The study was aimed to explore the differences in physical and chemical indexes and volatile components of different types of Amomum tsaoko powder. The physicochemical indexes of A. tsaoko powder such as color difference, essential oil content, moisture content, particle size and surface microstructure were investigated. The volatile components of A. tsaoko powder were analyzed by headspace solid-phase microextraction and gas chromatography-mass spectrometry. The color difference ∆E of seven different fruit types of A. tsaoko powder was from 19.17±0.29 to 25.15±0.17, L^* value was from 72.50±0.23 to 76.87±0.07, a^* value was from 5.17±0.05 to 6.97±0.15, b^*value was from 12.35±0.43 to 16.91±0.43. The content of volatile oil was from (0.76±0.01)mL/100 g to (1.30±0.26)mL/100 g. The moisture content was from 11.13%±0.12% to 15.05%±0.23%. In terms of particle size, NL5 and NL6 fruit powder particles had the largest difference. A total of 31 volatile components were detected in the seven fruit powder, and 17 common components were detected, mainly aldehydes and alcohols, including 2-decenal, (E)-, eucalyptol, citral, geraniol, geranyl acetate, etc. Among them, 28 volatile components were detected in NL2 fruit types, and the relative content of 2-decenal, (E)- was the highest (22.24%±2.29%). The relative content of eucalyptol in NL5 fruit type was the highest (17.52%±2.16%). Therefore, there are some differences in color difference, essential oil content, moisture content, particle size and surface microstructure of the powder of different fruit types. The volatile components of different fruit types of A. tsaoko fruit powder have both common characteristics and differences. The research could provide theoretical guidance for the production and application of high-quality pure natural A. tsaoko powder.

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.

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 intercropping of Mallotus peltatus under the forest helps to break the bottleneck of land use. It is of great significance to apply green nanotechnology to improve the benefits of its compound planting. In order to clarify the regulatory role of nano-iron in the intercropping of M. peltatus under the coconut forest, the annual seedling of M. peltatus was taken as the research object to carry out the cultivation experiment. We investigated the comprehensive effects of five concentrations of nano-iron treatments (CK: 0 mg/L, T₁: 25 mg/L, T₂: 50 mg/L, T₃: 75 mg/L, T₄: 100 mg/L) on the leaf growth, photosynthetic and chemical characteristics of M. peltatus. After the first nano-iron treatment, the leaf length, width and dry weight of M. peltatus in T₃ treatment were significantly higher than those in CK, while the leaf number in each treatment was significantly more than that in CK. Compared with CK, the chlorophyll content of M. peltatus treated with four nano-iron concentrations increased significantly by 14.96% (T₁), 16.18% (T₂), 17.91% (T₃) and 20.58% (T₄). As the concentration of nano-iron increased, the leaf net photosynthetic rate, transpiration rate, stomatal conductance, efficiency of primary conversion of light energy of PSⅡ, actual photochemical efficiency of PS Ⅱ and electron transport rate of M. peltatus overall increased. After the second nano-iron treatment, leaf length, width, dry weight and number of M. peltatus treated with T₁, T₃ and T₄ were significantly higher than those of CK. Compared with CK, the chlorophyll content of M. peltatus in each treatment significantly increased by 10.28% (T₁), 7.53% (T₂), 11.13% (T₃) and 11.41% (T₄). With the increase of nano-iron concentration, the leaf net photosynthetic rate, transpiration rate and stomatal conductance of M. peltatus increased significantly, but decreased when the concentration reached T₃ treatment. The potential activity of PSⅡ and efficiency of primary conversion of light energy of PSⅡ of M. peltatus also decreased significantly in T₃ treatment. After two treatments, the contents of flavone, fat and ash of M. peltatus increased significantly in T₁ treatment compared with CK. The contents of fat and ash decreased with the increase of nano-iron concentration. To sum up, nano-iron has a positive regulatory effect on the growth of M. peltatus under the coconut forest, but high concentration will inhibit its photosynthesis and growth. We recommend that the appropriate concentration is 25-50 mg/L. This study could provide theoretical reference for the application of nano-iron in intercropping M. peltatus under the coconut forest.

The traditional method for detecting the copy numbers of exogenous gene in transgenic plants is Southern hybridization, which is costly and time-consuming, and is difficult to meet the breeding needs of high-throughput detection of the copy numbers of exogenous gene. Therefore, this study aims to establish a fast and high-throughput method for detecting the copy numbers of exogenous gene in transgenic papayas. In this study, two single copy genes, Cpa03g018830 and Cpa03g018770, were selected from the papaya genome. Using the known exogenous gene as a single copy integrated transgenic papaya as a reference, the copy numbers were identified by digital PCR. Further, using them as reference genes, and the commonly used screening marker gene NPTII in papaya transgenic breeding as an exogenous target gene, methods for detecting the copy numbers of exogenous gene in transgenic papaya using digital PCR and fluorescence quantitative PCR were established. The results showed that Cpa03g018830 and Cpa03g018770 were both single copy genes; the established digital PCR method was accurate and reliable in detecting the copy numbers of exogenous gene in transgenic papayas, while fluorescence quantitative PCR had a higher accuracy in detecting single or low copy integration of exogenous genes in transgenic papayas, and a lower accuracy in detecting multiple copy integration of exogenous genes. Therefore, fluorescence quantitative PCR is suitable for initially screening out single or low copy integration plants from a large number of transgenic plants. The single copy Cpa03g018830 and Cpa03g018770 identified in this study can be used as reference genes for detecting the copy numbers of exogenous gene in transgenic papayas. The established methods for detecting the copy numbers of exogenous gene in transgenic papayas using digital PCR and fluorescence quantitative PCR techniques are simple, fast and suitable for batch detection, providing new methods for selecting single or low copy lines in transgenic resistance breeding of papayas.

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.

The study was aimed to analyze the genetic diversity of the phenotypic traits and chemotypes of different Ocimum basilicum germplasm resources, to provide theoretical reference for the innovative utilization of basil germplasm resources and variety selection. The botanical traits of 15 basil germplasm resources and the volatile components of the leaves investigated and determined using gas chromatography-mass spectrometry (GC-MS), together with the relative odour activity values (ROAV). At the same time, principal component analysis and cluster analysis were carried out on the tested germplasms. The 15 basil germplasms differed significantly in plant height, plant width, leaf length, leaf width and stem thickness, except for the number of branches. 104 volatile compounds were identified, including 37 alkanes, 32 terpenes, 8 esters, 5 phenols, 4 alcohols, 3 aldehydes, 1 ether, and 14 other compounds, of which there are two types of common components, 2,4-di-tert-butylphenol and heptadecane. According to the ROAV values obtained from the enquiries and calculations, the key aroma substances were found to be eugenol, linalool, eucalyptol, cis-citral, methyl cinnamate, 4-allyl anisole, etc. The principal component analysis and cluster analysis of the volatile substances the germplasms could be classified into five groups, namely, Thai basil, Anise basil, Siam queen basil and Sweet basil were grouped together, Jiu Cengta basil, Genovese basil, Red rubin basil, Purple dark opal basil and Purple ruffles basil were grouped together, Clove basil and Lemon basil were grouped together, Tuscany basil, Pluto basil and Italian large leaf basil were grouped together, Cinnamon basil was grouped one category. The phenotypic trait cluster analysis also classified basil into five groups, with Pluto basil into a group, Clove basil, Anise basil and Purple dark opal basil into a group, Thai basil into a group, Italian large leaf basill and Cinnamon basil into a group. The remaining eight germplasm were clustered into a group. The 15 germplasms have significant differences in botanical characters and volatile components, and are rich in genetic diversity, which could be targeted for breeding of basil-specific germplasms.

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.

Tobacco is an important economic crop, and its leaves have great economic value. In recent years, with the increase of tobacco planting areas, the varieties of leaf diseases are on the rise. Two strains of tobacco leaf spot disease pathogenic bacteria were isolated from the tobacco leaf disease samples in Hezhou, Guangxi. Through polygenic phylogenetic analysis, they were identified as Cumuliphoma indica, which is the first report on the tobacco leaf spot disease caused by C. indica in China. To clarify the biological characteristics of the pathogen and screen the control agents, this study used the mycelial growth rate method to study the lethal temperature of the mycelia of the strain, and its growth in different media, temperatures, pH, carbon sources, nitrogen sources, light cycles and to determine the sensitivity of the pathogen to nine chemical agents. The biological characteristics showed that the temperature range of C. indica mycelium growth was wide, and the optimum temperature was 28 ℃. Weak acid environment was more favorable for mycelium growth, and the optimal pH was 5. It grew fastest on CMA and CDA. The optimum nitrogen source was peptone. The optimum carbon sources was soluble starch. The lethal temperature of mycelium was 49 ℃, and the water bath was 10 min. Light had a significant effect on the growth of the mycelia, and 24 h full light was the most favorable. The results of laboratory screening showed that the nine tested fungicides had different inhibition on the growth of C. indica mycelia, among which boscalid 50% WG had the best inhibitory effect, EC₅₀ was 0.025 mg/L. The second was fludioxonil 50% FS (0.084 mg/L), iprodione 500 g/L SC (0.217 mg/L), prochloraz 450 g/L EW (1.354 mg/L), mancozeb 80% WP (6.565 mg/L), difenoxazole 10% ME (9.576 mg/L), pyraclostrobin 25% SC (34.237 mg/L) and myclobutanil 40% SC (38.804 mg/L). The inhibitory effect of tebuconazole 430 g/L SC was the weakest, EC₅₀ was 42.574 mg/L. The study revealed the biological characteristics of C. indica for the first time, and recommended 50% acetanilide WG as a candidate fungicide for the prevention and control. The results could provide a reference for the effective prevention and control of tobacco leaf spot disease caused by C. indica.

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.