 4 months. (3) In late March of the next year, 2 erect ovules were born at the base of leaf axils of each bract in megasporophyll. In late April, the megaspore mother cell underwent meiosis Ⅰ and Ⅱ, and formed 4 linear megaspores. In mid-May, 3 megaspores at the micropylar end degenerated and the megaspores at the chalazal end finally developed into female gametophytes. (4) T. jiulongshanensis had 2 solitary oval archegonia, which lasted about 7 months from pollination to fertilization.   Conclusion  The development cycle of male and female reproductive system of T. jiulongshanensis is longer than that of other species in the family Taxaceae. The main reasons for low seed-setting rate and difficult natural regeneration of T. jiulongshanensis include long reproductive cycle, complicated reproductive process, the development of female reproductive system which lags behind that of the male reproductive system, as well as the extremely limited population (1 female plant and 2 male ones). [Ch, 3 fig. 1 tab. 34 ref.]
Seasonal changes of photosynthetic characteristics of seedlings of Magnolia sinostellata under different light intensities
CHEN Chao, JIN Zexin, YUAN Meng, LUO Guangyu, LI Yueling, SHAN Fangquan
2022, 39(5): 950-959.   doi: 10.11833/j.issn.2095-0756.20210814
[Abstract](12) [PDF](2)
Abstract:
  Objective  This study, with an investigation of the seasonal variation of photosynthetic capacity and adaptation mechanism of Magnolia sinostellata, an endangered plant under different light intensity, is aimed to provide a theoretical basis for population reproduction and rejuvenation and ex-situ protection.   Method  With two-year-old seedlings planted under three light conditions, including 100% of natural light intensity, 40% of natural light intensity, and 10% of natural light intensity, their photosynthetic characteristics in spring, summer and autumn were measured respectively.   Result  (1) The diurnal variations of the net photosynthetic rate of M. sinostellata under 100% of natural light intensity in spring and 100% of natural light intensity and 40% of natural light intensity in summer were all featured with a bimodal curve. (2) The maximum net photosynthetic rate, light saturation point, light compensation point under 100% of natural light intensity and 40% of natural light intensity in summer were significantly higher than those under 10% of natural light intensity whereas the maximum net photosynthetic rate and light saturation point under 100% of natural light intensity in autumn were significantly lower than those under 40% of natural light intensity and 10% of natural light intensity (P<0.05). (3) The maximum rate of electron transport and triose phosphate utilization rate under 100% of natural light intensity in summer and autumn were significantly lower than those under 40% of natural light intensity(P<0.05). (4) Under 100% of natural light intensity, the maximum quantum yield of photochemical energy conversion (Fv/Fm) value was 0.68 in summer and 0.72 in autumn while the photochemical quenching and the effective quantum yield of photochemical energy conversion under 40% of natural light intensity in summer were significantly higher than that in spring and autumn (P<0.05).   Conclusion  Under 100% of natural light intensity, the net photosynthetic rate of M. sinostellata seedlings in autumn significantly decreased, which might attribute to the damage done to leaves by the high temperature and high intensity of light in summer. However, M. sinostellata seedlings under proper shading could maintain relatively higher photosynthetic rate in three seasons. Therefore, it is recommended that photosynthetically active radiation at more than 40% of the natural light intensity is adopted in cultivation. [Ch, 5 fig. 1 tab. 23 ref.]
Population structure and dynamic characteristics of Quercus mongolica in Wudalianchi Volcanoes, China
XIE Lihong, HUANG Qingyang, CAO Hongjie, YANG Fan, WANG Jifeng, WANG Jianbo, NI Hongwei
2022, 39(5): 960-970.   doi: 10.11833/j.issn.2095-0756.20210785
[Abstract](27) [HTML](3) [PDF](8)
Abstract:
  Objective  This study aims to investigate the population structure characteristics of Quercus mongolica on the south slope of four old volcanoes in Wudalianchi, reveal the survival status of the population and predict the population development trend, so as to provide scientific basis for the succession, restoration and sustainable development of forest vegetation in Wudalianchi.   Method  Based on field survey and data analysis, the population age structure diagram, static life table, and survival curve were drawn. The population structure and dynamics were studied using survival analysis and quantitative dynamics analysis. The population development trend was predicted by time-sequence model.   Result  The population of Q. mongolica in the four volcanoes was young and insufficient, mainly composed of mature trees of age class Ⅴ−Ⅶ, which showed a stable population, and the survival curve was Deevey Ⅱ type. The survival analysis showed that the four populations gradually declined in the early stage and tended to be stable in the middle stage, but the risk function increased sharply, and the population began to enter the physiological decline period after this age class, indicating that the population had a decline trend in the later stage. The population dynamic analysis indicated that the population index Vpi of Q. mongolica in East Jiaodebu Volcano, Xiaogu Volcano and South Gelaqiu Volcano was greater than 0, belonging to the growing type, and V'pi was equal to or close to 0, indicating that the population was a stable type. The population dynamic index Vpi <0 and V'pi<0 in Wei Volcano indicated that the population was a declining type. And the four populations were highly sensitive to external random interference. Time series prediction showed that the number of Q. mongolica individuals of the four populations would decrease after 2, 4, and 6 age classes in the future.   Conclusion  The four populations are stable at present, but the number of individuals decreases significantly due to the limited resources in the sapling stage, which leads to the low development potential of aged individuals in the population and forms a bottleneck of regeneration and development, and the population tends to decline in the later stage. [Ch, 5 fig. 5 tab. 40 ref.]
Forest above ground biomass estimation using airborne P band polarimetric SAR data
JI Yongjie, YANG Congrui, ZHANG Wangfei, ZENG Peng, ZHANG Fuxiang, QU Ya’ni
2022, 39(5): 971-980.   doi: 10.11833/j.issn.2095-0756.20220111
[Abstract](47) [HTML](23) [PDF](9)
Abstract:
  Objective  Forests play an important role in carbon sequestration in terrestrial ecosystems. The spatial accurate quantification of forest biomass is of great significance to understand terrestrial carbon reserves, carbon budget, carbon balance and the resulting global climate change. Taking the advantage of the longer wavelength of P-band and higher penetration ability in the forest, the feasibility of improving the accuracy of forest above ground biomass (AGB) estimation using airborne P-band SAR data need to be studied .   Method  Based on the domestic airborne P band full polarimetric SAR data, 20 polarimetric SAR features are extracted, and were analyzed their sensitivity to change of forest AGB. Multiple linear regression model (MLR), k-nearest neighbor method (KNN), support vector regression (SVR) and random forest (RF), which were more popular forest AGB estimation models in previous studies, were used and compared in forest AGB estimation in this study.   Result  The results showed that polarimetric features including co-polarimetric backscatter coefficients, odd and double bounce scattering components extracted from Freeman-Durden and Yamaguchi decomposition methods, alpha from H-A-ALPHA decomposition method and polarization discrimination ratio (PDR), the extended polarimetric feature were sensitive to the change of forest AGB. The relative errors of estimated AGB using the four estimation methods were all about 30%, among which the accuracy of MLR estimation result was the lowest, with accurancy of 63.55% and root mean square error (RMSE) of 19.16 t·hm−2; The accuracy of RF estimation result was the highest, with Acc of 72.97% and RMSE of 15.98 t·hm−2; There is no significant difference between the accuracies between the estimated results of KNN and SVR, and the values of RMSE for them were 17.04 and 17.09 t·hm−2, respectively.   Conclusion  P-band SAR data has certain potential for estimating forest AGB. The estimation results of nonparametric method are significantly better than those of MLR. The AGB estimation accuracy of P-band is obviously affected by the level of forest AGB to be estimated, and the estimation accuracy is higher in the group with higher forest AGB level. In the study area, with an average forest AGB around 45 t·hm−2 and maximum value around 120 t·hm−2, the accurancy value for the estimated forest AGB at group with all AGB values lower than 50 t·hm−2 was lower around 6% than the value at group with all forest AGB values higher than 50 t·hm−2. [Ch, 5 fig. 3 tab. 34 ref.]
Estimation method of Phyllostachys edulis forest canopy density based on UAV visible image
WANG Yuyang, WANG Yixiang, LI Mingzhe, LIANG Dan
2022, 39(5): 981-988.   doi: 10.11833/j.issn.2095-0756.20210576
[Abstract](42) [HTML](26) [PDF](9)
Abstract:
  Objective  Due to the growth and management characteristics of Phyllostachys edulis forest, the canopy density of Ph. edulis forest is a very important factor in the management. This study aims to explore the estimation method of canopy density of Ph. edulis forest based on unmanned aerial vehicle (UAV) visible image, which can achieve real-time and rapid acquisition of Ph. edulis forest canopy density.   Method  The visible light image of Ph. edulis forest of common rotor UAV was taken as the research object. 4 mature digital image processing methods were adopted, namely, threshold classification based on pixel, supervised classification based on pixel, threshold classification based on multi-scale segmentation, and supervised classification based on multi-scale segmentation. 36 sample plots with different truncation conditions and canopy density were selected. Using the existing software and MATLAB programming, the Ph. edulis canopy area in each sample plot was rapidly extracted, and then the canopy density was estimated. The estimation accuracy of the canopy density of each method was compared with the true value calculated by visual interpretation, and the performance of the 4 methods under different truncation and different canopy density conditions was compared and analyzed.   Result  The overall accuracy of threshold classification based on pixel, supervised classification based on pixel, threshold classification based on multi-scale segmentation, and supervised classification based on multi-scale segmentation was 91.81%, 92.96%, 93.47% and 98.86%, respectively. The absolute error of the estimated value of canopy density of the 4 methods was 0.038, 0.030, 0.024 and 0.004, respectively. Truncation condition and canopy density had no significant effect on the extraction results.   Conclusion  The supervised classification method based on multi-scale segmentation has the highest overall accuracy and the smallest absolute error. It can quickly and accurately extract and estimate the canopy density of Ph. edulis forest, and is suitable for different management types of Ph. edulis forest. [Ch, 2 fig. 6 tab. 28 ref.]
Potential distribution of Camellia chekiangoleosa under future climate change
WANG Yannan, LAI Guozhen, HUANG Jianjian, LIU Liting, YU Liangsen, WEN Qiang, GONG Chun
2022, 39(5): 989-997.   doi: 10.11833/j.issn.2095-0756.20210641
[Abstract](101) [HTML](46) [PDF](11)
Abstract:
  Objective  As a unique Camellia tree species in south China as well as an emerging resource of Camellia with oil, medicinal and ornamental value, Camellia chekiangoleosa has great development potential. Therefore, this study is aimed to make a prediction of the potential distribution range of C. chekiangoleosa and conduct an analysis of the main environmental variables which impact its distribution so as to promote its conservation, utilization and introduction.   Method  With the employment of MaxEnt model, on the basis of the environmental variables of 55 distribution points in China, a prediction was made of the potential geographical distribution and change of C. chekiangoleosa in China under three RCPs climate change scenarios.   Result  (1) Precipitation of the coldest quarter, temperature and soil characteristics were the main environmental factor affecting the potential distribution with the first contributing the most, followed by the second and the third; (2) With central and southern China as the potential distribution areas currently, the core areas are mainly located in Jiangxi, Fujian and Zhejiang; (3) With future climate change as a norm, the overall potential distribution areas will expand to different degrees, showing a significant expansion trend from central China to the southwest.   Conclusion  Precipitation, temperature and soil characteristics were the main factors affecting the potential distribution of C. chekiangoleosa, with altitude playing a less significant role. It was also found that C. chekiangoleosa enjoys wide range of potential distribution in most areas of south China where efforts in their introduction, cultivation and popularization should be encouraged. [Ch, 2 fig. 2 tab. 41 ref.]
Functional analysis of AtJAR1 gene in salt tolerance of Arabidopsis thaliana
LI Dandan, LIN Rong, LI Xinguo, ZHENG Yueping
2022, 39(5): 998-1009.   doi: 10.11833/j.issn.2095-0756.20210742
[Abstract](131) [HTML](50) [PDF](12)
Abstract:
  Objective  Jasmonal amino acid conjugate synthase (JAR1) can catalyze jasmonic acid (JA) to form jasmonic acid-soleucine (JA-Ile), an active form of jasmonic acid, and activate the JA signal pathway. JA signaling pathway plays an important role in mediating the response of plants to salt stress. This study aims to explore the function of AtJAR1 in plant salt tolerance, which plays an important role in studying the mechanism of JA signal pathway affecting plant salt tolerance.   Method  CRISPR/cas9 gene editing technology was used to create two different Arabidopsis thaliana AtJAR1 gene mutants. The aboveground biomass of the two mutants and the expression of JA signal marker gene were analyzed to determine the loss of AtJAR1 gene function. Then, the effects of different concentrations of NaCl and ABA treatment on seed germination and seedling establishment of jar1 mutants were observed and analyzed to clarify the effect of AtJAR1 gene on salt tolerance of A. thaliana. Finally, the role of AtJAR1 gene in salt tolerance of A. thaliana was investigated by comparing the content of potassium and sodium ions in wild type and mutants before and after salt treatment, as well as the expression of AtHAK5, a high affinity potassium ion transporter gene.   Result  The expression of JA signal marker genes AtVSP1 and AtVSP2 decreased significantly, indicating the loss of AtJAR1 gene function. Different from the jar1-1 mutant produced by point mutation, the growth of the two mutants accelerated in the first three weeks, then gradually slowed down and the leaves wilted. At the same time, AtJAR1 mutation can alleviate the inhibition of salt stress and ABA on seed germination and root growth. In addition, AtJAR1 mutation can promote the expression of AtHAK5 and the absorption and transport of potassium ions in roots under salt stress.   Conclusion  JA signaling pathway may affect the expression of AtHAK5 through interaction with ABA, so as to regulate the absorption and transport of K+ by plant roots, change the intracellular K+/Na+ balance, and finally affect plant salt tolerance. [Ch, 8 fig. 2 tab. 52 ref.]
Effect of low phosphorus stress on growth and nutrient physiology of Phyllostachys edulis seedlings
ZHOU Jianfei, SHI Wenhui, PAN Kaiting, YING Yeqing, SUN Cui
2022, 39(5): 1010-1017.   doi: 10.11833/j.issn.2095-0756.20210782
[Abstract](88) [HTML](34) [PDF](15)
Abstract:
  Objective  To explore the effects of low phosphorus (P) stress on rhizosphere soil nutrient environment, as well as the growth and nutrient physiology of Phyllostachys edulis seedlings at different growth stages and their sustained effects, so as to analyze the adaptation mechanism of Ph. edulis seedlings to low P stress.   Method  Seeds of Ph. edulis were sown in pots to cultivate young seedlings. Rhizosphere soil nutrient environment, the biomass and its distribution of Ph. edulis seedlings, and the nutrient absorption, utilization and distribution of Ph. edulis seedlings at the end of the current growing season (T1) and the next rapid growing season (T2) were determined under four different soil available phosphorus conditions, 2.5 mg·kg−1 (very low phosphorus, P1), 5.0 mg·kg−1 (low phosphorus, P2), 10.0 mg·kg−1 (medium phosphorus, P3), 20.0 mg·kg−1 (suitable phosphorus, P4).   Result  Low P treatment group (P1, P2) significantly decreased pH in rhizosphere soil (P<0.05), and maintained the high N content of the rhizosphere soil at T1; The low P effect continued to T2, and the organic matter content of rhizosphere soil of P1 and P2 was significantly increased by 10.70% compared with that of P4 at this season (P<0.05). Low P treatment group significantly reduced the biomass and the accumulation of N, P, K nutrients of Ph. edulis seedlings at both stages (P<0.05), but the decline at T2 was higher than that at T1. At T1, the low P treatment group significantly reduced the root shoot ratio (R/S) and relatively reduced the proportion ratio of nutrients in the root of Ph. edulis seedlings; However, at T2, the R/S of the low P treatment group was significantly increased by 44.30% and 37.97% compared P4 (P<0.05), and the distribution ratio of N and K nutrients in the root was also significantly increased. The low P treatment group significantly increased the phosphorus use efficiency (PUE) of the whole plant of Ph. edulis seedlings (P<0.05), the PUE decreased with the passage of seedlings time, only P1 significanlty increased by 19.05% compared with P4 at T2 (P<0.05).   Conclusion  Low P stress inhibited the growth and nutrient accumulation of Ph. edulis seedlings, but increased the overall PUE. With the extension of seedling time to the next rapid growing season, the inhibition effect of low P stress on the plant was enhanced, but the adaptability of Ph. edulis seedlings to low P stress was improved by increasing the root-shoot ratio and the proportion of nutrient distribution to root. [Ch, 2 fig. 4 tab. 25 ref.]
Effect of litter physical barrier on emergence and early growth of Metasequoia glyptostroboides seedlings
XU Laixian, GUO Qiuju, YAO Lan, HONG Jianfeng, MOU Furong, AI Xunru, LIU Xuequan, ZHAO Huandun
2022, 39(5): 1018-1027.   doi: 10.11833/j.issn.2095-0756.20210704
[Abstract](68) [HTML](43) [PDF](16)
Abstract:
  Objective  This study aims to explore the effect of physical barrier of litter from Metasequoia glyptostroboides mother tree on its natural regeneration, so as to provide scientific basis for removing obstacles of M. glyptostroboides natural regeneration and protecting its population.   Method  Through field simulation experiments, different types of litter (fresh litter and natural litter) with different mass gradients (0, 100, 300, 500, 700 and 900 g·m−2) were used to investigate the effect of litter on emergence and early growth of M. glyptostroboides seedlings by spreading litter on the lower layer of seeds and covering litter on the upper layer of seeds.   Result  (1) Litter inhibited the seed emergence rate and seedling survival rate of M. glyptostroboides, and the inhibitory effect was significantly enhanced when the litter mass was 300−900 g·m−2 (P<0.05). (2) Except for spreading natural litter on the lower layer of seeds, the other treatments promoted the growth of seedling height and ground diameter M. glyptostroboides seedlings when the litter mass was 300 g·m−2 (P>0.05), but the difference with the control was not significant. When the litter mass was higher than 300 g·m−2, all treatments inhibited seedling growth. With the increase of litter mass, the inhibitory effect on the root length of M. glyptostroboides seedlings enhanced gradually. (3) With the increase of litter mass, the aboveground biomass and underground biomass of M. glyptostroboides seedlings first increased and then decreased. There was a certain fluctuation only after 300 g·m−2 natural litter treatment on the low layer of seeds, and the other treatments inhibited the underground biomass accumulation of seedlings. The accumulation of aboveground and underground biomass of seedlings was significantly hindered when the litter mass was above 500 g·m−2 (P<0.05). (4) Under the same litter mass (>300 g·m−2), the inhibitory effect of fresh litter on the emergence and early growth of M. glyptostroboides seedling was greater than that of natural litter, and the inhibitory effect of litter on the lower layer of seeds was stronger than that on the upper layer of seeds.   Conclusion  The litter of M. glyptostroboides mother tree has an obvious physical barrier effect on the emergence and early growth of M. glyptostroboides seedlings, which affects the natural regeneration of M. glyptostroboides. Therefore, it is suggested to treat the litter of different types under M. glyptostroboides forests in time before the peak of seed rain, so as to promote the natural regeneration of M. glyptostroboides. [Ch, 4 fig. 2 tab. 29 ref.]
Effects of arbuscular mycorrhizal fungi symbiosis on growth and photosynthetic characteristics of Fraxinus malacophylla in rocky desertification habitats
YANG Bo, WANG Shaojun, ZHAO Shuang, ZHANG Lulu, ZHANG Kunfeng, FAN Yuxiang, XIE Lingling, WANG Zhengjun, GUO Zhipeng, XIAO Bo
2022, 39(5): 1028-1036.   doi: 10.11833/j.issn.2095-0756.20210740
[Abstract](86) [HTML](42) [PDF](4)
Abstract:
  Objective  This study aims to explore the effects of arbuscular mycorrhizal (AM) fungal symbiosis on growth and photosynthetic characteristics of Fraxinus malacophylla in rocky desertification habitats, so as to provide data reference for selecting dominant AM fungal species for vegetation restoration.   Method  An experiment was designed with four treatments: Funneliformis mosseae+agroforestry biofertilizer (MN), Claroideoglomus etunicatum+agroforestry biofertilizer (YN), Rhizophagus intraradices+agroforestry biofertilizer (GN) and agroforestry biofertilizer (ck). The changes in F. malacophylla growth (tree height, diameter at breast height, leaf and root biomass, leaf area, leaf pigment and chlorophyll) and photosynthetic characteristics (net photosynthetic rate, stomatal conductance, intercellular CO2 concentration, transpiration rate, and leaf water use efficiency, etc.) were measured under different treatments.   Result  (1) Inoculation with AM fungi significantly promoted the growth of F. malacophylla and biomass accumulation of leaf and root(P<0.05). (2) Inoculation with MN and GN significantly increased the relative contents of chlorophyll a, chlorophyll b and lutein in plant leaves (P<0.05), and the increase rate was 6%−67%. (3) Inoculation with AM fungi significantly increased the net photosynthetic rate, stomatal conductance, transpiration rate, and water use efficiency of F. malacophylla (P<0.05), but significantly decreased the intercellular CO2 concentration (P<0.05). (4) Principal component analysis indicated that the stomatal conductance, tree height, and lutein were the key factors to increase the net photosynthetic rate, with an average contribution rate of 45.81%, followed by chlorophyll b, biomass and total chlorophyll.   Conclusion  AM fungal symbiosis can significantly improve the net photosynthetic rate of F. malacophylla by promoting plant growth and photosynthetic pigment content. The optimal strain is F. mosseae. [Ch, 5 fig. 2 tab. 33 ref.]
Effects of light intensity and nitrogen application on photosynthetic physiological parameters of Styrax obassia seedlings
ZHAO Nannan, WAN Qi, ZHANG Mingru, LI Qingxiang, ZHANG Tingyu, CAI Yihang
2022, 39(5): 1037-1044.   doi: 10.11833/j.issn.2095-0756.20210605
[Abstract](103) [HTML](31) [PDF](5)
Abstract:
  Objective   This study aims to screen the combination treatment of light intensity and nitrogen application that is more conducive to the expression of photosynthetic physiological parameters, so as to reveal the relationship between the changes of light intensity and nitrogen and the growth of Styrax obassia seedlings.  Method   Potted seedling cultivation method was adopted to construct the two-factor control test of light and nitrogen. Four shading treatments were prepared: all-light control with 100.00% transmittance, light shading with 47.30% transmittance (L1), moderate shading with 20.00% (L2) and high shading 7.75% (L3). Three nitrogen application treatments were included: N2 (0.63 g pure nitrogen), N1 (0.21 g pure nitrogen) and N0 (no nitrogen application). The light response process and the variation characteristics of photosynthetic pigment content were determined and analyzed.   Result   (1)With the increase of shading degree and nitrogen application rate, net photosynthetic rate (Pn), apparent quantum efficiency (AQY) and total chlorophyll (Chl) content of S. obassia seedlings increased, while dark respiration rate (Rd) decreased, and light saturation point (LSP) ranged from 140.00 to 481.33 μmol·m−2·s−1. Light compensation point (LCP) varied from 6.00 to 34.67 μmol·m−2·s−1, and the ratio of Chl a to Chl b was less than 2. (2) Under all light and L1 shading+N2 treatment, the plants died. (3) Under L1 shading, the change of Pn ranging from large to small was N1, N0, and N2. Under L3 shading, when photosynthetic effective radiation (PAR)was greater than 400 μmol·m−2·s−1, the Pn of N2 was significantly higher than that of N0 and N1 (P<0.05). (4) Both light intensity and nitrogen application had significant effects on photosynthetic pigment content (P<0.01), and the influence trend in descending order was light, nitrogen, and light+nitrogen.   Conclusion  The seedlings of S. obassia have strong shade tolerance, and the optimal combination treatment of light and nitrogen is L3+N2. [Ch, 1 fig. 3 tab. 26 ref.]
Replacing peat with garden waste compost in Cosmos bipinnata cultivation
YIN Zexin, ZHANG Lu, BAI Yifan
2022, 39(5): 1045-1051.   doi: 10.11833/j.issn.2095-0756.20210829
[Abstract](53) [HTML](30) [PDF](10)
Abstract:
  Objective  This study aims to explore the feasibility of using green waste compost as the Cosmos bipinnata cultivation substrate instead of peat, so as to achieve the scientific, economic and effective utilization of green waste and reduce the use of peat in flower cultivation.  Method  Green waste compost and peat were prepared into 5 kinds of cultivation substrates according to different proportions [100% green waste compost (T100), 75% green waste compost+25% peat (T75), 50% green waste compost+50% peat (T50), 25% green waste compost+75% peat (T25), and 100% peat (T0)]. T100 and T0 were used as the control for the cultivation test of C. bipinnata. By comparing the physical and chemical properties of different cultivation substrates and the growth index of C. bipinnata, the cultivation substrate with the best proportion of garden waste compost and peat was selected.   Result  Adding green waste compost could significantly increase the contents of total nitrogen, total phosphorus, total potassium, available phosphorus, and available potassium in the cultivation substrate(P<0.05), and improve the bulk density, maximum water content, total porosity, aeration pores, and acid-base environment of the cultivation substrate. The physical and chemical properties of the cultivation substrate were the best when the addition ratio of green waste compost was 50%. Compared with the control (T0), the fresh weight of aboveground parts, the dry weight of aboveground parts, the fresh weight of underground parts, and the dry weight of underground parts in T50 culture increased by 390.4%, 322.2%, 145.6%, and 93.1%, respectively. The plant height, the flower number, and the root length of C. bipinnata increased by 137.4%, 109.0%, and 95.7% respectively.   Conclusion  Green waste compost can partially replace peat for C. bipinnata cultivation, and the cultivation substrate composed of 50% green waste compost + 50% peat is the most favorable for the growth of C. bipinnata, which can better replace peat as the cultivation substrate of C. bipinnata for garden greening. [Ch, 5 tab. 25 ref.]
Dust-retention capability evaluation of six species of Syringa and their leaf surface micromorphology
ZHONG Yuting, ZHANG Ying, ZHAO Bing
2022, 39(5): 1052-1058.   doi: 10.11833/j.issn.2095-0756.20210587
[Abstract](71) [HTML](37) [PDF](8)
Abstract:
  Objective  This study is aimed to screen out Syringa plants with strong dust-retention capability so as to promote the ecological function of Syringa in urban greening.   Method  With six species of Syringa selected as the research materials, the three-layer filter method was first used to determine the particles of plants passing through filters with different pore sizes during the full-leaf period. Then the micromorphology of the leaf surface of the Syringa was observed before an investigation was conducted of the influence of the leaf micromorphology and the dust retention effect of the plant.   Result  (1) there were significant differences in the dust retention capabilities of Syringa plants(P<0.05) with the order of the comprehensive dust-retention capability per unit leaf area of the 6 Syringa species for the full-leaf stage being S. chinensisS. pekinensisS. vulgarisS. oblataS. reticulata var. amurensisS. oblata var. alta. (2) it can be seen that S. chinensis had the strongest comprehensive dust-retention capability per unit leaf area whereas through microstructure observation, it was found that the upper surface of the assorted S. chinensis had deep grooves and dense folds around the stomata on the lower surface, which helps with the retention of particles. (3) from the perspective of the partial correlation coefficient, there isn’t a significant correlation (P>0.05) between the leaf surface micromorphology parameters and the retention of dust (UTSP and UPM2.5).   Conclusion  The depth of the trench may be one of the factors that affect the dust retention of plants and S. chinensis is recommended as an excellent garden dust-retaining shrub specie and can be widely used to retent dust pollution. [Ch, 2 fig. 3 tab. 26 ref.]
Transfer coefficient and distribution characteristics of Cd in low absorption rice cultivars under Cd stress
JIA Junwei, CHEN Zhenhua, LIAO Shiyan, LUO Wenxuan, XU Weijie, ZHONG Bin, MA Jiawei, YE Zhengqian, LIU Dan
2022, 39(5): 1059-1066.   doi: 10.11833/j.issn.2095-0756.20210402
[Abstract](46) [HTML](30) [PDF](6)
Abstract:
  Objective  The purpose is to explore the difference of Cd absorption and accumulation among different low absorption rice (Oryza sativa) cultivars in Cd polluted farmland and their distribution characteristics in different growth stages.  Method  5 cultivars with low Cd absorption were selected: ‘Zhongzheyou 1’, ‘Zhongzheyou 8’,‘Huazheyou 71’,‘Yongyou 17’and‘Yongyou 1540’. A field experiment was carried out in a village of Jingning County, Lishui City, Zhejiang Province, to explore the growth and Cd uptake and transport characteristics of 5 low absorption cultivars of rice.   Result  There were differences in the accumulation of Cd in different organs of the same rice variety. At jointing stage and booting stage, the mass fraction of Cd from large to small was root, stem, leaf and ear. At the maturity stage, the Cd content of rice cultivars other than ‘Zhongzheyou 8’ was stem, root, leaf, brown rice and rice husk in descending order. Among the different rice cultivars, Cd content in the root of ‘Huazheyou 71’ was significantly lower than that of other cultivars (P<0.05), and Cd content in the stem and brown rice of ‘Zhongzheyou 8’ was significantly lower than that of other cultivars (P<0.05). The accumulation of Cd in the same organs of the same rice cultivars at different growth stages was different. The mass fraction of Cd in roots, stems and leaves from small to large showed as tillering stage, jointing stage, booting stage and maturity stage. The yield, 1000-grain weight and tiller number of ‘Zhongzheyou 8’ were higher than those of other cultivars. In different rice cultivars, the content of Cd in brown rice was not significantly correlated with 1000-grain weight, rice yield, soil total Cd content and soil available Cd content.   Conclusion  ‘Zhongzheyou 8’ is selected as the preferred cultivars in Cd polluted paddy field, and its low absorption and accumulation characteristics can be further discussed in the later stage. [Ch, 1 fig. 5 tab. 32 ref.]
Temporal and spatial relationship between spiders and Ricanidae in tea gardens
XU Yue, WU Xiaomeng, CHEN Shiyan, CHENG Honghao, ZHANG Lin, ZHOU Xiazhi, ZOU Yunding, BI Shoudong
2022, 39(5): 1067-1079.   doi: 10.11833/j.issn.2095-0756.20210734
[Abstract](74) [HTML](58) [PDF](5)
Abstract:
  Objective  The objective is to exlore the temporal and spatial relationship between natural enemies of spiders and Ricanidae, so as to provide scientific basis for the use and protection of natural enemies.  Method  Geostatistics, grey system analysis and niche analysis were used to analyze the population dynamics of Ricanidae and 11 spiders during their blooming period in 6 kinds of tea gardens, including ‘Anjibaicha’, ‘Huangshandayezhong’, ‘Longjing 43’, ‘Nongkangzao’, ‘Pingyangtezao’ and ‘Wuniuzao’. The close degree of temporal and spatial relationship between 11 species of spiders and Ricanidaein was studied.  Result  According to the sum of spatial closeness indices of the 6 tea plantations, the top 5 spiders closely related to the space of Ricanidae were Xysticus ephippiafus (5.7415), Oxyopes sertatus (5.6942), Erigonidium graminicolum (5.6986), Theridion octomaculatum (5.6502) and Clubiona japonicola (5.5373) in descending order. According to the sum of time relationship index, the top 5 spiders closely related to the time of Ricanidae were E. graminicolum (5.6026), Misumenops tricuspidatus (5.4279), Theridion octomaculatum (5.3519), Tetragnatha squamata (5.0791) and Tetragnatha maxillosa (5.0686).   Conclusion  According to the comprehensive analysis, the top 3 spiders closely related to the time and space of Ricanidae from large to small are E. graminicolum (11.2912), Theridion octomaculatum (11.0021) and M. tricuspidatus (10.9935). [Ch, 10 tab. 27 ref.]
Isolation and identification of pathogenic fungi of stem rot in Crocus sativus
WU Jiening, GUI Siqi, CAO Jiajia, DU Xue, LI Junbo, LI Xiujuan, KAI Guoyin, ZHOU Wei
2022, 39(5): 1080-1086.   doi: 10.11833/j.issn.2095-0756.20210768
[Abstract](101) [HTML](51) [PDF](9)
Abstract:
  Objective  This study, with an investigation into the identification and isolation of the rot disease pathogen of Crocus sativus, the main disease of which is fungal disease, is intended to provide scientific basis for the prevention and control of saffron stem rot and the development of special fungicides.   Method  First, the pathogenic fungi were isolated from infected corms by tissue separation method using ‘Saffron No. 1’ as the test material. Then an analysis was made of the sequences of conserved internal transcribed spacer (ITS) and RNA polymerase Ⅱ subfamily (RPB2) by PCR amplification, sequencing and phylogenetic tree construction. At last, pathogenic bacteria were isolated from infected corms and grafted back to plants to verify the pathogenic characteristics of fungi under the planting mode of saffron.   Result  The morphological characteristics of the corm-pathogenic fungi isolated were highly similar to those of Aspergillus niger. The conserved sequences of ITS and RPB2 of the candidate pathogenic fungi had 99.6% homology to the same DNA sequence of A. niger from other plants with the same evolutionary branch. In the soil planting mode, inoculation with A. niger solution significantly increased the incidence of corm (P<0.01).   Conclusion  A. niger is one of the fungal diseases that cause the rot of saffron bulbs. [Ch, 7 fig. 32 ref.]
Quantitative real-time PCR for rapid detection of Rhizoctonia solani and Sclerotium rolfsii in urban green space
LUO Shuhong, LUO Yuzhen, ZHAO Yingying, ZHANG Weiwei, LIU Wen, HE Shanwen, AN Lei, WANG Yongjie, HAN Jigang
2022, 39(5): 1087-1095.   doi: 10.11833/j.issn.2095-0756.20210801
[Abstract](54) [HTML](33) [PDF](10)
Abstract:
  Objective  This study aims to establish a rapid quantitative detection method for Rhizoctonia solani and Sclerotium rolfsii, 2 soil-borne pathogenic fungi that seriously threaten the normal growth of landscape plants in Shanghai.   Method  The reaction conditions were optimized by screening 2 pathogen specific primers.   Result  A quantitative real-time PCR (qPCR) method was established for the detection of the two pathogens. The primers ST-RS1/ITS4 and SRITSF/SRITSR could be used for qPCR detection of R. solani and S. rolfsii, with sensitivity of 24×106 and 22×106 copies·L−1, respectively. The coefficients of variation of the 2 repeated reactions were 3.37%−4.61% and 0.66%−8.61%, respectively. The detection results of soil samples in Shanghai green space showed that the detection rates of R. solani and S. rolfsii were 100% and 19%, respectively.   Conclusion  The established qPCR method has high specificity, sensitivity and repeatability, and can be used for rapid and effective quantitative detection of R. solani and S. rolfsii in Shanghai urban green soil. [Ch, 2 fig. 5 tab. 29 ref.]
A highly sensitive qualitative and quantitative immunochromatographic method for the detection of aflatoxin B1
ZHANG Xian, WANG Jixuan, CHENG Gaochuan, LI Ke, ZHANG Xiaofeng, SUN Mengjiao, CHENG Changyong, SONG Houhui
2022, 39(5): 1096-1103.   doi: 10.11833/j.issn.2095-0756.20210772
[Abstract](91) [HTML](42) [PDF](7)
Abstract:
  Objective  Fungal metabolites, commonly known as mycotoxins, can pollute agricultural products and food of animal origin, among which aflatoxin B1 (AFB1) is the most common, toxic and detrimental. Establishing a rapid, highly sensitive and convenient detection method of AFB1 is of great significance for the protection of human and animal health. The objective of this study is to optimize the immunochromatographic detection method based on the principle of lateral-flow chromatography and competitive mode, so as to realize the rapid qualitative detection and quantitative analysis of AFB1.   Method  A highly sensitive qualitative and quantitative immunochromatographic detection method for AFB1 was established by comparing and analyzing the labeling effects of gold particles of varying sizes, optimizing the material types of each component of immunochromatography, as well as relevant buffer solution and the optimal mass concentration.   Result  The qualitative and quantitative detection limits of the optimized AFB1 immunochromatographic method in samples were 2.5 and 0.5 μg·kg−1, respectively, with high sensitivity and specificity and no cross reaction with other common mycotoxins. Standard addition recovery experiment showed that the method was accurate and stable, and the quantitative detection results of AFB1 natural contamination samples were in good agreement with commercial kit and LC-MS/MS.   Conclusion  The immunochromatographic detection method prepared in this study can be used for rapid qualitative detection and quantitative analysis of AFB1 contamination in samples. It is suitable for grass-roots inspection and quarantine institutions and agricultural product processing enterprises that lack experimental conditions to quickly screen a large number of samples. If the sample test result is suspected to be positive, the instrument method can be used for confirmation, which can reduce the test cost, improve the test efficiency and provide reference for the establishment of immunochromatographic detection methods for other pathogenic microorganisms. [Ch, 9 fig. 2 tab. 26 ref.]
Spatial pattern and its influencing factors of water conservation services in Xijiang River Basin, Guangxi
ZHANG Chenghu, LIU Ju, HU Baoqing, CHEN Xiufen
2022, 39(5): 1104-1113.   doi: 10.11833/j.issn.2095-0756.20210616
[Abstract](78) [HTML](43) [PDF](11)
Abstract:
  Objective  Water conservation plays an important role in ecosystem services. This study aims to reveal the spatial pattern and its influencing factors of water conservation services and identify the important areas of water conservation services, which is of great significance to utilization, regional management and comprehensive protection of water resources in the basin.   Method  Taking Xijiang River Basin in Guangxi as the research object, with the support of the InVEST model, GeoDa, ArcGIS and other tools, the spatial pattern of water conservation services in the research area was tested by using global and local spatial autocorrelation, and the spatial error model was constructed to identify the key factors affecting water conservation services. Quantile classification method was used to classify the importance of water conservation services.   Result  The average annual water conservation capacity of Xijiang River Basin in Guangxi was 185.36 mm, with a total water amount of 37.61 billion m3 in 2015. The global Moran index was 0.769, indicating that the spatial distribution of water conservation services in the study area was spatially dependent. Considering the influence of multicollinearity, 7 of the 13 influencing factors were finally selected into the spatial error model. The results showed that soil saturated hydraulic conductivity, annual average precipitation, slope, net primary productivity of vegetation (NPP) and economic density had significant positive effects on water conservation services, while population density and impervious surface rate had significant negative impacts on water conservation services. Qianxunjiang River Basin and the southern region of Zuoyujiang River Basin were identified as important areas for water conservation services, which should be prioritized in relevant policy making and management decision.   Conclusion  The spatial distribution of water conservation services in Xijiang River Basin in Guangxi presents a clustering distribution, dominated by low-low aggregation and high-high aggregation types. Soil saturated hydraulic conductivity, annual average precipitation, slope and impervious surface rate are the main factors affecting water conservation services. [Ch, 5 fig. 2 tab. 28 ref.]
Evaluation of wetland ecological security in Wujiang District of Suzhou based on DPSIRM model
ZHU Ying, GU Chunwang, LI Xin, ZHOU Tingting, FENG Yuqing
2022, 39(5): 1114-1123.   doi: 10.11833/j.issn.2095-0756.20210758
[Abstract](73) [HTML](41) [PDF](7)
Abstract:
  Objective  This study is aimed to conduct a scientific evaluation of wetland ecological security in water network area so as to provide basis for regional ecological security and high-quality development.   Method  With Wujiang District of Suzhou as the research object, on the basis of the threats faced by the wetland in the water network area in the process of urban development, first, an evaluation index system was constructed employing the DPSIRM model (driving-force-pressure-stae-impact-response-management) after which the combined weighting method was used to give the index weight; then some indexes were spatially quantified in combination with Geographic Information System (GIS) grid technology; finally, the comprehensive evaluation method was adopted to evaluate the wetland ecological security of Wujiang District from 2012 to 2020.   Result  In 2012, 2016 and 2020, the ecological security values of wetlands in Wujiang District were 0.394 4, 0.455 2 and 0.516 4 respectively, which evolved from low security and medium security to high security. The high value areas in each period were mainly concentrated along the coast of Taihu Lake, Zhenze area, Beimayang area, Tongli Lake area, Sanbaidang area and Yuandang area. Based on the analysis of DPSIRM model, the safety value of management, impact and driving force subsystem had increased significantly, that of the pressure subsystem had decreased, whereas that of the state and response subsystem had first decreased and then increased.   Conclusion  During the study period, the ecological security values of wetlands in Wujiang District showed an overall upward state. However, in the future ecological protection of wetlands, devoted efforts should be made to the regulate pressure indicators, strengthen the control of areas with low ecological security level, and maintain high-intensity management measures. [Ch, 8 fig. 1 tab. 31 ref.]
Research on the spatial distribution of forest parks and tourism development in Zhejiang Province
ZHANG Jianguo, XU Xian
2022, 39(5): 1124-1132.   doi: 10.11833/j.issn.2095-0756.20210252
[Abstract](67) [HTML](114) [PDF](11)
Abstract:
  Objective  In order to explore the spatial distribution characteristics and tourism development model of forest parks in Zhejiang Province.   Method  Taking 128 national forest parks and provincial forest parks in Zhejiang province as research objects, this paper studied their spatial distribution characteristics, equilibrium situation and distribution density by using the nearest proximity index, kernel density analysis, geographic concentration index and other analysis methods, and combined with qualitative analysis, studied the development process and tourism development model of Zhejiang forest parks.   Result  (1) The overall spatial distribution of forest parks in Zhejiang Province is random, Zhoushan City, Taizhou City and Quzhou City are uniformly distributed, Ningbo and Shaoxing show random and discrete distribution, while Wenzhou City, Lishui City, Huzhou City, Hangzhou City and Jinhua City are randomly distributed. (2) The distribution of forest parks is divided into three echelons according to the difference in nuclear density, and the distribution of forest parks in Zhejiang Province is divided into three echelons. The northeast of the country is the first tier, the centre and south are the second tier, and the west is the third tier. (3) The construction and development of the forest parks in Zhejiang Province are divided into 5 stages: the initial period of exploration (1982−1992), the period of rapid growth (1993−2001), the period of standardized construction (2002−2010), the period of connotation improvement (2011−2017) and the period of comprehensive development (2018−). (4) The tourism development of the forest parks in Zhejiang Province could be divided into five modes: suburban leisure, landscape tour, ecological vacation, forest sports and ecological education.   Conclusion  Under the restriction of multiple factors, forest parks in Zhejiang Province are unevenly distributed among prefectural cities, and their development patterns are different. In the future, the construction and tourism development of forest parks in Zhejiang Province should, on the basis of making full use of the conditions of forest resources, actively dovetail with the demand for forest tourism consumption, optimise the spatial layout structure; Improve the infrastructure conditions and enhance the market service capacity; Create special tourism brands and increase publicity efforts. [Ch, 2 fig. 2 tab. 23 ref.]
Reviews
Advances in seed respiration detection and its application
GAO Lu, LI Xiangge, QI Hengnian, ZANG Ying, JIA Liangquan, ZHAO Guangwu, TANG Qizhe, ZHENG Wen
2022, 39(5): 1133-1143.   doi: 10.11833/j.issn.2095-0756.20210748
[Abstract](134) [HTML](38) [PDF](11)
Abstract:
Seed respiration reflects a variety of internal properties and physiological and biochemical characteristics of seeds. The development of seed respiration detection methods is of great significance to the study of seed respiration metabolism. The methods of seed respiration detection and their application were reviewed. The focus of the review included working principle, main detection objects and operation principle of common seed respiration detection methods, such as small-skep-method, Warburg trace method, Clark oxygen electrode method, infrared CO2 analyzer method, oxygen sensing technology (Q2) and tunable diode laser absorption spectroscopy (TDLAS). The advantages, disadvantages and applicable scope of the above seed respiration detection methods were summarized. Secondly, the research and application of seed respiration detection methods in seed respiration metabolism, seed storage and seed vigor determination were discussed, with emphasis on the research progress of the correlation between seed respiration detection technology and seed vigor. Finally, based on the research status, seed respiration detection methods, their research and application direction were prospected: (1) It is expected to develop a seed respiration detection method and equipment with higher sensitivity and simpler operation based on optical detection technology such as TDLAS. (2) The study of seed respiration metabolism and its influencing factors is helpful to enrich and deeply reveal the theory of seed respiration metabolism. (3) Research on seed respiration index and seed vigor parameters should be carried out to provide important parameters to explore the possibility of using seed respiration intensity as an effective indicator to judge seed vigor. [Ch, 1 tab. 60 ref.]
Research progress on soil microorganisms in eucalypt forests
WEI Juxian, WANG Cong, HE Bin, YOU Yeming, HUANG Xueman
2022, 39(5): 1144-1154.   doi: 10.11833/j.issn.2095-0756.20210701
[Abstract](105) [HTML](36) [PDF](7)
Abstract:
As one of the three major fast-growing tree species in the world, eucalypt is featured with great variety, strong resistance to stress and wide adaptability. It is significant to research the diversity and functions of soil microorganisms which affect the growth of trees by participating in the processes of nutrient element cycling and energy flow and play an important role in improving soil fertility and productivity. However, with limitations in knowledge of soil microbial communities and functions due to the complexity of the eucalypt forest ecosystem and research techniques of soil microbiology, researches on the characteristics of soil microbial communities in eucalypt forests so far are still in the primary stage. This study is aimed to conduct a systematic review of the research progress on soil microbial characters in eucalypt forests with different management patterns, stand types and stand ages. Compared with natural forests of eucalypt, there was generally a lower soil microbial abundance in eucalypt plantations whereas there was an increase in the abundance, diversity, and activity of soil microorganisms in eucalypt mixed forests compared with eucalypt plantation pure forests and the abundance of soil microorganisms in eucalypt forests generally increased with the age of the forest, while the diversity of ectomycorrhizal and endomycorrhizal fungi decreased with the age of the forest. In addition, with an analysis of the mechanism of soil microorganisms involved in nutrient element cycling and remediation of heavy metal pollution in eucalypt forests and prospects of future research and analyzing methods of soil microbiome and application of microorganisms, this study will provide scientific guidance for the maintenance of forest soil health and the promotion of green and sustainable forestry development. [Ch, 1 tab. 94 ref.]

Bimonthly, Start in 1984

Supervisor:Department of Education of Zhejiang Province

Sponsor:Zhejiang A&F University

Editor-in-Chief:SHEN Xi

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

Tel:0571-63732749,0571-61060968

E-mail:zlxb@zafu.edu.cn

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