For the study of Hainan Island typical farmland soil fertility conditions, the forest land, cultivated land, garden land and grass land of Hainan, China under the type of soil pH, mechanical composition, organic matter, cation exchange capacity, total nitrogen, alkali solution nitrogen, total phosphorus, effective phosphorus, total potassium were determined and statistically analyzed. Based on "the second soil census nutrient classification standard", the Nemerow Index Method was used to evaluate the comprehensive soil fertility of each land use type. The results showed that nitrogen content was deficient in different land use types. The phosphorus content was abundant or very abundant. Potassium content was abundant in woodland and cultivated land, moderate in garden land, and deficient in grassland. In the four types of farmland, and cation exchange capacity of soil organic matter, total nitrogen, hydrolyze nitrogen were significantly correlated (P<0.05) or extremely significant correlation (P<0.01), soil cation exchange capacity and total nitrogen and hydrolysis nitrogen showed strong correlation, and other soil nutrient showed virtually no correlation or weak correlation. The corresponding comprehensive soil fertility of the four land types was in the order of garden land (1.164)>forest land (1.058)>arable land (0.879)>grassland (0.784). The comprehensive soil fertility of garden land and forest land was average, while that of arable land and grassland was poor. Therefore, we should strengthen land management, rational use of land, improve soil nutrient structure, and finally improve land productivity.

Noni fruit is a characteristic fruit of Hainan with a variety of medicinal effects, but there are few studies on its plant proteins. In the present study, two-dimensional gel electrophoresis (2-DE gel) technology based on the BPP+phenol extraction method was used to extract and separate the proteins of noni fruits at different ripening stages including bud stage, half ripe stage, and mature stage by optimizing the experimental conditions to obtain the fingerprint of plant proteins. The gel images were analyzed by Image Master 5.0 software and some proteins with high expression were screened out. The enzymatic hydrolysates of the proteins were further identified by using MALDI-TOF-MS technology. The functional analysis of the highly expressed proteins of three kinds of noni fruits were preliminarily carried out by bioinformatics methods. The results indicated that there were respectively forty four, forty nine, and forty highly expressed proteins at three maturites noni fruits. Among the proteins, there were respectively thirty three, twenty two and thirty nine proteins by mass spectrum identification, which subordinated to various types of protein with different plant functions. Moreover, significant difference existed in the highly expressed proteins of different maturity stages, which involved in a variety of proteins such as chloroplastic ligase, cysteine proteinase, protein kinase, ubiquitin ligase, and auxin response factors. It could provided a scientific and reasonable theoretical guidance for the further development and utilization of the plant protein of noni fruits.

Self-incompatibility is a genetic mechanism to prevent self-fertilization and the consequent inbreeding and fitness decay in plant populations. In the gametophyte self-incompatibility mechanism represented by Solanaceae, Rosaceae and Plantaginaceae, the self/non-self recognition between pollen and pistil is determined by the polymorphic S locus. SLF (S-locus F-box)/SFB (S-haplotype-specific F-box) gene is the pollen S determinant of gametophyte self-incompatibility. In this study, 21 SLF/SFB family genes were screened and identified based on the genome-wide of the pineapple. Each AcSLF gene had an F-box conserved domain at the N-terminal. There were great differences in amino acid length, theoretical isoelectric point and molecular weight. The size range of the encoded amino acid sequence was 242-612 aa, and the molecular weight was 27.778-69.070 kDa. The isoelectric point ranged from 5.70 to 9.57. 18 AcSLF proteins were alkaline and most proteins were unstability, only AcSLF19, AcSLF21 were stability. It was predicted that 18 AcSLF proteins were located in the nucleus, one AcSLF protein in chloroplast, two AcSLF protein in both chloroplast and nucleus, and more than 60% of the secondary structure of the protein was composed of alpha helix and random coil. Bioinformatics analysis showed that the pineapple SLF/SFB family genes, which were unevenly distributed on 14 chromosomes, and the chromosome location of AcSLF21 was undetermined. Furthermore, AcSLF4, AcSLF5, AcSLF6, AcSLF8, AcSLF14 and AcSLF15 were linked with RNase T2 family genes, this was one of the main characteristics of pollen SLF gene. AcSLF genes contained different numbers of introns, most of which contained 1~2 introns, and AcSLF3 contained 4 introns. Based on the above analysis results, it showed that AcSLF proteins had different characteristics. Phylogenetic analysis indicated that the evolutionary relationship of AcSLFs in pineapple was far away from the SLF/SFB in Rosaceae, Plantaginaceae and Solanaceae, the degree of clustering was low on the branches of evolutionary tree. The expression levels of the AcSLF genes in pistil, stamen, leaf, sarcocarp, stem and root were analyzed by qRT-PCR. The results showed that AcSLFs had obvious expression differences in different tissues of pineapple. AcSLF1, AcSLF2, AcSLF4, AcSLF9, AcSLF10, AcSLF11, AcSLF15, AcSLF19, AcSLF20 and AcSLF21 genes were highly expressed in pineapple stamens. The expression of AcSLF3 and AcSLF7 in sarcocarp was higher than that of other tissue, and AcSLF5, AcSLF12, AcSLF18 were higher expression in root than other tissues. In general, most pineapple AcSLF genes are mainly expressed in pineapple stamens or leaves. It was found that the expression of AcSLF1, AcSLF2, AcSLF15 genes in pollinated pistil were significantly up-regulated than that in non-pollinated pistil. Especially at 6 h after cross-pollination, the expression level was significantly higher than that of non-pollinated pistils. With the extension of the pollen tube in the pistil, the expression level decreased, but it still had a high expression at 24 h after pollination. And the expression trend of AcSLF1, AcSLF2 and AcSLF15 in cross-pollination was consistent with the growth of pollen tube in the pistil. Therefore, it is speculated that AcSLF1, AcSLF2 and AcSLF15 play an important role in pineapple self-incompatibility. This is the first time to analyze the expression pattern of SLF/SFB family genes in pineapple. This study would provide a reference for the cloning of pineapple SLF/SFB family genes, and basis for the study of pineapple self-incompatibility mechanism.

The biological activity of loquat exosomes and cytosol on human skin cells in vitro was explored to provide a scientific basis for the development of skin care products. The loquat exosomes and cytosol were obtained by ultra-high-speed centrifugation and mechanical disruption, respectively. Firstly, the effect of different concentrations of loquat leaf-derived exosomes (loquat leaf-exo), loquat cell suspension culture-derived exosomes (loquat suspension-exo) and loquat cell suspension culture-derived cytosol (loquat suspension-cytosol) on cell viability of human skin fibroblasts (HSF) was detected by the CCK8 method. And then, HSF cells were treated with LPS (lipopolysaccharide) for inflammation modeling, and the concentration that significantly promoted the cell survival rate was selected, followed by adding exosomes or cytosolic treatment to detect cell apoptosis and migration ability. Secondly, the melanoma cells (A375) were subsequently treated with exosomes or cytosol, and the melanin content and tyrosinase activity were detected. The concentration of exosomes per gram of loquat leaves was 8.54×10⁹ particles, and the particle size was 86.78 nm; each milliliter (approximately equal to 1 g) of loquat suspension cells contained exosomes with a concentration of 8.67×10⁸ particles, with a particle size of 80.39 nm. At the concentration level of 20 μg/mL, loquat leaf-exo, loquat suspension-exo, and loquat suspension-cytosol all significantly increased the survival rate of HSF cells in vitro (P<0.05). Compared with the positive control (LPS treatment group), loquat leaf-exo at 20 μg/mL, loquat suspension-exo at 20 μg/mL and loquat suspension-cytosol at 10 μg/mL significantly reduced the apoptosis induced by LPS treatment (P<0.01), both significantly promoted cell migration (P<0.05). 5 μg/mL loquat suspension-exo and loquat suspension-cytosol could significantly reduce the melanin content of A375 cells in vitro, and loquat suspension-cytosol could also significantly reduce the tyrosinase activity (P<0.05).

In order to screen out the key metabolites that control the fragrance of areca nut, enhance the fragrance of areca nut, attract more pollinators, and then increase the yield of areca nut. In this study, Headspace Solid Phase Microextraction Gas Chromatography-Mass Spectrometry Combined Analysis Technology was used for non-targeted metabolomic detection of areca nut flowers in different periods. 236 metabolites were detected in the study. 75 differential metabolites were screened by combining VIP value and differential fold. Main metabolites were terpenes, ketones, alcohols. Among them, the volatile compounds of female flowers of Areca accumulated a lot from the female flower unopened stage to the initial blooming stage, and decreased slightly in the full bloom stage, so the initial blooming stage of female flowers of Areca may be the key period for the formation of female flower fragrance. The volatile compounds in the male flowers of Areca accumulated a lot from the initial blooming stage to the blooming stage, so the blooming stage of male flowers may be the key period for the formation of flower fragrance of male flowers of Areca. KEGG database was used to analyze the metabolic pathways of differential metabolites. The fatty acid biosynthesis was the metabolic pathway that was significantly enriched in the female flowers of areca nut and related to flower aroma synthesis, and the substance enriched in this pathway was capric acid. Capric acid is a fatty acid, which is mostly used in plant physiology and signal transmission and other functions. The capric acid content in the female flowers of betel nut increased from the unopened stage to the early flowering stage, and the release of floral fragrance also increased correspondingly. This may be because areca nut starts pollination at the beginning of female flower, and more chemical signals are needed to be transmitted to attract pollinators. So capric acid may be a chemical signal released by betel nut female flowers for pollination. Metabolic pathways significantly enriched in male areca nut flowers and related to flower aroma synthesis are diterpenoid biosynthesis and fatty acid degradation. Palmitaldehyde and (4aR,6aS,9R,11aR,11bR)-4,4,11b-trimethyl-8-methylene tetrahydro-6a and 9-methylcycloheptyl [a] naphthalene were enriched in two pathways. (4aR, 6aS,9R,11aR,11bR)-4,4,11b-trimethyl-8-methylenetetrahydro-6a,9-methylcyclohept[a]naphthalene is a terpenoid. Its enantiomer, ent-kaurene, is synthesized by ring-opening of trans-geranylgeranyl pyrophosphate with the use of kaurine synthase and is a precursor ofgibberellin. The content of this substance was down-regulated from the early flowering period to the full bloom period of male flowers, which may be due to the decrease of the required gibberellin content in male flowers during the full bloom period. Palmitaldehyde is an aldehyde substance, which is a metabolite released by the biodegradation of fatty acids. The release of the fragrance of areca nut male flowers increased from the early blooming stage to the blooming stage, and the content of palmitaldehyde also increased. There is a positive correlation between these two situations. In conclusion, the above three metabolites may be the key metabolites that affect the fragrance of areca nut.

In order to clarify the differences and similarities in climate conditions between major cigar producing areas in China and dominant cigar producing areas in foreign countries, this study selected 17 major cigar production areas in Hainan province, Yunnan province, Sichuan province and Hubei province of China, as well as the dominant major cigar production areas in foreign countries, including Pinar del Rio in Cuba, Santiago in Dominica, Jember in Indonesia and Bahia in Brazil. General statistical analysis and cluster analysis were used. The differences of six key meteorological factors including monthly average temperature, maximum temperature, minimum temperature, rainfall, relative humidity and difference in temperature in the field period, the drying period as well as the whole growing season of cigar production in the 17 production areas were studied. There was no significant difference in the overall climate conditions of the field period, drying period and the whole growing season between domestic and foreign major cigar producing areas, while the differences in the four meteorological factors of the maximum temperature, minimum temperature, rainfall and difference in temperature in the whole growing season between domestic and foreign major producing areas reached the significant level (P<0.05). Among them, the differences of the three meteorological factors of maximum temperature, minimum temperature and difference in temperature reached the level of extremely significant (P<0.01). Taking the Euclidean distance of 15 as the critical value, the 17 major cigar producing areas in the field period could cluster into four categories, the 17 major cigar producing areas in the drying period could cluster into three categories, and the 17 major cigar producing areas in the whole growing season could cluster into two categories. The results of this study would provide a scientific basis for major cigar producing areas in China to learn from dominant cigar producing areas in foreign countries in planting layout, variety selection and quality improvement, and also provide a data basis for climate assessment and variety optimization of cigar growing areas in China.

Trichoderma spp. is an important biocontrol microorganism in the fungal disease prevention and control of green agriculture. Which is widely developed as Trichoderma agent for biological control, biofertilizer and soil amendment. The development of traditional Trichoderma fungicide is limited to the screening of Trichoderma strains and the optimization of fermentation conditions. Therefore, it is necessary to explore a new application mode of Trichoderma. Due to intolerance to storage and high costs of transportation and development, coconut water is often directly discarded as waste in the production of coconut industry. In this study, coconut water was compounded with Trichoderma spores and medium elements as water-soluble fertilizers to explore the effects on seed germination and seedling physiological indexes of cucumber. The results showed that adding medium element to coconut water and adjusting pH to 7 had the best effect on the production of Trichoderma spore, and the sporulation reached 2.32×10⁷ CFU/mL. The treatment group A of water-soluble fertilizer compounded with medium element in Trichoderma spp. and coconut water and treatment group B of water-soluble fertilizer compounded with Trichoderma spp. and coconut water significantly promoted the germination of cucumber seeds, and the germination rates of cucumber seeds was 94.44%and 87.50%, respectively, compared with sterile water (CK), which increased by 28.30% and 18.87%, respectively. Pot experiment showed that the plant height and root length of treatment group A was 24.01 cm and 27.76 cm, respectively, which was 48.03% and 47.27% higher than those of CK, which significantly promoted the growth of cucumber seedlings. At the same time, the fresh weight and dry weight of stem and root of cucumber seedlings in treatment group A were also significantly higher than those of CK. Further, we determined the content of total chlorophyll, reducing sugar and soluble protein, the activity of peroxidase (POD) and catalase (CAT) of cucumber seedlings in treatment group A, compared with CK, which increased by 97.46%, 66.32%, 58.85%, 32.67%, and 40.31%, respectively; and the content of malondialdehyde (MDA) was significantly decreased, which was 79.96% lower than that of CK. In summary, the treatment group of water-soluble fertilizer compounded with medium element in Trichoderma spp. and coconut water could significantly promote cucumber seed germination and seedling growth, improve the contents of total chlorophyll, reducing sugar, soluble protein, POD and CAT activity, decrease MDA content of seedlings, and enhance the ability of cucumber to resist stress.

The pepper is a widely cultivated vegetable and its domestication and dissemination history have received significant attention from the academic community. This article summarizes the pathways of pepper's dissemination worldwide. The wild pepper species originated in the northwestern part of the Andes Mountains in South America and expanded, spread, and evolved in South and Central America. The Capsicum cultivars migrated outward from Mexico and underwent parallel domestication in multiple regions. After Christopher Columbus brought peppers back to Spain from South America, they began to spread to other European countries and eventually spread throughout Central Europe by the mid-16th century. Simultaneously, a large number of pepper varieties introduced into Asia, Africa, and Eastern Europe via the "Eurasian Trade Route" and the "Galleon Trade Route". The prevalent slave trade in the 17th century further facilitated the comprehensive dissemination of peppers in Africa and North America. With the development of global trade, the Capsicum cultivars from different regions were exchanged more extensively. Among them, C. annuum spread to Asia, Africa, North America, Oceania, and Eastern Europe, becoming the most widely cultivated peppers worldwide. C. frutescens and C. chinense were introduced to Eastern Europe, tropical regions of Africa, and Asia, while C. baccatum and C. pubescens are mainly grown in Central and South America, Indonesia, and South Africa. Genomic research results have provided important genetic evidence for the global dissemination history of pepper, while also offering a new perspective for the study of pepper evolution.

Cassava (Manihot esculenta Crantz) is an important food crop in tropical and subtropical areas. SWEETs participate in a variety of plant activities, including sugar transport, reproduction and development, plant stress, and interaction with pathogens, which play an important role in plant development. In order to clarify the function of SWEET in the growth and development of cassava, sugar transporter MeSWEET18 was cloned from Cassava South China 9 (SC9) for bioinformatics analysis and verified sugar transport capacity by yeast experiment in this study. The expression trend of MeSWEET18 in cassava in different organ, different developmental stages and under abiotic stress were determined via qRT-PCR method. MeSWEET18 contained a 714 bp open reading frame (ORF) encoding a protein of 237 amino acids residues with predicted molecular mass of 25.94 kDa and theoretical isoelectric point of 6.57. Through instability index (II) analysis by ProtParam, the instability index (II) of the protein encoded by MeSWEET18 was 37.50, indicating the protein of MeSWEET18 as stable. MeSWEET18 was a typical membrane protein with a conserved domain MtN3_slv at the N-terminal and a PQ-Loop Super family conserved domain at the C-terminal and seven transmembrane domains. ProtScale predicted that MeSWEET18 was a hydrophilic protein. Phylogenetic tree analysis revealed that MeSWEET18 belonged to Clade IV. MeSWEET18 was in the same evolutionary tree as AtSWEET16 and AtSWEET17. Alignment of amino acid sequences revealed 53.23% homology between MeSWEET18 and AtSWEET16, and 56.05%homology between MeSWEET18 and AtSWEET17. Yeast functional complementarity tests showed that MeSWEET18 primarily transported fructose. qRT-PCR analysis showed that MeSWEET18 was highly expressed in tuberous roots during the expansion and decreased sharply at maturity of cassava tuberous roots, while the expression levels in leaf, petiole and stem increased with the development of cassava, and reached the maximum at the maturity stage of cassava. qRT-PCR analysis showed that MeSWEET18 was significantly affected by fructose when the hydroponic seedlings of SC9 were treated with sucrose, glucose and fructose solutions under dark conditions. The hydroponic seedlings of SC9 were subjected to abiotic stress including high salt (8 g/L NaCl) stress, drought (100 mmol/L mannitol) stress, oxidation (10% H₂O₂) stress and low temperature (15 ℃ for 24 h, then reduced to 4 ℃ for 24 h) stress. The results show that MeSWEET18 is expressed differently in leaf, petiole, stem and root under abiotic stress. It can be speculated that MeSWEET18 play an important role under abiotic stress in cassava.

Southwest Guizhou Autonomous Prefecture is a typical mountainous area with low latitude and high altitude and has abundant water resources. The specific climate and geographical environment of this region enables the appearance of abundant wild sugarcane germplasm resources. In order to enrich the wild germplasm resources and genetic diversity of National Germplasm Repository of Sugarcane (NGRS), and reveal the distribution of wild sugarcane germplasm resources in the region, the wild sugarcane resource investigation team of Sugarcane Research Institute of Yunnan Academy of Agricultural Sciences conducted a survey and collection for 14 days in 4 cities of the region from May 9 to May 22, 2020. Four cities, Xingyi, Xingren, Qinglong and Pu'an, were selected as the main collection areas, and a total of 92 wild sugarcane resources were collected. We collected 6 materials of Erianthus rockii, 16 of Sacchuram spontaneum, 25 of Micanthus sinensis, 13 of Erianthus arundinacius and 32 of Erianthus fulvus. The results revealed that there were abundant phenotypic variation in the species collected from this region with variation coefficient ranging from 11.4% to 78.0% and the average over 30%. Cluster analysis showed that Sacchuram spontaneum group Ⅲ (Sp-2), Micanthus sinensis Group Ⅱ (Ma-8), Erianthus arundinacius Group Ⅲ (Ea-2, Ea-9), Erianthus fulvus Group Ⅲ (Ef-10, Ef-11), Erianthus fulvus Group Ⅴ (Ef-26) and Erianthus rockii (Er-1, Er-3, Er-4) had good yield and quality characters, and were recommended to be used as sugarcane breeding materials in further research. The germplasm collections changed the situation of CNNSGR collection system without collections from southwest Guizhou Autonomous Prefecture, and some specific materials had unique excellent characters that other wild sugarcane resources did not have, which might serve as the genetic resources for sugarcane breeding.