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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).
Metabolome of nematicidal fungus Esteya vermicola in carbon and nitrogen culture
LI Xingpeng, ZHANG Yang, WANG Ruizhen, DONG Leiming
, Available online  doi: 10.11833/j.issn.2095-0756.20210828
  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.]
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
, Available online  doi: 10.11833/j.issn.2095-0756.20220181
  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.]
Spatial pattern and its influencing factors of water conservation services in Xijiang River Basin, Guangxi
ZHANG Chenghu, LIU Ju, HU Baoqing, CHEN Xiufen
, Available online  doi: 10.11833/j.issn.2095-0756.20210616
  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.]
Effect of low phosphorus stress on growth and nutrient physiology of Phyllostachys edulis seedlings
ZHOU Jianfei, SHI Wenhui, PAN Kaiting, YING Yeqing, SUN Cui
, Available online  doi: 10.11833/j.issn.2095-0756.20210782
  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.]
Dust-retention capability evaluation of six species of Syringa and their leaf surface micromorphology
ZHONG Yuting, ZHANG Ying, ZHAO Bing
, Available online  doi: 10.11833/j.issn.2095-0756.20210587
  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 in industrial clusters, campuses, roads and other places in the treatment of air pollution. [Ch, 2 fig. 3 tab. 26 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
, Available online  doi: 10.11833/j.issn.2095-0756.20210820
  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.]
Potential distribution of Camellia chekiangoleosa under future climate change
WANG Yannan, LAI Guozhen, HUANG Jianjian, LIU Liting, YU Liangsen, WEN Qiang, GONG Chun
, Available online  doi: 10.11833/j.issn.2095-0756.20210641
  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.]
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
, Available online  doi: 10.11833/j.issn.2095-0756.20210801
  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.]
Research on the spatial distribution of forest parks and tourism development in Zhejiang Province
ZHANG Jianguo, XU Xian
, Available online  doi: 10.11833/j.issn.2095-0756.20210252
  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.]
Evaluation of wetland ecological security in Wujiang District of Suzhou based on DPSIRM model
ZHU Ying, GU Chunwang, LI Xin, ZHOU Tingting, FENG Yuqing
, Available online  doi: 10.11833/j.issn.2095-0756.20210758
  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.]
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
, Available online  doi: 10.11833/j.issn.2095-0756.20210704
  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.]
Advances in seed respiration detection and its application
GAO Lu, LI Xiangge, QI Hengnian, ZANG Ying, JIA Liangquan, ZHAO Guangwu, TANG Qizhe, ZHENG Wen
, Available online  doi: 10.11833/j.issn.2095-0756.20210748
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 in this paper. 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.]
Taxonomic study of Cayratia s.l. from Zhejiang, China
XIE Wenyuan, LU Yifei, CHEN Zhenghai, JIN Xiaofeng
, Available online  doi: 10.11833/j.issn.2095-0756.20210751
  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.]
Functional analysis of AtJAR1 gene in salt tolerance of Arabidopsis thaliana
LI Dandan, LIN Rong, LI Xinguo, ZHENG Yueping
, Available online  doi: 10.11833/j.issn.2095-0756.20210742
  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.]
Analysis of genetic diversity of Bletilla striata germplasm by ISSR and SRAP markers
WANG Jie, ZHU Xipeng, WANG Tengfei, ZHU Jianjun, LI Wenjun, XING Bingcong, ZHENG Ying
, Available online  doi: 10.11833/j.issn.2095-0756.20210690
  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.]
Research advances in the mechanism of adventitious root occurrence in woody species
MIAO Dapeng, JIA Ruirui, LI Shenghao, XI Shuo, ZHU Ge, WEN Shusheng
, Available online  doi: 10.11833/j.issn.2095-0756.20210652
The difficulty in the occurrence of adventitious roots which are produced by non-pericyclic tissues such as stems and leaves of plants, has been a bottleneck problem for the asexual reproduction and industrialized seedling raising of many woody species. However, there hasn’ t been a clear concept about the working mechanism of adventitious root occurrence, related mechanism is still unclear. At present, the research progress on the mainly includes the following three aspects: (1) With the formation time and position of root observed by paraffin section technology, it was found that the formation of root primordium is the key to adventitious roots and the process of adventitious root formation can be divided into three main periods according to the observation results of tissue morphology. (2) Adventitious root development is a complex physiological and biochemical process in which the dynamic changes of endogenous hormone content and rooting related enzyme activity play an important regulatory role with nutrients, phenols and polyamines as important influencing factors. (3) Efforts have been made to explore the key metabolic pathways in the process of adventitious root formation in some woody species, excavate the genes regulating adventitious root occurrence and identify the transcription factors and noncoding microRNAs involved in adventitious root occurrence. With a systematic summary of the research progress of histology, physiology and molecular regulation mechanism of adventitious root occurrence in woody species, this paper has provided reference for further exploration of the mechanism of adventitious root occurrence in woody species and an insight into future research direction in this field. [Ch, 1 tab. 80 ref.]
Diversity of macrofungi in different broad-leaved forests in Gaogestai Hanwula Nature Reserve
BAI Hui, JIANG Haiyan, CONG Lin, SHI Dongming, LIN Renjie, DI Jialin
, Available online  doi: 10.11833/j.issn.2095-0756.20210661
  Objective  This study, taking Gogestai Hanwula Nature Reserve as the research area, is aimed to investigate the distribution of macrofungi and its relationship with the local vegetation in five broad-leaved forests so as to provide plausible reference for the conservation of macrofungi in the future.   Method  First, macrofungi were collected from Betula platyphylla, Quercus mongolica, B. platyphylla-Tilia mongolica, B. platyphylla-T. mongolica and B. platyphylla-Q. mongolica-Populus davidiana-B. dahurica, and P. davidiana-Q. mongolica-B. dahurica in the nature reserve with the employment of random sampling and sample plot method. Then the collected specimens were identified from the perspectives of morphology and molecular chemistry before an analysis was conducted of the species distribution, diversity, community similarity and macrofungi-plant relationships.   Result  (1) There were 213 species of macrofungi in the reserve, which can be categorized into 2 phyla, 4 classes, 19 orders, 54 families, 119 genera. (2) There were a total of 8 dominant genera including Russula, Agaricus and Lepista. (3) Of the five vegetation types, Type Ⅳ wuranked the first in richness, diversity and evenness. (4) The diversity index and evenness index of tree layer, shrub layer and herb layer and the diversity index of tree layer and herb layer had significant influence on the indices of macrofungi. (5) The total vegetation coverage, herbage coverage, canopy closure and altitude were significantly correlated with the dominant genera of macrofungi. (6) The similarity between Type Ⅱ and Type Ⅳ was the highest (0.27) whereas the one between Type Ⅲ and Type Ⅳ and the one between Type Ⅰ and Type Ⅱ were the lowest (both being 0.14). (7) In terms of species clustering, with the distance coefficient being 25, they could be divided into two groups, while with the distance coefficient being 14, they could be divided into three clusters.   Conclusion  The diversity and similarity of plants affected the distribution of macrofungi to varying degrees, and the more similar the plant type was, the more similar the composition of macrofungi was. [Ch, 2 fig. 7 tab. 28 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
, Available online  doi: 10.11833/j.issn.2095-0756.20210768
  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.]
Research progress on soil microorganisms in eucalypt forests
WEI Juxian, WANG Cong, HE Bin, YOU Yeming, HUANG Xueman
, Available online  doi: 10.11833/j.issn.2095-0756.20210701
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.]
Cloning and functional analysis of SvAPETALA1 in Senecio vulgaris
HAO Yanmin, CHEN Keli, FENG Lijun, LI Feifei, CUI Minlong, PIAO Chunlan
, Available online  doi: 10.11833/j.issn.2095-0756.20210651
  Objective  Floral organ development is an important factor affecting the ornamental value of flowers, and APETALA1(AP1) genes regulate the formation of floral organs. This study aims to explore the important role of SvAP1 gene of Senecio vulgaris (Asteraceae) in floral organ formation, so as to reveal the regulatory mechanism of the complex inflorescence structure in Asteraceae.   Method  SvAP1 gene was cloned from S. vulgaris. The function of SvAP1 gene was predicted and analyzed by multiple sequence alignment, phylogenetic tree construction, qRT-PCR, overexpression vector construction, and histological staining observation.  Result  The open reading frame (ORF) of SvAP1 gene was 705 bp in length, and encoded 234 amino acids. Multiple sequence alignment and phylogenetic analysis showed that SvAP1 gene belonged to AP1 subfamily of MADS-box gene, and the C-terminus had a conserved motif of paleoAP1. Tissue specific expression analysis of S. vulgaris showed that SvAP1 gene was expressed in both vegetative organs and inflorescences. Morphological observation and paraffin section analysis of transgenic Solanum nigrum showed that compared with wild S. nigrum, the pistil development of transgenic S. nigrum was abnormal, which was characterized by enlarged ovary and increased pistil-like tissue.  Conclusion  The overexpression of SvAP1 gene in S. nigrum affects the pistil development, which is different from the effect of over expression of class A gene in ABC model on floral organ development, that is, the stamens of transgenic S. nigrum have no obvious changes and the pistils aren’t transformed into sepal or leaf-like organs, which may be related to the complexity of the floral organ regulation mechanism and the inflorescence structure of S. vulgaris. In conclusion, SvAP1 gene may play an important role in floral organ formation as a characteristic gene of floral organ. [Ch, 6 fig. 1 tab. 35 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
, Available online  doi: 10.11833/j.issn.2095-0756.20210734
  Objective  The objective of this study 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.]
Properties of bio-pretreated straw fiber and its composite materials
DU Keke, YONG Cheng, SUN Enhui, HUANG Hongying, QU Ping, XU Yueding, CHEN Ling, SUN Qian, GUAN Mingjie
, Available online  doi: 10.11833/j.issn.2095-0756.20210647
  Objective  This study aims to explore the influence of biological pretreatment on the properties of straw fiber and its composites prepared with urea formaldehyde resin, so as to provide theoretical basis for the preparation and development of straw based composites.   Method  Rice (Oryza sativa) straw was treated with microbial agent for aerobic fermentation. The changes of hemicellulose, cellulose and lignin in rice straw under different treatment time were measured. The crystallinity and microscopic morphology of straw fiber without biological pretreatment (S0), straw fiber bio-pretreated for 5 days (S5) and 10 days (S10) were tested and compared. Straw fiber/urea formaldehyde resin composites (F0, F5, F10) were prepared. Then the surface properties and mechanical properties of straw based composites under different biological pretreatment time were compared.   Result  Substances such as silicon and wax on the surface of straw fiber were removed after biological pretreatment, but the longer biological pretreatment time (10 d) could destroy the structure of straw fiber itself. Compared with S0 and S10, S5 had the highest relative content of cellulose (37.99%) and best crystallinity (47.8%). In contrast, F5 had the best hydrophobicity, lowest surface energy, and highest impact toughness (7 665.64 J·m−2). F10 had the best flexural performance. The static flexural strength and flexural modulus were 27.73 and 20 354 MPa, respectively, which were 59.00% and 50.17% higher than the composites prepared by S0, respectively.   Conclusion  Biological pretreatment can improve the surface properties of straw fiber and the properties of straw fiber/urea formaldehyde resin composites. The straw fiber bio-pretreated for 5 days is better, and the properties of the composites are superior. [Ch, 4 fig. 1 tab. 28 ref.]
Individual tree detection in high canopy density Larix principis-rupprechtii plantation based on airborne LiDAR
CHEN Siyu, LIU Xianzhao, WANG Yixiang, LIANG Dan
, Available online  doi: 10.11833/j.issn.2095-0756.20210399
  Objective  With low identification accuracy of individual trees in Larix principis-rupprechtii forest with high canopy density employing high resolution images, this paper is aimed to confirm the strengths of airborne Laser Detection and Ranging (LiDAR) 3D point cloud data as an alternative with a workable method proposed.   Method  Based on the preprocessing of point cloud data, an improved Mean Shift with Gaussian kernel function (MSP) position recognition method on the basis of the spatial characteristics of airborne LiDAR point cloud was proposed. The comparison is made with other three commonly used methods: regional growing segmentation algorithm based on point cloud (RGP), local maximum method based on canopy height model (LMC) and multi-scale segmentation method based on CHM (MSC).   Result  Identification accuracy of the four methods is: MSP (89.30%)>LMC (85.60%)>RGP (77.50%)>MSC (70.00%) and MSC, the proposed method, displayed high average individual tree crown extraction accuracy (90.18%) and relatively low omission error and commission error rate: 8.7% and 8.0% respectively.   Conclusion  The proposed MSP has good applicability in high crown density L. principis-rupprechtii forest and provides a new way of extracting L. principis-rupprechtii forest structure parameters accurately on the basis of airborne LiDAR point clouds. [Ch, 3 fig. 3 tab. 28 ref.]
Spatial distribution of endangered orchids in the Yangtze River Watershed
ZHANG Yilin, LI Gongquan, LIU Ying
, Available online  doi: 10.11833/j.issn.2095-0756.20210551
  Objective  This study, with an investigation of the scientific and standard identification of the migration of Orchidaceae, a protected and flagship group, in the Yangtze River Watershed, is aimed at an exploration of the spatial distribution of endangered orchids and the determination of key protected species and hot spots so as to serve the better research and protection of rare and endangered orchids.   Method  Taking the representative Orchidaceae plants in the Yangtze River Watershed from 1981 to 2019 as the research object, 130 species distribution points of 10 species including Neottianthe and Pleione were selected based on the field investigation and Global Biodiversity Information Facility (GBIF) database. Then, with the guidance of the theory of phytogeography and the conduct of a GIS spatial analysis, the spacial distribution of endangered orchids was investigated employing kernel density, Moran index and hot spot distribution.   Result  (1) The period between 1998 and 2019 witnessed the disappearance of Orchidaceae plants in Guangxi and Guizhou, a decrease in high-density areas of them in the Yangtze River Watershed, changes in the median density areas as well as their migration from central Sichuan to north Sichuan. (2) There was a significant positive correlation between the level of endangerment of Orchidaceae plants and their spatial location and the correlation between 1998 and 2019 was stronger than that of 1981−1997. (3) There was a shift of high risk areas: from 1981 to 1997, the high risk areas of Orchidaceae were mainly distributed in Guizhou and Hubei whereas from 1998 to 2019, they were mainly distributed in Hubei Province.   Conclusion  There have been changes in the distribution of Orchidaceae plants and a reduction in quantity which mainly attribute to global warming, infrastructure construction, illegal harvesting and excessive deforestation and in the future Hubei would become the focus of attention. [Ch, 1 fig. 5 tab. 31 ref.]
Development of 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
, Available online  doi: 10.11833/j.issn.2095-0756.20210772
  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.]
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
, Available online  doi: 10.11833/j.issn.2095-0756.20210740
  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.]
Response of leaf functional traits of Fraxinus malacophylla seedlings to calcium
ZHANG Mei, DONG Qiong, DUAN Huachao, YE Lan, LI Yanyan, JIN Youfan
, Available online  doi: 10.11833/j.issn.2095-0756.20210597
  Objective  This study, with an investigation of the effects of different calcium concentrations on leaf morphological indexes, chlorophyll content and enzyme activity of Fraxinus malacophylla seedlings, is aimed to better understand the growth and development of F. malacophylla seedlings under different calcium concentrations so as to further explore the environmental adaptability of F. malacophylla seedlings when treated with different calcium concentrations.   Method  With 1-year-old F. malacophylla seedlings selected as the materials, a research was conducted of the effects of 0 (ck), 25, 50, 75 mmol·L−1 calcium treatments on their leaf morphological indexes, chlorophyll content and enzyme activity.   Result  Different calcium concentrations had different effects on leaf morphological indexes, chlorophyll content and enzyme activity of F. malacophylla seedlings. When treated with different calcium concentrations, with the increase of calcium concentration, all indexes of leaf morphology and structure of F. malacophylla seedlings increased first and then decreased, except for specific leaf length and specific leaf area which increased, whereas leaf number, leaf biomass, specific leaf length, specific leaf area, chlorophyll content, catalase activity and peroxidase activity were significantly different from those in control (P<0.05). When the calcium concentration was more than 50 mmol·L−1, the treatment had no inhibitory effect on F. malacophylla seedlings, indicating that F. malacophylla seedlings responded favorably to medium-low calcium concentration. When the concentration of calcium was 75 mmol·L−1, it inhibited the growth and development of F. malacophylla seedlings, implying that too high a calcium concentration can inhibit the growth of F. malacophylla seedlings. When the calcium concentration was 50 mmol·L−1, the leaf morphological indexes, leaf related indexes, chlorophyll content and enzyme activity of F. malacophylla seedlings reached the maximum, and the growth and development of F. malacophylla seedlings were the best.   Conclusion  The optimal calcium concentration for the growth of F. malacophylla seedlings is 50 mmol·L−1 since too high a calcium concentration inhibits the growth, leaf chlorophyll mass fraction and leaf enzyme activity of F. malacophylla seedlings. [Ch, 1 fig. 2 tab. 28 ref.]
Analysis and evaluation of growth and wood fiber characters of seven poplar clones in southern China
YANG Yan, TANG Jie, LI Yongjin, TANG Yuxi, LI Lei
, Available online  doi: 10.11833/j.issn.2095-0756.20210481
  Objective  With an investigation of differences among wood fiber related traits and their correlation with growth traits among tested poplar (Populus) clones, this paper provides basic information and guidance for the targeted cultivation and selection as well as the utilization of high-quality poplar clones.   Method  Seven poplar clones, including XL-80, XL-86, XL-83, XL-58, XL-75, ZH-17 and I-69 (ck) with straight trunk and large growth were chosen before the principal component comprehensive score method was employed to evaluate the fiber traits of each clone with indexes including fiber length, fiber width, fiber length-width ratio, cellulose mass fraction and cellulose content per plant.   Result  The wood fiber length range of the seven poplar clones was 0.95−1.12 mm, all meeting the standard of intermediate fiber length 0.91−1.60 mm stipulated by the International Society of Wood Anatomy. The length to width ratio of fiber varied from 49.09 to 54.62, which is 63.67%−82.00% of the length to width ratio (30) required for paper making. The cellulose mass fraction varied from 53.06% to 59.66%, exceeding the basic requirement (40%) of paper making cellulose content. Fiber width was positively correlated with height, diameter at breast height (DBH) and biomass but not significantly (P>0.05). Fiber length, fiber length-width ratio and cellulose mass fraction were negatively correlated with DBH, tree height and growth, respectively, but not significantly (P>0.05). Five clones with good traits were selected by principal component comprehensive score method, namely XL-80, XL-58, XL-86, ZH-17, and XL-83.   Conclusion  The five selected fiber clones have integrated the excellent characteristics of each character, which could maximize the utilization of poplar clones and provide more abundant genetic resources for poplar multi-objective breeding. [Ch, 6 tab. 24 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
, Available online  doi: 10.11833/j.issn.2095-0756.20210771
  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.]
Allelopathic effect of water extract of Brassica oleracea var. capitata leaves on seedling growth of Zea mays and Cucurbita pepo
ZHAO Cong, ZHAO Min, HUANG Xuefang, HUANG Mingjing, WANG Juanling
, Available online  doi: 10.11833/j.issn.2095-0756.20210683
  Objective  The objective is to probe the relationship between toxicity of Brassica oleracea var. capitata and stubble obstacles, so as to provide a theoretical basis for establishing a reasonable crop rotation system.   Method  Taking the air-dried leaves of B. oleracea var. capitata as test materials, two crops species (Zea mays and Cucurbita pepo) with relatively high economic benefits and suitable for cultivation in cold and arid area of Shanxi were used as receptor. The effects of water extract from B. oleracea var. capitata leaves with four mass concentrations 0, 0.06, 0.08 and 0.10 kg·L−1 on the nutritional growth of the above two receptor crops were compared by indoor bioassay method, and the corresponding allelopathic effect index and comprehensive effect index were calculated.  Result  When the water extract concentration of B. oleracea var. capitata leaves was ≥0.06 kg·L−1, the growth of roots and shoots of potted Z. mays seedling could be significantly inhibited (P<0.05). The seedling height and root length of C. pepo were significantly reduced (P<0.05) only when the mass concentration of water extract of B. oleracea var. capitata leaves was 0.10 kg·L−1. At the same concentration, the allelopathic inhibition on root length of Z. mays was always greater than that on seedling height. For C. pepo, the allelopathic inhibition on root length was greater than that on seedling height when the water extract concentration of B. oleracea var. capitata leaves was ≥0.08 kg·L−1. When the mass concentration decreased to 0.06 kg·L−1, the allelopathic inhibition on root length was less than that on seedling height. According to the results of allelopathic comprehensive effect index, the allelopathic comprehensive inhibition on C. pepo was less than that on Z. mays.   Conclusion  C. pepo can be used in the rotation system of B. oleracea var. capitata to alleviate the obstacles caused by other toxicity. [Ch, 2 fig. 3 tab. 28 ref.]
Spatial distribution characteristics and influencing factors of forest villages in Zhejiang Province
HUANG Xiaofen, BAI Ou
, Available online  doi: 10.11833/j.issn.2095-0756.20210558
  Objective  This study is to explore the spatial distribution characteristics and influencing factors of forest villages, so as to optimize the spatial layout and understand the forming factors, so as to comprehensively promote the construction of ecological civilization and rural revitalization.   Method  The spatial distribution characteristics of 447 forest villages in Zhejiang Province were analyzed using spatial Gini coefficient, nuclear density analysis and spatial autocorrelation, and the natural and human factors affecting their spatial distribution were explored by Pearson correlation analysis and geographic detectors.   Result  (1) The overall spatial distribution of forest villages was in an agglomerated distribution state, with the characteristics of multi-center clusters of “small-scale aggregation and large-scale dispersion”. (2) The regional spatial distribution was uneven at the level of five major districts and cities, displaying a distribution pattern of “more in the west and less in the east”. (3) In terms of overall spatial density, a dual-core agglomeration area and a dual-core continuous area were formed. (4) In terms of spatial distribution correlation, it showed the spatial correlation characteristics of hot in the southwest and cold in the northeast. The change of sub-cold spot area was small, and the hot spot area changed from strip distribution to strip and sporadic distribution. (5) The spatial distribution of forest villages in Zhejiang Province was affected by topography, climate conditions, river systems, forest resources, cultural resources, socio-economic foundation and traffic accessibility.   Conclusion  Due to the comprehensive influence of nature and humanity, the spatial distribution of forest villages in Zhejiang Province is significantly different. Topography, climate and rivers nurture their ecological environment, while transportation, cultural resources and socio-economic foundations are related to basic conditions, resource advantages and economic support of their development. We should, according to resource advantages, basic conditions and local development policies, adhere to scientific planning, local conditions, coordinated layout and other measures so as to achieve global development, providing high-quality Zhejiang models for the construction of ecological civilization.[Ch, 4 fig. 2 tab. 32 ref.]
Effects of biochar-based fertilizer and organic fertilizer substituting chemical fertilizer partially on soil microbial abundances and enzyme activities
REN Yi, JIANG Peikun, LU Changgen, SHAO Jianjun, ZHOU Xue’e, CHEN Junhui
, Available online  doi: 10.11833/j.issn.2095-0756.20210619
  Objective  The objective is to provide a scientific basis for improving rice paddy soil quality and for the application of new fertilizer, by investigating the effects of biochar-based fertilizer and organic fertilizer substituting chemical fertilizer partially on soil nutrients contents, microbial abundances and enzyme activities, and investigated the driving factors for soil enzyme activities.   Method  A field experiment was conducted in a typical rice paddy located in Hangjiahu Plain, which soil is Qingzini paddy soil. Four treatments, namely no fertilizer control (ck), conventional fertilizer (CF), biochar-based fertilizer (BF) and organic fertilizer substitution of 50% chemical fertilizer (OF), were laid out with the three fertilization treatments had consistent input of N, P and K amount. The field trail was initiated on June 2019 and soil sampling were collectted on November, 2019. Topsoils (0−20 cm) were sampled to investigate changes in soil carbon and nitrogen fractions, bacterial, fungal and archaeal abundances and enzyme activities involved in C, N and P cycling.   Result  Compared with CF, BF and OF treatments had no effects on soil pH, total C and N, available P and K and nitrate contents, but OF significantly increased soil ammonia and dissolved organic C contents. Compared with ck, OF treatment increased the content of soil microbial biomass carbon (MBC) by 164%, bacterial 16S rRNA gene abundance by 35% and fungal 18S rRNA gene abundances by 98% and fungi/bacteria ratio by 50%, while BF and CF had no effects on them. The three fertilization treatments had no effects on the activities of β-glucosidase, β-xylosidase and Leucine aminopeptidase, whereas BF and OF treatments significantly increased the activities of α-glucosidase (AG) by 111%和136%, β-cellobiosidase (BG) by 77%和100%, β-N-acetylglucosaminidase (NAG) by 109%和177% and acid phosphatase (PHOS) by 97%和199%, respectively. Redundant analysis indicated that changes in soil enzyme activities were strongly dependent on the contents of soil ammonia, dissolved organic C and N, and fungal abundances.   Conclusion  The application of organic fertilizer and biochar-based fertilizer significantly increased soil enzyme activities involved in C, N and P cycling, with the OF treatment further increased soil microbial abundance, which was beneficial for soil nutrient cycling. [Ch, 2 fig. 3 tab. 33 ref.]
Research progress on functional components and biological activities of wild edible vegetables
LI Yaochen, FAN Zipei, YANG Jing, LIU Tingfu, ZHU Biao, ZHU Zhujun, CHEN Xiaoyang
, Available online  doi: 10.11833/j.issn.2095-0756.20210550
There is a long history of use of wild edible vegetables in China. They have abundant functional components, including mineral elements, amino acids, vitamins, polysaccharides, flavonoids and so on. It has important scientific significance and application value to study the basic components of wild edible vegetables for a comprehensive understanding of the nutrients and biological activities. We listed the main nutritional and functional components, summarized the current main research results in the biological activity, including: (1) the content of basic nutrients in wild edible vegetables; (2) the profiles of functional compounds in wild edible vegetables; (3) analysis of active components and efficacy of wild edible vegetables; (4) common methods and technologies to component analysis of wild edible vegetables. Wild edible vegetables are rich in basic nutrients and bioactive substances, including vitamins, phenols and terpenes, which have good activities in antibacterial, antioxidant, antitumor and anti-inflammatory. Future research should focus on functional components and biological activities, and serves as a reference for subsequent development and application. [Ch, 2 tab. 74 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
, Available online  doi: 10.11833/j.issn.2095-0756.20210605
  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.]
Rural landscape construction model based on the recognition and evaluation of landscape features
HUANG Yingying, TAN Shizhu, CHEN Qianting, WU Qianqian, SI Nasha, SHEN Yamei, YAN Shaojun
, Available online  doi: 10.11833/j.issn.2095-0756.20210644
  Objective  With an investigation of the characteristics of the the rural landscape, the study is aimed to research its construction model and propose a planning method for optimization.   Method  First, taking Pingyao Town of Hangzhou as an example, with the conduct of rural landscape character identification and comprehensive landscape evaluation and the collection of spatial data and survey information, spatial pictorial representation was carried out of the landscape features whereas the areas were divided using ArcGIS. Then a landscape function evaluation model related to landscape character was constructed to assess the rural landscape featured areas.   Result  (1) Pingyao Town enjoys four rural landscape featured areas, namely, the northern mountain forest ecological and cultural area, the central plain agricultural and cultural area, the eastern plain cultural area and the southern plain wetland ecological and cultural area; (2) Of the four rural landscape featured areas, the northern mountain forest ecological and cultural area (ecological landscape>living landscape>productive landscape) scored the highest, followed by the central plain agricultural and cultural area (productive landscape>living landscape>ecological landscape), the eastern plain area of historical sites (living landscape>productive landscape>ecological landscape) and the southern plain wetland ecological and cultural area (ecological landscape>productive landscape>living landscape).   Conclusion  In accordance with the regional and historical features of Pingyao Town in Hangzhou, four landscape construction models have been proposed: the mountain settlement landscape model, the plain agricultural landscape model, the historical site landscape model and the plain wetland landscape model, which provides a scientific basis for other and further rural landscape construction. [Ch, 4 fig. 3 tab. 25 ref.]
Ratio of dominant dust retaining plants in waste dump of desert open-pit coal mine based on CATS model
LIU Qin, YANG Jianying, HOU Jian, TAN Jin, ZHANG Minghao
, Available online  doi: 10.11833/j.issn.2095-0756.20210604
  Objective  The dump of open-pit mine in arid desert regionis easy to produces and (powder) dust and cause air pollution. The purpose of this study is to obtain the ratio of dominant dust retaining plants and species in the restoration community based on the simulation of Community Assembly by Trait Selection (CATS) model, and put forward the vegetation restoration strategy.  Method  A quadrat survey was conducted around the waste dump of Wuhai Xinxing Coal Mine in Inner Mongolia Autonomous Regionin August 2020 to determine the trait values at species and community levels, calculate the target values of functional traits, and substitute the dust retention function and root volume of plants into the model as two factors.  Result  The root volume of plant species was inversely proportional to the dust retention per unit leaf area. The root volume and soil water content was U-shaped. The simulation results showed that the highest relative abundance of each species was Salsola collina and Peganum harmala, with amedian of 0.41 and 0.32, respectively.   Conclusion  To plant S. collina and P. harmala in the dumping site with the relative abundance ratio of 6 to 4 is beneficial to dust detention, which can also explain some mechanical problems in vegetation restoration and provide reference for other studies.[Ch, 2 fig. 1 tab. 40 ref.]
Biocontrol effect of Penicillium oxalicum and Trichoderma asperellum on Ralstonia solanacearum
FANG Qihang, YAN Guzhe, FANG Wei, GAO Jing, ZHAO Kai, JIANG Renqiang, ZHAO Mengli, XU Qiufang
, Available online  doi: 10.11833/j.issn.2095-0756.20210525
  Objective  This study aims to investigate the effect of two biocontrol strains Trichoderma asperellum QZ2 and Penicillium oxalicum QZ8 on Ralstonia solanacearum (bacterial blight for short) With the help of T. asperellum QZ2 and P. oxalicum QZ8 screened by our laboratory, the effect of two biocontrol strains on R. solanacearum was investigated. Hereinafter referred to as the biocontrol effect of bacterial blight.  Method  Using bacterial blight as the target, The the inhibition effect of biocontrol bacteria and their fermentation broth on the growth of bacterial bacterial blight was determined by plate culture method and growth curve method. Soil culture test and dilution coating method were used to determine the inhibitory effect of biocontrol bacteria on bacterial blight in soil.   Result  In plate confrontation culture experiment, test showed that QZ2 and QZ8 had significant inhibitory effects on bacterial blight (P<0.05), with inhibition rates of 80.9% and 45.9%, respectively. The plate culture with high temperature sterilized fermentation broth of QZ2 and QZ8 two biocontrol strains also showed significant inhibition effect on bacterial blight in plate culture (P<0.05), and the inhibition rates of QZ2 and QZ8 on bacterial blight reached were 33.3% and 34.8%, respectively. The fermentation broth on the growth of bacterial blight results showed that the D(600) value of the treatment was significantly lower than that of the control (P<0.05), and the inhibition effect of QZ2 was better than that of QZ8. Soil culture test results showed that the number of viable bacteria of R solanacearum in soil treated by with two biocontrol strains was significantly lower than that of ck (P<0.05).  Conclusion  In this experiment, the biocontrol strains of QZ2 and QZ8, which were extracted independently, had have significant inhibitory effects on bacterial blight wilt, and could can be positioned identified as potential biocontrol bacteria of tomato bacterial wilt. [Ch, 5 fig. 2 tab. 32 ref.]
Plant diversity in various sections of Jinsha River dry-hot valley under different site environments
DU Soukang, TANG Guoyong, LIU Yungen, LEI Chenyu, XU Yingjie, RUAN Changming, SUN Yongyu, ZHANG Chunhua, WANG Yan
, Available online  doi: 10.11833/j.issn.2095-0756.20210572
[Abstract](100) [HTML] (18) [PDF](2)
  Objective  This study is aimed at an investigation of the structural features and differences of the plant diversity in various sections of the dry-hot valley under different site environments so as to efficiently protect and restore the biological environment of Jinsha River dry-hot valley.   Method  With the employment of standard sample plot survey method, a survey was conducted of the plant species richness and diversity of 47 plots in the upper, middle and lower sections of the Jinsha River dry-hot valley.   Result  The plant species richness, diversity and uniformity of the Jinsha River dry-hot valley increased from the upper section to the lower one with the order of species richness being natural forest (20.56)>plantation (12.16)>sparse trees and shrubs (8.00) and no significant difference in diversity or uniformity between natural forest and plantation. The plant diversity tends to increase as the altitude increases with the plant diversity of shade slopes being significantly higher than that of sunny slopes (P<0.05). No significant differences have been found in diversity among the upper, middle and lower sections in the range of 800−1 400 m, while in the range of 1 400−2 000 m, the diversity in the middle section was lower than that in the lower section, but higher than the upper section. The plant diversity in the lower section was always higher than that in the middle section and the upper section of the same slope, and the Shannon-Wiener diversity index and Simpson diversity index in the lower section were significantly different from those of the upper section (P<0.05).   Conclusion  There are significant differences in plant diversity in various sections of the Jinsha River dry-hot valley, with altitude and slope as main environmental influencing factors, and local plantation may increase the plant diversity. [Ch, 1 fig. 4 tab. 27 ref.]
Ananalysis of the population quantitative characteristics of Carpinus tientaiensis and its associations with other tree species
XU Yuanke, ZHAO Changgao, LIAO Yujun, LIN Jian, WU Chuanbo, WU Chuping, WANG Zhigao
, Available online  doi: 10.11833/j.issn.2095-0756.20210307
  Objective  With an analysis of the population and community characteristics of Carpinus tientaiensis, an extremely small population as well as its interactions with other trees species, this study is aimed to explore its endangerment mechanisms so as to propose workable protection strategies.   Method  Sampling method was first used to investigate the community characteristics in Shangshantou, Jingning She Nationality Autonomous County of Zhejiang Province, and indicators including the importance value, species abundance, distribution of the diameters at breast height (DBH) and inter-specific associations were analyzed.   Result  C. tientaiensis is one of the main dominant species in the community with the largest DBH 74.6 cm, ranking the third in importance value and accounting for 10.6% of the total tree species number, while 17.79% of the total basal area. Individuals with DBH of 1−4 cm and above 30 cm accounted for 90.00% and 66.11% of the total trees in the community respectively, while those with DBH of 4−20 cm only took up 7.91%. Strong inter-specific associations between C. tientaiensis and other species were found by means of association coefficient and percentage of co-occurrence whereas χ2 test indicated that C. tientaiensis was in intense competition against 5 other tree species.   Conclusion  Although C. tientaiensis, is one of the dominant species in the community, it has displayed population regeneration limitation with individuals with DBH at 4−20 cm found, thus faced with strong competition from other species. It was suggested that intermediate felling measures should be taken to reduce the competitive pressure of C. tientaiensis and necessary light environment should be provided for seedling settlement and tree growth. [Ch, 4 fig. 1 tab. 24 ref.]
Restoration characteristics of Phyllostachys edulis community after clear-cutting in Mount Tianmu
CHEN Xu, LIU Zongyue, XU Junjie, QI Xiangbin, YU Shuquan
, Available online  doi: 10.11833/j.issn.2095-0756.20210595
  Objective  The continuous expansion of Phyllostachys edulisin recent years has severely threatened the species diversity and ecosystem stability of the forest. Therefore, the research on the renewal and management of Ph. edulis forest has attracted extensive attention. The purpose of this study is to analyze the dynamic changes of species composition, tree species characteristics and species diversity in the natural restoration process of the community through clear cutting of Ph. edulis forest in Mount Tianmu, so as to promote the protection and restoration of species diversity.  Method  Based on the location monitoring data from 2018 to 2020 in the natural restoration process of Ph. edulis community after clear cutting in Mount Tianmu, the restoration characteristics of plant community, such as composition of family, genus and species, changes of dominant species, the functional characteristic composition of tree species and species diversity were studied.  Result  (1) The species composition was rich and varied sharply: 45 families, 86 genera, and 131 species were found in the arbor layer, 65 families, 137 genera, and 224 species in the shrub layer, and 45 families, 99 genera, and 135 species in the herb layer. Compared with 2018, there was little change in the arbor layer in 2020, but the number of species in the shrub layer and herb layer decreased rapidly, by 54.1% and 65.5%, respectively. (2) The dominant species in tree layer were deciduous species, and the absolute value of the annual average population size change rate of most dominant species exceeded 10%. The dominant species in shrub layer were Theaceae and Rosaceae. The dominant species in the herb layer were Cyperaceae and Gramineae. (3) After clear cutting, community was dominated by deciduous tree species, and the proportion of species and plants in the community was about 80% and 90% respectively. The proportion of species of different growth types and light-tolerant species had little change, but the number of plants of neutral and negative species increased significantly, withgrowth rates of 88.1% and 56.2% respectively. (4) The species diversity of tree layer had no significant difference with time and showed a slight upward trend. Shannon index and Margalef richness of shrub layer decreased significantly, and Pielou evenness increased significantly (P<0.05). Shannon diversity, Simpson Index and Margalef richness of herb layer decreased significantly, but Pielou evenness had no significant difference (P<0.05).  Conclusion  In the natural restoration process of Ph. edulis community after clear cutting, the species composition is rich and the restoration effect of species diversity is obvious. Therefore, clear cutting of Ph. edulis forest is a feasible method to restore and protect biodiversity in National Nature Reserveof Mount Tianmu, and can also be used to improve the ecosystem stability of the spreading area of subtropical Ph. edulis forest. [Ch, 10 tab. 35 ref.]
Floral syndrome and breeding system of Stewartia rostrata
LI Qingxiang, ZHANG Mingru, GU Cuihua, LI Tongpan, WAN Qi, GAO Lei, ZHANG Tingyu, ZHAO Nannan, CAI Yihang
, Available online  doi: 10.11833/j.issn.2095-0756.20210563
  Objective  The objective is to study the floral syndrome and breeding system of Stewartia rostrata, so as to provide a scientific basis for its population renewal, artificial reproduction and garden popularization and application.   Method  Taking 3-year-old S. rostrata as material, the characteristics of pollination biology and breeding system were observed and analyzed by observing the floral syndrome and insect visiting characteristics, measuring the pollen viability and stigma acceptability, and calculating the hybridization index (OCI) and pollen-ovule ratio (P/O).   Result  (1) The flowering period of the population was about 17 days from early May to mid and late May, and the single flowering period was about 2 days. (2) The pollen vitality reached the highest on the day of opening, and the single flower bloomed for 24−32 h , the corolla and stamens were easy to fall off, and the pollen was easy to lose vitality after falling off. (3) The stigma was receptive before flowering, lasting for 7 days. The strong pollen vitality and stigma receptivity had a meeting period of 1−2 days. (4) Stigma was higher than anther in bud stage, and anther was higher than stigma after flowering. Both before and after flowering, stamens and pistils had a certain spatial separation. (5) The OCl of S. rostrata was 4 and P/O was 2 108.0−195 525.0. The breeding system was mainly outcrossing and some self compatibility was required for pollination. (6) Bombus sp. was the main pollinator.   Conclusion  S. rostrata has short pollen life, single pollinating insect, and pollination is easily affected by cloudy and rainy weather, so the reproductive process is greatly limited. The floral syndromes such as centralized flowering mode, large amount of pollen, 5-lobed stigma and long receptive period are the basic manifestations of reproductive success. [Ch, 5 fig. 1 tab. 31 ref.]
Measuring method of multiple trees attributes based on structure from motion
GU Wenjun, XU Aijun, YIN Jianxin
, Available online  doi: 10.11833/j.issn.2095-0756.20210547
  Objective  Tree attributes are generally measured by obtaining the tree height and DBH using a method based on three-dimensional point cloud, which is featured with either low efficiency or high cost. To solve this problem, this study is aimed to propose a measuring method of multiple trees attributes based on Structure from Motion.   Method  Firstly, a smart phone was used to shoot a video of a scene with multiple trees before its key frame images were automatically extracted using the fixed-frame sampling and dHash algorithm; Secondly, such key frame images of the trees were processed on the basis of Structure from Motion (SfM) algorithm to obtain the original 3D point cloud of the scene; Thirdly, after the pre-procession and initial segmentation of the original 3D point cloud, the conditional European clustering algorithm is used to segment the 3D point cloud of multiple trees to extract the 3D point cloud of a single tree; Finally, the most value traversal method and ellipse fitting method were employed to deal with the tree 3D point cloud to realize the automatic measurement of tree height and DBH.   Result   Compared with real values, the mean relative errors of tree height and DBH measured using this method are 1.96% and 3.19%, the root mean square errors were 0.1333 m and 0.5337 cm whereas the correlation coefficients were 0.9879 and 0.9621 respectively.   Conclusion  This method, with high measurement accuracy of tree height and DBH, serves as a convenient and low-cost three-dimensional measurement method for multiple trees attributes. [Ch, 6 fig. 1 tab. 27 ref.]
Spatial and temporal distribution characteristics and discoloration law of knots in Mytilaria laosensis plantation
HE Weijun, YANG Jinchang, HAO Jian, DONG Mingliang, YU Niu, QIN Guoming, LI Rongsheng
, Available online  doi: 10.11833/j.issn.2095-0756.20210517
  Objective  The objective is to explore the spatial and temporal distribution characteristics and discoloration law of knots in Mytilaria laosensis plantation, so as to provide theoretical reference for the cultivation of clear wood.   Method  A total of 1 101 complete knots were obtained by knot analysis from 20 trees of 11-year old M. laosensis plantation in Experimental Center of Tropical Forestry in Pingxiang City of Guangxi.   Result  In the development age of the knots, the branches of M. laosensis mainly began to grow in the 1st and 2nd year, and the death peak came in the 2nd to 4th year(91.9%). These branches (87.2%) completely healed and formed knots in the 5th to 8th year after death, and the healing time of most of them (76.7%) was 3 to 6 years. More branches of M. laosensis died in the 2nd to 4th year, which was a critical period to control the formation of knots. In the vertical distribution, the number of knots increased first and then decreased sharply with the increase of tree height and they were mainly concentrated on the trunk with a height of 0−8 m. The discoloration length of knots was positively correlated with knot diameter and healing time (P<0.05), but negatively correlated with branch angle (P<0.05). Through stepwise regression, it was concluded that knot diameter, dead knot length, knot age and knot healing time were the key factors affecting knot discoloration length, and their correlation was very significant (P<0.01).   Conclusion  Pruning the trunk below 8.0 m for the first time 2−4 years after planting is beneficial to the cultivation of clear wood. Taking corresponding forest cultivation measures to reduce the base diameter of branches and the time required for knot healing will help ease the impact of knots on wood. [Ch, 7 fig. 3 tab. 32 ref.]
Difference of biomass and understory vegetation diversity among different subtropical plantations in common gardens
LIU Xuan, XIAO Sa, ZHU Peng, DU Ting, LI Jihong, HONG Zongwen, YUAN Chunyang, LAN Ting, LI Han, TAN Bo, XU Zhenfeng, ZHANG Jian, YOU Chengming
, Available online  doi: 10.11833/j.issn.2095-0756.20210562
[Abstract](148) [HTML] (32) [PDF](14)
  Objective  The objective is to explore the differences of biomass and understory vegetation diversity in different stands, and to screen suitable and precious native broad-leaved tree species for subtropical plantations.   Method  Seven broad-leaved tree species (Cinnamomum platyphyllum, C. longepaniculatum, C. japonicum, C. camphora, Alnus cremastogyne, Toona sinensis and T. ciliata) were selected as the research objects in the common garden experiment in Chongzhou Base of Sichuan Agricultural University. The impact of tree species on biomass and understory vegetation diversity was quantified by measuring the average tree height, average diameter at breast height, and understory vegetation species of each tree species.   Result  There were significant differences in total plant biomass among different tree species (P<0.05). C. platyphyllum had the highest biomass, followed by A. cremastogyne and T. ciliata, and the lowest was C. japonicum. There were significant differences in the biomass of various organs of tree species (P<0.05), and the order from large to small was trunk, root, branch, and leaf. In general, the biomass of each organ of C. platyphyllum was the highest and the biomass of each organ of C. japonicum was the lowest. There were significant differences in the proportion of organ biomass to whole plant biomass among tree species (P<0.05), but there was no consistent rule in the size ranking among tree species. There was no significant difference in whole plant, leaf, branch and trunk biomass among different functional groups. However, the root biomass, proportion of root biomass and root shoot ratio of evergreen tree species were significantly higher than those of deciduous tree species (P<0.05), while the proportion of branch and trunk biomass was the opposite. The diversity of understory vegetation in deciduous tree stand was significantly higher than that in evergreen tree stand (P<0.05), and the Simpson index of understory herbaceous in T. ciliata, A. cremastogyne and T. sinensis stands were significantly higher than that of C. japonicum, C. camphora, C. platyphyllum and C. longepaniculatum stands (P<0.05). The Shannon-Wiener index of understory herbaceous in T. ciliata was significantly higher than that of the other six stands (P<0.05).   Conclusion  The cultivation of deciduous tree species in this area may be beneficial to the material circulation and understory vegetation diversity conservation of the plantation. Compared with other native tree species, the selection of A. cremastogyne and T. ciliata as breeding species may be more conducive to sustainable management of subtropical plantations. [Ch, 6 fig. 2 tab. 37 ref.]