This study aimed to identify the pathogen which causes Areca catechu Linnaeus leaf spot and study its biological characteristics. The pathogen was isolated and purified from disease samples by the tissue isolation method, and the pathogenicity of the strain was tested. Combined with morphological characteristics and multi gene (ITS-TUB-TEF) joint analysis, a phylogenetic tree was constructed to identify the pathogen, and to study its biological characteristics under different culture conditions. Leaf spot of A. catechu was caused by Neopestalotiopsis sonneratae. The hyphal growed the fastest on CA medium and the aerial hyphal was the most developed on MEA medium. The optimum temperature for both hyphal growth and spore germination was 28 ℃. 24 h illumination was most favorable for the hyphal growth. Hyphal growed the best at pH 5, and the optimum pH for spore germination was 6. The study would provide a theoretical basis for the control of the leaf spot on A. catechu.

Phosphorus is an indispensable element in the process of plant growth and development, but it is mostly in the form of ineffective bound phosphorus in the field. The microorganisms in soil can convert the ineffective phosphorus into free effective phosphorus, and fully improve the utilization rate of phosphorus. In this study, a phosphate-solubilizing fungus XZY3PSF was isolated and purified from the corn rhizosphere soil using the phosphorus-solubilized halo method, and the strain was identified. The activity of the strain to dissolve 2.5-20.0 g/L tricalcium phosphate and the phosphate solubilization ability of 10-10⁵ spores/mL to tricalcium phosphate in 1-25 d were analyzed. The mineralization ability of 2.5 g/L and 5.0 g/L calcium phytate was evaluated, and the interaction between it and Bacillus amyloliquefaciens and the pathogen of banana Fusarium wilt disease was evaluated. Based on the morphological characteristics combined with ITS and β-tubulin gene sequences, the strain XZY3PSF was identified as Talaromyces purpureogenus. The highest content of available phosphorus dissolved by phosphate-solubilizing strain under different concentrations of tricalcium phosphate was between 500 and 570 mg/L. The content of available phosphorus in the medium decreased with the prolongation of culture time. The decreasing range of the available phosphorus content in the tricalcium phosphate medium was weakened. On the 25th day, the available phosphorus content in the 15.0 and 20.0 g/L tricalcium phosphate medium was significantly higher than that of the other concentrations. With the increase of the spore concentration in the medium, higher peak value of the available phosphorus content in the culture medium appeared, and its decreasing range expanded with the increase of the spore concentration. During the test period, with the extension of culture time, the mineralization ability of XZY3PSF to calcium phytate was stronger. XZY3PSF and Bacillus X5 had antagonistic effects on the pathogen of banan Fusarium wilt, but the phosphate solubilizing fungus and Bacillus spp. also antagonized each other. The research results would lay a foundation for the development of microbial fertilizers composed of phosphorus-solubilizing fungi and antagonistic bacteria. At the same time, the mineralization of XZY3PSF on calcium phytate would provide a basic theoretical basis for subsequent studies on whether it can degrade organophosphorus pesticides.

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.

Leaf anatomy, plant growth traits and leaf ecological stoichiometry were analyzed in 8 pineapple cultivars (Gold diamond, Red skin, Red fragrant, Hand torn, Gold, Bali, Watermelon, and Mango) in a common garden in Jiangmen, Guangdong, China. The purpose was to explore the differentiation of functional traits between different pineapple cultivars, and the relationships between leaf ecological stoichiometry and plant growth as well as the plant nutrient limitation. The results showed that leaf stomatal density was the highest in the middle of leaves in most pineapple cultivars, and leaf thickness increased from the upper position to the lower position. There were significant differences in stomatal density, guard cell length, leaf thickness and anatomical proportion in different leaf positions within the same cultivar or in the same leaf position between different pineapple cultivars. Different pineapple cultivars differed in the leaf C, N, P and K content. Pineapple plants required large amount of K, as leaf K content was much higher than N and P content. Leaf N and P content in pineapples were lower than those in grassland plants in China. The leaf content of N and P of pineapple was higher than that of the plants in grasslands and in farmland ecosystems in China, while the leaf content of C, C∶N and C∶P were higher than those of the plants in grasslands and in farmland ecosystems in China, indicating that pineapple plant is reducing the dependence on nutrients through special leaf morphological or histological structure, agreement with the "Demand reduction strategy". Moreover, leaf C content, C∶P and N∶P were significantly negatively correlated with total leaf biomass, which was consistent with the growth rate hypothesis. Ranging from 6.40 to 19.07 across all pineapple cultivars, leaf N∶P values indicated that plant growth of Golden and Mango pineapples were limited by P; Golden diamond, Red skin, Hand torn and Watermelon pineapples were restricted by N, while Red fragrant and Bali pineapples were co-limited by N and P. This study twould provides a theoretical foundation for the cultivar selection and the agricultural management of pineapples.

The harvested Newhall navel orange fruits are easy to quality deterioration and spoilage, which seriously affecting the commodity value and shelf-life. Kadozan, a novel commercial liquid chitosan formulation, can be conveniently used for fresh produce postharvest treatment by diluting Kadozan to the required concentration with water. The influences of Kadozan with dilution of 1∶800 (V_Kadozan∶V_{Kadozan+water}) on the storage quality and storability of Newhall navel orange fruit were investigated. Postharvest Newhall navel oranges were immersed with distilled water (the control) and chitosan for 5 min, respectively, and then stored at (18±1)℃ and 80% relative humidity. During the storage, the samples were taken every 30 days to determine the rate of commercially acceptable fruit, the percentage of weight loss, respiration rate, fruit appearance color characteristics, the contents of chlorophyll and carotenoid in pericarp, and the contents of pulp nutrients. Compared with the control fruits, during storage, chitosan (Kadozan) treatment could reduce fruit weight loss, fruit respiration rate, retain higher rate of commercial acceptable fruit, higher contents of pericarp chlorophyll and carotenoid, higher values of pericarp L^*, b^* and h°, but lower values of pericarp a^* and citrus color index (CCI). In addition, Kadozan treatment could maintain higher contents of soluble solids (TSS), titratable acid (TA), soluble total sugar, sucrose, vitamin C, carotenoids, flavonoids and total phenol in the pulp of Newhall navel orange during storage. When stored for 120 d, the rate of commercially acceptable fruit and the percentage of weight loss in Kadozan-treated oranges was 95.56% and 4.39%, respectively. From the above data, it is concluded that the treatment of chitosan (Kadozan) can improve the storability and maintain the better quality of postharvest Newhall navel orange fruit, indicating the dilution of 1:800 (V_Kadozan∶ V_{Kadozan+Water}) could be a safe and facile approach to maintain the quality and extend the shelf life of Newhall navel orange after harvest.

Breadfruit is considered as the most potential food crop to solve tropical famine with high economic value. Breadfruit was introduced from several countries, and there are no research on the systematic taxonomic and genetic diversity analysis about it. The objective of this study was to specify the genetic distance and relationship among breadfruit and its closest wild relatives. For genetic diversity analysis, 33 pairs of SSR primers with clear amplified bands, high polymorphism and good stability were selected from 75 pairs of SSR primers. PCR amplification was performed, and the products were detected by 8% denaturing polyacrylamide gel. Genetic diversity correlation analysis was performed by NTSYS software. The results showed that the polymorphism ratio of amplified bands of the 33 SSR markers was 94.57%. 199 number of polymorphic sites were detected, with an average of 6.030 per marker. The PIC values of the SSR markers ranged from 0.623 to 0.940, with an average of 0.865. The genetic similarity coefficients among the breadfruit resources ranged from 0.517 to 0.951, with an average genetic similarity coefficient of 0.685. Furthermore, germplasm ZZP possessed the greatest variation among individuals, with an average genetic similarity coefficient of 0.626. Germplasm XYS1-3 possessed the least variation among individuals, with an average genetic similarity coefficient of 0.723. At the genetic similarity coefficient of 0.713, the 30 breadfruit resources were clustered into five groups, with XBL and breadnut type I (ZZP, LX, STH, HJ5) which used for landscaping clustered into one group, breadfruit SLLK, XYS2, XYS3, XYS5, XYS6 and YN clustered into one group, breadnut type Ⅱ SLM2, YDNXY1, G1 and G2 clustered into one group, breadnut type Ⅱ W1, W3, SMY, 8-4, 8-3, 5-5 and 5-6 clustered into one group. The three-dimensional diagram could better distinguish XBL and breadnut type I ZZP, LX, STH, HJ5 from the breadfruit and breadnut type Ⅱ resource with edible value. Based on the cluster analysis, we speculated that XYS2, XYS3, XYS5 and XYS6 might be introduced from Vietnam, XYS1-3, YBG and XYS1 might be introduced from Indonesia. Furthermore, FJ was regarded as a breadfruit germplasm. The present study reported the genetic diversity of breadfruit resources in China firstly, and elucidated the genetic relationship among breadfruit resources. In addition, the results could provide theoretical basis for variety breeding and identification of breadfruit complex.

The study of the leaf anatomical structure of macadamia germplasm resources and its drought resistance was aimed to provide theoretical basis for macadamia seed breeding, introduction and cultivation. 11 leaf anatomical parameters of 20 macadamia germplasm resources were analyzed and compared using paraffin section technique. The drought resistance of different germplasm resources was comprehensively evaluated by the principal component analysis, membership function method and systematic clustering method. The results showed that macadamia leaves were typical leaves with different faces, and there were significant differences among the anatomical structure indexes of different germplasm resources (P<0.01). Principal component analysis showed that the order of the eleven indexes reflecting the drought resistance of macadamia was thickness of palisade parenchyma thickness>leaf thickness>cell tense ratio>palisade/spongy tissue>sponge ratio>upper cuticle thickness>lower epidermis thickness>upper epidermis thickness>lower cuticle thickness>midrib thickness>spongy parenchyma thickness. According to the membership function method and the weight of each index, the order of drought resistance of the 20 macadamia germplasm resources was as follows: No. 1>No. 19>No. 5>No. 10>No. 14>No. 11>No. 16>No. 7>No. 2>No. 20>No. 8>No. 13>No. 18>No. 15>No. 9>No. 3>No. 6>No. 4>No. 17>No. 12. After "Z-score" standardization, the 20 germplasm resources were classified into 3 groups at 15 genetic distances. No. 1, No. 5, No. 10, No. 11, No. 14, No. 16 and No. 19 had thicker leaves, developed palisade tissue, higher palisade/spongy tissue and cell tense ratio than other germplasms, and had higher water retention and photosynthetic capacity, so they were high drought-resistant groups. The leaves, epidermis and cuticle of No. 3, No. 4, No. 6, No. 9, No. 12, No. 15 and No. 17 were thin, and the leaves were relatively loose, showing low drought resistance, so they were low drought resistance groups. The drought resistance of other germplasms was in the middle.

Potato is the fourth largest food crop in the world, but little research has been done on this crop about rice husk mulching and copper (Cu). Rice husk is a by-product of rice processing and has great potential to reduce environmental pollution. Plastic film mulching gives us a non-negligible problem of environmental pollution, and even crop yields will be affected. Compared with black film, it has the advantages of wide source, lower cost and no need for recycling, which can basically be used locally. Previous studies have shown that the photosynthetic pigment content, photosynthetic rate, nutrient content, plant height, stem thickness, tuber number, above ground dry weight and yield of potato plants were enhanced by both Cu solution dip treatment and foliar spray of Cu. In this experiment, the accumulation and distribution of Cu in potato plants under different mulching patterns were investigated by using potato "Favorita" as the material and three mulching patterns: bare ground (CK), rice husk (6 000 kg/hm²) mulching (DK) and black film mulching (HM) for winter cultivation in the field. The results showed that the accumulation of Cu in stems and leaves showed a trend of increasing and then decreasing under different mulching patterns, while the accumulation in tubers and whole plants showed a trend of gradually increasing. The accumulation of Cu in stems and leaves ranged from 13.45%~17.70% and 82.30%~86.55% of the whole plant 10 d after full seedling emergence to 2.99%~3.53% and 8.40%~10.56% 58 d after full seedling emergence, respectively. The accumulation of tubers increased from 26.76%~29.60% 22 d after full seedling emergence to 85.91%~88.68% 58 d after full seedling emergence. The Cu accumulation of plants under DK treatment was generally higher than that of LD and HM treatments in the whole growth period. The Cu accumulation of plants under DK treatment was 38.01%, 80.92%, 40.24%, 72.45% more than that of CK treatment in stem, leaf, tuber and whole plant respectively, and 92.21%, 47.22%, 48.12%, 45.16% higher than than that of the HM treatment, respectively. The accumulation of Cu in potato plants 10 d after full seedling emergence was positively correlated with the accumulation of Cu at the later stage, and the accumulation of Cu in stems and leaves was also positively correlated with the yield until 58 d after full seedling emergence. The difference in accumulation by site is due to the fact that in the early growth period, when potato plant is still in the seedling stage, stems and leaves are the sites of Cu accumulation. As the plant grows, tubers are gradually formed. About 31 days after full seedling emergence, the growth of stems and leaves gradually slow down, while the tubers are in the growth phase. At this time, the accumulation center shifts to the tuber, from stems and leaves, which shows that the accumulation of stem and leaves gradually decreases, while the accumulation of tuber continues to increase. The reasons for the higher accumulation of DK than CK and HM may be as follows. First, rice husk, on the other hand, can not only act as a thermal insulation layer to isolate strong external heat, but also improve soil water storage efficiency, increase soil water content, and have significant effects in reducing soil temperature. Second, rice husk can increase soil organic carbon content after being degraded as exogenous organic matter, and the study found that the soil available Cu content was significantly and positively correlated with soil organic carbon content. The experiment showed that under the test conditions, the accumulation of Cu by potato plants could be effectively increased under rice husk mulching at 6000 kg/hm² level.

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.

Based on specimen diagnostics and literature studies, six new records of Angiosperm in Guizhou Province were reported, namely Lepidium didymum L. (Brassicaceae), Lactuca serriola L. (Asteraceae), Dactylicapnos lichiangensis (Fedde) Hand.-Mazz. (Papaveraceae), Dinetus duclouxii (Gagnep. & Courch.) Staples (Convolvulaceae), Zingiber atrorubens Gagnep. (Zingiberaceae), Carex phyllocephala T. Koyama (Cyperaceae). Main morphological identification characteristics, distribution descriptions, voucher specimens and photographs were provided for all species, and the systematic position changes of some species were also discussed. The voucher specimens were deposited in the Herbarium of the Natural Museum of Guizhou University (GACP).