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    25 August 2022, Volume 43 Issue 8 Previous Issue   
    Omics & Biotechnology
    Functional Analysis of a MiNAC1 Gene in Mango
    YANG Xiaozhou, ZHOU Shaoli, HE Xinhua, LIU Yuan, YU Haixia, LU Tingting, WANG Zhuo, LUO Cong
    2022, 43 (8):  1527-1534.  doi: 10.3969/j.issn.1000-2561.2022.08.001
    Abstract ( 110 )   HTML ( 8 )   PDF (5354KB) ( 56 )  

    NAC transcription factors play important roles in the response to abiotic stress in plants. Studying the function of the mango MiNAC1 gene may provide genetic resources for mango stress tolerance breeding. Abiotic stresses such as drought, salt and low temperature affect the growth and development of mango. In a previous study, a MiNAC1 gene was obtained from the transcriptome of mango stress samples, and the expression pattern analysis showed that it was related to the stress response of mango. In this study, the function of the mango MiNAC1 gene was verified. The pBI121-MiNAC1 overexpression vector was constructed and transferred into the model plant Arabidopsis thaliana. The T3 homozygous lines were used for phenotypic observation and stress treatment. The results showed that the phenotypes of the transgenic mango MiNAC1 gene and WT wild-type Arabidopsis thaliana were similar with each other. The transgenic mango MiNAC1 gene did not affect the number of rosette leaves, bolting time, flowering time and plant height at flowering. Transgenic and WT Arabidopsis thaliana were treated with Mannitol (0, 200, 300, 400 mmol/L), salt (0, 100, 150, 200 mmol/L) and low temperature stress at 4℃, respectively. Stress treatment was performed by comparing the changes in root length, lateral root number and root crown ratio with the transgenic and control plants. Under drought stress treatment, the root length of WT and transgenic plants was obviously inhibited with the concentration increase of mannitol treatment, but the degree of inhibition was significantly lower in transgenic lines than that of WT plants. The lateral root number increased, but the transgenic plants were significantly higher than that of WT plants. In addition, the root crown ratio of transgenic plants was also significantly higher than that of control plants. For example, under 300 mmol/L mannitol treatments, the root length increased significantly, with OE9 was 1.51 times longer than that of WT. The number of lateral roots increased significantly, with OE7 having 5 times more lateral roots than that of WT. The root crown ratio was significantly higher in transgenic plants than that in control plants, and that in OE2 was 1.53-fold higher than that of WT. Similar results were obtained under salt stress and low temperature stress. These results indicated that transgenic mango MiNAC1 gene could improve the resistance of transgenic plants to drought stress, salt stress and low temperature stress by increasing root length and lateral root number. This study initially revealed the function of MiNAC1 gene, and laid a foundation for further study of MiNAC1 gene involved in regulating the regulatory network of mango stress.

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    Identification of Key Sucrose-degrading Enzymes and the Relevant Gene Family Members in the Development of Sweetpotato Storage Roots
    ZHANG Wenjie, XIN Shuli, HUANG Zherui, ZHU Zhixin, SI Chengcheng, CHEN Yanli, ZHU Guopeng, LIU Yonghua
    2022, 43 (8):  1535-1544.  doi: 10.3969/j.issn.1000-2561.2022.08.002
    Abstract ( 148 )   HTML ( 7 )   PDF (1118KB) ( 46 )  

    Sucrose catabolism plays important roles in the development of potato tuberous roots and carrot taproots, but the roles of sucrose catabolism in the development of sweetpotato storage roots remain elusive. In this paper, two sweetpotato lines ‘Kokei 14' and the mutant were employed in the research, which have significant differences in the storage root number per plant and fresh weight per storage root. In order to identify the key sucrose-degrading enzymes and the relevant gene family members that regulate the number and size of storage roots, the content of soluble sugar (sucrose, glucose and fructose) and starch, the activities of four sucrose-degrading enzymes and the expression level of the genes were measured at different development stages (30 d, 60 d, 90 d and 120 d) of the storage roots of the two sweet potato lines. The results are as follows: (1) The dynamic changes of the activities of four sucrose-degrading enzymes during the development of storage roots were clarified. The overall change trend of cytoplasmic invertase (CIN) and vacuolar invertase (VIN) activities showed a ‘u' curve, i.e. the activities were relatively higher in the early and late stages of development, but the lowest in the middle stage of development; The overall change trend of cell wall invertase (CWIN) and sucrose synthase (Sus) were just reverse and showed an ‘n' curve, i.e. the activities were relative lower in the early and late stage of storage root development, and were the highest in the middle stage of development. (2) As compared with the mutant, ‘Kokei 14' with higher number and fresh weight of storage roots had higher Sus and CIN activities in the early stage of storage root development (30 d), and higher Sus and CIN activities could promote the transport of sucrose from leaves to storage roots, and consequently increase the content of starch, sucrose and glucose in storage roots, which finally provided energy and carbon skeleton for the development of root tubers to increase the number and fresh weight of storage roots. (3) Nine Sus gene family members and twelve CIN gene family members were identified from the sweet potato genome. Among them, the expression levels of one Sus gene (IbSus6) and five CIN genes (IbCIN4, IbCIN6, IbCIN8, IbCIN10 and IbCIN11) were significantly higher in 30 d of storage roots of ‘Kokei 14' than in that of the mutant. Furthermore, IbSus6 and IbCIN4, IbCIN8, IbCIN10, IbCIN11were the main members of Sus and CIN gene family expressed in 30 d storage roots, respectively. Therefore, the Sus gene and four CIN genes may be the key genes regulating the development of sweet potato storage roost. In conclusion, Sus and CIN play important roles in the early developmental stage of of sweet potato storage roots and identification of the key gene family members can provide a theoretical basis for the breeding of excellent new sweetpotato varieties.

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    Assembly and Sequence Analysis of Chloroplast Genome of Amygdalus persica
    GONG Yihui, ZHOU Guihua, LI Limei, ZENG Yongxian, CHEN Zhiyin
    2022, 43 (8):  1545-1553.  doi: 10.3969/j.issn.1000-2561.2022.08.003
    Abstract ( 118 )   HTML ( 2 )   PDF (1463KB) ( 33 )  

    In this study, the complete chloroplast genome of Amygdalus persica L. ‘Jinxiu' was assembled and sequenced. Illumina NovaSeq 6000 platform was used to sequence DNA of A. persica L. ‘Jinxiu', and the chloroplast genome was assembled and annotated by SPAdes v3.10.1. We used the chloroplast genome of Prunus persica as the reference, the feature analysis and phylogenetic analysis study were investigated, laying a foundation for the further development of the genetics and identification of A. persica. The total length of the complete A. persica L.Jinxiu' chloroplast genome was 157 786 bp, including typical quadripartite structure, with a GC content of 36.77% and a AT content of 63.23%. The chloroplast genome had a large single copy region (LSC), a pair of inverted repeats (IR), and a small single copy region (SSC), and the sequence length was 85 924 bp, 26 381 bp, and 19 100 bp, with GC contents of 34.61%, 42.58%, 30.41%, respectively. A total of 130 genes were annotated, consisting of 85 protein-coding genes, 37 tRNA genes and eight rRNA genes. The genes were divided into four categories according to the functions, including photosynthesis, self-replication, other genes and genes of unknown function. The genes included 18 double-copy genes, which were the subunit of NADH dehydrogenase gene (ndhB), four self-replication genes (rpl2, rpl23, rps12 and rps7), four rRNA genes (rrn16, rrn23, rrn4.5 and rrn5), seven tRNA genes (trnA-UGC, trnI-CAU, trnI-GAU, trnL-CAA, trnN-GUU, trnR-ACG and trnV-GAC), two unknown function protein genes (ycf1and ycf2). A total of 248 microsatellites were founded in the chloroplast genome of A. persica L. ‘Jinxiu'. The simple sequence repeats (SSRs) were spaced disproportionately through the chloroplast genome, with the largest number of SSRs distributed in the LSC region, followed by the SSC and IR regions. LSC, SSC and IR regions had 165, 44 and 39 SSRs, respectively. The number of SSRs in LSC, SSC and IR regions was 66.53%, 17.74%, and 15.73%, respectively. The SSRs were mononucleotides, especially for A/T. The second most abundant motif type was the trinucleotide type, especially ATA, TAT and TTA. Phylogenetic analysis showed that ‘Jinxiu' was closely related to the plant of Prunus persica (MW042696.1) This study would provide a method suitable for the assembly of the complete chloroplast genome and the analysis of feature of the whole chloroplast genome of the ‘Jinxiu', which also could provide evidence for its identification and phylogeny of ‘Jinxiu'.

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    Cloning, Bioinformatics and Expression Analysis of ADP-glucose Pyrophosphorylase Gene Family in Colocasia esculenta
    HE Fanglian, LIU Lili, JIANG Huiping, QIU Zuyang, HUANG Shiyu, DONG Weiqing
    2022, 43 (8):  1554-1564.  doi: 10.3969/j.issn.1000-2561.2022.08.004
    Abstract ( 27 )   HTML ( 4 )   PDF (2390KB) ( 24 )  

    Taro (Colocasia esculenta) is a member of the genus Colocasia in the family Tenaxaceae and is widely grown worldwide, and the main storage material of its corm is starch. ADP-glucose pyrophosphorylase (AGPase) is the first key and rate-limiting enzyme for starch synthesis and plays a critical role in plant starch synthesis, but the molecular structural features and expression patterns of the taro AGPase gene family are still unclear. In this study, six AGPase genes were selected from the full-length transcriptome annotations using the new taro variety ‘Lipuyu No.1' as the test material. The coding regions of the six genes were cloned by RT-PCR, and the physicochemical properties, evolutionary relationships and conserved motifs were analyzed by bioinformatics. The results showed that the cDNA sequences of the coding regions of six taro AGPase genes were ranged from 1398 bp to 2028 bp and the proteins encoded were ranged from 350 aa to 543 aa in size, of which four genes (CeAGPL1 to CeAGPL4) encoded large subunits of AGPase and two genes (CeAGPS1, CeAGPS2) encoded small subunits of AGPase. Phylogenetic analysis showed that all AGPases were divided into two groups, large and small subunits, with four large subunits in the large subunit group and two small subunits in the small subunit group. The molecular mass of CeAGP family proteins ranged from 38 753.22 kDa to 59 743.05 kDa, with an isoelectric point range of 5.64 to 8.82 and subcellular localization to chloroplasts, amyloplasts and cytoplasm, etc. The conserved motif analysis of the proteins revealed that a total of 11 conserved motifs were predicted for CeAGP family proteins, six motifs were functionally annotated as NTP_transferase, and the other five CeAGP proteins contained 11 motifs except for CeAGPS2. In different tissues, all six CeAGP genes were expressed in all tissues, with high expression of CeAGPL3 and CeAGPS1 in leaves and petioles, high expression of CeAGPL1 and CeAGPS1 in corms, and low expression of all six CeAGP genes in roots. CeAGPL1 and CeAGPS1 were highly expressed in different developmental stages of the corm and both showed a tendency to increase and then decrease, with the highest expression of both genes at 4 and 5 months of age, respectively. These results provide a basis for the subsequent elucidation of the mechanism of taro starch synthesis.

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    Germplasm Resources, Genetics & Breeding
    Using the SSR Fluorescent Labeling to Establish SSR Fingerprints for 37 Cultivars in rubber tree (Hevea brasiliensis)
    WEI Mingming, HUANG Xiao, LI Weiguo, HUANG Huasun
    2022, 43 (8):  1565-1576.  doi: 10.3969/j.issn.1000-2561.2022.08.005
    Abstract ( 69 )   HTML ( 2 )   PDF (2077KB) ( 25 )  

    37 rubber tree cultivars were used as the materials to establish DNA fingerprints and to analyze the genetic relationship with SSR fluorescence labeling technology. A total of 34 pairs of SSR primers were screened and determined as the core primers for the construction of rubber tree variety DNA fingerprint library. Of which 30 pairs of SSR primers could be used for variety identification and 4 pairs of SSR primers could be used as alternative primers for the identification of subsequent newly selected varieties. The core SSR primers screened and determined showed high polymorphism information content (PIC value). Among them, the number of primers with PIC value higher than 0.5 was 97%, the number of primers with PIC value greater than 0.7 was 12, and the number of primers with PIC value greater than 0.8 was 2. Primer rbm28 had the highest polymorphism and could be used as the best primer to identify the genetic diversity of the main strains of rubber tree in China. The other four primers HESR025, HESR163, H-084 and H-122 had high heterozygosity and polymorphism at the same time, so they could be considered as alternative primers. A total of 161 alleles were detected by 34 pairs of core SSR primers in 37 rubber tree varieties, with an average of 5.4 alleles per pair of primers and an average polymorphism information content (PIC) value of 0.65. 30 pairs of core SSR primers were used to amplify 37 rubber tree strains to obtain the accurate SSR site information of related varieties. The standard DNA fingerprint library of 37 rubber tree varieties was constructed, of which 33 rubber tree varieties had unique DNA characteristic fingerprints, which could be used as the specific fingerprints of each variety, so as to provide a basis for rubber tree variety identification and breeding practice.

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    Difference Analysis of Main Mineral Elements in Different Cassava Germplasm Resources
    WANG Siqi, SONG Jiming, CAO Min, WANG Rui, TANG Li, ZHANG Rui, TIAN Rongzhi, WU Jinshan, ZHANG Xiaofei, CHEN Yinhua
    2022, 43 (8):  1577-1586.  doi: 10.3969/j.issn.1000-2561.2022.08.006
    Abstract ( 81 )   HTML ( 2 )   PDF (1093KB) ( 44 )  

    In order to understand the mineral element content of different cassava germplasm resource and to select the germplasm with rich content, and provide data support for the comprehensive utilization of cassava, the contents of ash and mineral elements in 113 cassava germplasm resources were determined by muffle furnace method, atomic absorption spectrometry and atomic fluorescence spectrometry. The results showed that the content of mineral element of Cr, Cu and Se was lower than 1 mg/kg (dry weight), and the content of Ca, Fe, K, Mg, Mn, Na and Zn was 66.39-1609.81 mg/kg, 4.35-38.93 mg/kg, 1954.56-8762.78 mg/kg, 149.04-1143.73 mg/kg, 4.48-37.40 mg/kg, 36.80-530.40 mg/kg, and 6.35- 24.83 mg/kg, respectively. The ash content and mineral element content of the 113 cassava varieties were divided into five grades by the probability grading method, namely extremely high, high, medium, low and very low. Extremely high strains were recommended as basic parent materials. In the correlation analysis, ash content had a significant correlation with Fe, Mg, Na and Zn content, Ca content had a very significant positive correlation with K and Mn content, Ca content had a very significant negative correlation with Mg and Na content, Fe content had a very significant positive correlation with Mg, Na and Zn content, K content had a very significant positive correlation with Mn content, a very significant negative correlation with Na content, Mg content had a very significant negative correlation with Na and Zn, and Zn content had a very significant positive correlation with Mn and Na content. Therefore, the absorption of Zn and various mineral elements in cassava germplasm resources had a strong mutual promotion, Fe content and Mg, Na content had a strong mutual promotion, Ca content and K, Mn content had a strong promotion, while the absorption of Ca, K, Mn and Fe, Mg, Na content may have a certain antagonistic effect. Further combined with principal component analysis and cluster analysis, the mineral element contents of different cassava varieties were comprehensively evaluated, and two principal components with eigenvalues greater than 1 was obtained, with a cumulative variance contribution rate of 61.707%. Cluster analysis could divide the 113 cassava varieties into three categories. According to the difference of mineral element contents, different cassava varieties could be divided into high Na, Mg, Zn, Fe content group and high Mn, Ca, K, Zn content group. Cassava varieties such as ‘274' ‘50' ‘571' ‘521' ‘417' had higher scores in the comprehensive evaluation of principal components.

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    Development of Distinctness, Uniformity and Stability Test Guidelines for New Cultivars of Primulina Hance
    LAI Bidan, DENG Zhengyu, CUI Zhongji, LI Ruifeng, WEI Yigang, HUANG Zhangjie, WEN Fang, LIU Mengjiao
    2022, 43 (8):  1587-1594.  doi: 10.3969/j.issn.1000-2561.2022.08.007
    Abstract ( 64 )   HTML ( 0 )   PDF (788KB) ( 17 )  

    The species of the genus Primulina of Gesneriaceae are abundance in biodiversity, and most of them have high ornamental value. Those diversified flowers, leaves and plants of this group hint that they can be developed as one group of new ornamental crops, which rich in Chinese characteristics. Those domestic Gesneriaceae plants, especially in Primulina, are gaining more attentions in recent years. There are more and more new artificially bred ornamental cultivars of this genus were registered in the Gesneriad Society (GS), which is the international registration authority for Gesneriaceae cultivars. In the near future, this genus is expected to be listed in the list of Protection of New Varieties of Plants by the Ministry of Agriculture office for the Protection of New Varieties of Plants. However, there is no related DUS test guideline for Primulina plants in both China and abroad. It is urgent to develop the test for Primulina. Thus, according to the testing theory and technology of distinctness, uniformity and stability of new varieties of plants, based on the resources in and abroad and UPOV guidelines of different genera from different countries in Gesneriaceae and resource situation, the subject, selection and adoption of characteristics, states of expression and selection of standard varieties, assessment of DUS of the Testing Guidelines for Primulina, were elucidated in detail in this paper. The DUS test guidelines for Primulina will provide technology structure for this kind of new variety and offer professional standard for the new variety cultivation, horticulture, industrialization and plant variety protection of this group.

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    Research Progress on Germplasm Resources and Cultivation Techniques of Pogostemon cablin
    GU Yan, MEI Yu, XU Shiqiang, SUN Mingyang, ZHOU Fang, LI Jingyu, WANG Jihua
    2022, 43 (8):  1595-1603.  doi: 10.3969/j.issn.1000-2561.2022.08.008
    Abstract ( 92 )   HTML ( 0 )   PDF (933KB) ( 31 )  

    Pogostemon cablin (Blanco) Benth. is a perennial herb or semi-shrub plant, which is one of the famous medicinal herbs in China. The dry aboveground part is usually used as medicine which has the effects of aromatizing turbidity, appetizing and stopping vomiting, releasing and relieving heat and thus becomes the raw material of many kinds of Chinese patent medicine. Besides, the patchouli oil extracted from it is also an important raw material of pharmaceutical and chemical industry in the world, with high economic value and broad market prospect. Patchouli was brought into China for cultivation from tropical areas, resulting in single germplasm type, narrow genetic basis and extremely limited resources. Due to the long-term effect of natural environment and cultivation, the germplasm of patchouli has several variation and differentiation. Currently, patchouli is mainly distributed in Guangdong, Guangxi, Fujian and Hainan provinces of China and could be divided into four species including Paixiang, Zhaoxiang, Zhanxiang and Nanxiang. There are serious continuous cropping obstacles during the cultivation of patchouli. Due to extensive field management, the yield and quality of patchouli are unstable, which are affected by many factors such as variety, production area and cultivation technology. In recent years, with the development of molecular pharmacognosy, researches related in internal regulation of the active ingredients patchouli alcohol and pogostone of patchouli were carried out smoothly. The current study of patchouli mostly focused on its pharmacodynamics, biosynthesis and metabolism regulation, but the systemic research on germplasm resources and cultivation techniques were insufficient. Excellent varieties and efficient and standard cultivation techniques are the basis of stable yield and quality of medicinal materials. In order to make the best use of patchouli medicinal materials resources and further promote patchouli cultivation scale development and industrialization, the biological characteristics of patchouli, distribution of germplasm resources, bottlenecks in the cultivation techniques and the problems in the industrial development of patchouli were summarized in this paper. It was pointed out that the nutrient management technology of patchouli was lacking and the continuous cropping obstacle was serious. It was also suggested that the research on propagation technology and variety breeding of patchouli should be strengthened, and the standardized planting of patchouli should be promoted. Our study might provide reference for the industrial development and utilization of patchouli.

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    Screening of Excellent Strains and Resource Characteristics of the Medicinal Fungus Cordyceps militaris
    HAN Lihong, FU Xiaolin, WANG Yuanxian, TAO Wu, GAO Zhongming, LIU Chao
    2022, 43 (8):  1604-1612.  doi: 10.3969/j.issn.1000-2561.2022.08.009
    Abstract ( 26 )   HTML ( 1 )   PDF (1608KB) ( 18 )  

    Cordyceps militaris is an important medicinal and edible fungus with great development and utilization potential. In order to further explore the resources of C. militaris, eight wild strains of C. militaris, collected from Pinus yunnanensis forest of Qujing, Yunnan Province, were isolated, identified and purified (No. QJ1-QJ8). The mycelial morphology, growth rate, biomass accumulation, culture cycle and active substance content (cordycepin, adenosine and crude polysaccharide) were compared. The results showed that the mycelial growth rate of QJ2 and QJ3 strains were the fastest on PDA solid medium, and the mycelial biomass accumulation of QJ2 strain in liquid medium was significantly higher than that of other strains. Six strains (QJ1, QJ2, QJ3, QJ4, QJ7 and QJ8) produced stroma successfully. The maturation cycle of QJ2 and QJ7 strain was short, displaying 48 d and 50 d respectively, and the biological efficiency was 48.63% and 40.85%, respectively. The fruiting bodies were neat and uniform, bright color and high yield. The contents of cordycepin and adenosine in the fruiting bodies of QJ7 and QJ8 strains were significantly higher than those of other strains, with the highest values of 6.35 mg/g and 1.02 mg/g respectively. The contents of crude polysaccharide in the fruiting bodies of QJ3 and QJ7 strains were significantly higher than those of other strains, with 100.23 mg/g and 73.05 mg/g, respectively. The comprehensive score of QJ7 strain is higher than that of other strains, and the distribution pattern of parameters is more uniform, indicating that the strain has excellent comprehensive properties and is expected to be developed, utilized and industrialized as a cultivation strain. The data offer a better understanding of Cordyceps biology and provide germplasm resources and theoretical basis for the variety improvement and new variety breeding of C. militaris.

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    Plant Cultivation, Physiology & Biochemistry
    Photosynthetic and Dry Matter Accumulation Characteristics of the Two Crops in the Cassava / Peanut Intercropping System
    CHEN Chen, LIU Zifan, HUANG Jie, WEI Yunxia, SU Bimeng
    2022, 43 (8):  1613-1619.  doi: 10.3969/j.issn.1000-2561.2022.08.010
    Abstract ( 51 )   HTML ( 2 )   PDF (1214KB) ( 49 )  

    In order to study the characteristics of photosynthesis and dry matter accumulation of each component crop under the cassava and peanut intercropping model, this study took the cassava and peanut intercropping row ratio of 2∶4 as the object, and cassava monocropping (SC) and peanut monocropping (SP) as the control, under field conditions, the dry matter accumulation rules and photosynthetic characteristics of each component crop in the intercropping system (cassava represented by IC and peanut represented by IP) at different periods were measured. The actual and expected yield of peanut had a trend of increasing first and then decreasing. The actual yield of peanut was larger than its expected yield before the 92th days after planting, and later, tthe actual yield and expected yield of peanut began to decline. The actual yield of cassava was higher than expected from the 75th days after planting to harvest, and the increase rate of its actual yield was higher than that of the expected yield. During tuber formation and tuber enlargement stages, Pnmax and LSP of IC leaves were significantly higher than that of SC, while Rd of IC leaves was less than SC during the seedling and tuber enlargement stage. During the shell inflation stage, LCP, LSP and Rd of IP leaves were significantly lower than those of SP, while α was significantly higher than that of SP. The theoretical maximum dry matter accumulation of IC increased by advancing the occurrence time of maximum dry matter accumulation rate, prolonging the duration of fast growth period and increasing the maximum dry matter accumulation rate, the theoretical maximum dry matter accumulation of IP reduced by shortening the duration of the fast growth period, advancing the start time and end time of the fast growth period, advancing the occurrence time of the maximum dry matter accumulation rate. In summary, The dry matter accumulation of cassava could be increased by increasing light capture and utilization efficiency and reducing its own consumption. The growth and development of peanut could be affected because of the shading of high crops during the later stage of peanut. The utilization efficiency of low light was improved by reducing LCP, LSP, and effective accumulation of nutrients of peanut was increased by reducing Rd during the shell inflation stage.

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    Analysis on the Brix Distribution of Pitaya ‘Mihong' and ‘Baiyulong'
    YANG Lei, HU Yingju, HE Yun, LI Hongli, HONG Qingmei, PU Wenhui, HU Wenbin, LI Qiong
    2022, 43 (8):  1620-1627.  doi: 10.3969/j.issn.1000-2561.2022.08.011
    Abstract ( 76 )   HTML ( 4 )   PDF (1209KB) ( 35 )  

    In order to analyze the characteristics of the Brix distribution t in pitaya, this study used the red and white pulp pitaya varieties ‘Mihong' and ‘Baiyulong' pitaya which are the representative as the materials. To explore the Brix distribution in pitaya, we divided the fruits into five layers along the vertical and horizontal directions, with 13 points in each layer, measured the Brix of the pulp at each point, and 15 repetitions were made for each combination of variety and cutting direction. And we used the average Brix of all sampling points in a single fruit as the total Brix of the fruit to explore the relationship between different position Brix and total Brix of the fruit. The results showed that among the five layers pitaya fruits equally divided along the vertical and horizontal directions, the Brix was high in the middle and successively decreased on both sides. The third layer in the middle had the highest average Brix, and the second layer on both sides. Compared with the fourth level, the average Brix of the first and fifth levels at both ends was lower. The Brix of the 13 points taken in each level of stratification showed the characteristics of high center and successively lower surroundings. The average Brix of 13 points at the center was the highest, followed by 9-12 points on the periphery, and 1-8 points on the outer side. Cluster analysis was performed on all sampling points inside the dragon fruit according to their Brix. When the Euclidean distance was 10 and 15, the internal sampling points of the 'Mihong' and 'Baiyulong' fruits could be divided into two types, which were different in combination with the dragon fruit. In the relationship with the total sugar content of the fruit, compared with other equal layers, the horizontal cutting middle layer had a higher correlation with the total Brix of the fruit. The R square of the linear regression equation of the average Brix of the horizontal cutting middle layer and the total Brix of the ‘Mihong' and ‘Baiyulong' was 0.929 and 0.917, indicating that the average Brix of the horizontal cutting middle layer was the representative of the total sugar content of the fruit to a certain extent, and the linear regression equation established by it could predict the total Brix of dragon fruit to a certain extent. This study preliminarily clarified the internal Brix distribution law of pitaya, and provided a theoretical basis for the Brix evaluation of pitaya variety resources.

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    Effects of Different Proportion of Red and Blue Light and Light Intensity on Physiology and Chlorophyll Fluorescence Characteristics of Anoectochilus roxburghii
    PAN Keke, WANG Kelei, LI Binqi, ZHANG Xiwen, CHEN Faxing
    2022, 43 (8):  1628-1635.  doi: 10.3969/j.issn.1000-2561.2022.08.012
    Abstract ( 29 )   HTML ( 2 )   PDF (973KB) ( 42 )  

    In order to explore the application of LED lamp in the industrialized cultivation of Anoectochilus roxburghii, the LED lamp with different proportion of red and blue light was used as the light source. The white fluorescent lamp was used as the control (CK), with R/B(3/7), PPFD 20 μmol/(m2·s)(T1), R/B(7/3), PPFD 20 μmol/(m2·s)(T2), R/B(3/7), PPFD 30 μmol/(m2·s)(T3), R/B(7/3), PPFD 30 μmol/(m2·s)(T4), R/B(7/3), PPFD 50 μmol/(m2·s)(T5) five treatments. The effects of different ratios of red and blue light and light intensity on the growth, photosynthesis, chlorophyll fluorescence and physiological characteristics of A. roxburghii were studied. The results showed that plant height, stem diameter and dry and fresh weight of A. roxburghii treated with T4 and T5 were significantly higher than those treated with CK. Pn of A. roxburghii leaves in T5 was significantly higher than that in the other treatments, there was no significant difference between T1 and T3, but it was significantly higher than that in T2 and T4. Under different proportion of red and blue light treatment, the chlorophyll content of A. roxburghii leaves was significantly higher than that of CK. Under the same light intensity, the chlorophyll content of A. roxburghii leaves treated with R/B(7/3) was higher than that treated with R/B(3/7). Fv/Fm and Fv/Fo of A. roxburghii leaves treated with different red blue ratio light were significantly higher than those treated with CK. The decrease of red light ratio and the increase of blue light ratio could reduce Fv/Fm and Fv/Fo, and ΦPSII and ETR also decreased. T2 could effectively improve the activities of SOD and CAT, but the activity of POD decreased. The activities of POD and CAT decreased and SOD increased under T4. Compared with CK, the MDA content of A. roxburghii leaves in T1 increased significantly, 19.4% higher than CK, while there was no significant difference between T5 and CK. According to the growth of A. roxburghii, the treatment with R/B(7/3), PPFD 50 μmol/(m2·s) (T5) grew best and maintained high photosynthetic rate and physiological activity.

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    Plant Protection & Bio-safety
    Isolation and Identification of Antagonistic Bacteria BACYitc8-7 Against Deciduous Disease Pathogen (Corynespora cassiicola) and Analysis of Antibacterial Components of Volatile Organic Compounds from Rubber Tree
    DAI Liming, LI Lanlan, SHI Yuping, LIU Yixian, DENG Yueye, WU Zhonghua, CAI Zhiying
    2022, 43 (8):  1636-1645.  doi: 10.3969/j.issn.1000-2561.2022.08.013
    Abstract ( 22 )   HTML ( 0 )   PDF (1186KB) ( 18 )  

    Corynespora cassiicola is an important pathogen causing Corynespora leaf fall disease of rubber trees. Chemical fungicides are widely used to prevent and control the disease at present, which brings severe ecological environmental issues in rubber planting areas. Isolating and screening bacteria strains with inhibitory activity against C. cassiicola from rhizosphere soil of rubber trees would provide theoretical foundation for researches and development of biological control agents on Corynespora leaf fall disease. Bacteria with high antagonistic activity was obtained from the rhizosphere soil of rubber trees with leaf fall disease by using dilution plate coating and plate-confrontation, its bacteriostatic diameter was (57.68±0.66)mm. It was observed that nine important plant pathogenic fungi could be inhibited by the strain as well. Based on morphological, physiological, biochemical characteristics and 16S rRNA gene sequence, the strain was basically consistent with Pseudomonas aeruginos, and was named BACYitc8-7. The activity of the volatile compounds of BACYitc8-7 against C. cassiicola was evaluated when LB, NA, Gause, Kim B and PDA were used as nutrition sources. The strongest antagonistic effects were found in Kim B and LB mediums, and the inhibition rate was 43.47%-48.69%. 35 substances, including amines, alcohols, alkenes, phenols, esters and pyrazines were obtained from the antimicrobial components of BACYitc8-7 collected and detected by headspace solid phase micro extraction-gas chromatography-mass spectrometry (HS-SPME-GC-MS), and the top five contents were amine, borane dimethyl sulfide complex, isoamyl alcohol, 1-triene and 2-methyl-3-methylthiofuran, respectively.

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    Influence of Adjuvant 380 to the Adhesion Property of Fungicides on Mango Leaves
    YAN Chao, GU Liushuang, LIU Zhijun, YE Huochun, ZHU Fadi, ZHANG Jing, FENG Gang
    2022, 43 (8):  1646-1653.  doi: 10.3969/j.issn.1000-2561.2022.08.014
    Abstract ( 20 )   HTML ( 2 )   PDF (1178KB) ( 15 )  

    Nowadays, the low effective utilization rate of existing pesticides has caused a series of social problems, such as the impact on the safety of non target organisms, human and livestock, and even environmental pollution. How to improve the utilization of existing pesticides is more urgent and necessary. Therefore, in order to improve the utilization of existing pesticides, the effects of pesticide additives playing an important role on the wetting distribution and pesticide retention of fungicides on mango leaves were studied in combination with crop characteristics, so as to provide theoretical guidance for improving the utilization rate of mango fungicides. Through measuring the contact angle of liquid in mango leaves and the surface tension of different concentrations of liquid, according to the results of surface tension and contact angle, the critical surface tension of mango leaves and the critical micelle concentration (CMC) of additives were obtained. The effects of additives on the distribution and maximum retention (Rm) of liquid medicine on the surface of mango leaves were analyzed. In this study, the fungicide for the control of mango bacterial angular spot was used as the research object. The effects of adjuvant 380 to different fungicides on the wetting property and retention on mango leaves were studied. According to the results of γ and contact angles tested by a contact angle/interfacial tension meter, the critical surface tension value of mango leaves and the critical micelle concentration (CMC) of adjuvant 380 were determined. The selected concentration of adjuvant 380 was added to different fungicides to analyze the change of wetting property and Rm. Adjuvant 380 could reduce the surface tension and increase the wetting property. It could reduce the surface tension of the agent by 23.54%-75.94%, and the surface tension value could be reduced to (17.62±0.65)mN/m, which was lower than the critical surface tension value of mango leaves. And the contact angles on the front and back sides of mango leaves were less than 30°, which could be well wetted on mango leaf surface. The adjuvant had more obvious effects on increasing the retention and 80% ethylicin emulsifiable concent with a 203.53% increasing of the amount of retention on the leaves was maximized of all the fungicides. Therefore, in the process of mango bacterial angular spot control, the distribution effect and liquid holding capacity of liquid medicine on crop leaves can be improved by adding additive 380 when mixed in barrels, so as to improve the utilization rate of existing pesticides.

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    Induction and Biological Characterization of Mutants of Colletotrichum gloeosporioides to Pseudolaric Acid B
    WEN Xiaodong, ZHU Fadi, GU Mengxuan, YE Huochun, FENG Gang, ZHANG Jing
    2022, 43 (8):  1654-1662.  doi: 10.3969/j.issn.1000-2561.2022.08.015
    Abstract ( 20 )   HTML ( 1 )   PDF (5880KB) ( 19 )  

    Pseudolaric acid B (PAB) is a natural diterpenoid acid with unique structure. Previous studies found that PAB has antifungal activity with broad-spectrum against a variety of plant pathogenic fungi such as Colletotrichum gloeosporioides. However, its antifungal mechanism is unknown. In this study, C. gloeosporioides strain JB-Q was selected for resistance induction by three methods, including chemical acclimation, UV irradiation and cobalt radiation. The biological characteristics of the stable resistant mutants were analyzed in order to provide research materials and clues for exploring the mode of actions of PAB. The results showed that 18 strains of C. gloeosporioides with stable inheritance and different resistance levels were obtained by chemical acclimation, and the resistance frequency was 1.69 × 10-7. The evaluation of biological characteristics showed that both the parent strain JB-Q and the resistant mutants could grow in the range of 15-35℃, and the mycelium grew fastest at 25℃. The growth rate of mutants with different resistance levels was different, and the resistance level was negatively correlated with the growth rate. The results of osmotic pressure test showed that JB-Q was more sensitive to 0.02% SDS, and its inhibition rate was as high as 70%. Under metal ion stress, the resistant mutants were more sensitive. The above results suggested that PAB could not be easy to cause the resistance of C. gloeosporioides, but the survival competitiveness of the induced resistant mutant strains is equivalent to that of the parent strain. In addition, we found that there was no cross resistance between PAB and pyraclostrobin, prochloraz and tebuconazole, while there was positive cross resistance with carbendazim, and its Pearson correlation coefficient was 0.7729 (P<0.01), indicating that PAB may have a similar action mechanism with microtubule inhibitor carbendazim, then further experiments are needed to verify this.

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    Effects of Five Commonly Used Insecticides on Chelonus formosanus
    YU Zirong, LIN Zhufeng, JIA Jingjing, QIN Shuang, JI Xuncong
    2022, 43 (8):  1663-1670.  doi: 10.3969/j.issn.1000-2561.2022.08.016
    Abstract ( 25 )   HTML ( 1 )   PDF (1153KB) ( 22 )  

    The fall armyworm, Spodoptera frugiperda, first invaded in Yunnan, China, in January 2019, is a notorious agricultural pestinsects. It is characterized by fast migration, broad host range, high reproductive capacity, strong damage ability, and wide adaptability. It seriously threatens the development of China's corn industry due to its establishment in China. It is first found on maize in Haikou in April, and poses a serious threat to the production of fresh eating maize. Chelonus formosanus of Chelonus Panzer was recorded in Hainan Island, China. C. formosanus is an egg-larval intertemporal parasitic wasp and mainly parasitizes Lepidoptera pests including S. frugiperda, it's highest parasitism rate to the eggs of Spodoptera indoor is 100%. To evaluate the effects of commonly used insecticides for the control of S. frugiperda on C. formosanus, the effects of the recommended concentrations of 200 g/L chlorantraniliprole SC, 30% indoxacarb EC, 5% amectin benzoate ME, 10% chlorfenapyr SC and 5.7% cyhalothrin EW 5 were studied. The performances included the mortality rate, parasitic rate, life span and pupal eclosion and were determined by the residual film and foliar spray under indoor conditions. The results showed that the order of LR50 of the adult parasitoids treated by the five pesticides as flows: chlorantraniliprole > indoxacarb > cyhalothrin > chlorfenapyr > amectin benzoate. Chlorantraniliprole had a higher risk for adult C. formosanus (HQ=1.55), HQ of other agents was less than 1, and the risk was low. After spraying the pupa, amectin benzoate 80 mg/L treatment had no significant effect on the emergence rate. The emergence rate of chlorfenapyr 1000 mg/L was the lowest (63.33%). Chlorantraniliprole 60 mg/L treatment significantly reduced the adult life after pupa eclosion, but indoxacarb 180 mg/L, amectin benzoate 80 mg/L and 90 mg/L treatment had no significant effect. The parasitism rate of adult parasitoids decreased by 5.50% and 4.98% respectively under the treatment of indoxacarb 180 mg/L and chlorfenapyr 1000 mg/L, and the difference of other insecticides was not significant. According to the experimental results of this paper, at the recommended concentration, 5% amectin benzoate ME, 30% indoxacarb EC and 10% chlorfenapyr SC in the right concentration can be combined with the biological control of C. formosanus against S. frugiperda. The effects of different types of insecticides on C. formosanus were evaluated by mortality, eclosion rates, life span and parasitism rate of adult C. formosanus, which would provide a theoretical basis for the use of C. formosanus for the comprehensive control of S. frugiperda and the coordination of biological and chemical control.

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    Effects of Temperature on the Functional Response of the Fifth Instar Orius maxidentex Ghauri Nymphs to Scirtothrips dorsalis Hood
    LI Jinlei, HAN Shanni, ZHOU Shihao, FU Yueguan, YE Zhengpei, HAN Dongyin
    2022, 43 (8):  1671-1677.  doi: 10.3969/j.issn.1000-2561.2022.08.017
    Abstract ( 27 )   HTML ( 1 )   PDF (979KB) ( 18 )  

    Orius maxidentex Ghauri is an important natural enemy insect of thrips. O. maxidente is a dominant enemy in the tropics which has strong adaptability to high temperature and more suitable for pest control in tropical areas. At present, the control of O. maxidentex to Scirtothrips dorsalis Hood is not clear. To understand the control effect of O. maxidente on the predation of S. dorsalis, it is important to clarify the effects of temperature on the predation of O. maxidentex Ghauri nymphs to S. dorsalis Hood. The study assessed the predatory function response of the fifth instar O. maxidentex to the second instar and adult S. dorsalis at 16℃, 20℃, 24℃, 28℃ and 32℃. In the range of 16-32℃, the predation of O. maxidentex increased with the increase of the prey density. When the temperature increased, a trend of gradual increase in predation was also observed. Within the experimental temperature range, the predatory function of O. maxidentex to S. dorsalis fit to the Holling Ⅱ equation. There was no significant difference between the predation ability of the 5th instar nymphs of O. maxidentex on the 2nd instar nymphs of S. dorsalis and the adult nymphs of S. dorsalis. In the range of 28-32℃, the predation of O. maxidentex on the S. dorsalis was significantly higher than that of the other test temperature. The 5th instar nymph of O. maxidentex had the largest prey when the test temperature was 32℃, and the prey density was 60, which was 34.6 and 34.0, respectively. The instantaneous attack rates of O. maxidentex to the second instar and adult S. dorsalis were also the highest at 32℃, which was 0.0119 d and 0.0115 d, respectively. The predatory capacity of O. maxidentex on S. dorsalis was positively correlated with the prey density, whereas the searching efficiency was negatively correlated with the prey density. At the same prey density, as temperature increased, the searching efficiency gradually decreased. The fifth instar O. maxidentex showed a relatively high searching efficiency of S. dorsalis. When the prey density was greater than the maximum predation, the 5th instar nymphs of O. maxidentex had selective feeding, only feeding on the abdomen of S. dorsalis. It seems that the predatory bug O. maxidentex has good ability to control the pestiferous thrip S. dorsalis under high temperature condition and is an important natural enemy for the thrips in the tropic area.

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    Post-harvest Treatment & Quality Safety
    Effect of Coffee Peel Powder on Biscuit Quality and Starch Digestibility
    LUO Bailing, DONG Wenjiang, LIU Dunhua, HU Rongsuo, ZHAO Wencheng
    2022, 43 (8):  1678-1685.  doi: 10.3969/j.issn.1000-2561.2022.08.018
    Abstract ( 20 )   HTML ( 0 )   PDF (1077KB) ( 21 )  

    Coffee peel is the by-product of coffee processing, accounting for about 50% of coffee fruit. The experimental results show that coffee peel is rich in dietary fiber, and the total dietary fiber content can reach 64.80%, and the fat content is only 1.62%. However, only a small part of coffee peel is used as compost and animal feed, and most of it is discarded, resulting in environmental problems and resource waste that can not be ignored. In order to explore the processing and utilization of coffee peel in baked food, this study used 0%, 5%, 10%, 15% and 20% of superfine coffee peel instead of wheat flour to make biscuits. By measuring the moisture content, dietary fiber content, DPPH clearance rate, starch digestibility, glycemic index, color, texture and sensory characteristics of biscuits, it was found that compared with the control group (0%), with the increase of coffee content, the quality of biscuits was improved. The moisture content of biscuits decreased from 6.57% to 5.32%, and the dietary fiber content and DPPH scavenging rate increased significantly, from 1.84% to 10.65% and from 2.89% to 36.69%, respectively. The digestibility of starch, C and K value were negatively correlated with the substitution amount of coffee peel powder, and the finally predicted glycemic index of biscuits decreased from 91.16 to 66.35. However, biscuits with 5%, 10% and 15% substitution amount are still foods with high glycemic index. The L* and b* values in color gradually decreased, while the a* value exceeded that of the control group at 5% and 10% substitution amount, and the biscuits were brown red in coffee peel. In addition, the hardness and chewiness of biscuits gradually increased, but the hardness increase was not significant at 5% substitution amount (P<0.05). The results show that coffee peel powder can be considered as a biscuit ingredient to increase consumers' intake of dietary fiber, antioxidant substances and low saccharified starch. This paper provides theoretical basis for comprehensive utilization of coffee peel.

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    Analysis of Volatile Flavor Components in Seedless Wampee Fruit at Different Maturity by Headspace Gas Chromatography-ion Mobility Spectrometry
    MENG Xiangchun, GENG Xing, HUANG Zepeng, HE Lihong
    2022, 43 (8):  1686-1695.  doi: 10.3969/j.issn.1000-2561.2022.08.019
    Abstract ( 23 )   HTML ( 0 )   PDF (5467KB) ( 19 )  

    In order to understand the volatile flavor components of wampee, headspace-gas chromatography-ion mobility spectrometry (HS-GC-IMS) technique, combined with fingerprint, peak intensity and principal component analysis (PCA) of flavor components, was conducted on volatile flavor components and differences analysis of seedless wampee fruit at four different maturity. The results showed that totally 60 known and 3 unknown volatile flavor compounds were identified from seedless wampee fruit. The known 60 compounds include 13 aldehydes, 12 alcohols, 9 alkenes, 6 kinds of ketones, 2 esters, 2 ethers, one benzene and one acetic acid. Fingerprint of volatile flavor compounds revealed the specific volatile flavor compounds of each maturity, STAGE2 has the largest kinds, followed by STAGE4, STAGE1 has only 2 kinds, and STAGE3 had no obvious specific flavor compounds. Moreover, STAGE1 and STAGE2 shared the most kinds of flavor compounds, STAGE3 and STAGE4 only shared acetic acid and ethanol. Signal peak intensity of the flavor compounds showed that hexanal, (E)-2-pentenal, (E)-2-hexenol, (E)-caryophyllene, α-phellandrene, limonene, 1-penten-3-one and methyleugenol were abundant in all the four fruit maturity. Methyleugenol and (E)-2-hexenol had the highest peak intensity, and the relative contents decreased gradually with the fruit ripening. Principal component analysis (PCA) showed that the flavor components of different maturity were clustered separately, but the distance between STAGE1 and STAGE2, STAGE3 and STAGE4 were close, respectively. The main volatile flavor compounds in seedless wampee fruit were aldehyde and alcohol, followed by alkene and ketone. Fruit at different maturity had common and unique characteristic peak regions of volatile flavor substances, and the closer the maturity, the more similar composition of flavor compounds. The research can contribute providing basic support for maturity, quality and standard determination, aroma and deep-processed products research and development of this unique fruit.

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    Application of Moringa oleifera Seed Residue Protein Emulsion Loaded with Tea Tree Essential Oil in the Preservation of Areca Nut
    ZOU Ying, LI Mi, ZHOU Wei, PENG Shaodan, GAO Yuanyuan, LI Ruyi, CAO Yupo, LI Jihua
    2022, 43 (8):  1696-1702.  doi: 10.3969/j.issn.1000-2561.2022.08.020
    Abstract ( 17 )   HTML ( 0 )   PDF (3025KB) ( 20 )  

    In this study, fresh areca nuts were used as the experimental materials to study the effects of Moringa oleifera seed residue protein emulsion coating solution loaded with tea tree essential oil (0.1%, 0.3% and 0.5%) on the fresh-keeping effect of fresh areca nuts at room temperature. The results showed that M. oleifera seed residue protein emulsion loaded with 0.1%, 0.3% and 0.5% tea tree essential oil had a good effect on inhibiting the rot of areca nut, and with the increase of concentration (0%-0.3%), the inhibition became more significant, but the effect weakened when the concentration of tea tree essential oil was up to 0.5%. M. oleifera seed residue protein emulsion loaded with 0.3% tea tree essential oil incorporated into edible coating could effectively reduce water loss, inhibit respiration intensity, and slow weight loss, but also could effectively maintain good color and texture, delay yellowing of the peel and softening of fruit, compared to the control group, during the 11 days storage at room temperature. In addition, the antibacterial experiments showed that the inhibitory zone diameter of M. oleifera seed residue protein emulsion loaded with 0.3% tea tree essential oil was (1.33±0.81)mm for Escherichia coli and (13.38±0.88)mm for Staphylococcus aureus, indicating that M. oleifera seed residue protein emulsion loaded with 0.3% tea tree essential oil had a significant inhibitory effect on foodborne pathogenic bacteria, and the inhibitory effect on S. aureus was better than that on E. coli. In conclusion, M. oleifera seed residue protein emulsion loaded with 0.3% tea tree essential oil incorporated into edible coating had the best effect, which could not only achieve antibacterial effect, but also maintain the appearance and nutritional quality of areca nut to the greatest extent. It could be used as an appropriate treatment condition to prolong the preservation time and storage quality of areca nut at room temperature.

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    Analysis of Volatile Chemical Constituent in Fruits, Stems and Leaves of Litsea cubeba from Three Regions
    LIU Yuanyuan, PENG Weiyao, ZHANG Jian, CHA Yunsheng, HE Jiangbin, YOU Shengjun, LI Ping, YAN Jian, HU Jian
    2022, 43 (8):  1703-1715.  doi: 10.3969/j.issn.1000-2561.2022.08.021
    Abstract ( 29 )   HTML ( 0 )   PDF (2164KB) ( 25 )  

    To make full use of the fruit, stem and leaf parts of Litsea cubeba, the chemical composition differences were compared by GC-MS. The characteristics of the three regions were comprehensively evaluated, to provide basis for expanding the application of L. cubeba. The corresponding volatile components were extracted from the fruits, stems and leaves of L. cubeba collected from the areas by dichloromethane ultrasound. And the content differences of the volatile components in the dichloromethane extract were analyzed and compared by GC-MS to find the chemical components with potential application value. The results showed that there were significant differences in the types and content of volatiles in the different areas of the L. cubeba. And in the same area, there were differences in the types and content of volatile in different parts of L. cubeba. The types of volatiles of L. cubeba from Yaping were more varied and the contents of which were more abundant. The fruit, stem and leave parts of L. cubeba from Jinding contained 192, 60 and 76 volatile compounds respectively. The fruit stem and leave parts of L. cubeba from Yaping contained 254, 66 and 60 volatile compounds respectively. And the fruit, stem and leave parts of L.cubeba from Yaojiaping contained 251, 43 and 55 volatile compounds respectively. There were 43 common volatiles in fruits, 21 common volatiles in stems, and 24 common volatiles in leaves in the three regions. The content of aldehydes was the most in fruits, followed by organic acids. Most of the esters in stems, followed by alkanes, and most of the alkanes and alkenes in leaves. The contents of palmitic acid, n-decanoic acid, lauric acid, oleic acid and linoleic acid were higher in L. cubeba from Jinding and Yaping areas. In L. cubeba from Yaojiaping area, the content of 4,8-dimethyl-3,7-nonadien-2-ol, epoxy-linalooloxide, geranic acid, (Z)-3,7-dimethyl-2,6-octandienal, 2-methyl-5-(1-methylvinyl) cyclohexenone, 3-methyl-2-cyclohexene- 1-one was higher. The above mentioned substances are widely used in chemical industry, medicine and other fields. The difference of chemical composition and content in different parts of the L. cubeba in the three regions would lead to the difference in its application. This study would provide a certain scientific basis for the development and utilization of the stems and leaves of the L. cubeba in different areas of Nujiang Prefecture, Yunnan Province.

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    Agricultural Ecology & Environmental Protection
    Soil Microbial Community Characteristics in Tropical Vegetable Soil under Different Chemical Fertilizer Reduction Based on Metagenomic Analysis
    HUANG Rui, WANG Jinchuang, CHEN Miao, LI Qinfen
    2022, 43 (8):  1716-1727.  doi: 10.3969/j.issn.1000-2561.2022.08.022
    Abstract ( 25 )   HTML ( 1 )   PDF (2212KB) ( 23 )  

    To investigate the effects of chemical fertilizer reduction combined with organic fertilizer on the community structure and composition of bacteria, fungi and archaea in a tropical vegetable rotation soil, a field-oriented fertilization experiment was performed in Wenchang, Hainan Island. Metagenomic sequencing technology was used to investigate the differences in the composition, diversity, and structure of the bacterial and fungal communities under different fertilization condition. Furthermore, the main environmental factors driving the changes of soil bacterial, fungal and archaea communities under different fertilization treatments were analyzed in combination with soil chemical characteristics. The results showed that compared with the treatment of organic fertilizer combined with chemical fertilizer (M100NPK), organic fertilizer combined with 75% reduction of chemical fertilizer (M75NPK) increased the content of soil SOM, TN, NH4+-N and NO3--N, and organic fertilizer combined with 50% reduction of chemical fertilizer (M50NPK) increased the content of soil TK and AK. The application of M50NPK, M75NPK and M1000NPK fertilization treatments significantly increased the abundance soil bacterial, fungal and archaea. Compared with M100NPK, M50NPK and M75NPK increased the relative abundance of Proteobacteria and Acidobacteria, but decreased the relative abundance of Actinobacteria and Chloroflexi in the dominant bacteria community at the phylum level. Meanwhile, M50NPK and M75NPK increased the relative abundance of Basidiomycota, but decreased the relative abundance of Ascomycota in the dominant fungi community at the phylum level. The relative abundance of Thaumarchaeota, the dominant archaea community at the phylum level, increased in M75NPK treatment, but decreased in M50NPK treatment. For the soil bacteria and fungi, the Shannon and Ace index increased, but the Simpson index decreased after the M50NPK, M75NPK and M100NPK treatment. For the soil archaea, the Simpson index increased, but the Shannon and Ace index decreased after the M50NPK, M75NPK and M100NPK treatment. However, there was no significant difference in Alpha diversity among the three fertilization treatments. There was no significant difference in the response of soil bacteria, fungi and archaea to the application of different chemical fertilizer reduction combined with organic fertilizer. pH, TP, TN, SOM and AK were the main influencing factors driving for the variation in the community structures of bacteria, fungi and archaea. The results showed that compared with M75NPK and M100NPK, M50NPK did not change soil properties, microbial community diversity and structure, but could reduce the environmental risks caused by excessive fertilizer application. Therefore, M50NPK is an optimal fertilization regime for vegetable planting in tropical areas.

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    Responses of Soil Organic Carbon Components and Microbial Communities to Organic Management
    HAN Xingxiu, LI Qinfen, WANG Jinchuang
    2022, 43 (8):  1728-1737.  doi: 10.3969/j.issn.1000-2561.2022.08.023
    Abstract ( 29 )   HTML ( 1 )   PDF (1267KB) ( 28 )  

    Soil organic carbon and microbial community structure are important evaluation indexes for soil quality and health changes. In order to explore the effects of different management models on soil organic carbon fractions and microbial community composition in tea plantations, two tea plantations management models including organic tea plantations (OTP) and conventional tea plantations (CTP) in Baisha County, Hainan Province were selected as the research objects. 13C-NMR and phospholipid fatty acids (PLFA) were used to explore the changes of soil organic carbon components and soil microbial community composition under different management models. The effects of organic and inorganic managemen tmodels on soil organic carbon fractions (alkyl C, O-alkyl C, aromatic C and carboxyl C) and microbial community composition were clarified. Compared with inorganic management model, organic management model significantly changed the nutrient content in tea plantations soil. The content of organic matter (SOM), total nitrogen (TN) and total phosphorus (TP) increased by 47.86 %, 37.40 % and 100 %, respectively (P<0.05). The content of nitrate nitrogen (NO3--N) increased by 78.80 % (P<0.05), and the content of total potassium (TK) and available potassium (AK) decreased significantly (P<0.05). Organic management increased the relative content of alkyl C and O-alkyl C in tea garden soil. At the same time, the ratio of aliphatic C/aromatic C was higher than that of inorganic management tea garden. The total PLFAs content in the organic management tea plantation soil increased by 29.70 % (P<0.05), and the phospholipid fatty acid content of bacteria, G - and actinomycetes was significantly higher than that in inorganic tea garden soil (P<0.05). The RDA analysis revealed that soil TN, TK, alkyl C, O-alkyl C and carboxyl C were the main influencing factors driving for microbial community structure in tea garden (P<0.05). The correlation analysis results revealed that alkyl C of organic carbon fractions was significantly positively correlated with total PLFA, fungi, actinomycetes and mycorrhizal fungi. O-alkyl C was also positively correlated with fungi, bacteria and fungi/bacteria ratios in microorganisms. The results indicated that the organic management of tea plantation could regulate the microbial community structure, improve the degree of soil organic carbon fatty infiltration, then affecting the accumulation and turnover mechanism of soil organic carbon.

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    Research on Beach and Paddy Depression Resource Distribution of Dongting Lake Region
    ZHOU Hongcan, JIE Hongdong, YIN Weidan, FENG Yi, XING Hucheng, ZHOU Qing, JIE Yucheng
    2022, 43 (8):  1738-1749.  doi: 10.3969/j.issn.1000-2561.2022.08.024
    Abstract ( 27 )   HTML ( 1 )   PDF (4976KB) ( 23 )  

    Dongting Lake is the second largest freshwater lake in China. It is also a regulating and storage lake that receives the four rivers (Xiangjiang River, Zijiang River, Yuanjiang River and Lishui River) of Hunan, and it also is the flood channel of the Yangtze River. With the completion of the Three Gorges and the change of global climate, Dongting Lake area is subject to alternating change of flood and drought seasons, showing the change law that the rising water is a lake and the falling water is a continent, and the area of paddy depression and beach is changing with it. However, there is no exact data on its temporal and spatial distribution law, its relationship with water level change and the total amount of resources. The systematic grasp of its succession law is of great significance to the construction and development of Dongting Lake Ecological Economic Zone. Therefore, this study uses the 18 periods of Landsat TM remote sensing image data from 1996 to 2016 to extract the area of beach and paddy depression in Dongting Lake area before and after the completion of the Three Gorges. Combined with the hydrological and meteorological data of Chenglingji, this study analyzes the temporal and spatial evolution law of water surface, water land ecotone beach and paddy depression resources in Dongting Lake area. The results show that the average area of beach in the lake area is 21.93 × 104 hm2, spatially concentrated, distributed in the lake embankment, the lake bank zone and the river embankment with three ports and four waters, before the impoundment of the Three Gorges (23.27×104 hm2) after impoundment (21.26×104 hm2), with a decrease of 8.62%, East Dongting (12.43×104 hm2) > South Dongting (5.71×104hm2) > West Dongting (3.80×104 hm2), which is positively correlated with the area of administrative division, and the interannual change is negatively correlated with the change of water level in the lake area; The average area of paddy depression is 4.75×104 hm2, randomly and evenly distributed in space, patches are distributed in the embankment formed after land reclamation in the lake area and the lake basin formed by the alluvium of three ports and four rivers, far away from the center of the lake, before impoundment (5.14×104 hm2) after impoundment (4.56×104 hm2), a decrease of 11.34%, Yueyang City (2.29×104 hm2) > Changde City (1.61×104 hm2) > Yiyang City (0.85×104 hm2) in sequence. Before and after the completion of the Three Gorges project, the beach and paddy depression in the county-level administrative divisions decreased significantly; According to Pearson correlation analysis and principal component analysis, the factors affecting the distribution of beach and paddy depression can be divided into two principal components. The first principal component is the characteristics of “Dry Season”, including monthly average temperature in winter, water level in winter, rainfall in winter, area of paddy depression and flow in winter; The second principal component can be called “Wet Season” character, including summer monthly average temperature, summer flow, summer water level, beach area, summer rainfall and other indicators. The analysis model is more reliable and can provide a better theoretical basis for the comprehensive utilization of lake beach and paddy field depression.

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