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Physiological and biochemical responses of seedling roots of Pinus massoniana to different phosphorus gradients
LIU Yahui, XU Jin, LEI Lei, WAN Yi, ZENG Lixiong, XIAO Wenfa
, Available online  doi: 10.11833/j.issn.2095-0756.20220226
Abstract:
  Objective  This study, with an investigation of the physiological and biochemical responses of roots in Pinus massoniana seedlings to different phosphorus (P) gradients, is aimed to explore the physiological and biochemical mechanisms of P. massoniana in response to low P stress, so as to provide theoretical support for the managements of P. massoniana plantations in low phosphorus area.   Method  First, two-year-old seedlings of P. massoniana planted in potted with quartz sand were treated with six available P concentrations, including 0 (P0)、0.562 5 (P1)、1.125 0 (P2)、2.250 0 (ck)、4.500 0 (P3)、9.000 0 (P4) mg·kg−1 before a control check (ck, 2.250 0 mg·kg−1) with the effective phosphorus content of the national P. massoniana forest soil survey. Then, the physiological and biochemical characteristics of roots, including activities of acid phosphatase (ACP), total organic acid content (TOC), root vigor, malondialdehyde (MDA) and activities of three antioxidant protective enzymes including superoxide dismutase (SOD), peroxidase (POD) and catalase (CAT), were determined and analyzed in both 1.5 and 3.0 months after treatments.   Result  (1) Both ACP activity and organic acid content decreased with the increase of phosphorus concentration with the ACP activity of P0 in August and September being significantly higher than that of ck (P<0.05), and the ACP activity of P4 being significantly lower than ck both in August and September (P<0.05) whereas in September, the ACP activity of P3 was also significantly lower than that of ck (P<0.05) with the organic acid content in P0 and P1, and organic acid content in P4 being significantly lower than in ck (P<0.05) in two sampling times. (2) In August, the root vigor in ck was significantly lower than in P0, P1, P3 and P4 (P<0.05), and in September, the root vigor increased with the increase of phosphorus concentration. (3) The root MDA content increased with the decrease of phosphorus concentration with the MDA content in P0 being significantly higher than that in ck (P<0.05), and the MDA content in P4 being significantly lower than that in ck (P<0.05). The antioxidant enzyme activities showed a tendency of increasing as phosphorus concentration decreased whereas SOD, POD and CAT were significantly higher in P0 and P1 than that in ck (P<0.05) though their activities showed no significant variation among ck, P2, P3 and P4 treatments.   Conclusion  In response to low P stress, P. massoniana seedlings had their MAD, ACP, TOC and antioxidant system enzyme activities increased in roots with the root vigor regulated. [Ch, 3 fig. 1 tab. 39 ref.]
Effects of light intensity on growth, chemical composition and antioxidant activity of Isatis indigotica
LI Xinyao, HUANG Jiabin, GUO Qiaosheng, LIU Lijun, GONG Min, SU Yong, LU Lixian, ZHAO Kun
, Available online  doi: 10.11833/j.issn.2095-0756.20220263
Abstract:
  Objective  The present study, with an exploration of the effects of light intensity on growth of Isatis indigotica, and chemical composition, antioxidant activity of isatidis folium, is aimed to provide reference for the artificial cultivation of I. indigotica.   Method  With seedlings of I. indigotica planted under 100%, 60% and 20% of full sunlight, their growth indexes were measured at the vigorous growth period, whereas chemical compounds such as indigo, indirubin, total flavonoids, total polysaccharides and total free amino acid, as well as antioxidant activity were determined after harvest.   Result  The growth of leaves was positively correlated with the light intensity, and the plant height, leaf length, leaf width, number of leaves, and the single leaf area in 100% of full sunlight treatment were the largest. Indigo, total flavonoids and total polysaccharides of isatidis folium were decreased with the decrease of light intensity, and there were significant differences among three groups (P<0.05). Indirubin showed a trend of increasing first and then decreasing, with that of the 60% of full sunlight treatment being the highest (P<0.05), yet no significant differences between the ones of 100% and 20% of full sunlight treatment. The total free amino acid was negatively correlated with light intensity and increased with the decrease of light intensity. The antioxidant activity was positively correlated with the light intensity and the IC50 (half maximal inhibitory concentration) for DPPH of 20% of full sunlight treatment was significantly higher than that in 60% and 100% of full sunlight treatment (P<0.05).   Conclusion  The 100% of full sunlight treatment was the optimum light intensity condition to achieve high yield and intrinsic quality of isatidis folium, which is more conducive to the cultivation of isatidis folium than the 60% and 20% full sunlight treatment. [Ch, 8 tab. 39 ref.]
Effects of different nitrogen and phosphorus combinations on seedling growth and nutrient accumulation of Pinus yunnanensis seedlings
LI Yaqi, XU Yulan, TANG Junrong, HE Yingnian, WANG Dan, LI Jiangfei, CAI Nianhui
, Available online  doi: 10.11833/j.issn.2095-0756.20220223
Abstract:
  Objective  This study tries to reveal the response of Pinus yunnanensis seedling growth and nutrient accumulation to exogenous N and P combined application, and to provide a theoretical basis for optimizing nutrient management and seedling cultivation of P. yunnanensis.   Method  2-year-old potted seedlings of P. yunnanensis were taken as the research objects. 9 different fertilization treatments were set to analyze the effects of different fertilization treatments on the growth and nutrient accumulation of P. yunnanensis seedlings, including ck (control group), P1 (P, 0.8 g per seedling), P2 (P, 1.6 g per seedling), N1 (N, 0.4 g per seedling), N2 (N, 0.8 g per seedling), N1P1 (N, 0.4 g per seedling, P, 0.8 g per seedling), N1P2 (N, 0.4 g per seedling, P, 1.6 g per seedling), N2P1 (N, 0.8 g per seedling, P, 0.8 g per seedling), N2P2 (N, 0.8 g per seedling, P, 1.6 g per seedling).   Result  The total biomass and seedling quality of each fertilization treatment were higher than those of ck, and those of N1P1 treatment were the highest. The nutrient accumulation of each organ ranging from large to small was leaf, stem and root. The N, P and K reserves of organs and individual plants of different fertilization treatments were significantly different from those of ck (P<0.05), and increased in different degrees compared with ck. The seedlings under N1P1 treatment had the largest N and K reserves in root, stem and individual plant, and the largest P reserves in root, stem, leaf and individual plant, while the seedlings under N2P1 treatment had the largest N and K reserves in leaf. The distribution pattern of N, P and K nutrients was leaf, stem and root from large to small.   Conclusion  N and P combined application significantly improves biomass accumulation, seedling quality, as well as nutrient accumulation in each organ. It also increases the nutrient distribution of root and stem, and decreases the nutrient distribution of leaf. The combined application of N and P is superior to the single application of either N or P. Therefore, N1P1 is the optimal treatment. [Ch, 6 fig. 5 tab. 38 ref.]
Transcriptome analysis of abscised and normal surviving young fruit of Morus alba
DENG Xuan, CHEN Chunbing, DENG Jing, LIU Lianlian, LI Juan, ZHA Xingfu
, Available online  doi: 10.11833/j.issn.2095-0756.20220205
Abstract:
  Objective  This study, with mulberry (Morus) fruits as the subjects, is aimed to conduct an investigation into its fruit abscission, a common physiological process which limits the yield of fruit so as to clarify the underlying abscission mechanism of the metabolism and biochemical reactions.   Method  High-throughput sequencing was employed to conduct transcriptome analysis of the young fruit of Morus alba in the abscission zone between the abscised and normal surviving mulberry fruits to screen the differentially expressed genes before they were subjected to functional annotation and metabolic pathway analysis, and the verification of transcriptome data using real-time quantitative PCR technology.   Result  A total of 262.92 Mb of raw reads and 10 481 differentially expressed genes were obtained by Beijing Genomics institution (BGI, Shenzhen, China), of which 5 239 were up-regulated, whereas 5 242 were down-regulated; As was shown by the GO functional enrichment analysis, a total of 37 significant items were found, and most of the differentially expressed genes were featured with catalytic activity, membrane composition, oxidoreductase activity and membrane intrinsic components. It was shown by the KEGG enrichment analysis that most differentially expressed genes were concentrated in metabolic pathways such as citric acid cycle, plant hormone signal transduction pathway, and flavonoid biosynthesis.   Conclusion  Mulberry is regulated by plant hormones and substances such as amino acids, flavonoid secondary metabolites and carbohydrates during the abscission process. [Ch, 9 fig. 2 tab. 35 ref.]
Cloning and expression characteristics of LiCMB1 gene in Lagerstroemia indica
SHANG Linxue, WANG Qun, ZHANG Guozhe, ZHAO Yu, GU Cuihua
, Available online  doi: 10.11833/j.issn.2095-0756.20220333
Abstract:
  Objective  The LiCMB1 gene of Lagerstroemia indica was cloned, and its expressions in different stages of flower bud differentiation and different tissues and organs were analyzed, so as to explore the expression characteristics of LiCMB1 gene.   Method  The gene sequence of LiCMB1 was cloned from L. indica by simple cloning technology. Physical and chemical properties of the protein were analyzed by online tools including ExPasy, and phylogenetic tree was constructed by MEGA 6.0 software. Combined with the phenotypic observation and paraffin section of L.indica flower bud differentiation, the expressions of LiCMB1 gene in different stages of flower bud differentiation and different tissues and organs were analyzed by real-time quantitative PCR (RT-qPCR).   Result  LiCMB1 gene belongs to SEP gene of MADS-box family, except for typical MADS_ MEF2_ like and K-box structure domain, there is also a SEP motif conserved motif near the C-end. The results of RT-qPCR showed that the expression trend of LiCMB1 increased first and then decreased in the process of flower bud differentiation of L. indica. It is expressed in different tissues and organs, and the expression levels of LiCMB1 from high to low were in the order of pistil, sepal, bud, long stamen, short stamen, petal, leaf, stem, root, indicating that LiCMB1 may play an important role in flower bud differentiation and participate in the regulation of flower organ development.   Conclusion  LiCMB1 gene belongs to the SEP gene of MADS-box family. It plays an important role in the early stage of flower bud differentiation of L. indica, especially in the calyx differentiation period. Tissue specificity analysis indicated that it was likely involved in the regulation of floral organ development. [Ch, 7 fig. 28 ref.]
Transcriptional analysis of starch and sucrose metabolism pathways in Magnolia sinostellata under heat stress
ZHENG Chenlu, WANG Qianying, LU Danyin, SHEN Yamei, MA Jingjing, LIU Lu, WANG Yun
, Available online  doi: 10.11833/j.issn.2095-0756.20220170
Abstract:
  Objective   The purpose is to explore whether the shrub species of Magnolia sinostellata could adapt to the high temperature in the city and promote its application.   Method   The 1-year-old seedlings of M. sinostellata were treated with high temperature at 40 ℃ to determine the fructose, glucose, sucrose, starch carbon assimilates, fructose phosphatase, sucrose phosphate synthase, and transcriptome sequencing.   Result   With the extension of stress time, the contents of fructose, glucose, sucrose and starch in leaves of M. sinostellata were changed, but the difference was not significant(P>0.05). The fructose synthase was significantly decreased (P<0.05), but the sucrose synthase was not significantly changed (P>0.05). Transcriptomic data further revealed that SS (Unigene 40295), Glc-1-pa (Unigene 38453) and GBE (CL4668.contig3) regulated starch synthesis at 48 h compared with 24 h under heat stress. The expression of GBE (CL4668. Contig3) gene increased, and the SPS gene that regulates sucrose synthesis decreased with the deepening of heat stress. The above results were verified by qPCR.   Conclusion   All results indicated that M. sinostellata had a certain short-term tolerance to extreme temperature of 40 ℃. In order to cope with high temperature stress, not only the carbon assimilates were significantly changed, but also the expression of key genes regulating starch and sucrose metabolism were changed. It was further proved that high temperature could lead to mutual conversion of sucrose and starch in the leaves of M. sinostellata. [Ch, 4 fig. 3 tab. 25 ref.]
Allelopathy of the litter extracts from Robinia pseudoacacia forest on its seed germination and embryo growth
JING Rong, PENG Zuodeng, LI Yun, WANG Shaoming
, Available online  doi: 10.11833/j.issn.2095-0756.20220247
Abstract:
  Objective  This study, with an exploration of the allelopathic effects of understory litter extracts from different stand types of Robinia pseudoacacia on seed germination and embryo growth, is aimed to clarify causes of the difficulty in seedling regeneration under R. pseudoacacia forest.   Method  With the litter extracts of R. pseudoacacia plantation used as the source of allelochemicals and the seeds of R. pseudoacacia being the subjects of study, the Petri dish filter paper method was emoloyed to analyze the effects of the understory litter extracts of different management generations and different stand ages on the germination rate, germination potential, germination speed index, vigor index and embryo growth of R. pseudoacacia.   Result  (1) The litter extracts under the R. pseudoacacia forest inhibited the germination and embryo growth of R. seudoacacia and the inhibitory effect of the litter extract on the growth of the radicle was stronger than that of the embryo. (2) There were significant differences between different forest types and different concentrations in the second-generation forest and the third-generation forest, the inhibitory effect of R. pseudoacacia litter extract on seed germination and embryo growth decreased with the increase of forest age. (3) In the first-generation forest, the litter extracts of middle-aged forests could promote seed germination, but had a weak inhibitory effect on embryo growth with the allelopathic effect composite index being 0.006 and −0.032 respectively. (4) In middle-age forests, the inhibitory effect of R. pseudoacacia litter extract on seed germination and embryo growth increased with the increase of forest generations. (5) In mature forests, with the increase of forest generations, the inhibitory effect of the litter extract on seed germination showed an increasing trend with the allelopathy composite index increased from 0.044 to 0.097, whereas the inhibitory effect on embryo growth showed a decreasing trend, with the allelopathy composite index falling from 0.124 to 0.050. (6) The litter extract in some forest types had a concentration effect, and its inhibitory effect on seed germination and embryo growth weakened as the concentration decreased.  Conclusion  The litter extracts of different stand types of R. pseudoacacia undergrowth have an inhibitory effect on their own seed germination and embryo growth. In the second and third generation stands, the litter extract showed a weakening effect on the seed germination and embryo growth of R. pseudoacacia with the increase of stand age. In young-aged and middle-aged forests, the inhibitory effect of litter extract on seed germination and embryo growth of R. pseudoacacia increased with the increase of forest generation. In other words, continuous planting hinders the natural regeneration of seedlings of R. pseudoacacia, but as the forest age increases, the hindering effect on the regeneration of seedlings will be weakened. [Ch, 3 fig. 1 tab. 38 ref.]
Effect of conservation of C-terminal sequence of Solanum nigrum UNUSUAL FLORAL ORGANS family SnUFO2 on flower development
ZHOU Jiayuan, ZHONG Yu, Nurasiya Imam, CUI Minlong, PIAO Chunlan
, Available online  doi: 10.11833/j.issn.2095-0756.20220217
Abstract:
  Objective   UNUSUAL FLORAL ORGANS (UFO) gene belongs to the F-box gene family and is one of the most important floral organ identity genes. The N-terminal of UFO gene can combine with Skp1 genes to form Skp1-Cullin1-F-box (SCF) complex, which participates in the ubiquitination process and degrades the target protein binding with the C-terminal. In order to explore the effect of C-terminal sequence on the flower development of Solanum nigrum, a C-terminal deleted SnUFO2* gene was cloned and its expression vector was constructed transferred into S. nigrum plants to observe the changes of floral organs of transgenic S. nigrum plants, so as to further explore the important role of the complete C-terminal sequence of UFO gene in the flower development of S. nigrum.   Method   Comparative analysis of SnUFO2* and full-length SnUFO2 was performed using bioinformatics analysis software. Moreover, the expression levels of SnUFO2* in roots, stems, leaves, and buds of wild-type S. nigrum were analyzed by real-time quantitative PCR (RT-qPCR); the function of the SnUFO2* gene was verified by the construction of over expression vector, observation of phenotype of transgenic plants, and the employment of paraffin section technique.   Result   The ORF length of SnUFO2* was 1 302 bp, encoding 433 amino acids, when compared with the complete SnUFO2 in S. nigrum, the C-terminal of which was missing 23 amino acids. RT-qPCR results showed that SnUFO2* was specifically expressed in the buds of wild-type plants. The phenotypic observation of transgenic plants demonstrated that the petals of 35S::SnUFO2* transgenic S. nigrum plants transformed into sepals. Paraffin section analysis presented that the stamens of transgenic S. nigrum plants were missing and uncertain meristem was produced in the pistil.   Conclusion   35S::SnUFO2* transgenic plants lead to abnormal development of petals, stamens, and carpels of S. nigrum. The deletion of the C-terminal structure may reduce the ability of SnUFO2 protein to specifically recognize target proteins, indicating that the complete C-terminal of the gene is important for organ development of S. nigrum. [Ch, 5 fig. 1 tab. 23 ref. ]
Changes of soil organic carbon storage and carbon components in typical meadow communities in Napahai
LIU Pan, LU Mei, LI Cong, LÜ Jinghua, YANG Zhidong, ZHAO Xuyan, CHEN Zhiming
, Available online  doi: 10.11833/j.issn.2095-0756.20220377
[Abstract](15) [HTML] (0) [PDF](779)
Abstract:
  Objective  This study aims to explore the change characteristics of soil organic carbon(SOC) components in typical meadow wetlands of Napahai caused by different groundwater levels and their coupling relationship with environmental factors, so as to provide data support for understanding the process of soil carbon cycle in plateau wetlands.   Method  3 typical meadow communities of different underground water levels were selected as the research objects in Napahai Wetland in November 2020. The concentration of soil microbial biomass carbon(MBC) and total organic carbon(TOC), easily oxidized carbon(EOC), and particle organic carbon(POC) as well as the distribution pattern of carbon pool along soil profile were compared. The relationship between carbon components, plant diversity and soil physicochemical factors was analyzed.   Result  The total soil carbon stocks of different meadow communities (0−40 cm soil layer) ranking from high to low were Poa pratensis community (47.55 t ·hm−2), Carex nubigena community (42.28 t ·hm−2), and Gnaphalium affine community (32.14 t ·hm−2), which decreased along the deepening of soil layers. Soil TOC storage decreased the most in G. affine community. Soil TOC, MBC, EOC and POC decreased with the decrease of groundwater depth, ranging from1.8 to 3.4 times. SOC component decreased by 1.0−3.4 times along the deepening of soil layer in the communities of P. pratensis, C. nubigena and G. affine. Plant biomass, Shannon-Wiener diversity index of plant community, Pielou evenness index, Margalef richness index and Simpson dominance index all decreased by 1.5−2.8 times along the decrease of groundwater depth. Soil water content (SWC), pH and total phosphorus (TP) contents also significantly decreased with decreasing depth of groundwater. RDA redundancy and Pearson correlation analysis showed that aboveground biomass, SWC, soil bulk density(SBD), total nitrogen(TN), and TP had the strongest response to the change in groundwater depth, and were the controlling factors affecting changes of SOC components in typical meadow communities in Napahai.   Conclusion  The mass fraction and vertical distribution of SOC components in typical meadows of Napahai wetland mainly depend on the change of plant aboveground biomass and soil physicochemical properties caused by different groundwater depths. Therefore, in the process of protecting typical meadow wetlands in Napahai, it is recommended to monitor the groundwater level to prevent the impact of low groundwater level from affecting the stability of wetland carbon pool. [Ch, 3 fig. 4 tab. 42 ref.]
Rooting, anatomical analysis and changes of enzyme activity of softwood cuttings of Quercus variabilis at different ages
QIAN Jialian, LI Yingchao, XU Huihui, WANG Xi, QIN Aili, REN Junjie, WANG Libing, YU Haiyan
, Available online  doi: 10.11833/j.issn.2095-0756.20220143
Abstract:
  Objective   This study aims to explore the effect of mother tree age on the cutting rooting of Quercus variabilis as well as the possible causes, so as to provide basis for the cutting propagation of Q. variabilis.   Method   The semi-lignified shoots of 1, 5 and 10-year-old oak mother trees were soaked with 200 mg·L−1 root powder (ABT-1) for 2 h. The rooting rate, rooting number, root diameter, root length and activities of polyphenol oxidase (PPO), peroxidase (POD) and IAA-oxidase (IAAO) were determined after 60 d. The changes of tissue structure of stem segments of cuttings at different ages were observed by paraffin sectioning.   Result   (1) The older the mother tree was, the lower the cutting rooting rate was. (2) The adventitious root primordium of Q. variabilis was induced in the late stage of adventitious root formation. The adventitious root generation time of cuttings at different ages was different (17 d for trees of 1 year old , 44 d for 5 years old, and none for 10 years old). (3) The activities of IAAO, PPO and POD in the cuttings of 1-year-old and 5-year-old mother trees showed a single-peak trend of ‘first increasing and then decreasing’, while the activities of POD in the cuttings of 10-year-old mother trees showed an increasing trend. The activities of PPO and IAAO did not change significantly.   Conclusion   The age of mother trees affects the generation of adventitious roots of cuttings. The rooting rate and the average adventitious root number of Q. variabilis softwood cuttings from high to low are trees of 1 year old, 5 years old and 10 years old, with an average rooting rate of 92.69%, 10.79%, and 0, respectively. The rooting type of Q. variabilis is dermal rooting type and its adventitious root primordium is induced root primordium. High levels of POD and PPO activity are conducive to adventitious root induction, while increased IAAO activity is conducive to adventitious root formation. [Ch, 3 fig. 1 tab. 30 ref.]
Identification of Ph-TElncRNA1 in Phyllostachys edulis and its regulation of target genes
ZHAO Jiamin, YU Lu, DING Yiqian, ZHOU Mingbing
, Available online  doi: 10.11833/j.issn.2095-0756.20220396
Abstract:
  Objective   The purpose of this study is to explore the expression patterns of Ph-TElncRNA1 and target genes in Phyllostachys edulis, and to preliminarily analyze the function of lncRNA.   Method   Based on the whole transcriptome sequencing data of Ph. edulis seedlings under high temperature, low temperature, ultraviolet and high salt stress, lncRNAs differentially expressed under stress were screened. The coding characteristics of lncRNA were analyzed by four kinds of software(CNCI, Pfam, CPC2 and PLEK), and the target genes of lncRNA were identified by LncTar software. The expression patterns of lncRNA and target genes under UV stress and leaf coloration were analyzed by real-time fluorescent quantitative PCR.   Result   One differentially expressed lncRNA under UV stress was screened, which was derived from the lncRNA of the Large retrotransposons derivatives and named Ph-TElncRNA1(Ph. edulis transposable element derived lncRNA1). Ph-TElncRNA1 was a typical non-coding RNA with a total length of 342 bp, 185 bases from exons and 157 bases from introns. The target gene of Ph-TElncRNA1 was psbA, encoding photosystem Ⅱ protein D1. Real time fluorescence quantitative results showed that the relative expression of Ph-TElncRNA1 and psbA was the same, indicating that Ph-TElncRNA1 was positively correlated with psbA under UV stress. Through the analysis of the relative expression of Ph-TElncRNA1 and psbA in Ph. edulis leavesat different coloring stages, it was found that the expression of psbA and Ph-TElncRNA1 reached the peak during chloroplast formation stage.   Conclusion   Ph-TElncRNA1 and psbA are co-expressed under UV stress, andPh-TElncRNA1 can participate in the leaf development of Ph. edulis by regulating the target gene psbA.[Ch, 7 fig. 33 ref.]
Adsorption-degradation of oil in catering wastewater by the microorganism immobilized on sponge pyrolytic carbon
MA Shuwen, LIU Xin, ZHOU Xiaoqin, FANG Xiaobo, ZHENG Huabao, MAO Haonan, YANG Yu, MENG Qishen, ZHANG Cheng
, Available online  doi: 10.11833/j.issn.2095-0756.20220338
Abstract:
  Objective  The objective of this study is to explore the effective treatment of catering wastewater, which has become increasingly harmful to the environment with the rapid development of catering industry.  Method  Sponge pyrolytic carbon (SPCx) with good adsorption performance was prepared from waste sponge by pyrolysis and carbonization. The physical and chemical properties such as the morphology and structure of the materials were characterized by cold field emission scanning electron microscopy, Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy. Through the adsorption of soybean oil in wastewater by SPCx, the effects of pyrolysis temperature, wastewater pH and temperature on the adsorption performance were studied. The adsorption kinetics and adsorption isotherm of SPC600 adsorbent were analyzed, and the Langmuir and Freundlich models were used to analyze the data. Based on this, the oil adsorption-degradation law of SPC600 immobilized microorganisms in simulated wastewater and actual wastewater was explored.   Result  Sponge pyrolytic carbon (SPC600) had abundant “network” structure and fracture branches, and contained a large number of hydroxyl, carbonyl, ether bonds, and other oxygen-containing functional groups on its surface, which improved its ability to adsorb oil and immobilize microoganism. The optimized SPC600 had an adsorption capacity of 8 093.1 mg·g−1 at pH 7 and adsorption temperature of 30 ℃. The adsorption process of oil conformed to the pseudo-second-order kinetic equation, and was an exothermic process dominated by chemical adsorption. The screened oil-degrading strains and SPC600 were made into immobilized microbial adsorbents, and the degradation rate of actual oil wastewater reached 67.6%, which was 11.0% and 14.4% higher than that of free strain and free strain+SPC600 respectively.   Conclusion  The sponge pyrolytic carbon immobilized microbial technology can stabilize the degrading strain and improve the oil degradation rate, so as to achieve the effect of “treating waste with waste” and avoid secondary pollution, which has a good application prospect. [Ch, 8 fig. 3 tab. 42 ref.]
Effects of intercropping patterns on physiological characteristics and Pb uptake of edible plants in community gardens
YAN Yue, JIN Hexian, WANG Ying, CHEN Chaoyi, FAN Yingjia, LIU Dan
, Available online  doi: 10.11833/j.issn.2095-0756.20220365
Abstract:
  Objective  The objective is to study the physiological characteristics of plants in Pb contaminated soil and uptake characteristics of Pb in community gardens intercropped with Sedum alfredi, in order to screen out the best planting mode to reduce the uptake of Pb by edible plants.  Method  S. alfredii, Apium graveolens, Brassica chinensis, Capsicum annuum and Raphanus sativus were used as research materials. A pot experiment was carried out in Pingshan Nursery of Lin’an District of Hangzhou City, Zhejiang Province. The effects of intercropping S. alfredii on physiological and biochemical indexes of edible plants, uptake and transfer characteristics of Pb, the pH of rhizosphere soil and distribution characteristics of Pb were analyzed.  Result  (1) Intercropping significantly improved the biomass of S. alfredii, A. graveolens and C. annuum, and reduced the biomass of B. chinensis and R. sativus (P<0.05). (2) The content of MDA in leaves of S. alfredii and edible plants showed a consistent pattern, and intercropping was lower than monoculture. In the intercropping system, CAT activities in leaves of A. graveolens, C. annuum and R. sativus significantly increased by 33.92%, 41.94% and 53.80%, compared with the monoculture system (P<0.05). (3) Intercropping S. alfredii significantly reduced Pb accumulation in edible parts of A. graveolens, C. annuum and R. sativus, which decreased by 24.37%, 162.50% and 39.82%, respectively (P<0.05), compared with monoculture. (4) Intercropping decreased the pH of rhizosphere soil and changed the distribution of Pb in soil. Intercropping S. alfredii decreased the form proportion of weak acid extracted and oxidized Pb in the rhizosphere soil of edible plants, but increased the form proportion of reducible Pb in soil.   Conclusion  The intercropping mode can promote the enrichment and migration of Pb in S. alfredii and reduce the toxic effect of Pb on edible plants. Intercropping S. alfredii significantly reduces Pb content in edible parts of A. graveolens and C. annuum, reaching the safe edible standard. The Pb content in edible parts of R. sativus tends to decrease, which is an ideal combination mode for intercropping restoration. [Ch, 6 fig. 3 tab. 31 ref.]
Allelopathic effects of Phyllostachys edulis extracts on Fritillaria thunbergii
WU Haiping, YE Genhua, LI Weicheng
, Available online  doi: 10.11833/j.issn.2095-0756.20220471
Abstract:
  Objective  The purpose is to explore the allelopathic effects of forest extract of Phyllostachys edulis on Fritillaria thunbergii, so as to screen the suitable economic species for compound management of Ph. edulis and medicinal plants.   Method  F. thunbergii was selected as the target plant to carry out the allelopathy experiments of different extracts of Ph. edulis forest (roots, fresh branches and leaves, litter and 0~20 cm soil) at different concentrations (0.005, 0.010, 0.020, 0.050 and 0.100 kg·L−1).   Result  (1) The effects of root extract on the growth characters (plant height, biomass and leaf area), photosynthetic pigments (chlorophyll a, chlorophyll b and chlorophyll a+b) and active medicinal components (Fritillarin A and Fritillarin B) of F. thunbergii showed promotion at lower extract concentration while inhabitation at higher concentration. (2) Fresh branches and leaves, litter and soil extracts promoted the growth traits, photosynthetic pigments and active components, increased the leaf area and absorption capacity of direct and diffuse light, which was conducive to the growth of F. thunbergii under low light condition. The maximum net photosynthetic rate and light saturation point also increased under the treatment of these three extracts, which first increased and then decreased with the increase of the extract concentration. At the same time, the apparent quantum efficiency increased and the light compensation point decreased, indicating that Ph. edulis extracts changed the utilization rate of light energy and the absorption range of light intensity. (3) The comprehensive allelopathic effect of root extract on F. thunbergii was the strongest, while that of the soil extract was the weakest. (4) The MDA content increased when the root extract was in high concentration, indicating that F. thunbergii was under certain environmental stress.   Conclusion  F. thunbergii can adapt to the irrigation of other extracts except root extract of high concentration, and can improve biomass and active medicinal components. Land preparation and cleaning up the dead root of Ph. edulis forest is conducive to the high-quality growth of F. thunbergii. [Ch, 1 fig. 5 tab. 20 ref.]
Genetic analysis of phenotypic traits in F1 hybrids of 6 Clematis cultivars
CHEN Xiaolei, SHAO Weili, LI Siyuan, LIU Zhigao, MA Hongling, SHEN Yamei, DONG Bin, ZHANG Chao
, Available online  doi: 10.11833/j.issn.2095-0756.20220214
Abstract:
  Objective  This study, with an analytical comparison of the phenotypic traits between cross parents and F1 generation of Clematis, is aimed to explore the genetic variation of Clematis.   Method  Four cross combination experiments were conducted to statistically analyze the phenotypic traits of F1 generation with six Clematis cultivars as parents.   Result  (1) Compared with those of the parents, the flowering stage of F1 generation was separated, but mostly between the parents. (2) There is a general color separation within the F1 generation with the heritability of violet higher than that of red purple, and that of violet and purple more recessive than that of red purple whereas the anther color of F1 generation was not separated with yellow anther relatively dominant to pink and red anther. (3) The sepal width, leaf length and leaf width of F1 generation showed superparental traits, with the total mean values being 111%, 114% and 119% of the median parental values respectively; the pedicel length, flower diameter, sepal aspect ratio and leaf aspect ratio of F1 generation were lower than those of both parents, with the total average values of the offspring being 85%, 89%, 91% and 82% of the median parental values while the sepal length and segment spacing of F1 generation did not change significantly, with the total mean values being 98% and 102% of the median parental value respectively. (4) There were significant correlations (P<0.05) between five quantitative traits in flower and four quantitative traits in leaf, and leaf length was positively correlated (P<0.01) with leaf width, with the highest correlation coefficient of 0.940, which tended to be linked inheritance.   Conclusion  Most of the phenotypic traits (except anther color) in the offspring generation changed, with only sepal length and segment spacing showing maternal inheritance. On the hand, sepal width showed paternal inheritance, while nine traits, including flowering stage, flower color, anther color, pedicel length, flower diameter, sepal aspect ratio, leaf length, leaf width, and leaf aspect ratio, showed no obvious genetic tendency. [Ch, 1 fig. 7 tab. 24 ref.]
Molecular mechanism of glucosinolate-mediated Brassica campestris ssp. chinensis against feeding stress of Spodoptera exigua larvae
HAO Jiaojiao, MA Yonghua, LU Yanchi, XU Li’ai, ZHU Zhujun, YU Youjian
, Available online  doi: 10.11833/j.issn.2095-0756.20220172
Abstract:
  Objective  With an investigation of the effects of Spodoptera exigua larvae feeding on the content and components of glucosinolates (GSLs) in Brassica campestris ssp. chinensis, this study is aimed to figure out the initial molecular mechanism of GSL-mediated resistance to the feeding stress of S. exigua larvae in B. campestris ssp. chinensis.   Method  The effect of larvae feeding on the content and components of GSLs in B. campestris ssp. chinensis ‘Meiduheiyoutong’was determined with the application of high performance liquid chromatography before an analysis was conducted of the expression patterns of key genes related to GSLs metabolism using real-time fluorescence quantitative polymerase chain reaction (RT-qPCR), after which the activity of glutathione S-transferase (GSTs) in larvae after eating B. campestris ssp. chinensis was detected by GSTs kit.   Result  (1) Of the eight GSLs that enjoyed a significant increase in B.campestris ssp. chinensis after S.exigua larvae’ s feeding, 4-hydroxy-glucobrassicin (4OH), 1-methoxy-glucobrassici (NEO), glucobrassicin (GBC) and glucobrassicanapin (GBN) were the four important GSLs responsive to the feeding; (2) The significant up-regulation of aliphatic GSL synthesis-related genes BcBCAT4 and BcMAM1 in B. campestris ssp. chinensis might be related to the increase of aliphatic GSLs, and the up-regulation of BcSOT16 was positively correlated with 4OH, NEO and GBC after feeding by S. exigua larvae; (3) After feeding, the activity of GSTs in the larvae of S. exigua was significantly enhanced (P<0.05), and showed a consistency with the changes of the total GSLs and indole GSLs.  Conclusion  Feeding by S. exigua larvae can induce the synthesis of GSLs in B. campestris ssp. chinensis, and the increase of GSLs can induce the enhancement of GSTs activity in larvae. Under the feeding stress of S. exigua larvae, the activation of key GSLs synthesis genes such as BcSOT16, BcBCAT4 and BcMAM1in B.campestris ssp. chinensis may promote the increase of 4OH, NEO, GBC and GBN which will help better resist S. exigua larvae feeding stress. [Ch, 2 fig. 3 cab. 44 ref.]
Threshold gradient of water content of spraying substrate based on photosynthetic characteristics of Lolium perenne in summer and autumn
LIU Xiaoyong, SHI Changqing, ZHAO Tingning, XING Fuqiang, WANG Pu, HAO Peiwen, ZHANG Jingjing, WANG Jing, SUN Huijie
, Available online  doi: 10.11833/j.issn.2095-0756.20220116
Abstract:
  Objective  This study, with an analysis of how the over-irrigation of soil spraying substrate has caused soil erosion and affected plant growth, is aimed to put forward an optimal threshold of suitable water content of spraying substrate for vegetation growth.   Method  First, planting pots were used to simulate the experiment of soil spraying on bare slopes, and 5 kinds of water gradients of spraying substrates were designed. Then, efforts were made to measure the net photosynthetic rate (Pn), transpiration rate (Tr), stomatal conductance (Gs) and intercellular CO2 concentration (Ci) of Lolium perenne by Li-6400XT portable photosynthetic analyzer in summer and autumn before an analysis was conducted of the relationship between photosynthetic parameter of L. perenne and water content of spraying substrates.   Result  (1) The relative water content (CRW) of the spraying substrate at the net photosynthetic rate hydration compensation point of L. perenne in summer and autumn were 35.02% and 30.83% respectively (with the actual substrate mass water content being 10.63% and 9.36% respectively). (2) In summer and autumn, CRW of sprayed substrate, where the Pn of L. perenne decreased from stomatal limitation to non-stomatal limitation, was 55.00% (with the actual substrate mass water content being 16.70%). (3) The spraying substrate water content threshold of L. perenne comes in five types, namely “non-productivity and non-efficiency water”“low productivity and low efficiency water”“middle productivity and middle efficiency water”“middle productivity and high efficiency water” and “high productivity and high efficiency water”.   Conclusion  When the goal of soil spraying and greening is to quickly restore vegetation, the water content of the spraying substrate can be kept in the range of “high productivity and high efficiency water”, based on which irrigation is carried out: in summer, it is 76.25%≤CRW≤78.17%, with its actual mass water content being 23.15%−23.73% whereas in autumn, it is 73.61%≤CRW≤76.02%, with its actual mass water content being 22.35%−23.08%. On the other hand, when the goal of soil spraying greening is to improve the water use efficiency and restore the basic vegetation (that is, to restore the local natural vegetation coverage), the water content of the spraying substrate can be kept in the range of “middle productivity and high efficiency water ”, based on which irrigation is carried out: in summer, it is 55.00%≤CRW≤76.25%, with its actual mass water content being 16.70%−23.15% whereas in autumn, it is 55.00%≤CRW≤73.61%, with its actual mass water content being 16.70%−22.35%.[Ch, 10 fig. 4 tab. 26 ref.]
Preparation and algae inhibition of garlic oil microemulsion
HUANG Yang, GUO Ming, WANG Yiping, YE Bihuan, CHEN Youwu, WANG Weiyu
, Available online  doi: 10.11833/j.issn.2095-0756.20220336
Abstract:
  Objective  This study aims to prepare microemulsion from garlic oil in order to improve the stability of garlic oil and develop a new type of plant-derived algaecide.  Method  The effects of surfactant and co-surfactant types and mass ratio (Km) on the formation of garlic oil microemulsion system were investigated by phase transition method and pseudo-ternary diagram, and orthogonal experiments were carried out. The stability of garlic oil microemulsion prepared under the optimal conditions under different temperature, pH and centrifugation conditions of 5 000 and 10 000 r·min−1 was investigated, and the algae inhibition of garlic oil microemulsion experiment was carried out.  Result  The optimum preparation conditions were 25 ℃, Tween 80 as surfactant, ethanol and n-butanol as co-surfactants. The mass ratio of the three was 1∶1∶1, and the mass ratio of mixed surfactant and garlic oil was 4∶6. The obtained microemulsion was yellow clear transparent liquid with light blue luster. The average particle size was 20.1 nm and the polydispersity coefficient was 0.144. The algae inhibition rate of 320 mg·L−1 garlic oil microemulsion was 82.54%.  Conclusion  The successfully prepared oil-in-water type garlic oil microemulsion has good stability, suitable particle size, and obvious algae inhibitory effect. It is expected to be a new algaecide. [Ch, 9 fig. 3 tab. 31 ref.]
Characteristics and impact factors of self-pruning in natural Larix gmelinii forest
YU Bao
, Available online  doi: 10.11833/j.issn.2095-0756.20220220
Abstract:
  Objective  This paper, with an analysis of the natural pruning laws of natural forests, is aimed to clarify the indicators and main influencing factors of natural pruning so as to provide a basis for forest tending, optimizing stand structure and promoting natural pruning.   Method  First, with measured data collected of a total of 1 279 standing trees in 32 plots in the middle and young Xing’an larch (Larix gmelinii) natural forest, a correlation analysis with forest trees and stand factors was conducted to explore the natural pruning laws of forest stand with different structures using the height under live branches, the proportion of the height under live branches in tree height, the height under dead branches, the proportion of the height under dead branches in tree height, the difference between the height under live branches and the height under dead branches as natural pruning indicators. Then, on this basis, the stepwise regression analysis was carried out to determine the main factors that were likely to affect the natural pruning.   Result  The average value for the height under live branches, the proportion of the height under live branches in tree height, the height under dead branches, the proportion of the height under dead branches in tree height, and the difference between the height under live branches and the height under dead branches in Xing’an larch natural forest were: 4.8 m , 46.4%, 2.8 m, 25.2%, 1.4 m. The natural pruning indicators of the forest stands with different densities and aggregation coefficients were extremely significantly different (P<0.01). The factors affecting natural pruning include tree diameter at breast height (DBH), tree height, tree crown width, tree age, stand average DBH, stand average tree height, stand density, and aggregation coefficient. Except for the proportion of the height under dead branches in tree height, the other four natural pruning indicators were all affected by several factors, without a significant consistency in the indicators affected by each factor and among them, the forest stand density and aggregation coefficient, which were significantly and negatively correlated with the three indicators of the height under dead branches, the proportion of the height under dead branches in tree height, and the difference between the height under live branches and the height under dead branches, whereas the other factors were extremely positively correlated with the natural pruning indicators, showing extremely significant (P<0.01) or significant (P<0.05) positive correlation. Stepwise regression analysis indicated that tree height, tree age, stand average tree height and stand average DBH were the main affecting factors in natural pruning of which, the height under live branches was mainly affected by the tree height and age, the proportion of the height under live branches in tree height was mainly affected by the tree age, while the height under dead branches was mainly affected by the stand average tree height. The difference between the height under live branches and the height under dead branches were mainly affected by the stand average DBH and the tree height.   Conclusion  The four factors, including the tree height and age, stand average tree height and stand average DBH, are the main influencing factors in natural pruning. The four indicators such as the height under live branches, the proportion of the height under live branches in tree height, the height under dead branches, and the difference between the height under live branches and the height under dead branches can be used to better characterize natural pruning. Among them, the height under live branches and the proportion of the height under live branches in tree height are mainly affected by forest tree factors, and the height under dead branches, the difference between the height under dead branches and the height under live branches are mainly affected by forest stand factors. If the forest stand growth is better, it can promote natural pruning, but has no effect on the shedding rate of dead branches. The increase of stand density and aggregation coefficient not only promotes natural pruning, but also accelerates the shedding of dead branches. [Ch, 5 tab. 26 ref.]
Cloning and expression characterization of OfPSY, OfPDS and OfHYB gene promoters in Osmanthus fragrans
ZHOU Junjie, WANG Yiguang, DONG Bin, ZHAO Hongbo
, Available online  doi: 10.11833/j.issn.2095-0756.20220110
Abstract:
  Objective  This paper aims to investigate the regulation of high temperature and abscisic acid (ABA) on promoters of three carotenoid biosynthesis genes in Osmanthus fragrans including PSY, PDS, HYB, providing the research foundation for regulation of carotenoid biosynthesis in O. fragrans.   Method  According to the sequences in genome database of O. fragrans, promoters of OfPSY, OfPDS, OfHYB were cloned from an O. fragrans cultivar ‘Yanhong Gui’, which were used for bioinformatics analysis. Then, these promoters were inserted into PCAMBIA3301-LUC vectors and used for transient expression in tobacco(Nicotiana benthamiana) leaves under treatments of high temperature (37 ℃) and 200 mg·L−1ABA.   Result  Our research cloned the promoter of OfPSY, OfPDS and OfHYB from genomic database of O. fragrans in length as 1908 bp, 1521 bp and 1830 bp respectively. All three promoters contain promoter basic elements TATA-box and CAAT-box, light response element, ABA response element as well as the binding site of MYB and MYC. Moreover, there was gibberellins (GA) response element in OfPSYP; OfPDSP contains methyl jasmonate (MeJA) and GA response element, pathogen induction element as well as element involved in defense and stress responsiveness; OfHYBP contains hormone response elements as auxin, ethylene and MeJA, as well as low temperature response element and pathogen induction element. The assays of in transient expression in tobacco leaves showed that relative high temperature can activate the promoter activities of OfPSY, OfPDS and OfHYB, and ABA can activate the promoter activities of OfPDS and OfHYB.   Conclusion  High temperature and ABA probably affect the carotenoid accumulation in O. fragrans by regulating the promoter activities of carotenoid biosynthesis genes. [Ch, 4 fig. 5 tab. 28 ref.]
Response of soil respiration to understory vegetation management in Eucalyptus urophylla × E. grandis plantation
ZHU Wankuan, XU Yuxing, WANG Zhichao, DU Apeng
, Available online  doi: 10.11833/j.issn.2095-0756.20220138
Abstract:
  Objective  This study aims to investigate the impact of different understory vegetation management measures on soil respiration and its components in Eucalyptus urophylla × E. grandis plantation on Leizhou Peninsula, so as to provide a reference for accurate evaluation of soil carbon cycle in Eucalyptus plantation.   Method  Understory vegetation removal was conducted in 2 ways (physical removal and herbicide treatment) in E. urophylla × E. grandis plantation, and the non-removal group was used as the control. The LI-8100A automatic soil carbon flux measurement system was used to continuously monitor total soil respiration and its component rates, soil temperature and humidity (5 cm deep) for 1 year.   Result  Physical and chemical removal of understory vegetation significantly reduced total soil respiration and its components (except chemical removal of root respiration) (P<0.01). In addition, the total soil respiration rate of physical removal (3.45 μmol·m−2·s−1) was significantly lower than that of chemical removal (4.15 μmol·m−2·s−1) (P<0.01). There was no significant difference between the two approaches in mineral soil respiration rate and litter layer respiration rate. The root respiration rate showed physical removal (1.02 μmol·m−2·s−1) was significantly lower than that of chemical removal (1.37 μmol·m−2·s−1)(P<0.05). The contribution rates of litter layer respiration, mineral soil respiration, and root respiration to total soil respiration were 36.45%−39.40%, 26.34%−31.29%, and 30.10%−39.40%, respectively. The highest value of total soil respiration rate and its components occurred in the rainy season (April-October) and the lowest value of root respiration rate occurred in July and August. The fitting model of soil total respiration rate with soil temperature and humidity was the best, which could explain 75.1% (physical removal), 60.9% (chemical removal) and 57.1% (control) of the variation of soil total respiration rate. The temporal variation of litter respiration rate was mainly controlled by soil moisture; There was no significant correlation between root respiration rate and soil temperature, but a significant negative correlation with soil moisture (P<0.05). The temperature sensitivity (Q10) of total soil respiration was 2.12 for physical removal, 1.95 for chemical removal, and 1.93 for control.   Conclusion  The removal of understory vegetation affects soil respiration by changing biological and abiotic factors in the forest. Compared with chemical removal, physical removal of understory vegetation can reduce the total soil respiration rate and carbon emission of forest soil to a greater extent. [Ch, 4 fig. 3 tab. 49 ref.]
Effect of prescribed burning on soil anti-erodibility and anti-scourability of Pinus yunnanensis forest
YANG Fuyu, CHEN Qibo, LI Jianqiang, GONG Shunqing, FU Yishan
, Available online  doi: 10.11833/j.issn.2095-0756.20220321
Abstract:
  Objective  Prescribed burning is an essential measure for forest fire prevention. The purpose of this study is to explore the impact of prescribed burning on soil anti-erodibility and anti-scourability of Pinus yunnanensis forest, so as to provide scientific basis for sustainable forest management and optimization of prescribed burning in forest areas.  Method  The sample plots of P. yunnanensis forest in central Yunnan Plateau were selected as the research objects. The effects of prescribed burning on soil anti-erodibility and anti-scourability of P. yunnanensis forest were systematically studied by combining field investigation and sampling with indoor experimental analysis.   Result  (1) After prescribed burning, the content of mechanically stable aggregates(>2.00 mm) in 0−40 cm soil layer increased and the content of waterstable aggregates (>2.00 mm) decreased. The mean mass diameter and mean geometric diameter of the water stable aggregates decreased. The damage rate of soil aggregate structure increased, and the erosion resistance index decreased. The soil erosion resistance index of 40−60 cm soil layer did not change significantly. (2)After the prescribed burning, the litter accumulation decreased and the water holding capacity and storage capacity of the litter weakened, and the plant root system was burned. The decrease of litter and root system after periodic burning was the main reason for the decrease of soil erosion resistance coefficient in forest land.   Conclusion  Prescribed burning reduces water erosion resistance of soil surface. With the increase of soil depth, the impact of planned burning on soil erosion resistance gradually decreases. After prescribed burning, the surface litter and vegetation roots decrease and the erosion resistance weakens. [Ch, 1 fig. 6 tab. 37 ref.]
Advances in plant phylogeny in the genome era
WANG Jie, HE Wenchuang, XIANG Kunli, WU Zhiqiang, GU Cuihua
, Available online  doi: 10.11833/j.issn.2095-0756.20220313
Abstract:
Phylogeny is a basic issue in evolutionary biology and an important topic in other branches of biology as well, which focuses on the genetic relationship and evolutionary fate among various taxa. Using molecular data to investigate the evolutionary relationship between organism is an important means of phylogenetic research. Along with the development of sequencing technology and its decreasing cost, phylogenetic research has gradually developed from the early stage based on single gene or combined minority fragments to the present stage using massive genome data to study the evolutionary relationship among individuals, populations, and species. In this paper, the representative achievements of three sets of genomes (chloroplast genome, mitochondrial genome, and nuclear genome) in plant phylogenetic research are discussed. The characteristics of different plant genomes and their advantages and limitations in phylogenetic studies are summarized. The main methods of phylogenetic tree construction are explored and the future research is prospected. At present, the three sets of genomes in plants are suitable for phylogenetic studies of different order elements and taxa. The differences in genetic characteristics between different genomes have different advantages and applications in phylogenetic studies: (1) Chloroplast genome is relatively simple in structure, conservative in sequence, difficult to recombine, and uniparentally inherited. It is an ideal molecular data resource widely used in the fields of phylogeny and evolutionary biology. (2) The evolutionary rate of plant mitochondrial genome sequence is relatively slow, so it is only suitable for early plant and large-scale phylogenetic research. (3) The nuclear genome is biparental inheritance, which can comprehensively reveal the parental lineage and phylogenetic network evolutionary relationship, and has great application potential in phylogenetic research. Different tree construction methods are suitable for datasets with different characteristics, and reasonable methods should be adopted in the process of tree construction to avoid the effects of long-branch attraction and incomplete lineage sorting. In the future, nuclear genome will become the mainstream of phylogenetic research, and its biparental genetic characteristics can provide sufficient insights into hybridization and genomic introgression during speciation. With more taxon phylogenetic positions determined, biparental inheritance such as hybridization, backcross, nucleocytoplasmic interaction, polyploidy, functional adaptation, and convergent evolution during speciation and evolution will become the focus of phylogenetic research. [1 tab. 78 ref.]
Spatial heterogeneity of soil nutrients and the influencing factors in Zhejiang subtropical nature reserve
DU Fangfang, TONG Genping, GUO Rui, JIANG Niwen, YE Zhengqian, FU Weijun
, Available online  doi: 10.11833/j.issn.2095-0756.20220213
Abstract:
  Objective  This study aims to reveal the spatial variability of soil nutrients and the influencing factors in subtropical national nature reserves of China, so as to provide a theoretical basis for protecting rare vegetation and natural ecosystems in China’s subtropical hilly regions.   Method  Soil samples were collected from Longtangshan-Shunxiwu in Qingliangfeng Nature Reserve of Zhejiang Province. Classical statistics and geostatistical method were used to systematically analyze the soil variables such as pH, soil organic matter (SOM), total nitrogen (TN), total phosphorus (TP) and total potassium (TK), and the main influencing factors were explored.   Result  The soil in the study area was acidic as a whole. The average contents of SOM, TP, TN and TK were 65.04, 0.67, 1.63 and 18.45 g·kg−1, respectively, which belonged to moderate variation. Semi variance analysis showed that SOM, TN and TK displayed strong spatial autocorrelation while pH and TP displayed moderate spatial autocorrelation, indicating that the soil nutrients were mainly affected by structural factors. The global Moran’s I index revealed that the spatial autocorrelation of SOM reached a significant level and its spatial distribution was aggregated, while the distribution of soil pH tended to be random. Kriging interpolation results showed that the spatial distribution of various nutrients was fragmented and the patch characteristics were significant. Correlation analysis showed that SOM and TN were significantly correlated with altitude, bulk density, and slope (P<0.05), and there was a significant positive correlation between SOM and TN (P<0.01).   Conclusion  All the soil nutrients show an obvious spatial heterogeneity. Altitude and bulk density are strongly correlated with the spatial variation of SOM and TN in the study area. [Ch, 6 fig. 4 tab. 38 ref.]
Effects of biochar-based urea and common urea on soil N2O flux in Phyllostachys edulis forest soil
CAO Shanzhi, ZHOU Jiashu, ZHANG Shaobo, YAO Yihan, LIU Juan, LI Yongfu
, Available online  doi: 10.11833/j.issn.2095-0756.20220254
Abstract:
  Objective  The aim of this study is to explore the effect and mechanism of the application of biochar-based urea and common urea on soil N2O flux and environmental factors in Phyllostachys edulis forest, so as to provide scientific basis for the development of fertilization technology to reduce soil N2O emissions.   Method  A field control experiment was carried out in a typical subtropical Ph. edulis forest in Qingshan Town, Lin’an District of Hangzhou from September 2018 to September 2019. 5 treatments were set up: control (ck), low-level urea (100 kg·hm−2), high-level urea (300 kg·hm−2), low-level biochar-based urea (100 kg·hm−2) and high-level biochar-based urea (300 kg·hm−2). Soil N2O flux of Ph. edulis forest was determined by static chamber-gas chromatography, and the dynamic changes of soil N2O flux, temperature and water content, nitrogen forms and related enzyme activities were analyzed under the above fertilization treatments.   Result  Low-level urea and high-level urea treatments increased the annual cumulative N2O emission by 17.3% and 36.0%, while low-level biochar-based urea and high-level biochar-based urea treatments reduced it by 3.1% and 16.9%, respectively. Both urea and biochar-based urea treatments significantly increased soil NH4 +-N and NO3 -N concentrations (P<0.05). Urea treatment significantly increased the concentration of soil water-soluble organic nitrogen and activities of urease and protease, while biochar-based urea treatment significantly decreased the values of these 3 indicators (P<0.05). In addition, under the above 5 treatments, there was a significant correlation between soil N2O emission rate and soil temperature, NH4 +-N, water-soluble organic nitrogen, urease and protease activities.   Conclusion  Compared with urea, biochar-based urea has a significant reduction effect on soil N2O flux in Ph. edulis forest, and the key mechanism lies in that biochar-based urea reduces concentration of soil water-soluble organic nitrogen and activities of N-cycling enzymes. [Ch, 5 fig. 3 tab. 55 ref.]
Ecological risk assessment of alien landscaping plants in wetland parks on the west bank of Dianchi Lake
PENG Lindi, WANG Qiong, ZHANG Hongli, ZHENG Chengjie, WANG Nanyuan, PAN Qubo
, Available online  doi: 10.11833/j.issn.2095-0756.20220301
[Abstract](41) [HTML] (20) [PDF](844)
Abstract:
  Objective  This study aims to evaluate the ecological risk of alien species of landscaping plants in 3 wetland parks on the west bank of Dianchi Lake, and explore their potential ecological risk, risk characteristics and hazard status.   Method  By route inspection method and key regional reconnaissance method, 3 wetland parks on the west bank of Dianchi Lake were investigated. Data on the growth characteristics, ecological characteristics, geographical flora, diffusion and escape of alien species of landscaping plants were collected. Combined with expert consultation method, analytic hierarchy process and cluster analysis, the ecological risk assessment system was established to evaluate alien species of landscaping plants in small areas.   Result  There were 93 species of alien landscaping plants in the 3 wetland parks, belonging to 48 families and 77 genera, and geographical flora was dominated by world widespread and tropical widespread varieties. The proportions of trees (including bamboo), shrubs (including vine) and herbs were 39.78%, 30.11% and 30.11%, respectively. Among the 58 alien species evaluated, Pharbitis purpurea, Eichhornia crassipes, and Solidago canadensis were high risk plants, while Cortaderia selloana, Cosmos bipinnatus, and Trifolium pratense were medium risk plants. Hierarchical clustering analysis showed that the risk genetic characteristics of the medium and high risk plants were similar, and the distance to the cluster center was closer than that of the low risk plants. Under the same risk, trees and shrubs were closer to the cluster center than herbs because of their similar growth characteristics.   Conclusion  Among the 58 alien species evaluated, herbaceous plants account for the majority of the high and medium risk species, and most of them are widely distributed in the world. The application of alien species of landscaping plants in this area should be selected and controlled strictly. High risk plants need to be cleared in time especially S. canadensis. [Ch, 2 fig. 7 tab. 26 ref.]
Effects of biochar from Procambarus clarkii shells and Ficus microcarpa branches on soil nutrients and bioavailability of Cd and Pb
GU Shaoru, YANG Xing, CHEN Hanbo, YANG Bingshuang, DAI Zhinan, CHEN Junhui, FANG Zheng, WANG Hailong
, Available online  doi: 10.11833/j.issn.2095-0756.20220182
Abstract:
  Objective  This study aims to investigate the effects of biochar derived from Procambarus clarkii shells (CSB) and Ficus microcarpa (FMB) on physicochemical properties of contaminated soil and plant growth.   Method  The biochar was prepared by pyrolysis of both typical kitchen and garden wastes at 650 ℃ with limited oxygen supply. A pot trial was conducted using Raphanus sativus with different mass ratios (0, 1%, 3%) to investigate the effects of different doses of CSB and FMB on cadmium (Cd) and lead (Pb) bioavailability in soil, nutrient transformation, soil enzyme activity, and R. sativus growth.   Result  3% FMB treatment had the most significant effect on improving contents of soil organic carbon, available phosphorus and available potassium (P<0.05), which increased by 135.8%, 35.4%, and 173.7% respectively compared with the control. Except 1% CSB treatment, other biochar treatments significantly (P<0.05) decreased the concentrations of available Cd by 60.7%−91.1% and Pb by 21.0%−26.1%. 3% CSB treatment showed significant increase in soil enzyme activities such as β-glucosidase, leucine aminopeptidase and β-N-acetylglucosamine (P<0.05), which were 79.7%, 30.3% and 1668.5% higher than that of the control, respectively. All biochar treatments significantly (P<0.05) increased the biomass of the edible part of R. sativus. 3% CSB treatment had the most significant improvement effect (P<0.05), which increased by 171.5% compared with the control.   Conclusion  The CSB is more effective than the FMB in improving soil enzyme activity, reducing Cd and Pb bioavailability in soil, and improving crop quality and yield. It is more suitable as a potential material for the remediation of soils co-contaminated with Cd and Pb. [Ch, 7 fig. 1 tab. 46 ref.]
Stoichiometric characteristics of leaf litter at different decomposition stages in 4 forest types
WU Renjie, XING Wei, GE Zhiwei, MAO Lingfeng, PENG Sili
, Available online  doi: 10.11833/j.issn.2095-0756.20220289
Abstract:
  Objective  This research aims to study the stoichiometric characteristics of leaf litter at different decomposition stages in different stands in southwest Guizhou Province, so as to better understand the nutrient cycling law of different forest ecosystems in karst areas.   Method  4 typical forest types were selected in southwest Guizhou, including Pinus massoniana forest, Phyllostachys edulis forest, Cunninghamia lanceolata forest, and natural forest dominated by Quercus acutissima, Machilus cavaleriei and Cyclobalanopsis glaucoides. Leaf litter at different decomposition stages was collected and stoichiometric characteristics of C, N and P were measured.   Result  (1) The total C content of leaf litter in each decomposition stage of P. edulis forest was significantly lower than that in other stands (P<0.05), and the total C content of leaf litter at decomposed stage of P. massoniana and C. lanceolata forests was significantly lower than that at undecomposed and semi-decomposed stages (P<0.05). The total N content of leaf litter in C. lanceolata forest at undecomposed stage was significantly lower than that at semi-decomposed and decomposed stages (P<0.05). The total P content of leaf litter at decomposed stage of natural forest was significantly higher than that in other stands (P< 0.05), and the total P content at semi-decomposed stage of natural forest was significantly lower than that at undecomposed and decomposed stages (P< 0.05). (2) The C/N ratio of C. lanceolata forest at decomposed stage was significantly higher than that of Ph. edulis forest (P<0.05), and the C/N ratio at undecomposed stage was significantly higher than that at semi-decomposed and decomposed stages (P<0.05). The N/P ratio at undecomposed and decomposed stages of Ph. edulis forest was significantly higher than that of natural forest (P<0.05). The C/P ratio of leaf litter at semi-decomposed stage of C. lanceolata and natural forests was significantly lower than that of P. massoniana forest (P< 0.05), and the C/P ratio at decomposed stage of natural forest was significantly lower than that of other stands (P<0.05).   Conclusion  Both forest type and decomposition stage have significant effects on contents of total C, N and P, as well as stoichiometric characteristics of leaf litter. [Ch, 2 fig. 2 tab. 36 ref.]
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
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Abstract:
  Objective  The objective is to analyze the genetic diversity and genetic relationship of 32 Bletilla striata samples from different provenances by ISSR and SRAP markers, so as to provide theoretical basis for identification, classification, conservation and development of B. striata germplasm.   Method  Primers with high polymorphism, clear amplification bands and good repeatability were selected from 100 ISSR primers and 238 pairs of SRAP primers for polymerase chain reaction (PCR) amplification. Genetic diversity parameters and genetic distance of B. striata from 32 different provenances in Zhejiang, Yunnan, Guizhou and Sichuan were calculated by Popgene 32.0, and cluster analysis was performed by NTSYS-PC 2.10e.   Result  11 highly polymorphic primers were screened from 100 ISSR primers, and a total of 188 bands were amplified, with an average of 17.09 bands per primer, among which 174 were polymorphic loci, accounting for 92.20% of the total amplified fragments. 11 pairs of highly polymorphic primer pairs were screened from 238 pairs of SRAP primer pairs, and a total of 216 bands were amplified, with an average of 19.64 bands per primer, including 202 polymorphic loci, accounting for 93.52% of the total amplified fragments. Based on ISSR and SRAP markers, the genetic diversity level of B. striata population in Sichuan Province was the highest, while that in Guizhou Province was the lowest. UPGMA and PCoA analysis showed that the clustered B. striata samples were mostly from the same province. The genetic distance of B. striata population between Yunnan Province and Sichuan Province was relatively close, and that between Zhejiang Province and Guizhou Province was relatively close, indicating that there was a certain overlap between genetic distance and geographical distance, but there was no positive correlation.   Conclusion  B. striata provenances selected in this study have high genetic diversity. Both ISSR and SRAP markers can effectively reveal the genetic diversity and genetic relationship of B. striata. [Ch, 4 fig. 4 tab. 25 ref.]