Fujian Shuixian belongs to the semi-tree form of tea plant (Camellia sinensis), which is the main variety for processing Wuyi Rock Tea (WRT). At present, there is a widely phenomenon that Shuixian grows naturally (no-pruning) in the management of tea gardens of Wuyishan, and its quality is obviously different from that of pruned Shuixian. In order to clarify the basis and differences of aroma and flavor substances WRT under natural growth and pruning conditions, this study used gas chromatography-mass spectrometry (GC-MS) and high performance liquid chromatography (HPLC) technology, combined with multivariate statistical analysis, to explore the internal relationship among aroma substances, flavor components and quality of WRT before baking (raw tea) and after baking (finished tea) under natural growth and pruning conditions. The results showed that 261 volatile compounds were identified by GC-MS technology. It reveals that there are obvious differences in aroma substances between raw tea and finished tea of the natural growth Shuixian and pruned Shuixian with the help of principal component analysis (PCA) and orthogonal partial least squares discriminant analysis (OPLS-DA). Compared with the raw tea of pruning Shuixian, the raw tea of natural growth Shuixian showed significant differences in 41 volatile substances (Selection standard: VIP>1, and the FC≥1.5 or the FC≤0.67), in which the relative content of hexyl hexanoate, plant alcohol, isophytol, trans-nerolidol are higher, however, the relative content of β-cedrene, γ-junitene and 2-methoxyfuran are lower. Compared with the finished tea of pruning Shuixian, the finished tea of natural growth Shuixian showed significant differences in 71 volatile substances, such as hexyl hexanoate, methyl caproate, trans-nerolidol, (Z)-β-farnesene, 1-heptanol, 2-heptanone with fruity aroma, and 3-ethyl-1H-pyrrole, 2-formyl-4with baking aroma, whose relative content are higher. There are also great differences in aroma substances between natural growth Shuixian and pruned Shuixian before and after baking, with 91 and 70 different substances respectively. The analysis of aroma activity value (OAV) showed that (E)-3-hexenol, indole, trans-nerolidol, epoxy-β-ionone, (E)-linalool oxide, 2-phenylethanol and methyl salicylate may be important substances for the aroma formation of natural growth Shuixian. Analysis of the main flavor substances showed that there were obvious differences in catechin components and caffeine between natural growth Shuixian and pruned Shuixian. The results of sensory evaluation are consistent with the results of physical and chemical test, showing that natural growth Shuixian with rich fruit fragrance, mellow taste and better quality. This study has a guiding role in scientific management of tea gardens and tea quality control.

The study was aimed to explore the effects of applying different organic fertilizers on the yield, quality, soil fertility of sweet potato. Five different organic fertilizer treatments with no fertilization as the control were set up and sweet potato variety Qianshu 6 was used. The results showed that the application of organic fertilizer could effectively promote the growth of sweet potato vines and the expansion of root tubers. The yield of Shangcanli biological organic fertilizer (T₄) was the highest, which was 19.9% higher than that of the control. The effects of different organic fertilizers on the nutritional quality of sweet potato were different, but the accumulation of dry matter was not obvious. In addition, planting sweet potato significantly reduces the nutrient content of soil, while applying different organic fertilizers could supplement part of the nutrient requirements of sweet potato, but had no significant impact on soil pH value. Organic fertilization significantly increased the contents of soil microbial biomass carbon (MBC) and microbial biomass nitrogen (MBN). Organic fertilization significantly increased the activities of urease (URE), acid phosphatase (ACP), N-acetylglucosidase (NAG) and cellobiase (CBH), but significantly decreased the activities of nitrate reductase (NR) and-Glucosidase (BG), while did not significantly affected the activityof other enzymes. Correlation analysis showed that the effects of different components of organic fertilizer on the yield and quality of sweet potato root tubers were quite different. The pH value of fertilizer and the amount of organic matter input mainly affected the quality of root tubers, while the amount of pure nitrogen input was closely related to the yield and quality of root tubers. The physical and chemical properties of soil were mainly affected by the pH value of organic fertilizer, the input amount of organic matter and pure nitrogen, but had little correlation with the input amount of pure phosphorus and pure potassium. The correlation between organic fertilizer and soil MBC, soil URE, ACP, NR, PPO and LAP was stronger than that of soil microbial biomass nitrogen (MBN), N-acetylglucosidase (NAG), cellobiase (CBH) and polyphenol oxidase (PPO). Different organic fertilizers promoted the growth of sweet potato, increased the yield of sweet potato, increased the nutrient content of soil, and changed the microbial environment of soil to a certain extent. Therefore, the correlation analysis results of indicators could provide references for sweet potato production.

The fruit quality of different varieties (lines) of cultivated ginseng fruit in Shilin county was tested and evaluated to provide guidance for the development of ginseng fruit industry. Seven fruit quality indexes of soluble sugar, soluble protein, soluble solid, mineral elements, vitamin C, cellulose and amino acid were determined by using eight main ginseng fruit varieties (lines) of Dayuangguo, Yuangguo No. 1, Yuangguo No. 2, Yuangguo No. 3, Shiyou No. 1, Shiyou No. 2, Shiyou No. 3 and Ruiyu cultivated in the field of Shilin county. By multiple comparison of quality indexes of Panax ginseng fruit, it was found that the content of soluble sugar in Yuanguo No. 2 was the highest, while that in Dayuanguo and Yuanguo No. 3 was the lowest; The soluble protein content of Shiyou No. 2 was the highest, and that of Shiyou No. 1 and Ruiyu was the lowest; The content of soluble solids of Yuanguo No. 2 was the highest, while that of big round fruit was the lowest; Shiyou No. 3 has the highest content of vitamin C and Yuanguo No. 3 has the lowest content; The crude fiber content of Yuanguo No. 2 was the highest, and that of Shiyou No. 1 was the lowest; The content of trace elements in Yuanguo No. 2 was the highest, while that in Yuanguo No. 3 was the lowest; The amino acid content of big round fruit was the highest, and that of Shiyou No. 2 was the lowest. There were significant correlations between the quality indicators of different varieties (lines), among which soluble sugar and soluble solids were significantly correlated with each other (P<0.05). The principal component analysis of 6 quality indicators was carried out, and the cumulative contribution of the first three principal components reached 83.955%, which could reflect most of the information of the original quality index. The resulting comprehensive evaluation system was established to evaluate eight different varieties (lines) of ginseng fruit. In conclusion, the above eight ginseng fruit varieties (lines) all contain rich nutritional components, among which Yuanguo No. 2 has the best comprehensive quality, and can be selected as the parent material for the main variety or new germplasm creation.

Amomum tsao-ko (AT) is a medicinal and food homologous crop rich in polyphenols and flavonoids. The germplasm of AT is relatively mixed, and it is urgent to carry out research on AT germplasm resources and screening of high-quality AT seed sources. This study aimed to screen and evaluate the content of polyphenols and flavonoids and antioxidant activities of laxative active components of AT resources, and to explore the possible factors of component accumulation. In this study, a total of 57 samples were collected in Laos, Myanmar, Sichuan, Guangxi and Yunnan in China, and the polyphenol content and flavonoid content of AT aqueous extract were determined by forinphenol method and NaNO₂-Al(NO₃)₃-NaOH colorimetric method, and the DPPH radical scavenging ability of AT aqueous extract was detected. The correlation between polyphenol and flavonoid content, DPPH radical scavenging capacity and geographic factors was analyzed. The results showed that the content of polyphenols and flavonoids in spindle-shaped AT resources was higher than that of oval fruit and round fruit, and the content of flavonoids in AT resources abroad and Nujiang was higher than that in other regions (outside the province, western Yunnan, southwest Yunnan, Wenshan and Honghe). The content of AT polyphenols and flavonoids was significantly positively correlated with DPPH radical scavenging capacity and altitude (P<0.05), and negatively correlated with longitude (P<0.05) and latitude (P>0.05), so it was speculated that the accumulation of AT polyphenols and flavonoids may be related to temperature, light, ultraviolet rays and soil moisture. Finally, according to polyphenols, flavonoids, the classification standards were formulated, and the AT resources were divided into three grades, which would provide an analysis method for the establishment of the AT quality grade evaluation system. The excellent AT resources were screened by this method as Nujiang samples GS-3 and GS-10 and foreign samples MDL-1 and MGK-2. This study would provide a scientific basis for the investigation and collection of AT, as well as the study of origin and evolution, and also lay a solid foundation for the utilization of AT resources and the development of industry in the future.

In this paper, the seedlings of 27 inbred lines of bitter gourd with four leaves and one heart were used as materials. After pre-cultivated one day, the seedlings were subjected to 39 ℃ temperature stress. And the 27 germplasm resources were divided into three types: high heat resistance, medium heat resistance and heat sensitivity screened by the heat damage index (TDG) after 72 hours of high temperature stress. Among them, six inbred lines with different heat tolerance were selected to measure 12 morphological and physiological indexes subjected to 39 ℃ stress for 0 h and 48 h, respectively, including plant height (PH), stem diameter (SD), plant fresh matter (SFW) and dry matter (SDW) and leaf relative chlorophyll content (SPAD), electrical conductivity (REL), peroxidase activity (POD), catalase activity (CAT), superoxide dismutase activity (SOD), malondialdehyde content (MDA) ), proline content (Pro) and soluble sugar content (SS). The comprehensive evaluation values were obtained by the principal component analysis of heat resistance coefficients (α) of 12 morphological and physiological indexes to evaluate heat resistance of the seedlings. The mathematical model of heat resistanc evaluation was established by the stepwise regression analysis to obtain the heat resistance evaluation index system of bitter gourd. According to TDG, among the 27 bitter gourd inbred lines, three were heat-resistant, 18 were medium-heat-resistant and six were heat-sensitive. A mathematical evaluation model of heat tolerance of bitter gourd was established using the stepwise regression equation, which is Y=-0.426+0.049X₁-0.011X₂- 0.009X₃-0.018X₄. The established optimal regression equation was used to predict the heat resistance of the tested materials, and the predictive values were basically consistent with the comprehensive heat tolerance value. Therefore, the heat resistance coefficients of SFW(X₁), POD activity (X₂), CAT activity (X₃) and SS content (X₄) could rapidly and accurately estimate bitter gourd heat resistance and were suggested to be used as evaluation indexes for heat resistance of bitter gourd. In order to provide a basis for the breeding of new heat-resistant bitter gourd varieties in Hainan in summer season, the heat-resistant bitter gourd germplams were screened and a heat-resistant evaluation system was constructed.

The quality analysis of Chinese cherry fruit is beneficial to the selection and breeding of cherry varieties suitable for regional development. At the same time, it also lays a theoretical foundation for the protection of Chinese cherry germplasm resources. In this experiment, combining principal component analysis, correlation analysis and cluster analysis methods, 30 Chinese cherry fruits of different varieties (excellent lines) under the same cultivation conditions were selected for external and internal quality analysis. The results showed that there were significant differences in fruit quality among different varieties of Chinese cherry under the same cultivation conditions. The scores of comprehensive character evaluation ranked as C78, C6, C14, C34 and C32. Variety C20 (Manaohong) has excellent cultivation performance in some provinces in China, ranked 11th in this comprehensive evaluation. The 9 fruits intrinsic quality indexes had varying degrees of variation, with variation coefficients ranged from 11.27% to 36.32%. There was a correlation coefficient between the quality indicators, among which 12 were significantly correlated at 0.01 level and 17 were significantly correlated at 0.05 level. Principal component analysis of 13 quality traits showed that the cumulative contribution rate of the first 7 principal components was 88.196%, which could reflect the basic characteristics of quantitative traits. Cluster analysis with Euclidean method showed that 30 different Chinese cherry varieties (excellent lines) were preliminarily divided into 4 categories. The fruit quality analysis results obtained in this experiment could be used to explore the genetic variation map of cherry resources in China, and also be used as a reference for new varieties breeding.

Spathiphyllum Schott is a perennial herb of Araceae, which is an important foliage plant for ornamental. Phenotypic diversity of germplasm resources is the basis of ornamental plants breeding and application. In the current study, 27 important ornamental traits of 20 Spathiphyllum germplasm resources were observed and the phenotypic diversity was analyzed by multivariate statistical analysis methods including variance analysis, correlation analysis, hierarchical cluster analysis (HCA) and principal component analysis (PCA). The results of variance analysis showed that the coefficients of variation of the 16 quantitative traits ranged from 27.2% to 69.9%. The plant height, number of shoots, number of leaves, blade width, petiole diameter, spadix length and number of flowers were highly variable, while the plant width and spadix diameter had small variation. Eleven descriptive traits could be divided into 2~4 grades according to the observed characteristics. And the Shannon-Wiener indices of 11 descriptive traits ranged from 0.20 to 1.01, among which the Shannon-Wiener indices of leaf shape were the highest, whereas that of perianth separation and perianth color were the lowest. The hierarchical cluster analysis tree of 27 traits supported that when the euclidean distance was 3, they could be divided into two groups: Group A and Group B. The result of Pearson correlation analysis revealed that the correlation coefficient between 27 traits ranged from -0.72 to 0.91. In Group A, most of the traits were significantly correlated with each other, and the correlation coefficients between bud length and bud width, bud length and inflorescence length were 0.91. In Group B, most of the traits pairs were not significantly correlated. Both hierarchical cluster analysis and principal component analysis supported that the 20 Spathiphyllum germplasm resources could be divided into 2 Groups (Group I and Group II) based on data of 27 traits. Group I contained 7 accessions including S. cannifolium, S. ortgiesii, S. Clevelandii, S. Bright, S. Princess, S. Middle Flower and S. Sensation, and they were taller and had larger leaves, larger spathes, and larger spadixes. Group II was consisted of S. floribundum, S. Coddy Color, S. Water Grass, S. Parrish, S. Mini, S. Vicki Lynn, S. Mojo, S. Tyler Green, S. Crisis, S. Sweet Chico, S. Sweet Claudio, S. Dark Green and S. Sunshine Dream. And the 13 accessions of Group II had more buds and leaves, and were smaller and more compact. The research results could provide a reference for evaluation and breeding of Spathiphyllum germplasm resources.

Tea quality is closely related to the growth and ecological environment of tea plant (Camellia sinensis). The difference between day and night temperature (DIF) affects the synthesis and accumulation of tea plant metabolites, which in turn affects the quality of tea. In this study, Fuyun No. 6 was selected as the research object, and four DIF treatments (0 ℃, 5 ℃, 10 ℃ and 15 ℃) were simulated to explore the effects of DIF on photosynthesis and volatile and non-volatilequality components of tea fresh leaves. The results showed that the net photosynthetic rate (P_n), stomata conductance (G_s) and transpiration rate (T_r) of tea plants increased significantly with the increase of DIF (P<0.05). Increasing DIF significantly increased the contents of chlorophyll a (Chl a), chlorophyll b (Chl b), chlorophyll (a+b) [Chl (a+b)] and carotenoids (Car), and reached the maximum when DIF was 10 ℃. In addition, the change of DIF had an effect on the volatile components and relative contents of main components in fresh tea leaves, and the relative contents of alcohols and aldehydes were the largest in the volatile components of fresh tea leaves. The increase of DIF could significantly enhance the relative contents of aldehydes, and the relative contents of volatile components and main aroma components in fresh tea leaves were different with the change of DIF. The content of hexanal increased with the increase of DIF, with the highest value of 39.94% at DIF=15 ℃, while the relative content of cis-3-hexenol decreased with DIF increasing. The change of DIF significantly affected the activities of β-glucosidase, β-primeverosidase and lipoxygenase. The activities of β-glucosidase and β-primeverosidase first increased and then decreased with the increase of DIF, and reached the maximum when the DIF was 5 ℃, while the activity of lipoxygenase was opposite. Furthermore, the contents of free amino acids and caffeine increased significantly with the increase of DIF, which were 2.44 and 2.55 times at DIF=15 ℃ than those at DIF=0 ℃, respectively. The total flavonoids content and ratio of tea polyphenols to amino acids decreased significantly with the increase of DIF (P<0.05), with the lowest value of 2.84% and 3.24 at DIF=15 ℃. The contents of free amino acids in fresh tea leaves were significantly positively correlated with P_n, while the ratio of tea polyphenols to amino acids showed significantly negatively correlated with P_n (P<0.01). This study indicated that the increase of DIF could significantly affect the volatile aroma substances of fresh tea leaves and improve the taste and quality of tea, which could provide a certain theoretical basis for tea plantation site selection and tea planting.

Papaya is an economically important tropical fruit. Papaya ringspot virus (PRSV) is an important virus disease of papaya, often causing significant yield losses and quality deterioration. Since the introduction of the first transgenic papaya in 1998, PDR-based breeding strategies for disease resistance have been successfully applied. The contradiction between disease resistance based on sequence homology and increased virus genetic diversity became a new challenge for papaya breeding. In this study, we propose to use RNAi strategies aim at nuclear inclusion b gene (Nib) to obtain broad-spectrum resistance to PRSV papaya. With optimized embryo callus generation-Agrobatium meidated transformation-shoot regeneration, 52 shoots were obtained after resistance screening and a total of 24 transgenic positive shoots were obtained by specific PCR screening for the T₀ generation. In the T₀ generation field natural disease test, the transgenic papaya strains were significantly more resistant to disease than the non-transgenic control, with NibB5-2 having the best resistance in the field. Molecular charaterization of the insertion site of Nib5-2 was located at position 1976766 on chromosome 2 supercontig_30 by hiTAIL-PCR method. Green house inoculation test of NibB5-2 T1 generation, there was no virus accumulation and no disease symptoms, confirmed the resistance. Our resulst reveal that RNAi silcencing the Nib gene enhance the papaya virus resistance, meanwhile enriched the candidated genes for virus resistance breeding.

The alkaloid content of different samples in different seasons and different developmental stages of MHLC of two tea varieties, Nongdao Yecha (MHLC) and Yunkang 10 (YK10) was determined by HPLC. Caffeine synthase 1 gene (TCS1) was cloned from the cDNA of tea plant by RT-PCR in different samples, and its expression level was analyzed. The results showed that MHLC was a natural tea germplasm resource with low caffeine and high theobromine. Theobromine content of MHLC in different seasons was greater than 23.00 mg/g, while the caffeine content was less than 4.00 mg/g. In addition, the accumulation of caffeine and theobromine in MHLC shoots was the highest, and the leaves at the same stage had higher caffeine and theobromine than stems, and the caffeine and theobromine in leaves and stems gradually decreased with the increase of maturity. Through gene cloning and quantitative analysis, it was found that MHLC had two TCS1 allelic variants: TCS1b (with only theobromine synthase activity) and TCS1d (with both theobromine and caffeine synthase activities). Among them, the high expression of TCS1b and the extremely low expression of TCS1d are likely to be the key reasons for MHLC high theobromine and low caffeine. This research would provide material for low-caffeine tea breeding and molecular basis for the efficient utilization of MHLC.

Anthracnose is a common disease of coffee, which causes serious loss to the yield and quality of coffee fruit. The research on pathogenicity and biological characteristics of the pathogenic bacteria causing coffee anthracnose and screening of effective antagonists would provide reference for the biological control of coffee anthracnose. Four coffee anthracnose pathogens Wyq1 (Colletotrichum siamense), Yyq1 (C. fructicola), Xbd1 (C. gloeosporioides) and Hb1 (C. theobromicola) were isolated and tested for pathogenicity by spore suspension, and the most virulent strains were selected for further experiments. The biological characteristics of the pathogenic bacteria were studied by the plate culture method. Screening of antagonistic bacteria was done by the plate confrontation method. Xbd1 strain could infect healthy coffee leaves, and its virulence was the strongest among the four strains. The most suitable medium for the vegetative growth was PDA. The optimal nitrogen source was tryptone. The most suitable carbon source was glucose. The optimum temperature was 28 ℃. The optimal pH was 7. The difference of vegetative growth was not significant under different light conditions. Bacillus subtilis MC4-2, B. tequilensis D5-8, B. velezensis MC2-1 and B. flexus ZLSY3 and B. amyloliticus GJ7 showed good antagonistic effect in indoor screening. B. subtilis MC4-2 had the best antagonistic effect, with an inhibitory rate of 57.8%. The study would lay the foundation for the control of anthrax and the development of biocontrol agents.

The adsorption and desorption rates of nine cationic exchange resins on ergothioneine (EGT) were investigated to screen out the ion exchange resin suitable for the separation and purification of EGT from natural rubber serum (NRS) and determine the optimum process parameters. The results showed that the SA-2 cation exchange resin was the most suitable for the separation and purification of EGT from NRS, and the optimum parameters were as follows: pH of sample loading 3.0‒4.0, sample loading flow rate 2 BV/h, and eluted with 0.5% ammonium hydroxide at the flow rate of 1 BV/h. Furthermore, a higher sample loading concentration was more conducive to the adsorption capacity of resin. Under the conditions, the EGT elution rate could reach 97.83%. This research indicated that the SA-2 cation exchange resin is an ideal medium for the separation and purification of EGT from NRS, which would lay a theoretical foundation for the industrial production of EGT.

In 2022, a stiff fruit disease was found on seedless litchi in Hainan, which was obviously different from the common litchi diseases in Hainan, such as anthracnose and acid rot. It mainly damaged young fruits. There was no significant change in the appearance of young fruits when the disease occurred. When the fruit was broad bean, the outer peel of the diseased fruit became darker, and the inner peel became irregularly brown after dissection. The fruit no longer expanded, forming fleshless stiff fruit, which was easy to cause serious economic losses. In this study, the pathogen of the disease was isolated, identified, invasion way and rapid detection techniques were studied. The pathogen was identified as Fusarium pernambucanum by morphological identification, ITS, RPB2 and TEF1 gene sequence analysis. The pericarp of seedless litchi fruit at young fruit stage was susceptible to pathogen invasion after being damaged by farming operations, wind, piercing-sucking insects, while the fruit surface was not diseased without wounds. The main invasion period of the pathogen was 3.2-4.8 mm in the longitudinal direction of the fruit. After the fruit was bigger than 9.8 mm, the probability of pathogen invasion gradually decreased. Based on the TUB gene sequence, the specific primers for rapid detection of F. pernambucanum were obtained, and a rapid and efficient molecular detection method based on ordinary PCR was constructed. The detection method is sensitive and efficient, and would provide support for early diagnosis and prevention of seedless litchi stiff fruit disease.

Rice (Oryza sativa L.) is an important food crop, and the normal germination of rice seeds is related to the growth and yield of the plant in the later period. The germination begins with water absorption by dry seeds and ends with cotyl elongation. Water transport within and between cells is highly selectively regulated by aquaporins (AQPs). The seeds of cereal are rich in starch. And the endogenous gibberellin can induce the synthesis of hydrolase such as α-amylase in the embryo and secrete them into the starchy endosperm to degrade starch into small molecules for seed germination. Studies have shown that only α-amylase can complete the degradation of starch in rice seeds. Nitric oxide (NO) is a signaling molecule that forms a variety of active nitrogen substances. It also participated in the signaling process of seed dormancy removal. NO donor plays a role in seed germination by enhancing amylase activity. NO donor can promote seed germination by improving the activity of amylase. Rice hybrid seeds of ‘BoⅡ you 767’ were used as experimental materials to investigate the effects of aquaporins (AQPs) and nitric oxide (NO) on the germination of rice seeds. In this study, NO synthesis inhibitors N-(G)-nitro-L-arginine methyl ester (L-NAME) and sodium tungstate (ST), sodium nitroprusside (SNP), an exogenous donor of NO, and mercury chloride (HgCl₂), an activity inhibitor of AQPs, were used to treat rice seeds. The changes of water absorption capacity, amylase activity and starch degradation rate during germination of rice seeds were determined in virtue of apparent analysis and index detection. The results showed that the water absorption capacity, amylase activity and germination rate decreased in the rice seeds treated with 90 mg/L HgCl₂, while the starch content remained high, and the growth of radicle and germ was inhibited. However, NO exogenous donor SNP could reverse the effect of HgCl₂. And the effect of NO synthesis inhibitors L-NAME (15 mmol/L) and ST (80 µmol/L) on the germination of rice seeds was similar to that of HgCl₂. The results indicated that AQPs could induce water uptake, stimulate amylase, accelerate starch degradation and promote seed germination in the early germinating stage of rice seeds through NO. The study would lay a theoretical foundation for improving rice yield.

Reasonable planting density and depth are the common cultivation techniques to increase sugarcane yield per unit area. However, the effect on sugarcane lodging is often neglected when the yield is increased. Sugarcane variety Zhongtang 3 was used as the experimental material to determine the effect of different planting density and depth on the yield and lodging. Four planting density 3.0, 4.5, 6.0 and 7.5 buds/m² and two planting depth of shallow planting (30 cm) and deep planting (40 cm) were designed in the experiment. The agronomic characters, lodging related index (root lodging and stalk lodging) and yield of sugarcane were measured. The results showed that as the growth period of sugarcane continued to advance, the safety factor of sugarcane root and stem gradually decreased, and the risk of root lodging and stem lodging of sugarcane was higher at 180 days after planting, which was in a sensitive period. When the planting density increased from 3 buds/m² to 6 buds/m², sugar yield (+32%) and yield (+36%) of sugarcane were significantly increased, and the stem lodging resistance of sugarcane was also increased. However, when the planting density was further increased to 7.5 buds/m², the sugar yield and yield did not increase significantly, but the risk of root lodging was increased. Compared with planting depth of 30 cm, planting depth of 40 cm had a tendency to increase sugar yield (+2.8%) and yield (+4.8%), although there was no significant difference between them. Therefore, considering sugar yield, yield and lodging resistance of sugarcane, we believe that planting depth of 40 cm and planting density of 6 buds/m² can improve lodging resistance of sugarcane while ensuring yield and sugar yield.

Iron (Fe) is one of the essential trace mineral elements in plants to maintain normal growth and development that plays an important role in various life processes. Researches towards molecular mechanism of Fe uptake, transport and distribution are mainly focused on the annual model plants. Biological functions of genes towards Fe uptake and transport in fruit trees are still unknown. In this study, 11 ferric reduction oxidase encoding genes (FROs) were isolated and identified from diploid mango Guire82, named by MiFRO1~MiFRO11. All mango FRO had ten typical motifs except for MiFRO1 lacking Motif2~Motif5. All mango FRO possessed similar tertiary structure, with the exception that MiFRO3 exhibited distinct tertiary structure. The amino acid sequences of FRO from 11 plants shared an overall identity of 42.07%, while mango FRO shared an overall identity of 62.43%. Phylogenetic tree analysis showed that mango FRO were prone to be closely clustered together lonely, which was far away from the homologs of the other ten plants in genetic distance. Quantitative real-time PCR (qRT-PCR) analysis showed that MiFRO3 was the most abundant expressed gene during different parts of Guire82 mango on the whole. In particular, MiFRO4, MiFRO5, MiFRO8 and MiFRO11 were highly expressed in the leaves of both mature trees and grafted seedlings. MiFRO6 and MiFRO7 were highly expressed in phloem or stem, MiFRO1 and MiFRO10 were highly expressed in young fruits, MiFRO2 and MiFRO9 were highly expressed in seedling roots, while MiFRO3 was highly expressed in full bloom flowers. In addition, expression of FRO in mango roots were mainly induced under iron depletion and NaCl stress, respectively, while MiFRO3, MiFRO5 and MiFRO8 were significantly reduced under iron toxicity. Expression of MiFRO2, MiFRO5 and MiFRO7 were increased under ABA treatment, and MiFRO1 and MiFRO5 were enhanced under PEG treatment. Expression of MiFRO2, MiFRO6 and MiFRO7 were decreased under low temperature (4 ℃). However, FRO changed little under heat stress (45 ℃) in mango roots. This study would provide gene resources to elucidate the molecular mechanisms of Fe uptake and transport in mango, and lay a theoretical foundation to reveal Fe nutrition and high utilization in tropical fruit crops.

The study was aimed to cope with the rapid increase in demand for patchouli [Pogostemon cablin (Blanco) Benth.] and to solve the problems of lack of patchouli medicinal materials, germplasm degradation, confusion of germplasm sources, and vulnerability to diseases and pests. Callus, cluster buds and rooting seedling of patchouli were irradiated with a gradient dose of ⁶⁰Co-γ rays. The appearance and morphology of regenerated plants were observed, the mutated plants were screened, the agronomic traits and physiological and biochemical indicators were measured, and the content of pogostone and patchouli alcohol, the main volatile components, were determined by gas chromatography-mass spectrometry (GC-MS). The results showed that calluses and cluster buds were more sensitive to ⁶⁰Co-γ rays and had higher mortality rate, while rooting seedlings were more tolerant to ⁶⁰Co-γ rays and had lower mortality. The best way to breed mutagenesis is ⁶⁰Co-γ treated rooting seedlings with irradiation doses of 100 Gy with a mutagenesis rate of up to 10%. In this experiment, 29 patchouli variant plants were obtained, which were divided into seven morphological types, namely three-leaf whorls, heteromorphic leaves, deep-split leaves, narrow leaves, coiled leaves, undercoiled leaves and purple leaves. The contents of osmotic conditioning substances [soluble sugar, soluble protein and free proline (Pro)], antioxidant substances [malondialdehyde (MDA), peroxidase (POD), catalase (CAT)], pogostone and patchouli alcohol were compared and analyzed. According to the analysis results of the above determination indicators, 15 potential plants were finally screened, namely: stress-resistant plants with high effective components SY7 and ZY1; environmentally sensitive plants with high effective components SY15, SY18 and XY1; stress-resistant plants SY2, SY6, SY19, YY2, YY9 and XJY1; high active ingredient plants SY10 and SY17; “pogostone-type” patchouli plants SY3 and JY1. Among them, SY7 and ZY1 are new germplasms with double excellent characteristics, and the two “pogostone-type” patchouli plants have application value for solving the problems of the lack of authentic medicinal materials and the degradation of germplasm. In this study, patchouli variant plants bred by the ⁶⁰Co-γ ray irradiation mutagenesis method have the advantages of strong stress resistance and high active ingredients, which would provide mature methods and potential germplasm for patchouli mutagenesis breeding and new variety breeding.

Cordyceps chanhua is an important Chinese traditional medicine and food, that has important application value in the development of green functional food and new resource drugs. Taking one wild fungi Chanhua collected from Qujing of Yunnan province as the experimental material, the biological characteristics and artificial cultivation conditions were studied for the purpose of domestication and cultivation. Based on the morphological anatomy and molecular phylogenetic analysis, a wild ascomycetes was identified as C. chanhua. The biological characteristics and domestication of C. chanhua strain were studied by single factor experiments and orthogonal tests. The result showed that the branch stalk of C. chanhua was orange yellow or yellow white, (8.0-28.0)mm×(1.5-3.0)mm, and the conidia was oblong, (4.0-8.5)µm×(1.5-3.5)µm. The optimum temperature for the mycelial growth was 24 ℃, the optimum pH value was 6, the carbon source, nitrogen source and mineral salt was sucrose, yeast powder and magnesium sulfate respectively. The results of orthogonal test based on three factors under the optimum pH value and temperature showed that carbon source had the greatest impact on the mycelial growth, followed by nitrogen source and mineral salt, with range 1.21, 0.39 and 0.13 respectively. Therefore, the optimal combination of factors for the mycelial growth of C. chanhua was sucrose 20 g/L, yeast powder 2 g/L and magnesium sulfate 2 g/L. The artificial cultivation of C. chanhua utilized the 1∶1 mixed medium of wheat and rice, and the harvest cycle of fruiting body was about 40-45 days, and the average dry weight of each cultivated Chanhua was about 9.56 g. The external morphological characteristics of artificially harvested C. chanhua were significantly different from those of wild fruiting body. The fruiting body was yellowish to light yellow, with few branches, 1.5-5.0 cm in length, 0.3-0.8 cm in width and 0.1-0.2 cm in depth. The sporangium bundles were covered with dirty white flocculent or powdery conidia. The screening of excellent strains and optimal culture conditions of C. chanhua would provide a theoretical basis for its study on the diversity of germplasm resources, protection and utilization.

Oil Palm (Elaeis guineensis Jacq.) is the most efficient oil-producing plant in the world. Fruit development is the basis of yield formation, but rancidity occurs after 24 h of harvesting, which seriously affecting the quality of palm oil. At present, the key regulatory genes and pathways for the differences in the synthesis of free fatty acid metabolism in pulp development and postharvest fruits have not been identified. In this study, oil palm fruits were collected from 95 days (MS1), 125 days (MS2), 185 days (MS3), 24 h (MS4) and 36 h (MS5) after pollination. The second generation high-throughput transcriptomics (RNA-Seq) and liquid chromatography-tandem mass spectrometry (LC-MS/MS) were used to analyze the transcriptomes and metabolomes of the fruits during the development and postharvest storage. The unsaturated fat of oil palm was significantly higher than that of fatty acid during the middle and late stages of fatty acid accumulation, LACS4, LACS4-X1, FATA, FATB, KASⅠ, KASII, SAD1 were highly expressed in pulp and were positively correlated with oleic acid, linoleic acid, palmitic acid, palmitoleic acid acid, stearic acid and linolenic acid, DGAT and PDAT were over-expressed in the pulp and negatively correlated with the content of the six fatty acids, indicating that the expression of the above-mentioned genes may promote and inhibit the synthesis and accumulation of the fatty acids in oil palm fruit, respectively, suggesting that LACS4, LACS4-A1, FATA, FATB, KASⅠ, KASII and SAD1 may be the key genes with high content of unsaturated fat during postharvest storage. GDSL2, GDSL7, SAD2, LACS9 genes and GDSL1, KAT were positively and negatively correlated with oleic acid, and negatively and positively correlated with palmitic acid, palmitoleic acid acid, stearic acid, linoleic acid and linolenic acid, respectively, suggesting that GDSL2, GDSL7, SAD2 and LACS9 might promote oleic acid production and inhibit palmitic acid, palmitoleic acid acid, stearic acid, linoleic acid and linolenic acid production during rancidity, while GDSL1 and KAT might inhibit linolenic acid production, suggesting that GDSL2, GDSL7, SAD2 and LACS9 are the key genes causing oil palm rancidity after harvest. The aim of this study is to provide candidate genes for improving unsaturated fat content and altering fatty acid composition by using molecular biotechnology, and to provide theoretical reference for screening unsaturated fat and storability varieties.

Considering that the serious shortage of available silicon content in typical paddy soil of Hainan Island, it is urgent to make reasonable application of silicon fertilizer. In this study, paddy soils developed from five typical parent materials (basalt, marine sediments, fluvial alluvium, sand shale, and granite) in Hainan Island were selected to investigate the effect of silicon fertilizer application on rice in a field plot experiment. Rice yield, quality and the related physiological, biochemical and agronomic indicators under different silicon fertilizer treatments were analyzed. Results showed that compared with the blank control, the silicon fertilizer application in both T₂ and T₃ treatments significantly increased the rice yield and its related indicators such as the number of stem tillers and effective heads, seed rates, 1000-grain weight, root activity, chlorophyll and crude cellulose content relative to the control. Rice quality such as milled rice, chalkiness and amylose content also reached a good level. It is generally recommended that the optimal amounts of Si fertilizer application are 750-950 kg/hm² (available SiO₂: 187-238 kg/hm²) for basalt-developed paddy soil and 625-935 kg/hm² (available SiO₂: 156-234 kg/hm²) for granite-developed paddy soil, respectively. Meanwhile, compared with the control, the amount of silicon fertilizer application in T₂ and T₃ treatments significantly increased the number of tillers, root activity, chlorophyll and crude cellulose content in paddy soil developed from marine sediments, river alluvial and sand shale. Rice yield reached the highest and rice quality reached a good level in T₂ treatment, but rice yield and its related agronomic indicators did not increase significantly with the increasing of silicon fertilizer application (T₃), and even some indicators exhibited a downward trend. It is recommended that the optimal amounts of Si fertilizer application are 560 kg/hm² (140 kg/hm² of available SiO₂) for paddy soil developed from marine sediments and river alluvial sediments, and 750 kg/hm² of silicon fertilizer (187 kg/hm² of available SiO₂) for paddy soil developed from sandy shale, respectively. Thus, this study revealed the effect of silicon fertilizer application in typical paddy soil of Hainan Island, providing a scientific basis for formulating the standard of silicon fertilizer application as well as demonstrating and popularizing high efficiency silicon application technology and of rice in Hainan province.

Field experiments were conducted to study the relationship between nitrogen source, nitrogen application rate and the interaction on the source-sink development during the whole growth period of sweetpotato Mingmenjinshi and its relationship with yield and quality. The results showed that nitrogen application increased the chlorophyll content and net-photosynthetic rate of sweetpotato at 70 to 110 days after planting, the number of storage root per plant, average storage root weight and yield, the content of soluble sugar, sucrose, soluble protein, polyphenols and vitamin C, and significantly decreased the content of starch. Under the same nitrogen source, at 30 to 120 days after planting, the fresh weight of stems and leaves increased significantly with the increase of nitrogen application; the average number of storage root per plant, the average weight of storage root and the average weight of storage root per plant increased first and decreased then with nitrogen application, and were the highest when the nitrogen application rate was 120 kg/hm²; T/R first decreased and then increased with the increase of nitrogen application rate, and was the lowest when the nitrogen application rate was 120 kg/hm²; and the number of storage root per plant and yield was the highest with nitrogen application of 120 kg/hm². Under the high-yield nitrogen application rate of 120 kg/hm², compared with amide nitrogen and nitrate nitrogen, ammonium nitrogen significantly increased chlorophyll content and net-photosynthetic rate at 70 to 110 days after planting; significantly increased the fresh weight of leaves and stems at 30 days after planting; significantly increased the number of storage root per plant at 30 to 120 days after planting; significantly increased the weight of storage root per plant at 60 to 120 days after planting. At harvest, ammonium nitrogen significantly increased the yield of commercial storage root by significantly increasing the number of storage root per plant, also significantly increased the content of soluble sugar, sucrose, soluble protein and vitamin C, and improved flavor quality.

Rhododendron hainanense Merr. has high ornamental and ecological value. It is of great significance for the protection and application of this plant through the study of ecological requirement and applicable range. In this paper, MaxEnt model and ArcGIS were used to simulate the potential geographical distribution of R. hainanense in China, based on the existing geographic distribution information, climate factors of this plant. And the key environmental factors, affecting the potential distribution of R. hainanense and suitable thresholds are analyzed. The results showed that under the contemporary climate scenario (1970—2000), the maximum entropy model (MaxEnt) can predict the suitable area of R. hainanense with high accuracy. The temperature and precipitation have a great influence on R. hainanense. The main factors affecting the potential distribution of R. hainanense are precipitation of warmest quarter (bio18) and mean diurnal range (bio2). When the precipitation of warmest quarter (bio18) is between 610-3990 mm and the mean diurnal range (bio2) is 5-7 ℃, the climate environment is suitable for the growth of R. hainanense. In a certain range, the probability of presence of R. hainanense will increase with the increase of precipitation. In China, the suitable habitat area of R. hainanense is mainly distributed in Hainan, Guangxi, Guangdong, Taiwan, eastern Sichuan, Chongqing and Guizhou. The total suitable habitat area of R. hainanense under contemporary climate scenarios is 132.36×10⁴ km². The purpose of this paper is to provide a scientific basis for the protection and application for the species.

Anacardium occidentalie Linn is a typical tropical fruit tree, which is mainly planted in Yunnan and Hainan provinces of China. Cashew cultivation has important economic, social and ecological values. It is of great value to realize the strategy of rural revitalization in China, increase farmers' production and income, and achieve common prosperity. Cashews are very sensitive to low temperatures, and they will be severely damaged at 8 ℃and the growth will stop. Therefore, lowtemperature stress is an important abiotic stress that restricts cashew growth. CBF transcription factors play important roles in plant response to abiotic stresses such as low temperature, drought and salt. However, the role of CBF gene family in cashews has not been elucidated, and the expression pattern of this family in response to low temperature stress is unknown. In this study, in order to explore the basic characteristics of the CBF gene family in cashew nuts, six AoCBF gene family transcription factors were identified and obtained from the cashew transcriptome by bioinformatics methods, and the physical and chemical properties, protein structure, phylogeny, promoter action elements and expression patterns under low temperature induction were analyzed. The length of the six AoCBF proteins ranged from 189 to 334 aa, and the molecular weight of the proteins ranged from 21.31 to 37.89 kDa. The isoelectric points of the six AoCBF proteins were less than 7, indicating that the proteins were acidic. The proteins all contained an AP2/ERF domain. Motif analysis showed that there were five motifs in AoCBF genes, and the absence of different AoCBF gene motifs implied the absence of related functions. Phylogenetic tree analysis showed that the six AoCBF genes could be divided into two subgroups, A and B, in which group A contained one gene and group B only contained five genes. The analysis of homeotropic elements of promoter showed that AoCBF gene might be involved in the response to hormone and abiotic stress. Fluorescence quantitative expression analysis showed that all the six AoCBF genes responded to low temperature and cold stress to different degrees, indicating that AoCBF played a role in the biological process of cashew nut in response to low temperature stress. The results summarized the basic characteristics of the AoCBF gene family and accumulated basic data for further molecular resistance research and application of cashews AoCBF genes.

In recent field survey and specimen examination, eight species of pteridophytes belonging to seven genera in five families are reported as new records in Fujian Province, Gymnocarpium oyamense (Baker) Ching, Pronephrium parishii (Beddome) Holttum, Athyrium drepanopterum (Kunze) A. Braun ex Milde, Diplazium okinawaensis Tagawa, D. hainanense Ching, Hymenasplenium excisum (C. Presl) S. Lindsay, Asplenium ensiforme Wallich ex Hooker & Greville and Microsorum membranaceum (D. Don) Ching. Among them, G. oyamense is a newly recorded genus in Fujian Province, and P. parishii, A. drepanopterum, D. okinawaensis, D. hainanense and M. membranaceum are newly recorded species in East China.

Natural rubber latex (NRL) is susceptible to spoilage, and current high ammonia preservation systems have serious contamination problems. In this study, NRL was preserved by thione derivative LS, and the preservation effect on NRL was investigated. The volatile fatty acid value (VFA No.) and viscosity value of LS-preserved fresh latex were relatively low, and the preservation effect of LS at 0.1% was better than that of 0.25% ammonia. LS-ammonia composite preservation was used to prepare low-ammonia concentrated natural rubber latex (CNRL), and CNRL could be preserved stably for 180 days by the dosage at 0.01%~0.05%. The preserved low-ammonia CNRL had low VFA No. and good stability, and all the indexes met the requirements of production. The stability of the preserved low ammonia CNRL was outstanding, and all the indexes met the current production application requirements. The LS-ammonia composite preserved low ammonia CNRL also had excellent physicochemical and film-forming properties, and the tensile strength and tear strength of the vulcanized film were generally better than those of the current high ammonia preserved CNRL vulcanized film. By infrared absorption spectroscopy, the structure of the preservative LS-ammonia composite preserved low ammonia CNRLvulcanized film did not change significantly; thermal analysis showed that the thermal stability of the vulcanized film was basically the same as that of the high ammonia CNRL film. In addition, the safety analysis showed that the LS-ammonia composite preserved low ammonia CNRL dry rubber film did not have potential toxic effects. There was no skin irritation reaction, and the safety was better. The preservative LS has excellent preservation effect on NRL, and the composite preservation preparation of low ammonia CNRL has good performance, which can be used in the production of a variety of pure rubber products, and at the same time, the low cost has a broad application prospect.

Low temperature is one of the main environmental factors affecting the growth, yield and distribution of sugarcane. It is of great significance to explore the physiological response characteristics of sugarcane under low temperature stress and screen strong cold-tolerant sugarcane parent materials for guiding sugarcane breeding and promoting the development of sugarcane industry. In this study, eight different sugarcane varieties and one sugarcane wild species (Erianthus fulvus 99-1 clone) were used as the experimental materials to study the physiological index response after low temperature stress treatment, and the cold tolerance of the nine materials was comprehensively evaluated by principal component analysis, fuzzy membership function method and cluster analysis. The contents of malondialdehyde (MDA), chlorophyll (Chl), soluble sugar (SS) and soluble protein (SP) in most materials were higher than those of CK after low temperature stress (3 ℃, 3 days). The content of proline (Pro) in all materials was higher than that of CK, while the activity of superoxide dismutase (SOD) was lower. The activities of peroxidase (POD) and catalase (CAT) in most materials were higher than those of CK. According to the comprehensive evaluation value (D) and cluster analysis, the nine materials were divided into three groups: strong cold resistance type (E. fulvus 99-1, Yacheng 89-9, ROC10), moderate cold resistance type (ROC20, Yuetang 93-159, Huangjiali, ROC16) and weak cold resistance type (Dianzhe 01-58, ROC22). The results indicate that different sugarcane varieties have different adaptability to low temperature. Strong cold-tolerant sugarcane varieties can quickly adjust themselves under adversity, reasonably increase the content of osmotic adjustment substances and the activity of antioxidant enzymes, further remove harmful substances such as reactive oxygen species (ROS) in the body, and balance cell metabolism process, so as to better adapt to low temperature environment. This study would lay a foundation for exploring the regulation mechanism of sugarcane response to low temperature stress and breeding new sugarcane varieties with strong cold tolerance.

In this study, 75% ethanol solution was used to prepare the total extracts of arecanut nut (ANE). Then different fractions of the extracts were prepared by fractionating with petroleum ether (PE-ANE), ethyl acetate (EAC-ANE), n-butanol (BU-ANE) and water (W-ANE) in turn. The inhibition of hypertension from ANE was determined by angiotensin converting enzyme (ACE) activity inhibition assay in vitro. The inhibitory was evaluated with the fraction displayingthe best ACE inhibitory activity by the enzyme kinetic method. In addition, the contents of total polyphenols, total sugar and total protein in each fraction of ANE were determined. The correlation between the contents of the compositions and ACE inhibitory activities was analyzed. Finally, phenoliccomponents in the four fractions were analyzed. The results showed that all the fractions of ANE at different polar parts exhibited ACE inhibitory activity, and EAC-ANE displayed the best. Enzyme kinetics tests showed that the inhibitory effect of EAC-ANE from tender areca on ACE was a mixed type of competitive inhibition and non-competitive inhibition. The correlation analysis showed that the IC₅₀ value of the ACE inhibitory activity of each polar part of ANE was significantly negatively correlated with the content of polyphenols and total sugar. And the absolute value of the correlation coefficient between the IC₅₀ value of ACE inhibitory activity and the polyphenol content reached a very strong correlation (r=‒0.912). And a variety of polyphenol components such as catechin, L-epicatechin, procyanidin B₂, protocatechuic acid, and quercetin were identified in the four different polar parts, and the content of polyphenol components in EAC-ANE was the highest. In conclusion, ANE has a certain blood pressure lowering potential, and the ethyl acetate extraction site is the best, and the polyphenol content has a strong correlation with the ACE inhibitory activity of each extract. It can be preliminarily inferred that polyphenols may be the main substances that inhibit the activity of ACE in ANE.

Oryza officinalis Wall. ex G. Watt has excellent characteristics such as disease and insect resistance, stress tolerance, high biological yield and high light efficiency, and contains many excellent genes. In this study, 199 representative resources collected from all Oryza officinalis distribution sites in Guangxi were used to analyze the genetic diversity and principal components for five important agronomic traits, including heading stage, anther length, grain width, grain length and grain weight. The results showed that O. officinalis from Guangxi had rich genetic diversity, with coefficients of variation of 9.12%, 11.90%, 3.39%, 4.64% and 6.24% for heading stage, anther length, grain width, grain length and grain weight, respectively, and diversity index was 1.4878, 2.0453, 1.7727, 1.1567 and 2.0379, respectively. Principal component analysis showed that the first and second principal components were mainly related to yield traits, with a cumulative contribution rate of 63.759%. The third and fourth principal components had a cumulative contribution rate 16.306% and 15.542%, respectively. The heading stage and anther length were the influential determinants, mainly reflecting the plant growth characteristics. According to the genetic diversity, the seven geographic populations are ranked as follows: Wuzhou (1.6731)>Yulin (1.5784)>Guigang (1.5070)>Nanning (1.3325)>Laibin (1.2131)> Hezhou (0.9629)>Qinzhou (0.3819), and Wuzhou had the highest diversity index, indicating that Wuzhou was the phenotypic diversity center of Oryza officinalis in Guangxi.

In order to explore the effects of N, P and K fertilizers on the growth and nutrient uptake of areca nut seedlings and provide a scientific fertilizer application in field management, areca nut seedlings were used to conduct the “3414” fertilizer ratio in pots at the greenhouse. Fertilization significantly increased biomass and fertilizer utilization of areca nut seedlings. In balanced nitrogen, phosphorus and potassium fertilization, N and P fertilizers had the maximum utilization. Balanced nitrogen and potassium fertilization without phosphate fertilizer, K fertilizers had the maximum utilization. The N content was the main factor affecting the stem and leaf biomass, while the P content was the main factor affecting root biomass. Correlation and path analysis indicated that N and P could synergistically improve the growth of areca nut seedlings, but they were affected by the application of K fertilizer. However, N, P and K fertilizers could reach balance and synergy to improve the growth of seedlings. In conclusion, N, P and K fertilizers in a rational proportion was beneficial for the nutrient uptake and utilization of areca nut seedlings, and N:P:K=2:2:2 (T₆) was the most suitable fertilization ratio.

Colletotrichum siamense is the main pathogen of anthracnose in many crops in tropical and subtropical regions. SSK1 is a response regulator protein of the two-component system. Studies have shown that SSK1 in pathogenic fungi is related to the morphogenesis, stress response, drug resistance and pathogenicity of pathogens, but SSK1 homologues have distinct functions in different fungi. In order to understand the function of CsSSK1 in C. siamense, the CsSSK1 gene deletion mutant ΔCsSSK1 and the complement strain ΔCsSSK1 (CsSSK1) were constructed and phenotypically observed. The results showed that the deletion mutant ΔCsSSK1 showed slightly retarded mycelial growth, shorter conidia, lower sporulation and conidial germination rate. ΔCsSSK1 significantly increased the sensitivity of C. siamense to NaCl, sorbitol, sucrose, glucose and Congo red, and the sensitivity to fluconazole and tebuconazole, but decreased the sensitivity to fludioxonil. The pathogenicity of ΔCsSSK1 was significantly reduced. The results showed that CsSSK1 gene was involved in the regulation of C. siamense morphogenesis, response to salt stress, osmotic stress, Congo red stress and fungicide stress, affecting the pathogenicity of C. siamense. The results would lay a foundation for further understanding the function of CsSSK1 gene in C. siamense and analyzing the molecular mechanism of pathogenic fungi response to stress.

To explore the relationship between the expression of psoralen synthase gene (PS) and psoralen synthesis, quantitative real-time PCR (qPCR) and high performance liquid chromatography (HPLC) were used to determine the expression of PS and the content of psoralen in roots, stems, leaves and fruits of Ficus hirta Vahl (FH) from Guangxi and Fujian. PS was expressed in roots, stems, leaves and fruits of Guangxi and Fujian FH, and the expression was tissue-specific. The relative expression level in roots was the highest (expression in branch roots was higher than that in principal roots), followed by leaves (expression in entire margined leaves were higher than that in incised leaves), and the expression levels in stems and fruits were extremely low. The psoralen contents of FH had some differences from the two producing areas. They were accumulated in the principal root, branch root, entire margined leaf, incised leaf, stem and fruit from Guangxi and Fujian provinc FH, and the contents were the highest in branch roots, which was 3.206 mg/g and 2.947 mg/g respectively, followed by principal root (2.136 mg/g and 0.419 mg/g). The content in incised leaves was 0.022 mg/g and 0.028 mg/g respectively, that in entire margined leaves was 0.069 mg/g and 0.035 mg/g. The psoralen content of stem (0.003 mg/g and 0.003 mg/g) and fruit (0.002 mg/g and 0.001 mg/g) was lower than other parts. The psoralen content was correlated with the expression of PS. The study would provide insights into understanding the role of PS in the psoralen metabolic in Ficus hirta Vahl.

Spontaneous plants have strong growth adaptability, can self-multiply and form a good natural landscape, which are important materials for the construction of conservation-oriented landscape. The typical-sampling method was used to investigate the spontaneous plants in 16 city parks of Haikou, so as to comprehensively understand the diversity level of spontaneous plants and provide reference for the construction of conservation-oriented gardens. The results showed that 220 spontaneous plant species belonged to 59 families and 176 genera were recorded in this research. Among them, 154 plants were native plants (accounting for 70%) and 66 plants were exotic species (accounting for 30%), meanwhile, 48 plants were invasive alien species (accounting for 22.27%). Asteraceae, Poaceae and Fabaceae, the largest families, played a major role in the quadrats with 75 species from 64 genera, accounting for 36.36% and 34.09% of the total genera and species of Spontaneous plants. Perennial herbs and annual/biennial herbs were the main life forms, accounting for 51.36% (113 species) and 44.09% (97 species), respectively. Spontaneous plants have strong ecological adaptability and high potential for landscape application. In the future construction of urban landscape, the existing spontaneous plants in the parks should be reasonably planned and utilized, increasing the proportion of native plants and constructing the spontaneous plants landscape with regional characteristics according to different environments.

Coconut is an important economic crop in tropics. The area of coconut palm in Hainan Island accounts for 90% of the total production area in China. Up-to-date maps of coconut palm are essential for the industrial planning of tropical agriculture. In this study, an object-oriented image analysis method was used for mapping coconut palms based on high spatial resolution imagery of Gaofen-2. Dongjiao town in Wenchang was selected as the study area. An optimal segmentation scale of Gaofen-2 imagery was obtained using the fractal evolution approach. Then, a combined layer of four original bands, five vegetation indices and 32 gray-level co-occurrence (GLCM) texture indices were used as input features. Four different sets of features (including only original bands, original bands and textures indices, original bands and vegetation indices, and all features) were applied in object-based classification. The overall accuracy (OA) and user’s accuracy (UA) of pixel-based method achieved 87.05% and 85.21%, respectively. Compared with the pixel-based method, the object-based approaches significantly increased overall accuracy (OA) between 5.51%-8.72%. The OA and user’s accuracy (UA) reached 95.77% and 97.15% respectively, which was the optimal classification result, when the combination of original bands and textural features were used in coconut palms classifying. In addition, the combination of original bands and vegetation indexes achieved a satisfactory accuracy (OA=94.88% and UA=94.42%). While the combination of original bands, vegetation indexes and textural indexes performed a lower accuracy (OA=94.67% and UA=94.17%) in comparison with that of above two combination. Generally, our researches indicate that Gaofen-2 imagery has a good potential for coconut palms classification in complex tropical regions, and the textural indexes are very useful for identifying coconut palms at object-based level. The results would provide a reference framework for tropical agriculture decision management.

Tigernut (Cyperus esculentus L.), which belongs to the Cyperaceae family within Poales, is a novel herbaceous oil crop producing high amounts of oil in underground tubers. Like other tuber and tuberous root crops, water accounts for approximately 85% of immature tubers, implying a crucial role of water balance for tuber development in tigernut. Plasma membrane intrinsic proteins (PIPs), which include two groups (i.e. PIP1 and PIP2) typically localized to the cell membrane, constitute a subfamily of aquaporin facilitating the passive transport of water. Based on one PIP identified in the proteomes of tigernut tubers, its coding gene CePIP1;1 was cloned using the RT-PCR technique, followed by analyzing the exon-intron structure, sequence features, evolutionary relationships, expression profiles, and protein subcellular localization. CePIP1;1 was shown to contain three introns with a coding sequence of 867 bp, putatively encoding 288 amino acids with the theoretical molecular weight of 30.76 kDa, the isoelectric point of 8.82, the instability index of 32.95, the grand average of hydropathicity of 0.384, and the aliphatic index of 95.28, implying that it is stable, basic, and hydrophobic. The protein was predicted to harbor one conserved MIP (major intrinsic protein) domain, including six transmembrane helices, two half helices, and dual NPA motifs located at the N-termini of two half helices. Sequence alignment and phylogenetic analysis revealed that CePIP1;1 clustered with Oryza sativa PIP1s and possesses an extended N-terminus but a short C-terminus relative to Spinacia oleracea PIP2;1, supporting its classification. Transient over-expression in Nicotiana benthamiana leaves supported the plasma membrane localization of CePIP1;1, which is consistent with the bioinformatics prediction. Further expression analysis showed that CePIP1;1 was constitutively expressed in all tissues examined in this study. During tuber development, CePIP1;1 exhibited a typical bell-shaped expression pattern, which is consistent with that of the moisture content. These results lay a solid foundation for further functional analysis and genetic improvement in tigernut.

Banana plant has the characters of fruiting in high position and of hanging in non-fixed orientation, which is not conducive to the flower removal, bud removal breaking, pesticide spraying, bagging and harvesting of banana fruit in production, and make it vulnerable to wind damage, causing lodging and breaking. In order to reduce the height position of banana fruit, make it hang fruit directionally, facilitate management, realize mechanized harvest and improve field management efficiency, a guide outlet was excavated at the lower position on one side of banana pseudostem by physical method to guide banana to fruit at the lower position and predetermined direction, and the differences in fruit characters between physically induced fruit and naturally formed fruit were studied. The results showed that opening the outlet by physical method could guide the banana fruit grow in a low position and a predetermined direction. The average fruit yield per plant was 21.47 kg (with a variation range of 11.5 kg to 36.15 kg), the average number of fruit fingers per plant was 187(with a variation range of 137 to 237), the average weight of single fruit finger was 120 g(with a variation range of 60 g to 190 g), the average length of fruit axis was 41.82 cm (with a variation range of 27.5 cm to 54.5 cm), the average length of outer arc of fruit finger was 17.88 cm (with a variation range of 13.4 cm to 21.1 cm), the average perimeter of fruit finger was 11.44 cm (with a variation range of 9.6 cm to 12.9 cm). Correlation and regression analysis showed that the fruit weight per plant, fruit axis length and fruit finger length were significantly negatively correlated with the time interval from opening outlet day to heading fruit day, respectively. Compared with the natural heading fruit, there was no significant difference in average fruit weight per plant, average total number of fruit fingers per plant and average number of fruit fingers per comb, there was no significant difference in the thickness of the fruit fingers and the curvature of the fruit fingers; but there was significant difference in average weight of single fruit and of fruit axis respectively; The length of fruit axis and the length of fruit finger and the spacing between fruit combs was significantly shortened respectively, the differences are all very significant.

To further explore the molecular characteristics and pathogenicity of Sri Lankan cassava mosaic virus (SLCMV) isolates in China. Mosaic cassava leaves were detected, and the domestic SLCMV isolates full-length genomes of DNA-A and DNA-B were obtained by PCR amplification. It`s nucleic acid and amino acid sequence characteristics were analyzed by bioinformatics software. The infectious clones of strong and weak pathogenic isolates (SLCMV-Colombo and SLCMV-DG1922) were constructed. The DNA-A and DNA-B components of the two virulence isolates were recombined, and the pathogenicity differences of the two isolates were compared by tobacco (Nicotiana tabacum) inoculation. The results showed that SLCMV isolates belong to “Old World begomoviruses” encoding 8 open reading frames (ORFs) including the AV2 gene. It has a typical common region (CR), repeat sequence, TATA Box and TAATATT↓AC stem-loop structure of Geminiviruses, and 7-amino-acid are missing at the carboxyl terminal of Rep protein. Domestic SLCMV genome, coding and non-coding region sequences were 97.0%-100.0% similar to the isolates from Cambodia, Thailand and Vietnam, and 86.5%-98.6% similar to the early isolates from India and Sri Lanka. Coding region of DNA-B were 95.0%-97.6% similar to Indian cassava mosaic virus strain (ICMV), were less than 80.0% to the other 9 African cassava mosaic virus strains. Infection clone inoculation showed that the DNA-A (ColA) component of the strong virulent isolate SLCMV-Col played an important role in the typical mosaic symptoms of N. tabacum leaves, while the DNA-B (DG1922-B) of the domestic isolate could cooperate with Col-A to produce strong pathogenicity to tobacco plants. This study analyzed the whole genome structure of SLCMV in China, the infectious clone and its technology provide an important research basis for further pathogenesis research of SLCMV.

The hyperosmotic Ca²⁺ channel protein OSCA is crucial for controlling hyperosmotic stressors in plants. To understand the role of the OSCA gene family in tea plant response to drought stress, this study was conducted to identify the OSCA gene family based on the whole genome data of tea plant and analyze the gene and protein structures and promoter cis-acting element, and analyze the expression patterns of CsOSCAs in different tissues of tea plant, among different drought-resistant varieties and under drought stress. The results showed that the tea plants genome contained 12 members of the OSCA gene family, named CsOSCA1-CsOSCA12. The amino acid sequences encoded by the CsOSCAs were 667-831 bp in length, with protein molecular weight ranging from 76 630.55 kDa to 93 563.99 kDa and isoelectric points ranging from 6.15 to 9.33, containing 9-12 transmembrane structural domains, all containing the characteristic conserved structural domain DUF221, which could be divided into four subfamilies based on phylogenetic relationships. Ten CsOSCAs were localized to seven chromosomes of Camellia sinensis and two CsOSCAs were localized to the contig of unanchored chromosomes. The secondary structure of the CsOSCAs contained 32%-38% transmembrane structure and 60%-68% α-helix. The CsOSCAs were tissue expression specific, and CsOSCA2, CsOSCA3, CsOSCA11, and CsOSCA12 were significantly higher in the drought-sensitive variety CN98 than those in the other two drought-tolerant varieties. Nine genes were responded to PEG stress, among which CsOSCA2, CsOSCA3, CSOSCA5, CsOSCA8, CsOSCA10, and CsOSCA12 were strongly induced by drought stress. Six genes included drought-inducible response elements, and 11 genes contained abscisic acid response elements, according to further examination of the promoter cis-acting elements. It is hypothesized that the OSCA gene family of tea plants play an important role in the response to drought stress, and this study would provide a reference for the functional analysis and stress resistance of OSCA gene in tea plant.

The heat shock transcription factor MeHsfB3b is important in regulating the resistance to cassava bacterial blight. In the previous study, the candidate interaction protein MeFKBP20 of MeHsfB3b was obtained by the yeast two-hybrid technology, which belongs to the FKBP-type peptide prolyl cis-trans isomerase gene family. In this study, the full-length MeFKBP20 gene was cloned to be 561 bp, encoding 186 amino acids, with a molecular weight of 19.99 kDa and a FKPB_C domain. The expression pattern analysis showed that MeFKBP20 was highly expressed in mature leaves and roots of cassava, and the expression level of young leaves and petioles was low. It could quickly respond to the induction of pathogen XpmCHN11 and maintain a high expression abundance, suggesting that it is involved in response to pathogen infection. The interaction between MeHsfB3b protein and MeFKBP20 protein through 201-241 aa region was proved by the yeast two-hybrid point-to-point and bimolecular fluorescence complementation experiments. The results of this study are helpful to further analyze the mechanism of MeHsfB3b gene regulating cassava resistance to cassava bacterial blight.

To maintain the storage quality and prolong the storage period of postharvest bananas, the present study used ‘Guijiao No.6’ as the test material to investigate the 1-hexanol effect on the fruit quality and storability of the postharvest bananas under room temperature storage conditions. Banana fruits with intact fruit appearance and similar ripeness and size were selected and randomly divided into control and treatment groups. The control and treatment groups were treated with water and 0.1% (V/V) aqueous solution of 1-hexanol, respectively. Then, the bananas were removed to air-dry and packaged in polyethylene bags with a zipper. Finally, the samples were stored at 25 ℃ for 15 days. Changes in firmness, soluble solids, respiration intensity, condition index, malondialdehyde (MDA), membrane permeability, and PLD activity were measured every 3 days, and changes in PLDγ and PLDζ expression during storage were analyzed by quantitative real-time PCR (qRT-PCR). The results showed that 0.1% (V/V) 1-hexanol significantly (P<0.05) delayed the process of postharvest banana fruit softening, and the delaying effect was highly (P<0.01) significant on days 9 and 12. From day 9, 1-hexanol highly significantly inhibited the rise in total soluble solids and condition index. From day 6, 1-hexanol significantly inhibited respiration, where the peak respiration was reached on day 9 and was highly significantly reduced by 33.93% compared to the control. After day 12, compared with the control group, 1-hexanol highly significantly reduced the rise of MDA content and membrane permeability, by 26.70% and 62.20% on day 15, respectively. In addition, 1-hexanol significantly inhibited PLD activity, especially from 6 to 12 days, and the inhibition was highly significant (P<0.01). At day 15, compared with the control group, 1-hexanol highly significantly reduced the banana expression of PLDγ and PLDζ by 72.06% and 33.08%, respectively. In conclusion, 1-hexanol can effectively delay postharvest banana fruit softening, inhibit the respiration and PLD activity, and reduce postharvest fruit disease, thereby inhibiting total soluble solids, MDA production, and increased membrane permeability, and inhibiting PLDγ and PLDζ expression, thereby maintaining postharvest fruit storage quality and extending storage life. Therefore, 1-Hexanol can be used as a fruit preservative, which is not only important for maintaining the post-harvest fruit quality and the development of the banana industry, but also has good application prospects during post-harvest storage.

Insects use floral volatiles as the olfactory cues to locate flowers. Numerous studies have shown that the selection behavior of insects can be impacted by variations in the volatile component concentration of floral varieties. The flower of mango (Mangifera indica L.) rely on insect pollination and susceptible to florivorous pests. However, volatiles in different varieties of mango flowers are relatively insufficient, which is unfavourable to the development of attractants and repellents. Therefore, the volatile floral chemical components in seven mango varieties (M. indica var. Sijimi, M. indica var. Tainong 1, M. indica var. Guire 82, M. indica var. Kaite, M. indica var. Hongmang 6, M. indica var. Hongxiangya, and M. indica var. Jinhuang) were collected using the dynamic headspace adsorption technique. The volatile components were identified and analyzed using gas chromatography-mass spectrometry-mass spectrometry (GC-MS) to compare the composition differences and similarities of the components. The findings indicated that a total of 115 volatile components, comprising 44 terpenes, 30 alkanes, 16 esters, 16 alcohols, five ketones, three aldehydes, and one phenol, were found in the volatiles of the seven species of mango flowers. 82 distinct types of volatile substances were discovered in M. indica var. Sijimi, 49 distinct types of M. indica var. Tainong 1, 46 distinct types of M. indica var. Guire 82, 49 distinct types of M. indica var. Kaite, 60 distinct types of M. indica var. Hongmang 6, 49 distinctive types of M. indica var. Hongxiangya, and 59 distinct types of M. indica var. Jinhuang. Seven species of mango blossoms contained 14 common volatile components: α-pinene, camphene, β-pinene, β-myrcene, 3-carene, α-terpinene, D-limonene, β-ocimene, terpinolene, 1-caryophyllene, germacrene D, o-cymene, benzoic acid, ethyl ester and 2-propyl-1-pentanol; 33 different types of specific components existed, including 24 different types of M. indica var. Sijimi, four different types of M. indica var. Tainong 1, two different types of M. indica var. Jinhuang, one type of M. indica var. Guire 82, M. indica var. Hongmang 6, and M. indica var. Kaite. The volatile compounds of mango flowers had higher relative concentrations of terpenes (46.15%-89.41%), alcohols (2.01%-23.58%), esters (3.34%-14.67%), and alkanes (2.27%-13.75%). The most abundant terpenes were α-pinene, 3-carene and terpinolene, the most abundant alcohols was linalool. The most abundant esters were benzoic acid, ethyl ester, and the most abundant alkanes were cyclohexasiloxane, dodecamethyl. The flower volatiles of M. indica var. Sijimi and M. indica var. Jinhuang had highest similarity of 0.862 among seven mango species; and that of M. indica var. Sijimi and M. indica var. Hongxiangya had the lowest similarity of 0.255. The findings would provide a reference for flower-volatile-mediated behavior preference researches in pollination insects and florivorous pests to various mango varieties.