In this experiment, seven different camellia plants were used as rootstocks and four different camellia scions to form 28 combinations, to screen the stocks-scion combination and study the grafting affinity, and to measure and analyze grafting experiment indicator that is the survival rate, preservation rate and growth traits of grafted seedlings, to investigate the growth status of grafted seedlings after 18 months. The relationship between grafting anvil, soluble sugar content and graft compatibility was evaluated. The result showed that the grafted survival rate and preservation rate of Camellia gigantocarpa Hu grafted with C. rosmannii and C. achrysantha scion were more than 90%, and the grafting survival rate and survival rate of scions reached more than 80% when C. gigantocarpa Hu grafted with C. chrysantha,, it is proved that C. gigantocarpa Hu is the best rootstock for grafting affinity. The grafting seedlings of C. japonica Heimudan and C. rosmannii had a preservation rate was 6.67%, the preservation rate of C. japonica Heimudan and other 3 kinds of scion was 0, it is proved that C. japonica Heimudan had the worst affinity as rootstock. The scions of C. achrysantha and C. rosmannii had better affinity with different rootstocks. The grafting survival reached more than 90%when C. achrysantha was grafted with C. semiserrata, C. hirsuta, C. japonica Heimudan, C. gigantocarpa. The grafting survival reached more than 90% when C. rosmannii grafted with C. gigantocarpa and C. amplexicaulis. The grafting survival reached more than 80% when C. rosmannii grafted with C. semiserrata and C. polyodonta. Grafting affinity is related to the soluble sugar content of stocks-scion. Closer sugar content of stocks-scion leads to the ratio is closer 1 and the higher grafting survival rate will be. C. gigantocarpa/C. achrysantha, C. hirsuta/C. achrysantha, C. amplexicaulis/C. rosmannii, C. gigantocarpa/C. rosmannii, C. gigantocarpa/C. chrysantha were found to be the excellent combinations by principal component analysis.

Mango is known as the "king of tropical fruits" for its unique flavor and rich nutrition. However, mango is extremely perishable during postharvest ripening, and the decay loss caused by anthracnose is the most serious. Therefore, how to prevent and control mango anthracnose after harvest has become a bottleneck problem restricting the healthy development of mango industry. In this paper, Tainong No.1 mango was used as the experimental material, and the green cinnamon essential oil composite chitosan lotion was used as the treatment means to study its control effect and mechanism on postharvest mango anthracnose, which would provide theoretical basis and practical reference for the development of postharvest mango storage, transportation and preservation industry in China. The results showed that the treatment of 0.5% cinnamon essential oil+0.3% chitosan had the best control effect on mango anthracnose, the treatment of 0.03% cinnamon essential oil could completely inhibit the growth and spore production of mango anthracnose in vitro, and the treatment of 0.01% and 0.02% cinnamon essential oil had obvious destructive effect on mango anthracnose mycelium. The complex treatment significantly inhibited the expansion of mango anthracnose disease spot, increased the content of disease resistance related substances lignin, total phenol (TP) and hydrogen peroxide (H₂O₂), and increased the content of disease resistance related enzymes phenylalanine ammonia lyase (PAL), peroxidase (POD),β-1,3 glucanase (β-1,3-GA) and chitinase (CHI). It can be seen that cinnamon essential oil composite chitosan lotion has a good control effect on mango anthracnose by inhibiting or destroying the growth and spore production of mango anthracnose mycelium, and inducing mango fruit to improve disease resistance. Therefore, the proper concentration of cinnamon essential oil combined with chitosan lotion treatment would provide a new green way to control mango anthracnose after harvest.

Banana (Musa spp.) is one of the most popular fruits in the world and is widely loved for its sweet taste and nutritious value, it is usually eaten after ripened. Bananas are rich in more than 90% resistant starch before they are unripe, and the effective use of resistant starch in green bananas can significantly increase the added value of the banana planting industry. In addition, green bananas are prone to producing a large number of defective fruits during the harvesting process, resulting in a serious waste of starch resources. In order to study the effect of autoclaving treatment on the digestion and structure properties of flour, three different banana cultivars: Dajiao, Fenjiao, and Gongjiao were chosen. By using scanning electron microscopy, dynamic light scattering, rapid paste viscometer, differential scanning calorimetry, Fourier transform near infrared spectroscopy, and X-ray diffraction analysis. To investigate the relationship between the structural changes and digestion properties of the three green banana flours before and after an autoclaving treatment was applied to them. The content of resistant starch in green banana flour decreased from 91.50%-93.33%(RS2 type) to 39.17%-44.63% (RS3 type) after autoclaving treatment. The scanning electron microscope results showed that powder granules were completely pasted and disintegrated, with variable particle size distribution and irregular shape. The amylose starch content increased from 23.3%-28.3% to 32.7%-37.0%, so that the thermal stability and gel enthalpy of green banana flour were significantly decreased (P<0.05) while the peak viscosity and breakdown was increased. The relative crystallinity of the green banana flour decreased from 28.98%-32.56% to 20.66%-22.26% after the autoclaving treatment. Despite this, the B-type crystalline structure was still preserved after the treatment. The new chemical bonds or functional groups were not found after the autoclaving treatment compared with green banana flour, and the short-range order R_1047/1022 was decreased from 1.031-1.166 to 1.016-1.122. The findings revealed that although the content of the resistant starch was reduced after autoclaving treatment, the type of resistant starch was changed from RS2 to RS3. This suggests that the stability of the resistant starch is greatly enhanced after autoclaving treatment. This research could offer a theoretical foundation for the production of heat-stable banana resistant starch, support the development of naturally starch-based materials, and is crucial for resolving the disparity between banana industry production and sales.

Carica papaya L. belongs to Caricaceae, Brassicales, which is widely distributed in tropical and subtropical areas. In our previous study, the major constituent of C. papaya seeds essential oil was benzyl isothiocyanate (BITC) with a content of up to 99%. It had many advantages such as natural, non-pollution, high purity and strong antifungal activity against Candida strain. However, the application of BITC in pharmaceuticals, food industry and other fields is limited due to its poor aqueous solubility, volatility and easily degradation. In this study, in order to increase the stability and anti-Candida efficacy of BITC, nanostructured lipid carrier loaded with benzyl isothiocyanate from C. papaya seeds (BITC-NLC) was prepared by the melting emulsification ultrasonic method. The physicochemical properties such as morphology, particle size, Zeta potential, encapsulation efficiency, drug loading, etc. were evaluated and its anti-Candida activity was investigated. On the basis of single factor influence test, the orthogonal design was adopted to choose the preparation process of nanostructured lipid carrier (NLC) and formulation of BITC-NLC. The best preparation process was stirring for 20 minutes and ultrasonic dispersion for 15 minutes (amplitude 80%). The best prescription was composed of 50 mg monostearate, 50 mg octyl capric acid triglyceride, 400 mg poloxamer, 400 mg soybean lecithin, 100 mg BITC and 20 mL ultrapure water. The morphology was observed by a transmission electron microscope, the particle size and zeta potential were measured by Zetasizer Nano ZSE, and the encapsulation efficiency and drug loading were analyzed by high performance liquid chromatography. The final prepared BITC-NLC was quasi-spherical shapes and the average particle size, Zeta potential and encapsulation efficiency was 79.13 nm, -21.77 mV and 91.52%, respectively. The preliminary stability test results showed that BITC-NLC was stable for 30 d kept at 25 ℃. The minimal inhibitory concentrations (MICs) were determined using the broth dilution method. MICs of the BITC-NLC against all the selected Candida strains were 8-32 μg/mL, which were better than BITC. In addition, it could inhibit C. albicans and C. tropicalis that are resistant to the most commonly used antifungal drug - fluconazole. The new prepared formulation BITC-NLC from papaya seeds essential oil in this study has small particle size, good physical stability, high encapsulation efficiency and better antifungal effect on C. albicans and C. tropicalis. The results may provide theoretical and experimental basis for the application of papaya seeds which are abundant and typically discarded and the development of natural antifungal drugs.

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).

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.

Exploring the characteristics of dry-wet climate change and its impacts on crop yield can provide scientific basis for agricultural production planning and meteorological disaster prevention under climate change. Based on the daily ground observation data of meteorological stations in Zhanjiang area from 1960 to 2020 and the statistical data of rice, sugarcane and peanut yields from 1990 to 2020, the aridity index calculated by reference crop evapotranspiration (ET₀) and precipitation were used as drought index to analyze the characteristics of dry-wet climate change, and the impact of dry-wet climate change on crop yield was analyzed. The results showed that the interannual variation of precipitation in Zhanjiang area fluctuated greatly, and the annual average precipitation was 1534.41 mm, showing an insignificant rising trend. The temperature rised significantly at the rate of 0.18 ℃/10 a, and the annual average ET₀ and aridity index was 1242.72 mm/a and 0.87 respectively, showing an insignificant upward trend. According to the annual variation of the dryness index, from January to April and from October to December were the drought prone periods in Zhanjiang. The yield of rice, sugarcane and peanut showed a significant growth trend in the past 31 years, the increase of aridity index in April would reduce the yield of the three crops. The increase of aridity index in May would significantly increase the yield of peanut, but had no significant impact on the yield of the other two crops. The increase of temperature and the decrease of precipitation in June were conducive to the significant increase of rice and peanut yield. Sugarcane yield was not significantly affected by the change of temperature and precipitation, while the increase of dryness index in December significantly increased sugarcane yield. The results are of great significance for Zhanjiang and its surrounding areas agriculture to cope with climate change and improve the crop potential productivity.

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.

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.

Leaf color mutants are not only an ideal material for the study of rice functional genomics, but also of great significance for hybrid rice breeding. They can also be used as ornamental rice, committed to building rural leisure agricultural sightseeing spots and promoting rural revitalization. Based on a rice bright green leaf mutant bgl-2 obtained by radiation mutagenesis in the early stage of our research group, this study compared the difference in leaf color between the mutant bgl-2 and the wild-type SIPI, and showed that the mutant bgl-2 showed a bright green color different from the wild-type SIPI. The content of photosynthetic pigments in leaves was determined by 95% ethanol extraction at tillering stage. The results showed that the chlorophyll content of mutant bgl-2 was not significantly different from that of wild-type SIPI. By observing the other plant morphology of mutant bgl-2, it was found that the leaf tips of its flag leaf and the last two leaves were bent, and the flag leaf was significantly shorter than that of wild-type SIPI, and its plant height was also significantly shorter than that of wild-type SIPI. It was found that the 1000 grain weight, grain length and grain width of mutant bgl-2 was significantly smaller than those of wild-type SIPI, but its length width ratio was not significantly different from that of wild-type SIPI. The structure of flag leaf cells of wild-type SIPI and mutant bgl-2 at tillering stage was observed by the transmission electron microscope. The results showed that the cell wall of mutant bgl-2 was significantly thickened, but the thickness of outer membrane of cell membrane was significantly reduced, the inner membrane was almost degraded, and the lamellar structure of thylakoid in chloroplast ultrastructure was looser than that of wild-type SIPI. F₁ plants were obtained by hybridization with mutant bgl-2 as female parent and wild-type SIPI as male parent. The investigation found that its leaves were normal green, and the morphology of flag leaf and inverted two leaves were normal, while the F₂ population after self pollination isolated normal green leaf seedlings and bright green leaf seedlings with obvious leaf color differences. The segregation ratio of normal leaf color plants and bright green leaf plants in the population was counted, which showed that it conformed to the single gene model of 3 : 1. The above results clarify the phenotype and genetic characteristics of the mutant bgl-2, and provide a theoretical basis for the study of the molecular regulation mechanism of the mutant bgl-2 and promoting its application in rice breeding. The location cloning and functional analysis of BLG-2 gene will be carried out later.