The proteins on rubber particles of Hevea brasiliensis play key roles in a series of reactions of rubber biosynthesis. They directly determine the number and size of rubber molecules, thus affecting the yield and quality of natural rubber. Small rubber particle protein (SRPP) is the second highest abundance protein in rubber particles following after the rubber elongation factor (REF), which is closely related to rubber particle development and rubber biosynthesis. At present, it is known that there are many SRPP family proteins on rubber particles, but the functions of most SRPP family proteins have not been identified. SRPP may function by interacting with other rubber particle proteins. To screen the interaction protein of HbSRPP7, a normalized H. brasiliensis latex cDNA library was constructed based on the membrane yeast two-hybrid (MYTH) system. The capacity of the cDNA library was 1.5×10⁷ CFU, the average library recombination rate was about 100%, and the average amplification sizes of insert fragments in the cDNA library were above 1500 bp. The pBT3STE-SRPP7 and pBT3SUC-SRPP7 bait vectors were constructed and confirmed that they could be correctly expressed in the NMY32 yeast strain without self-activating activity. The latex MYTH cDNA library was screened using the bait plasmid pBT3STE-SRPP7, and 21 candidate proteins of HbSRPP7 were obtained, including three REF family proteins (HbREF1, HbREF3, and HbREF8), two SRPP family proteins (HbSRPP1 and HbSRPP2), two reactive oxygen species scavenging-related proteins (thioredoxin H-type-like and L-ascorbate peroxidase 2), and five stress-related proteins (high mobility group B protein 2-like, RPM1-interacting protein 4-like, stress-related protein-like, salt stress-induced hydrophobic peptide ESI3-like and F-box/kelch-repeat protein). It is shown that HbSRPP7 may participate in rubber biosynthesis through interaction with the rubber particle proteins related to rubber biosynthesis. In addition, HbSRPP7 may also participate in the regulation of rubber biosynthesis on rubber particles by interacting with biotic and abiotic stress-related proteins and responding to biotic and abiotic stress signals in laticiferous cells of H. brasiliensis. The research results are helpful to understand the function of SRPP family proteins and lay a foundation for revealing the composition of protein complexes involved in rubber biosynthesis on rubber particles and elucidating the molecular mechanism of rubber biosynthesis and its regulation.

Mangifera indica Linn. is a tropical and subtropical evergreen tree fruit, sweet fruit, rich nutrition, meat smooth and juicy, which is rich "tropical fruit king" reputation. In order to speed up the molecular identification of mango cultivars (lines), five mango cultivars (Red Ivory Mango, Jinhuang Mango, Red Mango No. 6, Red Jade Mango, Nan Doc Mai No. 4 Mango) with different phenotypic characteristics were selected from 19 test materials to screen SSR marker primers. The primers with better polymorphism were obtained by PAGE electrophoresis. Then, the primers were labeled with 5'-end modification with HEX and FAM fluorescent labels. The size of the amplified fragments were detected by capillary electrophoresis, and the polymorphic sites of each pair of primers were coded by numbers and letters. Finally, DNA fingerprint and DNA molecular ID card of mango were constructed by capillary electrophoresis. The results show that nine pairs of primers with good polymorphism were screened from the developed SSR primers from 115 pair primers through PCR amplification and PAGE electrophoresis. The primers were named M9, M15, M35, M40, M53, M59, M101, M102, and M103. After capillary electrophoresis detection and data analysis, bar code DNA molecular identification and quick response code DNA molecular identification of the mango cultivars (lines) were obtained combined with "number+letter" processing. For example, the fingerprint code of Jinhuang Mango is 9EE9F8933, the fingerprint code of Qianshan Mango No. 2 is H6F7564IC, and the fingerprint code of Qianshan Mango No. 4 is 3DGE47279. Finally, with the fingerprint code and basic information of 19 materials as the carrier, barcode DNA molecular ID and two-dimensional code DNA molecular ID were generated by online barcode generation program and two-dimensional code generation program. This study laid a foundation for standardizing the construction of molecular identification database of DNA of mango, and could provide data reference for mango genetics and breeding and excellent gene excavating.

Streptomyces catenulae XG40 is a biocontrol strain with antagonism to pathogens of pomelo black spot. In this study, the whole-genome sequence of S. catenulae XG40 was completed by the third generation sequencing platform PacBio Sequel. Three contigs were obtained, including one chromosomal DNA and two plasmid DNA. The total length of the genome sequencing was 9 772 324 bp with 70.58% GC content, and 8074 protein-coding genes were predicted which were accounted for 96.41% of all genes. Forty-six putative secondary metabolite biosynthetic gene clusters were found in the genome using the online antiSMASH software, among twenty-four PKS and NRPS, which were accounted for 52.17% of all gene clusters. Seven putative gene clusters showed 100% similarities to known gene clusters: desferrioxamin B, pristinol, neoantimyci, 2-methylisoborneol, nigericin, ectoine, geosmin gene clusters. Four putative gene clusters showed more than 80% similarities to known gene clusters: miharamycin A/B, SW-163C/E/F/G/UK-63598, gilvocarcin V, coelibactin. Clusters analysis showed that S.catenulae XG40 had certain ability of the biosynthesis of nigericin and gilvocarcin V with antibacterial activity. The analysis of synteny indicated that genome insertion, deletion, rearrangement and translocation happened among the genomes of S. catenulae XG40, S. rhizosphaericus DSM 41760, S. malaysiensis DSM 14702, melanosporofaciens DSM 40318 and S. himastatinicus ATCC 53653. This research would provide a theoretical basis for further discovering biocontrol potential of XG40 and the secondary metabolites for agricultural biological control.

The purpose of the study is to ascertain the molecular mechanism of the albino mutation of Aristaloe aristata, screen related functional genes, and provide basis for the breeding. The Illumina HiSeq sequencing platform was used to carry out transcriptome high-throughput sequencing for normal leaf color seedlings WT, albino mutant ls and qj. The sequencing results were annotated and analyzed. A total of 67.72 Gb clean data was obtained. A total of 122 665 unigene annotation results were obtained from functional annotation. For the analysis of Unigenes expression, a total of 914 differentially expressed genes (DEGs) in ls were screened out, among them, 453 genes were up-regulated and 461 down-regulated. There were 1851 differentially expressed genes (DEGs) screened in qj, of which up- and down-regulated genes were 868 and 983, respectively. According to a comparative analysis of GO functional enrichment and KEGG metabolic pathway, it was found that in the two mutant strains, there were many DEGs enriched in pigment accumulation, cell wall organization or biogenesis, cell wall, cell periphery, hydrolase activity of hydrolyzing o-glycosyl compounds, hydrolase activity acting on glycosyl bonds, and biosynthesis pathway of secondary metabolism, while the DEGs related to photosynthesis were not significantly enriched. In the pathway related to photosynthesis, the expression of porA and cab13 were significantly down-regulated in mutant ls, and porA and moda were significantly down-regulated in mutant qj. The results of real-time reverse transcriptase PCR (qRT-PCR) confirmed the consistency of the relative expression trend and the transcriptome data of these genes. The expression of the key gene, porA, which was down-regulated in both mutants, was assumed to be a key factor in the formation of albino seedlings of A. aristate since it was found to affect the enzymatic reaction of protochlorophyllin ester to chlorophyllin ester and thereby affecting the chlorophyll synthesis of the two mutants. Our study explored the transcriptome information of albinism mutation of A. aristate, screened the key genes with significant expression differences, and would provide an important theoretical basis for further exploring the molecular mechanism of albinism mutation of A. aristate.

An early-maturing, high-yield, high-starch, wide-adaptability cassava cultivar was bred in Guangxi for fresh consumption or further processing. A newly bred F₁ progeny of crossing between the high-yield, XX048 as the female parent and the high-starch NZ199 as the male parent was generated by artificial pollination and induction through prediction of graft breeding. After seedling selection, single row and a series of primary, intermediate, and advanced tests as well as regional and production trials, Guire No. 13 (GR13) was selected. As showed in the several years trial, GR13 delivered an average tuber yield of 47.06 t/hm², starch content was 32.0%, which was 22.93% and 21.48, 3.74 and 5.30 percentage point higher than that of NZ199 and SC205; Dry matters content of 45.2%, which was 4.7 and 7.5 percentage point higher than that of NZ199 and SC205, and HCN content was 25.7 mg/kg, lower than that of NZ199 and SC205; a rich content of nutrients (based on FW), such as 0.73% on crude fiber, 42.87 mg/hg on vitamin C, 0.75 g/hg on protein, 3% on total sugar, 1.1% on soluble sugar. The early-maturing (over 27.0% on starch content after planted 180 days), high and stable yield GR13 with wide-adaptability was resistent to drought, cold and mites, and its leaves did not fall off easily. It could be adequately cultivated in current cassava-producing areas in Guangxi, Jiangxi, and Yunnan provinces for either fresh consumption, further processing, or as a raw material for manufacturing starch products.

The heterozygosity, population structure and genetic diversity of Moringa oleifera and its progeny were analyzed using the SNP markers. The characteristics of genetic variation of M. oleifera and its progeny were studied. Simplified genome sequencing of 96 M. oleifera materials was performed by AFSM technology. The obtained sequencing filtering data were compared to the reference genome. SNP and Indel loci were detected and counted by using VCFtools and BCFtools. In order to analyze the reproduction types of M. oleifera, AWK language was used to analyze heterozygous loci, and compare the different loci of the progeny with the parents. The mutation sites were filtered by Plink software, and the high-quality mutation sites were reserved. The population structure was analyzed by ADMIXTURE software, and the optimal K value was determined according to the cross validation error rate. At the same time, GCTA software was used for principal component analysis, and the phylogenetic tree was constructed to analyze the population structure of the materials. VCFtools was used to calculate the genetic diversity index and population differentiation index for analyzing the genetic polymorphism of the population. LDBlockShow software was used for linkage imbalance analysis, and the linkage imbalance degree between loci was obtained. The result showed that a total of 1 187 831 SNP sites and 150 861 Indel sites were detected in this paper. We compared M. oleifera progeny genes with parents, which found that among the heterozygous genes in Moringa progeny, about 4.89% of the genes are self-heterozygous genes, and 19.96% of the heterozygous genes caused by foreign genetic materia. It indicates that M. oleifera produce offspring by the ways of self-pollination and cross-flowering. M. oleifera samples were divided into 3 subgroups by population structure and principal component analysis. The cluster analysis is roughly consistent with the above results. The subgroups can be clustered together, and there is a little crossover between the samples. The low genetic differentiation index (0.0049-0.0110) and genetic diversity index (0.001) among different populations of M. oleifera indicated that the level of genetic diversity was low and genetic differentiation was weak. The SNPS of 136 scaffolds which detected were counted and linkage imbalance analysis was performed, we found that scaffold 1 had the most SNPS (62 225), there was strong linkage imbalance between 6 748 044 and 6 748 185 loci. This study analyzed the genetic diversity of M. oleifera and its progeny. It would provide genetic basis for the cross breeding of M. oleifera.

Quickly obtain embryogenic callus is the key step to successfully establish the regeneration system in the somatic embryogenesis regeneration system of rubber tree. Rubber tree anthers were used as explants in the study. The effects of different concentrations of picloram, KT, 6-BA, and IAA on the induction of rubber tree anther embryogenic callus were studied through an orthogonal experimental design. The results showed that the optimal combination medium for rubber tree anther callus induction was MS basic medium, 0.4 mg/L thiamine, asparagine 300 mg/L, hydrolyzed casein 100 mg/L, proline 100 mg/L, arginine 100 mg/L, glutathione amino amide 100 mg/L, L-cysteine-hydrochloride 50 mg/L, sucrose 70 g/L, coconut water 50 mL/L, vegetable gel 2.2 g/L, picloram 20 mg/L, KT 2 mg/L and KT 2 mg/L and 6-BA 1 mg/L, and the callus induction rate reached 73.3%-100%. In all treatments, the callus was induced for about 25-28 days, and the callus reached the stage of rapid proliferation. The main effect of the induction of embryogenic callus was the concentration of picloram. It could promote the induction of embryogenic callus. Although low concentrations of picloram could also induce callus production, the callus were basically non-embryogenic potential-ie non-embryogenic callus. At the same time, 11 somatic embryos were used for plant regeneration. Among them, two plants emerged, seven only had roots without sprouting, and two had neither buds nor roots. The plant regeneration rate was 18%. By observing the leaf morphology and plant height of the plants, there was no significant difference with the rubber tree tissue culture seedlings and seedlings in production. In the future, on the basis of the research, the formulation of the callus induction medium would be further optimized, so that it could induce embryogenic callus from anthers more quickly, shorten the induction time of embryogenic callus, and reduce variation. Probability, it could provide callus with better conditions for RITA bioreactors as starting material.

In order to understand the C, N and P eco-chemometric characteristics of different tree age groups, the coffee from the Manxieba Xiaoaozi Nanpingzhen a Coffee Estate in Pu'er Simao District was studied in four tree age groups: 1 a, 7 a, 10 a and 20 a, the C, N, and P levels in coffee leaves and soil were determined, as well as the chemometric ratio between them. The N and P content of coffee leaves was proportional to the age of the tree, gradually increasing with the age of the tree, inversely proportional to the C content, gradually decreasing with the age of the tree. The differences in N and P content of coffee reached significant levels (P<0.05), and the chemometric ratios C∶N and C∶P decreased with tree age, among which C∶P was significantly different in different tree ages (P<0.01). Leaf N∶P threshold analysis found that the leaf N∶P ratio was less than 14 in all four tree age segments, indicating that the growth of coffee was mainly limited by N elements. There was significant variability (P<0.05) in SOC content between tree age groups, with 7 a coffee having the highest C, N and P content. The mean values of C, N and P content were slightly higher for 0-10 cm soils than for 10-30 cm soils and 9.79 for 0-10 cm soils than 6.87 for 10-30 cm soils. The range of C∶P variation for coffee was 11.51-46.80 for 0-10 cm soils and 4.53-20.82 for 10-30 cm soils, with large inter-soil variations. The range of N∶P variation was 1.00-5.12 and 0.81-2.08 for different soil layers, respectively. The correlation showed that N∶P and P elements were significantly correlated and P element was the main cause of C∶N variation. From the correlation analysis, coffee leaf C was significantly negatively correlated with N, P (P<0.05), leaf N was extremely significantly positively correlated with C∶N, C∶P (P<0.01) and leaf P was extremely significantly negatively correlated with C∶P (P<0.01). The SOC and TN of different soil layers were positively correlated (P<0.05), and the C, N, and P of the blade were not correlated with the TOC, TN, and TP of the soil, and the ratio of measurements was rarely correlated. It can be seen from the above that the SOC, TN and TP of coffee soil were relatively low, the soil was mainly limited by N nutrients. In addition, the absorption of N and P by coffee leaves had a synergistic effect, and there was a broad quantitative coupling relationship between coffee leaves and soil elements.

The object of this study was to investigate the growth, photosynthesis and carbohydrate of 'Shatangju' mandarin grafted on various rootstocks. The tree vigor, net photosynthesis (P_n), transpiration rate (T_r), stomatal conductance (G_s), intercellular CO₂ concentration (C_i), leaf chlorophyll, carbohydrates of 'Shatangju' mandarin budded on Ichang papeda (Citrus ichangensis Swingle), Trifoliate orange [P. trifoliate (L.) Raf.], 'Shatangju' mandarin (C. reticulata Blanco cv. Shatangju), Fragrant orange (C. junos Sieb.ex Tanaka), Rough lemon (C. jambhiri Lush) were evaluated. The scion height, trunk cross-section area (TCSA), leaf area and shoot length of 'Shatangju' on Fragrant orange and Rough lemon were significantly bigger than that on the Ichang papeda. The lowest affinity was found with Ichang papeda, which showed the highest rootstock/scion ratio (2.08). Total leaf chlorophyll content range from 0.85 mg/g FW to 1.40 mg/g FW, significantly higher leaf chlorophyll content was found in trees grafted on Rough lemon and Trifoliate orange than other grafting combinations. Trees on Fragrant orange had the highest net photosynthesis (P_n), transpiration rate (T_r), stomatal conductance (G_s), while Ichang papeda induced the lowest photosynthesis rates. As the production of CO₂ photosynthesis, high photosynthesis efficiency led to higher carbohydrate (total soluble sugar, sucrose, reduced sugar content) in 'Shangtangju' leaves budded onto Fragrant orange and Rough lemon rootstocks compared to trees on the Ichang papeda. The data confirmed that the low affinity of Ichang papeda rootstock and 'Shatangju' mandarin scion combination caused the lower photosynthesis efficiency and tree vegetative growth. The Fragrant orange rootstock could be a suitable candidate for the 'Shangtangju' mandarin production in citriculture.

Podocarpus macrophyllus is a common garden ornamental and greening tree species in southern China, with high economic and medicinal value. To study the physiological response of nitrogen addition under different phosphorus environments to P. macrophyllus seedlings, two-year-old P. macrophyllus seedlings were used as the material, two soil phosphorus conditions including low additional phosphorous (0.26 g/plant), high phosphorus addition (1.08 g/plant), three nitrogen addition levels including low nitrogen addition (0.53 g/plant), medium nitrogen addition (1.06 g/plant) and high nitrogen addition (2.12 g/plant) were set up and analyzed the differences of physiological characteristics, chlorophyll content, gas exchange parameters and leaf nutrient content of P. macrophyllus seedlings in each treatment group. Nitrogen addition increased the activity of POD, and high concentration nitrogen fertilizer decreased the activity of SOD. The application of nitrogen fertilizer in a low phosphorus environment increased soluble sugars and soluble proteins, decreased MDA and Pro. Soluble protein and soluble sugar accumulation decreased in high nitrogen and phosphorus environment, but MDA and Pro increased. The chlorophyll content of P. macrophyllus seedlings was the highest under medium concentration nitrogen treatment. The addition of nitrogen in low phosphorus environment increased the P_n, T_r and G_s of P. macrophyllus seedlings, while C_i (intercellular CO₂ concentration) of P. macrophyllus seedlings decreased. The P_n, T_r and G_s were the highest and C_i was the lowest in the medium nitrogen treatment group in high phosphorus environment. P_n, T_r and G_s decreased, and the C_i increased in the high nitrogen concentration and high phosphorus environment. The same change trend of P_n and T_r and correlation analysis showed that P_n of P. macrophyllus seedlings was mainly limited by stoma factors. Nitrogen addition promoted the increase of leaf nitrogen content in low phosphorus environment, but decreased the leaf nitrogen content in high phosphorus environment. Nitrogen addition limited the accumulation of phosphorus in the leaves of P. macrophyllus seedlings, but the increase of soil phosphorus content promoted the accumulation of phosphorus content in leaves. The increase of phosphorus fertilizer concentration increased the enzyme activity of P. macrophyllus seedlings under different nitrogen treatments. The increase of nitrogen fertilizer concentration decreased the content of MDA and Pro, and the content of soluble sugar and soluble protein increased in the low nitrogen and high nitrogen treatment groups. The increase of phosphorus fertilizer concentration increased the content of MDA and Pro, and the content of soluble sugar and soluble protein decreased in the high nitrogen treatment groups. Increasing the concentration of phosphate fertilizer promoted the chlorophyll content and photosynthetic efficiency of low and medium nitrogen treatment groups, while increasing the concentration of phosphate fertilizer decreased the chlorophyll and photosynthetic efficiency.

In order to analyze the effects of different intercropping patterns on the growth status, yield and quality of G. rigescens, six plant materials including Camellia sinensis (L.), Juglans regia L, Glycine max, Coix lacryma-jobi L., Glycine max (L.) merr and Vicia faba L. were selected to form seven crops patterns of G. rigescens monoculture and intercropping. Plant height, plant width, leaf length, leaf width and stem diameter of G. rigescens in vigorous growth period and harvest period were detected, fiber root number, root length, root diameter, gentiopicroside content were determined to explore the effects of different intercropping patterns on the yield and quality of G. rigescens. The results showed that the growth state of above ground part of G. rigescens intercropped with Juglans regia L. and Camellia sinensis (L.) was better than that of G. rigescens intercropped with Glycine max, Coix lacryma-jobi L., Glycine max (L.) merr and Vicia faba L. The intercropping with Juglans regia L. significantly promoted the growth of plant height of G. rigescens, while the intercropping with Camellia sinensis (L.) had large plant width, high leaf expansion and strong plants. The yield of G. rigescens in different intercropping cultivation was: Camellia sinensis (L.)>Juglans regia L.>Glycine max>Glycine max (L.) merr>control>Vicia faba L.>Coix lacryma-jobi L.. The yield of G. rigescens in intercropping with tea was the highest, 142.4 kg per hectare, 46.87% higher than that in the control. In different intercropping patterns, the number of fibrous roots of G. rigescens intercropping with Camellia sinensis (L.) was the highest, about 6-9 fibrous roots per plant, which was significantly higher than that of the control. The determination of gentiopicroside content in G. rigescens under different intercropping modes showed that: Camellia sinensis (L.) intercropping >Juglans regia L. intercropping>Vicia faba L. intercropping>Glycine max (L.) merr intercropping>Glycine max intercropping>control (monoculture)>Coix lacryma-jobi L. intercropping>Pharmacopoeia (1.5%), the gentiopicroside content in the roots and stems of Camellia sinensis (L.) intercropping was the highest, which was 3.36%±0.07%, significantly higher than that of the control and Coix lacryma-jobi L. intercropping intercropping. The correlation analysis showed that the root quality and yield of G. rigescens had a significant positive correlation with the aboveground plant width and leaf length, but had no significant correlation with the plant height of G. rigescens. The comprehensive score of the roots and stems by the membership function showed that the comprehensive quality of G. rigescens was better than that of the control: Camellia sinensis (L.) intercropping>Juglans regia L. intercropping>Vicia faba L. intercropping>Glycine max intercropping>Glycine max (L.) merr intercropping>control (monoculture)>Coix lacryma-jobi L. intercropping, Camellia sinensis (L.) intercropping, Juglans regia L intercropping, Vicia faba L. intercropping, Glycine max intercropping, Glycine max (L.) merr intercropping all higher than control, and the comprehensive score of intercropping Camellia sinensis (L.) was the highest, reaching 0.99.

The global quality cigar tobacco planting areas are basically dominated by tropical rain forest or tropical monsoon climate. The overall quality of cigar raw materials from Chinese and overseas planting areas has the certain disparity by multiple factors. In order to study the chemical constituents, a cluster and comparative analysis was conducted on some domestic and foreign cigar tobacco. The contents of carbohydrates and the distribution of amino acids reflected the characteristics of cigar tobacco. There were large differences among cigar tobacco samples from different planting areas in the content of conventional chemical components, and the chemical components of the cigar tobacco leaves had harmonious percentage in general. The average contents of total sugar, reducing sugar, anatabine, glutamic acid, linolenic acid and linoleic acid in cigar tobacco samples from Hainan and foreign planting areas were significantly lower than those in the other three planting areas in China, but the pectin content showed the opposite pattern. In terms of aroma components, the average contents of carotenoid degradation products such as megastigmatrienone, linalool and damascenone, non-enzymatic brown-reaction products such as pyrazine and furfural, and solanone in cigar tobacco samples from other three planting areas in China were significantly higher than those from Hainan and foreign planting areas. The average contents of neophytadiene, isoamyl alcohol, pyridine, phenyl ethanol and other aroma components in cigar tobacco samples from all domestic planting areas were higher than those from foreign planting areas, and the difference was significant or most significant. These planting areas fell into four categories according to clustering results. The first group included America areas and Hainan Province in China. The second group included Indonesian areas. Hubei Province, Yunnan Province was in the third group, and Sichuan province was in the fourth group.

Citrus reticulata cv. chachiensis, also known as Xinhui Mandarin Orange, has a long history of cultivation in Guangdong (Xinhui) and is a local agricultural product in Guangdong. There are no relevant studies on the symptoms description and distribution of Candidatus Liberibacter asiaticus (CLas) in C. reticulata cv. chachiensis infected with Citrus Huanglongbing (HLB). Through this study, it can provide a basis for the study of the movement of CLas in citrus plant branches and fruit pith and can also provide ideal plant materials for the subsequent acquisition of high concentration of CLas. In this study, C. reticulata cv. chachiensis branches and fruit pith infected with CLas were used as plant material to identify symptoms and analyze the distribution of CLas in different parts of citrus branches and different length fragments of the fruit pith based on real-time quantitative PCR (qPCR). Through the observation of the leaves and fruits from the infected citrus plants, the upper leaves of the branches infected with CLas showed mottled and element-deficient yellowing, especially the symptoms of the new leaves of the branches were more obvious, while the color of the lower old leaves was dark green and the texture was hard. Compared with the healthy fruit, the fruit infected with CLas showed uneven coloring, showing typical symptoms of "red nose fruit". Meanwhile, compared with the healthy fruit, the fruit infected with CLas showed uneven size, abnormal body and asymmetrical shape, the seed was small and the seed aborted. The concentration of CLas in the central axis of the fruit was close to that in the fruit pith, and significantly higher than that in other parts of the branches (P<0.05). CLas was also unevenly distributed in different length segments of the same fruit pith, and the concentration of CLas was the highest in the middle of fruit pith (1-3 cm fragment), the concentration of CLas in the central axis and fruit pith of HLB-infected C. reticulata cv. chachiensis fruits is significantly higher than that of other parts. The study could be a reference for the identification of HLB, a basis for the study of the movement of CLas in citrus plant branches and fruit pith, and used to select ideal plant materials for the subsequent acquisition of high concentration of CLas.

Neonicotinoids (NEOs) contain imidacloprid (IMI) and acetamiprid (ACE), which are widely used in the world. In this study, earthworms (Eisenia foetida) were used as soil animal. Through high-throughput sequencing and measurement of soil physical and chemical properties, the changes of bacterial communities between IMI and ACE contaminated red soil (BCK, DCK) and soil after earthworm introduction (B, D), and the relationship with environmental factors were analyzed to explore the animal remediation mechanism of contaminated red soil. The introduction of IMI and ACE reduced the diversity of microbial population, significantly changed the composition of soil bacterial community structure, and decreased the content of soil organic matter (SOM) and total nitrogen (TN), compared with the natural red soil (CK). The addition of earthworms increased the relative abundance of Actinobacteriota, Proteobacteria and Bacteroidota, which have the ability of insecticide resistance and degrading. pH value, TN, total phosphorus (TP) and total potassium (TK) contents of contaminated soil increased. Combined with the correlation analysis of soil physiochemical properties, it was found that pH, TN, TK and SOM had a great influence on the bacterial community structure among the treatment groups at the genus level. The study showed that IMI and ACE pollution reduced the contents of SOM and soil TN, and destructed the original bacterial community structure in the soil. Earthworm activity improved soil fertility of contaminated red soil, alleviated the adverse effects of IMI and ACE on soil microbial flora, restored and enriched the diversity of microbial species in NEOs-contaminated soil to a certain extent, and then accelerated the degradation of NEOs in soil. This study showed the feasibility to screen the efficiently IMI and ACE-degrading bacteria from drilosphere, and would provide theoretical basis for the earthworm remediation of IMI and ACE-contaminated soil.

In order to determine the optimal conditions for the preparation of jackfruit starch-coconut oil complexes by Rapid Visco Analyzer (RVA), the influence of addition of coconut oil, complexation time and complexation temperature on the complexation index of jackfruit starch-coconut oil complexes was studied. The Box-Benhnken response surface method was used to optimize the process conditions for the preparation of jackfruit starch-coconut oil complexes. The optimal preparation parameters of the jackfruit starch-coconut oil complexes were 4% of the addition of coconut oil, 2.40 min of complexation time, 90.70 ℃ of complexation temperature, respectively. Under the optimal condition, the experimental value of complex index was 24.33%, which was in good agreement with the value predicted by the model (24.64%). The gelatinization temperature, peak viscosity, and though viscosity of jackfruit starch-coconut oil complexes were higher than those of the raw starch, while the final viscosity and setback value were lower than those of the raw starch. This indicated the thermal stability of the complex was improved. The swelling ability of the starch was restricted when the jackfruit starch-coconut oil complexes was formed, resulting in the lower swelling power and a lower solubility than those of the raw starch.

Cymbidium sinensis is a typical fragrant orchid variety with high economic and ornamental value. HS-SPME/GC-MS was used to analyze the volatile components of different flower organs in C. sinensis. Seven categories and 54 volatile components were detected, mainly composed of 21 aldehydes, 12 alcohols, 10 ketones, 5 benzenes, 2 furans, 2 acids and 2 terpenoids. There were 48 compounds presented in four different flower organs, including petals, sepals, labellums, and pistil columns, including 19 aldehydes, 10 alcohols, 9 ketones, 5 benzenes, 2 terpenoids, 2 furans and caproic acid. There were three components in petals, sepals and pistil columns, only two components were detected in sepals, and Acrolein was only detected in pistil columns. The results showed that there were significant differences in the volatile matter and content in different floral organs of flowers. A total of 49 volatile substances were detected in sepals, with the highest content reaching 99 106.15 μg/L, accounting for 35.88% of the total volatile organic compounds. Among which the highest content was cyclopentyl formaldehyde, which had the camphor flavor of mint. 51 volatile compounds were detected in the petals, with a substance content of 56 571.48 μg/L, accounting for 20.48% of the total volatile organic compounds, with the highest content being 1-penten-3-ol, which had a fruity aroma. A total of 48 volatile substances were detected in the labellum flap, with the lowest substance content of 41 645.32 μg/L, the proportion of total volatile organic compounds was 15.08%, among which the highest content of volatile substance was cyclopentyl formaldehyde. A total of 51 volatile compounds were detected in the pistil column, with a content of 78 868.68 μg/L, accounting for 28.56% of the total volatile organic compounds, with the highest content being hexanal, which presented a fresh oil, green grass, and apple aroma. Through principal component analysis, it was found that among the four flower organs, there was little difference between the lip and petal, while the pistil column had a greater difference from other organs, and the sepals also had a greater difference from other organs. Glutaraldehyde, hexanal, E-2-pentenal, E-2-hexenal, cyclopentyl formaldehyde, E-2-heptaneal, 1-penten-3-ol, E-2-penten-1-ol were the main volatile components released by floral organs. During the peak flowering period, the sepals of the flowers were the main floral organs that released volatile components, and there were significant differences in the content of floral aroma components among different floral organs.

In order to explore the polymeric 2-(2-phenylethyl) chromones (PPECs) components and the structures from agarwood (Aquilaria spp.), ultra-performance liquid chromatography coupled with quadrupole time-of-flight mass/mass spectrometry (UPLC-Q-TOF-MS) was used to acquire the spectrum of TOF-MS and TOF-MS/MS of agarwood samples. The fragmentation pathway of PPECs was analyzed. The screening and structure confirmation of PPECs from agarwood was performed. A total of 55 PPECs components were identified. According to the structural characteristics, 55 components were grouped into three types, including dimeric 2-(2-phenylethyl) chromones (DPECs), trimeric 2-(2-phenylethyl) chromones (TPECs) and sesquiterpenoid-2-(2-phenylethyl) chromones (SPECs). All identified components were consisted of 44 DPECs, 3 TPECs and 8 SPECs, of which nine DPECs, one TPECs and one SPECs were firstly identified in agarwood. Furthermore, 2-4 isomers were observed for some PPECs components from agarwood. The results showed that agarwood were rich in PPECs components and the corresponding isomers. Meanwhile, the proportion of DPECs was the highest (80%) among total PPECs. The results could provide reference for the study of material basis of pharmacodynamics effect and utilization of agarwod.

Dioscorea esculenta (Lour.) brukill is a traditional miscellaneous grain in Hainan, and it is rich in polysaccharides. This study investigated the extraction process and anti-oxidant activity of the polysaccharides from D. esculenta by using the D. esculenta tuber powder as the raw material. The hot water extraction was used to optimize the extraction process of polysaccharides from D. esculenta by single factor experiments and three-factor and three-level L₉(3³) orthogonal tests. The crude polysaccharides from D. esculenta were purified by the Sveag method, dialysis, DEAE-52 cellulose column and SephadexG-100 gel column chromatography. The anti-oxidant activity of polysaccharide from D. esculenta was detected by DPPH method, hydroxyl radical method, superoxide anion method and reduction method. The optimal extraction method of the hot water extraction included temperature 70 ℃, solid-liquid ratio 1∶15, and extraction time 3 h. The polysaccharides extraction rate of D. esculenta was 1.94%. After multipleseparation and purification, neutral polysaccharides with uniform purity were obtained. The expriments of anti-oxidant activity of polysaccharides from D. esculenta showed that the DPPH radical scavenging capacity of polysaccharide from D. esculenta was weak. The polysaccharide from D. esculenta and scavenging rate of 1-5 mg/mL was maintained at about 10%, and with the increase of polysaccharide concentration, the scavenging capacity gradually decreased. The hydroxyl radical activity increased with the increase of polysaccharide concentration, and the scavenging rate reached 34.74% at 5 mg/mL. The superoxide anion free radical activity decreased gradually with the increase of polysaccharide concentration, and the scavenging rate reached 67.35% at 1 mg/mL. The reduction capacity of polysaccharides was weak, and the reduction capacity of 1-5 mg/mL remained 0.17. In this study, the extraction process of polysaccharides from D. esculenta was optimized, and it had certain antioxidant activity. It would lay the foundation for the functional product development and the mechanism research of drug function of D. esculenta.

Using the in vitro axillary bud of Anthurium (Anthurium andraeanum Lind.) as the materials, this article reports the influence of the droplet vitrification on Anthurium after cryopreservation, and plants regenerated tissues genetic stability were assessment. The results showed the highest survival rate of Anthurium (63.70%) was achieved after preculture for 4 days on MS solid medium containing 0.4 mmol/L sucrose and 2 mmol/L glycerol, dehydration with 80%PVS₂ at 0 ℃ for 50 min, cooling in droplets of PVS₂ placed on aluminum foil strips, after immersing in liquid nitrogen for 2 s, directly transferred it to a cryotube filled with liquid nitrogen, and kept it in liquid nitrogen for at least 30 min after rewarming them with MS liquid medium containing 1.2 mmol/L sucrose at room temperature for 20 minutes, transferred to recovery medium. Through ISSR and SSR molecular marker detection, the genetic stability of regenerated plants did not changed. The results would provide an effective way for long-term preservation of Anthurium andraeanum germplasm resources.

The islands are important pivots for the development of South China Sea, and which play an important role in ensuring the development sustainability of South China Sea and safeguarding national rights and territorial integrity. The islands in South China Sea have rich biodiversity and complex ecological functions, but they are also vulnerable to human disturbances. The paper summarizes the basic characteristics of the climate, water, soil, biology and agriculture development of the islands. It indicates that keeping ecological sustainability is the fundamental task during the development of islands, and it is important to reduce the disturbances of human factors on the islands ecology, and pay attention to the development of island agriculture and modern marine ranching, and build a comprehensive evaluation system for the ecology sustainable development of islands, that will ensure the realization of social, economic and national security services function of the South China Sea islands.

At present, the safety of natural rubber resources in China is becoming increasingly prominent. It is of great theoretical and practical significance to carry out dynamic monitoring of natural rubber production. Based on the long-panel data set, the spatial distribution characteristics, and evolution of natural rubber in China from 1995 to 2020 were studied by using production scale index, production concentration index, production gravity analysis method, efficiency advantage index, scale advantage index and aggregated advantage index in this paper. The results showed that the distribution of natural rubber production in China gradually concentrated to Yunnan and Hainan from 1995 to 2020, and the production concentration index of Yunnan and Hainan reached 97.87% in 2020. Yunnan surpassed Hainan to become the most comparative advantage rubber planting area in China, and Hainan belonged to the comparative advantage area. At the same time, the spatial center of gravity moved to the northwest obviously, and the comparative disadvantages of Guangdong, Guangxi and Fujian were more prominent. In the future, the spatial statistical analysis method based on multi-factor and multi-scale would become an important development direction of the research on the spatiotemporal evolution and prediction of natural rubber production distribution.