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Table of Content

    25 September 2020, Volume 41 Issue 9 Previous Issue    Next Issue
    Omics & Biotechnology
    Cloning, Physical Location and Expression Analysis of HbGRF in Hevea brasiliensis
    ZHANG Yuhang,PAN Ranran,LI Fei,TAO Zhiqiang,WANG Ying,GAO Heqiong,ZHUANG Nansheng
    2020, 41 (9):  1723-1732.  doi: 10.3969/j.issn.1000-2561.2020.09.001
    Abstract ( 463 )   HTML ( 48 )   PDF (6905KB) ( 262 )  

    Growth-regulating factor (GRF) is a plant-specific transcription factor. The transcription factor family has a large number of members and plays an important role in plant growth and development. In this study, the excellent clone ‘Reyan 7-33-97’ was used as the experimental material, and the HbGRF genes were cloned by RT-PCR. The bioinformatics method was used to study its gene length, physicochemical properties, basic structure and evolutionary relationship. The physical localization analysis was carried out by in situ PCR and fluorescence in situ hybridization. The expression pattern of HbGRF genes in rubber trees was analyzed by qRT-PCR. Three GRF genes were cloned into the female flowers of rubber trees, named HbGRF1, HbGRF2 and HbGRF3, respectively. The protein length was 609 aa, 384 aa and 494 aa with molecular weight of 65.663 kDa, 41.188 kDa and 52.858 kDa, respectively, and they were all unstable protein. All the three members had the complete characteristic domains WRC and QLQ of GRF gene family. Evolutionary analysis showed that the three genes belonged to three different groups. HbGRF1, HbGRF2 and HbGRF3 were located on the long arm of chromosome 11, the short arm of chromosome 5 and the long arm of chromosome 9, and the average percentage distance between the signal site and the centromere was 77.65, 42.66 and 65.27, respectively. The expression results showed that the three HbGRF genes in rubber trees were highly expressed in the vigorous growth tissues like stem tips and female flowers. Under the treatment of exogenous GA and ABA, the expression levels of the three genes increased first, and the expression levels at 48 h were basically the same as those under the initial conditions. The three genes had obvious expression specificity in stem tips and female flowers, which may play important roles in flower bud differentiation and female flower development. This study would provide a theoretical basis and materials for further exploration of the function of HbGRF, and provide molecular cytology basis for accurate breeding of rubber trees.

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    Cloning and Functional Verification of Rubber Tree F3’H Gene
    FAN Yueting,XIN Shichao,NAYCHI Koko,CHANG Jiao,HUANG Tiandai,HUANG Huasun,HUA Yuwei
    2020, 41 (9):  1733-1740.  doi: 10.3969/j.issn.1000-2561.2020.09.002
    Abstract ( 405 )   HTML ( 23 )   PDF (4289KB) ( 247 )  

    Based on the transcriptome database of rubber tree (Hevea brasiliensis) leaf tissues, we retrieved the nucleotide sequences of flavonoid 3’-hydroxylase (F3’H) gene, which is the key enzyme in anthocyanin biosynthesis pathways. Two rubber tree F3’H genes, HbF3’H1 and HbF3’H2 were amplified by RT-PCR. The expression levels of the HbF3’H genes were analyzed by quantitative real-time PCR and the expression of HbF3’H1 were shown to be completely correlated with the anthocyanin contents in the deffirent developmental stage of leaves and stems. Amino acid sequence analysis results showed that HbF3’H1 belonged to the super-family of cytochrome P450, and consisted of typical F3’H conserved domains. In the promoter region of HbF3’H1 gene, we observed multiple environment response elements, which revealed the possible role of HbF3’H1 in environment stress resistance in rubber trees. HbF3’H1 was over-expressed in tobacco (Nicotiana tabacum ‘Samsun NN’) by Agrobacterium tumefaciens mediated transformation for further functional verifications. Compared with the wild type control, the petals of transgenic tobacco lines exhibited enhanced red color pigmentation, which was positively correlated with the expression levels of HbF3’H1. The results demonstrated that HbF3’H1 played an important role in the biosynthesis of anthocyanin. The study would lay a foundation for understanding the anthocyanin biosynthesis pathways in rubber trees.

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    Cloning and Expression Analysis of Alkaline/Neutral Invertase Gene MiNI in Mangifera indica L.
    GUO Lijun,DENG Huidong,FENG Xuejie,LUO Zhiwen,CHEN Zhe,FAN Hongyan,HU Fuchu,HUA Min
    2020, 41 (9):  1741-1747.  doi: 10.3969/j.issn.1000-2561.2020.09.003
    Abstract ( 400 )   HTML ( 23 )   PDF (22210KB) ( 163 )  

    The cDNA sequence of alkaline/neutral invertase (NI) gene (MiNI) in mango was cloned with Reverse Transcription Polymerase Chain Reaction (RT-PCR) in this study. The molecular properties and genetic relationships of NI were compared with different organisms. MiNI contained an open reading frame of 2034 bp, encoding a protein of 677 aa with a theoretical molecular weight 76.6 kDa and an isoelectric point of 6.24. Bioinformatics analysis showed that the secondary structure of NI consisted of alpha helix accounting for 38.85%, random coil accounting for 35.45%, extended strand accounting for 18.91%, and beta turn accounting for 6.79%, of which had the conserved domain of glycoside hydrolase family 100 and the same motif locations as Citrus clementine, Dimocarpus longan, Hevea brasiliensis and Carica papaya. The amino acid sequence encoded by MiNI had the highest homology with that of Citrus clementine, Dimocarpus longan. The analysis of NI phylogenetic tree showed that the closest genetic distance between mango was Citrus clementine, the furthest were Zea mays and Lycium barbarum. qRT-PCR analysis showed that the expression of MiNI in exocarp was much higher than that in mesocarp. MiNI relative expression in exocarp decreased significantly during 10 to 40 days after flowering, while the gene relative expression was maintained at a relatively stable level during 40 to 100 days after flowering. However, MiNI expression increased significantly with fruit ripening during the period from 100 to 130 days after flowering. The gene expression in mesocarp was different from that in exocarp. The gene expression of MiNI in mesocarp decreased significantly during 10 to 40 days after flowering, while the gene relative expression remained at a very low level until the later stage of fruit development. The study would provide a foundation to understand the role of MiNI in sucrose metabolism and further dissection of the sugar metabolism mechanism from molecular perspective.

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    Construction of Yeast Two-hybrid Library of Agave hybrid No. 11648 and Screening of Proteins Interacting with AhKNOX2
    YANG Ziping,SUN Yihuan,YANG Qian,LU Zhiwei,ZHANG Yanmei,LI Junfeng,ZHOU Wenzhao
    2020, 41 (9):  1748-1755.  doi: 10.3969/j.issn.1000-2561.2020.09.004
    Abstract ( 330 )   HTML ( 10 )   PDF (7774KB) ( 139 )  

    To obtain the proteins interacting with AhKNOX2 in Agave hybrid No.11648, a full length-expression cDNA library was constructed in yeast strain Y187 using homologous recombination-mediated SMART technology. The capacity of the cDNA library was 3.9×10 6CFU and the transformation efficiency was about 9.15×105 CFU/μg pGADT7-Rec. The PCR amplification of 24 clones randomly selected from the cDNA library indicated that the length of most inserts was ranged from 0.5 kb to 3.0 kb, with a recombination rate of 92%. The cell density was 1.35×108/mL and the titer was up to 2.22×107CFU/mL. The bait vector (pGBKT7-AhKNOX2) was transformed into yeast strain Y2HGold, colonies appeared on SD/-Trp/-His media and was inhibited by 5 mmol/L 3-AT. After screening the library using bait plasmids,a total of 16 proteins interacting with AhKNOX2 were obtained by sequencing and homology analysis. In conclusion, a high-quality cDNA library was constructed and 16 proteins interacting with AhKNOX2 were screened from cDNA library.

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    Germplasm Resources, Genetics & Breeding
    Breeding of a New Cassava Cultivar ‘South China No. 16’
    LU Cheng,CHEN Xin,ZHOU Xincheng,XIA Zhiqiang,SUN Yufang,WANG Haiyan,ZOU Meiling,LI Kaimian,LI Zhaogui,XIAO Ziying,ZHOU Bin,HAN Quanhui,ZHANG Peng,WANG Wenquan
    2020, 41 (9):  1756-1761.  doi: 10.3969/j.issn.1000-2561.2020.09.005
    Abstract ( 430 )   HTML ( 15 )   PDF (1536KB) ( 262 )  

    Cassava, an important crop for industrial material in China, has potential for food and feeding. ‘South China No. 16’ (‘SC16’) is a new approved variety, which originating from F1 by crossing between female parent ‘SC8’ and male parent ‘Q10’ (I93/0665), and tested by seedling test, primary and advanced line performance test, regional line test and productive test. The average fresh root yields of ‘SC16’ in the regional trials and productive trials was 50.15 t/hm2 and 45.82 t/hm2, 55.45% and 35.85% more over ‘SC205’ , the main cultivated variety in China, respectively. The root starch content of ‘SC16’ was 25.42% and 26.10%, which was slightly less than that of ‘SC205’ . The average cyanogenic glycosides content was 29.70 μg/g in its fresh root, meaning that ‘SC16’ is a sweet cassava variety. Taken together, ‘SC16’ is a new variety with excellent plant type, high fresh root yield, lodging resistance, concentrated tuberization and better for high dense planting and mechanized harvesting, and could be used for starch industry, food processing and feeding. ‘SC16’ is suitable for planting in the coastland of Guangxi and Guangdong province, Hainan and Southeast Asia.

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    Genetic Diversity of Phenotypic Traits in 25 Jasminum Germplasm Resources
    JING Lingxia,BU Chaoyang,LI Chunniu,DI Qinglin
    2020, 41 (9):  1762-1769.  doi: 10.3969/j.issn.1000-2561.2020.09.006
    Abstract ( 343 )   HTML ( 15 )   PDF (1403KB) ( 319 )  

    The diversity and relationship of 21 phenotypic traits in 25 ornamental Jasminum germplasm resources were studied. The frequency of different quality traits were different in the population, and the variation range of the quality traits was 26.92% to 59.54%, the variation range of the quantitative traits was 23.81% to 88.08%. Which indicating that there were great variation among the phenotypic traits of the tested germplasms. The principal component analysis of floral and leaf traits of Jasminum was carried out. Twelve flower traits were attributed to four principal components. Nine leaf traits were attributed to three principal components. According to the cluster analysis of the principal component analysis of the phenotypic characters, the 25 germplasms were clustered into three groups, and the characteristics of bud diameter and 100-floral weight were the basis of phenotypic clustering. Through comprehensive analysis of flower and leaf traits, Jasminum sambac No.9 with the best comprehensive characteristics and the highest ornamental value was screened out, which has the best ornamental application potential.

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    Establishment and Application of Ornamental Evaluation System for Oxalis
    DONG Na,LI Chengru,CHEN Lei,ZHAO Yamei,ZHUANG Qiurong,ZHAI Junwen,WU Shasha
    2020, 41 (9):  1770-1778.  doi: 10.3969/j.issn.1000-2561.2020.09.007
    Abstract ( 388 )   HTML ( 11 )   PDF (1352KB) ( 299 )  

    In this paper, 14 evaluation indexes of ornamental characters such as plant type, plant height and flower color were selected by chromatographic analysis, and 40 randomly selected plants were evaluated. The application of analytic hierarchy process could effectively evaluate the ornamental value of Oxalis. Among the 14 indexes, the weight values of plant type, flower color, crown width and flower quantity were all larger (>0.09), which were the most important indexes affecting the ornamental value of Oxalis. In the scoring standard, the scores of heart-shaped leaf, white flower, fleshy leaf and large flower diameter were all 5 points. The purpose of this study is to provide a reference basis for the selection of ornamental potted varieties / species of Oxalis, the selection of character indexes of DUS testing guidelines and the selection of breeding parents. Among the 40 plants, there were six kinds of plants with high ornamental value such as O. obtusa ‘Kunzite’, O. purpurea ‘Alba’ and O. ambigua, all of which scored more than 3.499. The Oxalis plants are highly ornamental and adaptable, and are excellent plant materials with great development and application value.

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    Four New Records Species of Orchidaceae from Fujian Province
    MA Liang,CHEN Xinyan,SU Xiangxiu,LAN Siren,CHEN Shipin
    2020, 41 (9):  1779-1782.  doi: 10.3969/j.issn.1000-2561.2020.09.008
    Abstract ( 412 )   HTML ( 11 )   PDF (3965KB) ( 286 )  

    Cheirostylis monteiroi S. Y. Hu, Cestichis pingtaoi G. D. Tang, X. Y. Zhuang & Z. J. Liu, Calanthe trifida T. Tang et F. T. Wang and Vanilla shenzhenica Z. J. Liu et S. C. Chen were reported as the new records of Ochidaceeae from Fujian Province. All the vouchers specimens were preserved in Herbarium of Forestry College, Fujian Agriculture and Forestry University.

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    Plant Cultivation, Physiology & Biochemistry
    Establishment and Application of a Betel Nut Biomass Prediction Model
    CHEN Caizhi,ZHOU Xiaoxia,WANG Fengtang,LI Peizheng,CHEN Qi,LI Han,ZHANG Han,JIU Fengfeng,YANG Fusun
    2020, 41 (9):  1783-1789.  doi: 10.3969/j.issn.1000-2561.2020.09.009
    Abstract ( 408 )   HTML ( 8 )   PDF (1521KB) ( 217 )  

    In this paper, the plants of Hainan native betel nut species were used as the materials to measure the leaf length (LL), leaf width (LW), number of leaves (LN), number of flower buds (BN), node number (NN),stem diameter (SD), plant height (PH), stem height (SH) and internode length (IL). To predict the dry weight of single leaf (LDW), dry weight of the stem (SDW) and total dry weight in the aboveground part (ADW). The results showed that the estimated model for the dry weight of betel nut stems by model fitting and selection was SDW=0.2518S D0+0.0423 PH-23.8883, the dry matter accumulation of betel nut stems was mainly affected by the plant height (PH) and 0 m stem diameter (SD0), the coefficient of determination R 2 was 0.7157, the number of samples was 36, and another 18 were used as the external verification with a correlation coefficient r 0.9165. The model for estimating the dry weight of the leaves was LDW=3.9726 LL+2.8402 LW-297.6869, the dry matter accumulation of the leaves was mainly affected by the combined effects of LL and LW, the coefficient of determination R 2 was 0.6054, the number of sample leaves was 177, and another 88 were used as the external verification with a correlation coefficient r 0.7528. The model for estimating the total dry weight of the aboveground part was ADW=0.3283 SD0+0.0415 PH-23.7333, the total dry weight in the aboveground part was mainly affected by SD0 and PH, the coefficient of determination R 2 was 0.6932, the number of samples was 36, and another 18 were used as the external verification with a correlation coefficient r 0.9028. Based on the observation and analysis of a large number of data, the empirical model of betel nut biomass prediction was established in this paper, which could be used as the optimal biomass prediction model to estimate the biomass of betel nut.

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    Effects of Direct Replanting Seed Caneon Ratoon Sugarcane, a Case Study in Rongshui Miao Autonomous County, Guangxi in 2017
    YOU Jianhua,LIANG Tian,FAN Baoning,WU Kaichao,TAN Hongwei,HUANG Rihong,JIA Zhaoxiong,CAI Yongming
    2020, 41 (9):  1790-1796.  doi: 10.3969/j.issn.1000-2561.2020.09.010
    Abstract ( 300 )   HTML ( 7 )   PDF (1168KB) ( 216 )  

    In order to explore the use of ‘GF98-296’ to solve the problem of seedlingless ridges in sugarcane roots, the effects on the agronomic traits of the directly replanted cane seed of ‘GF98-296’ in the ‘GL05-136’ ratoon were studied, which would provide a scientific basis for popularization and application. Three treatments including ‘GF98-296’ seed cane directly replanted in ‘GL05-136’ ratoon (A), ‘GL05-136’ seed cane directly replanted in ‘GL05-136’ ratoon (B) and ‘GL05-136’ natural ratoon (CK) were designed in this experiment. ‘GF98-296’ seed cane replanted was carried out in the 2-4 leaf stage of ‘GL05-136’ ratoon. The agronomic traits of the treatments were investigated and the economic benefits were analyzed in harvest stage. The yield of treatment A was 79.55 t/hm 2, which increased 19.29 t/hm2and 13.91 t/hm2, or 32.01% and 21.18%, respectively, compared with that of CK and treatment B, and the difference was extremely significant. There was no significant difference in yield between treatment B and CK. Direct replanting treatments did not affect the growth, yield and sucrose content of ‘GL05-136’ ratoon. The sucrose content of ‘GF98-296’ in treatment A was almost the same as that of ‘GL05-136’ ratoon at the technology maturity stage. Economic benefit analysis showed that sugarcane growers could increase income of 5071.0 yuan/hm 2 and sugar enterprises increase industrial output of 15 573.0 yuan/hm2 using ‘GF98-296’ seed cane directly replanting ‘GL05-136’ ratoon. The study indicated that ‘GF98-296’ was suitable for directly replanting ‘GL05-136’ ratoon, and this new technology should be extensively demonstrated and popularized.

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    Effects of Combined Application of Seaweed Residue and Magnesium on Physicochemical Properties of Red Soil and Tobacco Growth
    HUANG Zhenrui,CHEN Diwen,LI Jiqin,LI Shuling
    2020, 41 (9):  1797-1802.  doi: 10.3969/j.issn.1000-2561.2020.09.011
    Abstract ( 290 )   HTML ( 9 )   PDF (1224KB) ( 279 )  

    To improve the soil fertility and tobacco growth in red soil areas for its strong soil acidity, low available nutrient content and poor air permeability, the soil physicochemical properties and tobacco growth with the application of magnesium sulfate and seaweed residue were investigated. A pot experiment with 6 treatments was conducted, i.e., CK: Control, without magnesium and seaweed residue, MS: Single application of 0.375 g magnesium sulfate per 1 kg soil, SF: Single application of seaweed residue 50 g per 1 kg soil, C1: Application of 0.375 g magnesium sulfate + 50 g seaweed residue per 1 kg soil, C2: Application of 0.563 g magnesium sulfate +75 g seaweed residue per 1 kg soil, C3: Application of 0.75 g magnesium sulfate +100 g seaweed residue per 1 kg soil. The effects of seaweed residue and magnesium on soil pH, organic carbon, mineral nutrient content, soil bulk density, and porosity, agronomic characteristics of tobacco and mineral nutrient contents of tobacco leaves were analyzed. The results showed that with the application of magnesium sulfate, seaweed residue alone or magnesium sulfate with seaweed residue, the agronomic traits, such as plant height, stem diameter, leaves of tobacco and biomass were significantly improved. Meanwhile, the contents of P and Mg in the tobacco leaves were significantly increased under the application of magnesium sulfate only. In addition, the contents of P, K and Mg in the tobacco leaves were also significantly higher in the application of seaweed residue alone or combined with magnesium sulfate. Compared with CK, soil pH of C3 treatment was significantly increased by 0.38 units, and the contents of alkaline - N, available - P, available- K, exchangeable - Ca and exchangeable - Mg were increased by 42.85%, 60.01%, 33.73%, 253.02% and 689.07% respectively. Soil organic carbon content of C1, C2 and C3 treatments increased by 212.9%, 385.7% and 540.7% than that of CK, respectively. The soil pH and soil organic carbon content were increased significantly with magnesium sulfate and seaweed residue application. The contents of available phosphorus, available potassium, exchangeable calcium and magnesium in soil were significantly increased by applying seaweed residue alone or in combination with magnesium. The application of seaweed residue alone or in combination with magnesium could significantly reduce soil bulk density and increase total soil porosity. Compared with CK, C3 treatment significantly reduced soil bulk density by 9.78%, and increased total porosity by 8.87%. It suggests that the growth of tobacco and physicochemical properties of red soil could be significantly improved by application with seaweed residue.

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    Effects of Rooting Plant Growth Regulators on Rooting of Air-layers of Phoebe bournei
    ZHENG Yupan,YANG Jinchang,ZOU Wentao,WANG Xu,YU Niu,LIU Xiaodong,LAI Xuen,LI Rongsheng
    2020, 41 (9):  1803-1807.  doi: 10.3969/j.issn.1000-2561.2020.09.012
    Abstract ( 288 )   HTML ( 10 )   PDF (1177KB) ( 203 )  

    Phoebe bournei is a precious and endemic tree cultivated in China. To explore the effects of growth regulators on rooting of P. bournei, research was conducted with different concentrations by a randomly complete block design. Single root stimulator, i.e., indole acetic acid (IAA), indole-3-butyric acid (IBA) and naphthalene acetic acid (NAA), and mixed root stimulators namely ABT1#rooting powder were applied to the 6-year-old branches. NAA was the optimum auxin for rooting of the air-layered branches, and the branches treated with 1000 mg/L had the highest rooting rate of 54.67%. For ABT1# rooting powder consisted of IBA and NAA, 1000 mg/L was the optimal concentration, and the maximum first-order root length and root biomass of the air-layered branches at the concentration were better than that of the control. It is concluded NAA or ABT1# rooting powder was recommended to be applied at the level of 1000 mg/L in the air layering for saplings of P. bournei.

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    Developmental Anatomy of Flower Apparatus of Male Sterile Plant of Camellia vietnamensis
    JIA Zechong,LIU Yunhao,CHEN Xia,WANG Hai,DENG Yajie,HU Xinwen,ZHOU Yang,PANG Zhenzhen,LAI Hanggui
    2020, 41 (9):  1808-1815.  doi: 10.3969/j.issn.1000-2561.2020.09.013
    Abstract ( 394 )   HTML ( 9 )   PDF (2267KB) ( 299 )  

    The flowering sterility of Camellia vietnamensis is common in Hainan, which would seriously affect the production level of Camellia oil. In this study, the normal and sterile plants of C. vietnamensis in Hainan were used as the experimental materials, the external morphological characteristics of flower bud development were compared and observed, and the differences of pollen germination and pollen tube development were detected by the pollen in situ germination technique. The paraffin section method was used to observe the pistil and stamen during flower bud differentiation, and the correlation between the period of pistil and stamen development and the external morphology of flower bud was analyzed. In this study, the causes of sterility caused by flower organ development of C. vietnamensis in Hainan were analyzed in developmental biology, reproductive genetics and cell anatomy. There was no significant difference in the external morphology between the sterile flower and the normal flower, but the ovary of the sterile plant fell off after flowering, indicating that there was no normal insemination, the pollen grain did not germinate and the pollen tube did not elongate after stigma pollination. From the paraffin sections of pistil and stamen, it could be seen that the flower organ of the male sterile plant was abnormal, the tapetum of the anther was abnormally degraded and could not form mature pollen grains, but the sterile plant failed to form a mature embryo sac in the process of ovule development, resulting in hollow ovules.

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    Exogenous Betaine Modulating the Tolerance of Osmotic Stress in Watermelon Cells
    WANG Shihao,ZHU Fangming,SUN Mengli,XU Zijian,JIANG Xuefei,QIAO Fei
    2020, 41 (9):  1816-1821.  doi: 10.3969/j.issn.1000-2561.2020.09.014
    Abstract ( 308 )   HTML ( 9 )   PDF (1456KB) ( 209 )  

    In order to explore the influence of exogenous glycine betaine on watermelon cell growth under osmotic stress and determine the correlation between the glycine betaine and the watermelon’s osmotic stress resistance, measurement of fresh cell weight, cell volume, intracellular reactive oxygen species (ROS) and extracellular pH was performed with the suspension cultured cells of diploid watermelon as the experimental materials, the mannitol simulating the osmotic stress and the exogenous glycine betaine being applied simultaneously. Under osmotic stress, the fresh weight and growth weight of watermelon cells were both inhibited, and extracellular alkalization and burst of intracellular ROS were also induced. The exogenous glycine betaine was found to be able to alleviate the inhibition effect of osmotic stress on the growth weight of the suspension cultured cells of watermelon to a certain degree, and be of regulative effect on extracellular pH and intracellular ROS level. In a word, the exogenous glycine betaine could maintain the watermelon cell growth and regulate the resistant reaction under osmotic stress.

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    Effects of 27 Strains of Arbuscular Mycorrhizal Fungi Inoculation on Physiology and Biochemistry and Major Components of Terpenoids in Potted Saussurea costus
    YANG Wenwu,GUO Dongqin,CAO Weiguo,PAN Xingjiao,XUE Yanbing,ZHANG Jie,ZHOU Nong
    2020, 41 (9):  1822-1830.  doi: 10.3969/j.issn.1000-2561.2020.09.015
    Abstract ( 268 )   HTML ( 8 )   PDF (1557KB) ( 226 )  

    A pot experiment was conducted to investigate the effects of 27 exogenous arbuscular mycorrhizal (AM) fungi strains on the root mycorrhiza infection rate, physiological and biochemical characteristics, root biomass and terpenoids accumulation of Aucklandia lappa seedlings at room temperature. A. lappa had a good symbiotic relationship with AM fungi, but there was difference in the preference of 27 exogenous AM fungi species for A. lappa. Compared with CK, some AM fungi increased the soluble protein and soluble sugar content and antioxidant enzyme activity in the leaves of A. lappa, reduced the malondialdehyde content, enhanced the ability of A. lappa to resist adverse environment. Biomass of the roots of A. lappa increased significantly in some AM fungal treatment groups. In most AM fungi treatment groups, the content of costunolide, dehydrocostus lactone and total lactones in the roots of A. lappa increased significantly (P<0.05), while some AM fungi treatment groups showed no significant difference or decrease. According to the comprehensive inoculation effect, Gigaspora decipiens, Scutellospora calospora, Racocetra coralloidea, Septoglomus deserticola, Entrophospora colombiana, Paraglomus brasilianum are the potential strains to inoculate A. lappa seedlings under artificial cultivation conditions, which could help to improve the yield and quality of A. lappa.

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    Effects of Arbuscular Mycorrhizal Fungi on Artemisia annua L. Growth and Chemical Composition of Root Exudates
    SUN Chenyu,ZENG Yanhong,MA Junqing,LIU Lu,WANG Wenqi,HUANG Jinghua
    2020, 41 (9):  1831-1837.  doi: 10.3969/j.issn.1000-2561.2020.09.016
    Abstract ( 312 )   HTML ( 17 )   PDF (1382KB) ( 417 )  

    The effects of arbuscular mycorrhizal fungi (AMF) Glomus mosseae on the growth index and the root exudates chemical composition of Artemisia annua L. were studied under potted conditions. The results showed that the height, shoot dry weight and root dry weight of A. annua inoculated with AMF increased significantly, with an increase of more than 20%; in addition to root radius, root length, root surface area, root volume, tips, forks and root activity of A. annua increased by 87.0%, 97.0%, 10.7%, 38.4%, 75.6% and 19.6%, respectively; compared with the root exudates obtained from the matrix of A. annua without AMF inoculation (NM-S), the content of soluble protein, soluble sugar and free amino acid in the root exudates obtained from matrix of A. annua with AMF inoculation (AM-S) increased by 74.38%, 16.13% and 203%, respectively, following the types and contents of organic acids increased significantly; but the effects of AMF on the root exudates of hydroponic solution showed an opposite trend. In the substrate, AMF may improve root morphology, root activity and secretion of the root exudates so that A. annua could absorb more nutrients and improve its biomass.

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    Correlation Between Soil Characteristics of Tea Plantations and the Growth and Fresh Leaf Quality of Wuyi Tea (Camellia sinensis cv. Shuixian)
    YE Jianghua,HU Wenwen,ZHANG Qi,ZHANG Bo,WANG Peng,LUO Shengcai,WANG Haibin,JIA Xiaoli,HE Haibin
    2020, 41 (9):  1838-1846.  doi: 10.3969/j.issn.1000-2561.2020.09.017
    Abstract ( 337 )   HTML ( 12 )   PDF (1408KB) ( 256 )  

    In this study, tea trees of Wuyi Shuixian (Camellia sinensis) growing in three tea plantations, namely, Yu, Guiyan and Qishan were selected as the materials. The physico-chemical properties and enzyme activities of tea soils, and the growth and photosynthesis, and the quality indexes of tea leaves were determined. And the relationship of the indexes was analyzed. The results showed that in Qishan plantation, the total nitrogen and available nitrogen were 37% and 45% higher, and total phosphorus and available phosphorus were 62% and 38% higher than the first-grade fertility standard. While organic matter was 44% lower than the first-grade fertility standard. The organic matter of Yu was 2.35 times than that of Qishan. The trend of five soil enzymes activity was generally Qishan > Guiyan > Yu, except catalase activity, and there were significant differences (P<0.05) among the three tea plantations. The enzymatic activity of five enzymes in the soil was negatively correlated with pH value and N, P contents, and positively correlated with K and organic matter contents. The trend of growth and photosynthetic indexes was generally Qishan> Guiyan>Yu, and was positively correlated with pH value and N content and negatively correlated with organic matter content, and with activity of urease, acid phosphatase, polyphenol oxidase, and protease. The quality indexes of fresh tea leaves was generally Yu > Guiyan > Qishan. The content of theanine, free amino acid, catechin, and tea polyphenols in fresh leaves of Yu was 1.93, 1.64, 1.57 and 1.54 times than that of Qishan, respectively. The 6 quality indexes (except caffeine) were negatively correlated with pH value, NP, and catalase activity, and positively correlated with K, organic matter and 5 soil enzyme activity. Most of the quality indexes were negatively correlated with the growth and photosynthetic indexes. The results suggested that higher nitrogen increased the pH value and enhanced catalase activity of the soil, which was beneficial to the tea growth, whereas decreased other soil enzyme activities, which resulting in low recycling and utilization of nutrients and organic matter, in turn affected leaf photosynthesis, reduced the synthesis of primary and secondary metabolites, then decreased the quality of tea leaves. The management measures of "reducing nitrogen, controlling phosphorus and supplementing potassium, and increasing organic matter" should be adopted to improve the quality of Shuixian tea in Wuyishan plantation.

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    Plant Protection & Bio-safety
    Effects of Citrus Huanglongbing on Tree Traits and Fruit Quality of Citrus maxima (Burm.) Merr. cv. Shatian Yu
    WANG Feiyan,ZHANG Ruimin,WU Wen,ZHU Congyi,HUANG Yongjing,CHEN Jiezhong,ZENG Jiwu
    2020, 41 (9):  1847-1855.  doi: 10.3969/j.issn.1000-2561.2020.09.018
    Abstract ( 310 )   HTML ( 8 )   PDF (2407KB) ( 306 )  

    Citrus Huanglongbing (HLB) is a devastating disease that seriously affects the development of citrus industry. It not only leads to leaf yellowing and affects the fruits quality, but also affects the life cycle of citrus trees. In order to investigate the effects of HLB on Shatian pomelo [Citrus maxima (Burm.) Merr. cv. Shatian Yu], the effects of HLB on the leaf morphological characteristics and fruit appearance and internal quality as well as mineral elements of Shatian pomelo were systematically analyzed. The result could provide references for the control of citrus HLB. In this study, the HLB positive Shatian pomelo trees and fruits were used for the experimental group (HLB+) and the HLB negative Shatian pomelo trees and fruits were used as the control group (HLB-). The leaf area, content of chlorophyll a, chlorophyll b and carotenoid of HLB+ leaf decreased by 28.13%, 40.38%, 44.00% and 40.47%, respectively. The color of the HLB+ fruits was abnormal and the fruits of HLB+ was smaller. The average fruit weight of HLB+ fruits decreased by 45.62%. The HLB+ fruits had thinner peels and its most seeds could not develop normally. The vitamin C content of HLB+ fruits was significantly higher than that of HLB- fruits, increased by 26.44%. The content of mineral elements in different tissues changed obviously after infection with HLB. The content of N and Ca of the leaves decreased by 19.00% and 49.72%, respectively, and the content of N of the pulp decreased by 18.00%, but the content of Ca of HLB+ peel and pulp significantly increased compared to the HLB- peel and pulp. And the content of S of the HLB+ trees was significantly lower than that of the healthy trees. The content of B and Cu of the HLB+ leaf decreased by 35.07% and 54.45%, respectively. The content of Cu of the HLB+peel decreased by 42.96% and the content of Zn of the HLB+pulp increased by 41.30%. HLB seriously affected the leaf morphology, fruit quality and mineral element metabolism of Shatian pomelo trees. So more attention should be paid to the prevention and control of HLB-infected Shatian pomelo.

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    Interspecific Molecular Phylogeny and Biological Characteristics of Colletotrichum acutatum Complex Species Causing Colletotrichum Leaf Disease on Rubber Trees in China
    JIANG Tao,LIU Xianbao,LI Boxun,ZHENG Xiaolan,CAI Jimiao,FENG Yanli,HUANG Guixiu
    2020, 41 (9):  1856-1864.  doi: 10.3969/j.issn.1000-2561.2020.09.019
    Abstract ( 363 )   HTML ( 8 )   PDF (1798KB) ( 229 )  

    In order to clarify the biological characteristics and interspecific differences of Colletotrichum acutatum complex species from rubber trees in China, four representative strains (C. bannanense YNML52, C. laticiphilum YNJH17109, C. australisinense GX1655, YNJP162) were evaluated for the utilization of different carbon, nitrogen sources and colony growth at different temperature, pH and water activities. The pathogenicity of the strains to different rubber varieties and crops was also evaluated. There were significant differences in the utilization of carbon and nitrogen sources, suitable growth temperature, lethal temperature, pH value and water activity of the tested strains. There were significant differences in pathogenicity spectrum of the tested strains. YNML52 had a narrow host range and strong host specificity. Evaluating the effects of ecological factors on the biological characteristics of the pathogen of rubber tree anthracnose is of certain guiding significance for understanding the occurrence regularity of the disease and formulating effective control strategies.

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    Analysis on Difference of Nutrient Content in Leaf Tissue of Resistant and Sensitive Cassava Varieties Before and After Damage to Tetranychus cinnabarinus
    ZHANG Zhe,CHEN Qing,LIANG Xiao,WU Chunling,CHEN Qian,Zhang Yindong
    2020, 41 (9):  1865-1869.  doi: 10.3969/j.issn.1000-2561.2020.09.020
    Abstract ( 348 )   HTML ( 7 )   PDF (1307KB) ( 197 )  

    The difference of nutrient contents in leaf tissues of resistant and susceptible standard cassava varieties before and after being damaged by Tetranychus cinnabarinus was analyzed by spectrophotometry. The content of free amino acids (FAA), soluble sugars (WSS), soluble nitrogen (SN) in the leaves of C1115, a standard cassava cultivar for mite resistance, significantly decreased damaged by T. cinnabarinus. The content of FAA, WSS and SN 1, 4 and 8 days after damaged by T. cinnabarinus was, 69.69%, 69.29% and 63.42%, 73.16%, 73.71% and 72.75%, 45.97%, 46.21% and 46.13%, respectively (P<0.05) of that before damaged. S/N increased significantly, which was 159.15%, 159.46% and 157.83% 1, 4 and 8 days after damaged by T. cinnabarinus respectively (P<0.05) of that before damaged, while the content of free proline (Pro) did not change significantly. There was no significant difference in the content of FAA, WSS between the leaves of the mite-susceptible reference standard cassava variety BRA900 after damaged for 1, 4 and 8 days. The content of SN increased significantly, which was 148.50%, 148.73% and 148.77% 1, 4 and 8 days after damaged by Tetranychus cinnabarinus respectively of that before damaged. S/N decreased significantly, which was 62.61%, 61.48% and 61.92% of that before damaged. The content of free proline (Pro) increased significantly, which was 373.82%, 367.33% and 362.61% of that before damaged.

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    Sporangium Induction and Development Process Microscopy of Black Pepper Phytophthora Foot Rot Pathogen, Phytophthora capsici
    GAO Shengfeng,YANG Kaihu,LU Daqian,LIU Aiqin,GOU Yafeng,SUN Shiwei,WANG Zheng,MENG Qianqian
    2020, 41 (9):  1870-1875.  doi: 10.3969/j.issn.1000-2561.2020.09.021
    Abstract ( 407 )   HTML ( 9 )   PDF (10948KB) ( 184 )  

    Sporangium is an important basis for the Phytophthora foot rot disease control and the pathogen (Phytophthora capsici) research in black pepper, but the sporangium-inducing methods and the micro development processes have not been reported yet. Three sporangium-inducing methods were tested and the sporangia development processes were observed by light microscope and laser confocal microscope. Abundant sporangia could be detected by all the three methods. The most sporangia were obtained by the method of lighting and glass rod-plastering induction on V8-A plates, followed by the lighting induction on V8-A plates and lighting induction in V8 liquid. Under light microscope, sporangia initially formed at the top of the hypha with the shape of small sphere, and gradually formed into an inverted pear shape. When matured, the sporangia released a large number of zoospores from an apical pore. Interestingly, a few sporangia germinated directly and formed a germ tube. Under laser confocal microscope, the protoplast of a sporangium was separated into dozens of small cells by membrane structure at first, and then multiple nuclear DNA was accumulated in each cell, and finally the multinuclear cell developed into several mononuclear zoospores. The study revealed the morphological characteristics of the P. capsici sporangium development progress would provide sporangium-inducing methods for further pathogenic mechanisms research and field disease management.

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    Screening and Identification of Antagonistic Actinomycete Against Anthracnose Disease of Guanxi Honey Pomelo Cultivar
    LAI Baochun,WU Zhenqiang,DAI Ruiqing,LIN Minghui,LI Feng,LIN Defeng,WANG Jiarui
    2020, 41 (9):  1876-1882.  doi: 10.3969/j.issn.1000-2561.2020.09.022
    Abstract ( 268 )   HTML ( 7 )   PDF (1744KB) ( 245 )  

    This study was conducted to screen resources for the biological control of Colletotrichum gloeosporioides which cause anthracnose disease for Guanxi honey pomelo cultivar. An antagonistic actinomycete of C. gloeosporioides was isolated from the soil samples by the plate-confrontation method and growth speed rate method, and the inoculated fruit was treated with the fermented broth. The taxonomic identification of the strain FX28 was carried out using morphological, physiological and biochemistry characteristics and 16S rDNA sequence. From the 25 soil samples, 16 of 105 antagonistic actinomycete isolates showed againstantifungal activity against C. gloeosporioides. FX28 showed an inhibition zone with a diameter 15.3 mm and strongest inhibition rate 86.4%. FX28 had broad-spectrum inhibition activity to all the 14 plant pathogenic fungi such as C. gloeosporioides, Diaporthe citri, Phyllosticta citriasian. FX28 could break down hyphae, turn hyphal thickened, fractured and enlarged. The protection and curation effects of the fermented broth against C. gloeosporioides were up to 83.8% and 71.1%, respectively. Based on the morphological, physiological-biochemical characteristics and molecular analysis, FX28 was identified as Streptomyces violaceorubidus.

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    Biological Characteristics of Paurocephala sauteri Enderlein (Hemiptera: Psylloidea: Psyllidae)
    LU Fuping,GENG Tao,WU Huazhou,WANG Nayu,WANG Yongsong,LOU Dezhao,WANG Shuchang
    2020, 41 (9):  1883-1888.  doi: 10.3969/j.issn.1000-2561.2020.09.023
    Abstract ( 301 )   HTML ( 5 )   PDF (2790KB) ( 205 )  

    The terminal bud and tender leaf of mulberry in Hainan has been found to be seriously damaged by Paurocephala sauteri Enderlein in recent years. The reproductive mode, developmental duration, fecundity and morphological characteristics of various developmental stages of P. sauteri on the host mulberry were investigated under laboratory conditions [temperature of (27±1)℃, RH (70±5)% and a photoperiod of 12L∶12D] in the life cycle of P. sauteri including egg, 1st-5th instar nymphs and adults (female and male). The egg was water drop shaped, with short egg pedicle and long terminal filament, milk white and transparent in appearance and had 2 red ocellus before hatching. The 1st instar nymph had milk white colour on the head and thorax, orange red in the compound eye and the abdomen, without wing bud. The instar nymphs of 2nd to 5th were yellow green in colour, the body length increased and the two pairs of wing pads developed as the instar increased. 2nd instar appeared wing pads with slightly bulged at apex. 3rd instar had wing pads more sharply triangular and pointed downward. 4th and 5th instar had wing pads directed backward, but extended beyond the first abdominal segment in 5th instar. Nymphs and adults could secret ball shaped white wax. P. sauteri produced offspring by sexual reproduction. Adults began mating after eclosion for 3 d, and became yellowish-brown in colour from yellow green of new eclosion. The mating behavior could continue 0.5 to 3 h. Then the female laid eggs after 18 to 21 h, with the number of eggs laid per female ranging from 20 to 42. The eggs were singly laid on both sides of the leaf vein underside of the leaf, and occasionally, some eggs also could be found at the upside edge of young leaves. The eggs hatched after 5 to 7 d with hatching percentage 98.19% and female percentage 70.44%. The developmental duration of the nymphs was 12 to 18 d, and that was 18 to 24 d from eggs to adults. The results would provides a theoretical basis and prerequisite for the management of P. sauteri.

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    Post-harvest Treatment & Quality Safety
    Preparation and Thermal-oxidative Stability of Camellia Oil Microcapsules by Complex Coacervation
    KANG Binbin,ZHANG Jinliang,WANG Xiang,ZHANG Lingyan,LIN Hetong,CHEN Tuanwei
    2020, 41 (9):  1889-1889.  doi: 10.3969/j.issn.1000-2561.2020.09.024
    Abstract ( 282 )   HTML ( 3 )   PDF (2652KB) ( 260 )  

    Camellia oil microcapsules were prepared by complex coacervation using gelatin and gum arabic as wall materials, tea polyphenols as the curing agent. The preparing process of camellia oil microcapsules was optimized by the orthogonal experiment on the basis of single factor experiments. The effects of the ratio of gelatin to gum arabic, concentration of wall material, pH, coagulation time and the ratio of core material to wall material on the microencapsulation efficiency and morphology of camellia oil microcapsules were investigated. The oxidative stability of the native and microencapsulated camellia oil were also analyzed and compared. The optimal preparation conditions of camellia oil microcapsules were obtained as follows: ratio of gelatin to gum arabic 1∶1, pH 4.2, concentration of wall material 1.0%, ratio of core were in the form of light brown, and the average microencapsulation efficiency, the angle of repose, moisture content and the thermal stabilization temperature was 82.36%, 39.2°, 3.67% and 280 ℃, respectively, meaninging they were of good fluidity and thermal stability. Moreover, the higher oxidative stability of camellia oil microcapsules compared to native camellia oil were achieved according to the results of accelerated oxidation storage experiment.

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    Comparison of Biochemical Components and Antioxidant Activities among Sun-dried Green Tea Produced by Fresh Leaves of Bush and Arbor Tree
    JIAO Wenwen,NIAN Bo,CHEN Lijiao,LIU Qianting,JIANG Bin,ZHANG Zhengyan,LIU Mingli,Ma Yan,ZHAO Ming
    2020, 41 (9):  1897-1904.  doi: 10.3969/j.issn.1000-2561.2020.09.025
    Abstract ( 286 )   HTML ( 5 )   PDF (1663KB) ( 191 )  

    Bush, transforming and transformed arbor tea trees would be formed during the transformation of tea plantation from bush to arbor trees. In this study, the biochemical components and antioxidant activities of sun-dried green tea processed by the above three kinds of tea plants were compared. The contents of various components were determined by spectrophotometry and high performance liquid chromatography methods. The content of theanine, glutamic acid and other 15 amino acids in arbor tea were higher than those in bush tea, exception threonine, arginine and gamma-aminobutyric acid (P<0.05), while the content of tea polyphenols, gallic acid, 1,4,6-O-gallic acyl-beta- D-glucose and epigallocatechin gallate (EGCG) in arbor tea were significantly lower than those in bush tea (P<0.05). Sensory evaluation showed that the taste of bush tea was bitterer than that of arbor tea. Arbor and bush tea grouped into different clusters in orthogonal partial least squares analysis of the content of the compounds, which confirmed the difference of the biochemical components between these two teas. The activities of spring arbor tea including the total antioxidant capacity, DPPH free radical and superoxide anion scavenging capacity were higher than those of bush tea (P<0.05), while hydroxyl radical scavenging abilities between these two types of teas were not different. In autumn tea, the total antioxidant capacity of arbor tea was higher than that of bush tea (P<0.05), while the scavenging capacity of superoxide anion were lower than bush tea (P<0.05), while the scavenging capacities of hydroxyl free radical and DPPH were not different (P>0.05). In summary, comparison to bush sun-dried green tea, the content of amino acid in arbor tea was increased, and the level of polyphenol and bitterness were reduced. Partial antioxidant activities were also increased. Thus, the transformation of tea plantation from bush to arbor tree can improve the quality of sun-dried green tea.

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    Preparation and Controlled Release of Nanofertilizer Mediated by Mesoporous Silica Nanoparticles
    SUN Dequan,LU Xinhua,CHEN Haili,WANG Chao,HU Huigang
    2020, 41 (9):  1905-1905.  doi: 10.3969/j.issn.1000-2561.2020.09.026
    Abstract ( 410 )   HTML ( 10 )   PDF (2664KB) ( 267 )  

    Nanotechnology-based agrochemical delivery systems will provide novel ways for improving the efficiency of very important agricultural inputs. In the present study, mesoporous silica nano particles (MSNs) with particle diameter of approximate 20 nm and pore size of around 3.0 nm were synthesized and functionalized. The fertilizer of urea was encapsulated inside the mesopores of MSNs by free diffusion loading and physisorption using aqueous urea solution. The highest loading rate of 69.15% was achieved when the urea concentration was 10 mg/mL. The loaded urea was blocked inside the mesopores using a novel decanethiol gatekeeper system grafted onto the surface of MSNs through disulfide linkages, and that was confirmed by Raman and nitrogen sorption isotherm analyses. The controlled release of encapsulated urea was obtained through the reaction between the gatekeeper and trigger factor of glutathione (GSH), which led to the cleavage of disulfide bonds. The in vitro release of urea from decanethiol gated MSNs indicated that almost no premature release was observed in the absence of stimulus GSH, and the release rate was highly determined by the amount of GSH. Herein, a MSN-mediated delivery system with redox-responsive gatekeepers was created. The fertilizer urea was effectively loaded and the controlled release was achieved using the novel system, which would offer the base for developing new type nano-fertilizer in the future.

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    Agricultural Ecology & Environmental Protection
    Comparison of Three Methods for Determination of Soil Exchangeable Aluminium
    LI Zhaoying,ZHENG Lu,YANG Wenjuan
    2020, 41 (9):  1912-1917.  doi: 10.3969/j.issn.1000-2561.2020.09.027
    Abstract ( 871 )   HTML ( 5195 )   PDF (1360KB) ( 923 )  

    Suitable detection methods to accurately and efficiently detect the soil exchange aluminum content were found. The differences, precision, accuracy and applicability of the exchange-neutralization titration of potassium chloride method, the aluminum reagent method and the chromoxane cyanine R method were analyzed. The results showed that there was no significant difference between the three methods. However, the precision of Chromoxane cyanine R method was better than that of the exchange-neutralization titration of potassium chloride method and the aluminum reagent method, and the average recovery rate of the wool-chromium-green R method was 99.28%, with a higher accuracy than the other two methods. The linear range of the chromoxane cyanine R method was 0 to 0.32 mg/L, and the linear range of the corresponding absorbent value was 0 to 0.778. The linear range of the aluminum reagent method was 0 to 0.8 mg/L, and the corresponding absorbent value range was 0.006 to 0.157. Compared with the aluminum reagent method, the linear range of chromoxane cyanine R method was smaller than that of the aluminum reagent method, but its absorbent value range was larger than that of the aluminum reagent method. The color rendering agent of the chromoxane cyanine R method was far from the absorption peak of the color rendering substance, the background interference was small, and the method sensitivity was higher. The average time of a single sample was 4.2 min, the detection efficiency was higher than that of the other two methods, and the operation was simple and the applicability was higher. Therefore, the chromoxane cyanine R method was recommended for the determination of soil exchange aluminum.

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    Growth and Soil Fertility Characteristics of Rubber Seedlings in Different Biogas Slurry Irrigation
    SUN Fengxia,WANG Xinyao,TANG Peng,WANG Xu,WU Shuhua,LI Chao,CHENG Yikang,REN Haotian
    2020, 41 (9):  1918-1927.  doi: 10.3969/j.issn.1000-2561.2020.09.028
    Abstract ( 304 )   HTML ( 2 )   PDF (1595KB) ( 195 )  

    The growth of rubber seedlings and the main soil fertility factors were measured by the soil culture method with seven different biogas slurry treatments to clarify the growth status and soil fertility characteristics of rubber seedlings in different quantity of biogas slurry irrigation and to guide its fertilization scientifically. The total amount of biogas liquid irrigation was 0 mL (T0), 471 mL (T1), 942 mL (T2), 1413 mL (T3), 1884 mL (T4), 2355 mL (T5) and 2826 mL (T6) respectively. Biogas slurry irrigation was beneficial to the growth of rubber seedlings with the order of quality index (QI) of rubber seedlings in different treatments T4 (1884 mL)>T3 (1413 mL), T5 (2355 mL)>T2 (942 mL)>T0 (0 mL), T1 (471 mL)>T6 (2826 mL). The plant height and ground diameter of treatment T4 were better, and the survival rate of the seedlings was higher after planting. Biogas slurry irrigation was beneficial to the increase of soil nutrient content and the activities of urease, catalase, acid phosphatase and polyphenol oxidase. Using principal component analysis and membership function to calculate the comprehensive index of soil quality in the experimental group, the comprehensive index of soil quality in the experimental group was T3 (0.933)>T5 (0.906)>T4 (0.855)>T2 (0.826)>T6 (0.794)>T1 (0.742). The results showed that the chemical properties of soil could be improved by biogas slurry irrigation, but the quality index of seedlings might be decreased by over irrigation, and the optimal irrigation amount was when the biogas slurry was 1413-1884 mL.

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    Cassava Rhizosphere Soil Collected by “Root Bag” Method and Its Bacteria Diversity
    WEI Yundong,LUO Yanchun,ZHENG Hua,LI Jun,PAN Huan,LEI Kaiwen,XU Chuan
    2020, 41 (9):  1928-1938.  doi: 10.3969/j.issn.1000-2561.2020.09.029
    Abstract ( 351 )   HTML ( 5 )   PDF (4532KB) ( 216 )  

    In order to collect cassava rhizosphere soil and study its bacteria community, and further deepen the knowledge of the micro-ecology of the rhizosphere soil, a field trial with the “root bag” method was carried out with two soil textures (clay and sandy roam) and a series of soil quantity from 100g to 500g in the root bag. Cassava plant height was significantly influenced by the soil quantity in the root bag, while cassava shoot weight was not. Soil available nutrients were strongly affected by roots when soil quantity in the root bag was only 100g, ammonium content (NH4-N) and available potassium (AK) was enriched significantly compared to bulk soil. Results from high throughout sequencing by Illumina Hiseq showed that the dominant bacterial community was Proteobacteria (31.272%), Actinobacteria (25.753%), Acidobacteria (12.761%), Chloroflexi (8.799%) et al. Results from α diversity indexes showed that the diversity of bacteria was increased in the rhizospheric soil, and the species richness was also increased in the clay. Compared to bulk soil, the soil samples collected from the inside “root bag” was relatively rich in Sphingobacteriales, Rhizobiales, Xanthomonadales, Verrucomicrobia and related phylum, class, genus and species for the clay, and for the sandy roam, rich in Sphingobacteriales and genus and species in gemmatimonadaceae. Results from Redundancy analysis (RDA) triplots demonstrated that soil available phosphorus (AP) was positively correlated to Actinobacteria and Chloroflexi, and negatively correlated to Proteobacteria; Soil available nitrogen (AN), AK, NH4-N, nitrates nitrogen (NO3-N) were negatively correlated with Gemmatimonadetes, Acidobacteria, Parcubacteria, Elusimicrobia, Armatimonadetes, TM6_Dependentiae, Chlorobi et al., and positively correlated with Firmicutes, Cyanobacteria, Fusobacteria, Bacteroidetes. In concusion, the 100g soil in the root bag could be seen as cassava rhizospheric soil according to soil nutrients and bacteria diversity. And NH4-N and AK could be regarded as the indicators as cassava rhizospheric soil. Soil microbial diversity was improved in the rhizosphere, and Sphingobacteriales was the enriched bacteria in both soil textures. Soil nutrients were correlated with some classification of soil bacterial.

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    Population Structure and Dynamics of Hopea reticulata, a Plant Endemic to Ganshiling, Hainan Island
    HU Xuan,XU Ruijing,SHU Qi,GUO Wen,ZHANG Jian,SHANG Zean,QI Lianghua
    2020, 41 (9):  1939-1945.  doi: 10.3969/j.issn.1000-2561.2020.09.030
    Abstract ( 293 )   HTML ( 6 )   PDF (1406KB) ( 222 )  

    Hopea reticulata is an endemic specie of China and the second-class national key protected plant. It is only naturally distributed in Ganshiling Region where is at the junction of Ya County and Baoting County in Hainan. But it has a high population density and forms a single dominant tropical rainforest with itself as advantage. In order to investigate the natural population of H. reticulata in Hainan Ganshiling, we drew the population survival curve and described the features of the population structure by means of establishing the static life table of this population, as well as conducting the quantitative study on its future development trend with the use of dynamic prediction of the population quantity and time series analysis. The results showed that the development of H. reticulata population in Hainan Ganshiling was stable, which is the growth form population. The analysis of population static life table indicated that the individual death rate of H. reticulata population in the stage of Ⅱ age-class sapling was low, and the death rate in the stage of Ⅲ age-class medium-sized tree was the highest; the population survival curve tended to Deevey -Ⅱ type; the curve of death rate and disappearance rate showed a consistent variation trend. The survival analysis showed that the H. reticulata population had the characteristics of well growth in the early stage, high competition pressure in the middle stage and gentle growth tendency in the late stage. The result of time series prediction indicated that the well-developed H. reticulata population had better stability of resistance, once going through the transitional period from the stage of Ⅲ age-class medium-sized tree to the stage of Ⅳ age-class grown tree, the population could develop very steadily. Therefore, it is suggested that on the basis of establishing nature reserves at present, the protection of middle-aged plants of H. reticulata should be strengthened to improve the survival rate and enable more individuals to enter the growth and development stage of the next age class, so as to ensure the normal renewal of the population.

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