The sugar transporter SWEET (sugars will eventually be exported transporter) family has sugar transportation activity for glucose, fructose or sucrose, which is involved in the phloem loading and unloading of photosynthetic product, as well as physiological processes such as flower, fruit and seed development in higher plant. To explore the physiological functions of CitSWEET15 (Cs7g02970) during fruit development and ripening of sweet orange, gene cloning, expression patterns, subcellular localization and sucrose transport activity were performed in the study. The ORF (open reading frame) of CitSWEET15 gene was 918 bp, which encoded 305 amino acids, and possessed seven transmembrane domains. The theoretical isoelectric point of CitSWEET15 was 6.29, and the relative molecular weight was 34.15 kDa. Phylogenetic analysis suggested that CitSWEET15 together with AtSWEET15, VvSWEET15, LcSWEET15 and PuSWEET15 were orthologous genes, and belonged to the SWEET III clade. Sequence alignment showed that nucleotide and amino acid sequence identities of CitSWEET15 with those of Clementine mandarin, Mangshan wild mandarin, Kumquat, Pomelo, Citrus ichangensis Swingle and Citron were 98.69%-99.9% and 97.38%-100%, respectively. CitSWEET15 and the mentioned Citrus SWEET15 members were completely consistent with four sucrose recognition sites and three sucrose transport activity sites of AtSWEET13, which suggested that all CitSWEET15 and Citrus SWEET15 members may have sucrose transport activity. Quantitative real-time PCR analysis demonstrated that the expression of CitSWEET15 was high in the seed and fruit pulp of sweet orange, the expression level of CitSWEET15 in fruit pulp was low at 80-140 days after flowering, then significantly up-regulated as fruit development, and reached the highest at 230 days after flowering. CitSWEET15 was fused with green fluorescent protein at the C-terminus, and then transiently expressed in Arabidopsis mesophyll protoplasts. The subcellular localization analysis suggested the fluorescence signal was distributed around the outer edge of protoplast, indicating that CitSWEET15 was located in the plasma membrane. By heterologous expression in Saccharomyces cerevisiae W303a (W303-1A) strain and incubation in the sucrose analogue Esculin, the fluorescence intensity was detected to test the sucrose transportation activity of CitSWEET15 and AtSWEET10 (At5g50790, positive control). The fluorescent intensity of yeast cells expressing CitSWEET15, as similar as AtSWEET10, was significantly higher than vector control, indicating that CitSWEET15 had sucrose transportation activity. In conclusion, CitSWEET15 is highly conserved in Citrus species, functions as a plasma membrane sucrose transporter, and involves in apoplastic sucrose transport during fruit ripening of sweet orange. The results would provide a basis for understanding the soluble sugar accumulation in sweet orange fruit, and a candidate gene for improving fruit flavor and quality.

As one of the most prominent spices in the world, pepper (Piper nigrum L.) is extremely popular due to its aroma and flavor. Current study focuses mostly on the production of piperine in pepper, although starch, the primary component of pepper granules, has been researched infrequently and nothing is known about it. The potential for pepper starch to interact with pepper's active components is crucial to pepper production and industrial development. This study separated the starch in black pepper and white pepper using the sodium thiosulfate method and analyzed the two types of pepper starch using various characterization techniques to investigate the characteristics of starch in pepper (black pepper and white pepper) produced by different processing methods. The results indicated that the purity of black pepper starch and white pepper starch was 96.38 and 97.70%, respectively, with low protein, fat, and ash content, and that they belonged to the high-purity starch; SEM and particle size distribution analyses revealed that both black pepper starch and white pepper starch contained exceptionally small starch granules (volume-weighted average diameters of 3.44 μm and 4.80 μm, respectively), although the particle size distribution of black pepper starch was more irregular and broader. Both types of pepper starch had an A-shaped structure; White pepper starch contained more amylose (24.21%), relative crystallinity (34.21%), gelatinization temperature (90.42 ℃), gel strength (1466.72 g), tackiness (157.53), chewiness (87.55), gel enthalpy (15.80 J/g), and retrogradation value (1294.00 cP) when compared to black pepper starch. However, white pepper starch's molecular short-range order (0.67), peak viscosity (3074.00 cP), trough viscosity (2615.67 cP), breakdown viscosity (458.33 cP), and final viscosity (3909.67 cP) were significantly lower than those of black pepper starch (P<0.05), indicating that there are variations in the structure and physicochemical properties of pepper produced by various processing methods. In conclusion, the morphologies of the two types of pepper granules are comparable, and white pepper starch has more amylose concentration and molecular short-range order, as well as better gel qualities and retrogradation characteristics. The primary distinction between white pepper and black pepper is the presence or absence of exocarp; this distinction may be attributable to the presence of a small amount of starch in the exocarp of black pepper. The results of this study would lay a theoretical foundation for the application of pepper starch as a novel unconventional crop small-granular starch in the food and non-food industries and promote the sustainable growth of the pepper business.

Tibet is rich in orchid plant resources, mainly distributed in the eastern Himalayas. Among them, Motuo County, Bomi County and Chayu County of Nyingchi City, Yadong County, Dingjie County, Nielamu County and Jilong County of Xigaze City are the main distribution areas of orchid plants in Tibet. With the release of Latest National Key Protected Wild Plant List, more and more orchids are listed for protection. In this paper, four species of the Subtribe Goodyerinae (Orchidaceae) found in the southeast of Tibet are reported. They are Anoectochilus, Anoectochilus brevilabris Lindl., Cheirostylis moniliformis (Griff.) Seidenf., Goodyera hispida Lindl and Goodyera yunnanensis Schltr. The voucher specimens are deposited in the Herbarium of Tibet Institute of Agriculture and Animal Husbandry (TAAHUC) and Herbarium of Wuhan Botanical Garden, CAS (WIB). Most of the plants of the Subtribe Goodyerinae have extremely high medicinal value. The report of this new record is of great significance to the introduction, propagation and domestication, biodiversity protection and development and utilization of medicinal Orchidaceae in Tibet.

Peroxidase (POD) is a ubiquitous and highly active enzyme in plants, which plays an important role in plant growth and development and stress response. There are few reports on the analysis of POD family genes and the response to salt stress. In this study, 94 POD family members were identified in luffa genome by bioinformatics methods. They had similar gene structure, most of them contained 3-4 exons. The number of coding amino acids were ranged from 89 to 688, with an average of 309. The pI of the protein was between 4.58 and 10.34. 57 of them were basic amino acids. 82 members were hydrophilic proteins. POD family members were unevenly distributed on 13 chromosomes of luffa, of which chromosome 7 was the most (20) and chromosome 12 was the least (1). Phylogenetic analysis divided the POD family members into 8 subfamilies. The analysis of the collinearity of POD family genes with Arabidopsis showed that there were 12 pairs of collinearity genes between the two species, and the POD family genes in luffa had expanded. Protein conserved domain analysis showed that POD family members all contained plant peroxidases conserved domains and had similar conserved bases. The gene promoter contained a large number of plant hormone response elements such as abscisic acid, gibberellin, auxin, ethylene, salicylic acid, methyl jasmonate, and stress response cis elements such as low temperature, hypoxia, light, drought defense and stress response, indicating that it may be induced by abiotic stress. The analysis of cis acting elements in the promoter showed that the promoter contained a large number of phytohormone (abscisic acid, gibberellin, auxin, ethylene, salicylic acid, methyl jasmonate) response elements and stress (low temperature, low oxygen, light, drought, defense and stress response) response cis elements. When luffa seedlings were stressed by 200 and 500 mmol/L NaCl, the POD activity increased, and the gene expression of 56 POD family members increased significantly. Through expression trend analysis, two significant enrichment trends were obtained, including 35 genes that were significantly up-regulated under salt stress, indicating that the genes may participate in the response to salt stress. This study is the first time to identify the members of the POD family of luffa at the genomic level, and analyzed the physical properties and expression under salt stress. The results of this study would lay a theoretical foundation for exploring the biological functions of POD family members in luffa.

Powdery mildew caused by Erysiphe quercicola is one of the major diseases of rubber trees. There have been large outbreaks in rubber tree planting areas in China in recent years, seriously reducing the rubber yield. As a common protective forest species in rubber plantations, the evergreen tree Acacia mangium is one of the important host of rubber tree powdery mildew. The study of the biological interactions between E. quercicola and A. mangium could improve the understanding of the behavior of E. quercicola and provide technical guidance for effectively controlling of the primary source of the disease. In this study, cold acclimation significantly enhanced the resistance of A. mangium to rubber tree powdery mildew. The young leaves of A. mangium cultured at 23 ℃ had severe lesions when inoculated with E. quercicola, the young leaves of plants acclimated at 19 ℃ for 30 days had less lesions, and the young leaves of plants acclimated at 15 ℃ for 30 days and the mature leaves cultured at 23 ℃ had no lesion. Electron microscopy scans revealed that the surface of young leaves of A. mangium cultured at 23 ℃ was uneven. The surface of the young leaves cultured at 19 ℃ tended to be flat, with a raised and well-arranged waxy crystal structure. The raised and irregularly waxy crystal structure superimposed and entangled with each other. The surface of young leaves of plants acclimated at 15 ℃ and mature leaves of plants cultivated at 23 ℃ was flat. The surface of the waxy crystal structure was smooth and had obvious crystal-like waxes. Gas chromatography-mass spectrometer (GC-MS/MS) was used to analyze the wax content of A. mangium leaves on both the qualitative and quantitative level. Compared with the young leaves of A. mangium cultivated at 23 ℃, the wax composition of the young leaves acclimated at 15 ℃ and 19 ℃ and the mature leaves of the plants cultured at 23 ℃ were more complex. The main wax components and contents of young leaves acclimated at 15 ℃ were more consistent with those of mature leaves cultured at 23 ℃, and the relative contents of C₃₆ alkane, C₃0 ketone, C₃₂ ester, and C₃₀ alcohol were significantly decreased. In addition, cold acclimation at 15 ℃ could increase the SOD, CAT and POD oxidase activities of young leaves of A. mangium infected by E. quercicola, with SOD enzyme showing the greatest increase. In summary, cold acclimation may improve plant disease resistance by promoting the maturation of the structure and composition of the waxes of young leaves of Acacia mangium and restraining the infection of E. quercicola. This study is useful for understanding the interactions between rubber tree powdery mildew and its hosts, and provides a theoretical basis for efficient control of this disease.

In this paper, on the basis of potato sucrose agar medium, the single factor and L₁₆(4⁵) orthogonal optimization experiments were used to study the effects of 5 environmental factors on the mycelial growth and coremium formation of P. cystidiosus. The results showed that the mycelium of P. cystidiosus could grow in the range of temperature 10-30 ℃, agar concentration 0.5%-3.0%, pH 4.00-10.00, petri dish diameter 60-100 mm, and light time 0-24 h. The mycelium grew the fastest under the conditions of temperature 25 ℃, agar concentration 3.0%, pH 5.80, petri dish diameter 100 mm and dark conditions. The coremium of P. cystidiosus can be formed in the range of temperature 15-30 ℃, and the other environmental conditions were the same as that of its mycelium. The number of coremium formation was the largest under pH 8.00, petri dish diameter 100 mm and light duration of 24 h. The orthogonal optimization test showed that the optimum environmental conditions for mycelium growth of P. cystidiosus were temperature 25 ℃, agar concentration 3.0%, pH 5.80, petri dish diameter 100 mm, and dark conditions. The optimum environmental conditions for its coremium formation were temperature 25 ℃, agar concentration 2.0%, pH 8.00, petri dish diameter 100 mm, and light duration 14 h. In a word, the environmental conditions had a great influence on the mycelium growth and coremium formation of P. cystidiosus, and there was an interaction.

In order to study the changes of cassava yield, quality, photosynthetic performance and soil enzyme activities under cassava intercropping mode of muskmelon, and to provide theoretical basis for improving the cultivation technology of cassava intercropping muskmelon in Changsha, cassava (Nanzhi 199) and muskmelon (Xiangtian thin crisp) were used as the experimental materials, cassava monoculture (CK) was used as the control, and three planting densities (T₁, T₂, T₃, plant spacing of 0.5, 0.7, 0.9 m) of muskmelon in cassava intercropping were used as treatments. Compared with monoculture cassava, the number of tuber per plant, dry matter percentage and starch content of cassava were not significantly changed under intercropping treatment, but the yield per plant, economic yield, soluble protein and vitamin C content of cassava increased under intercropping treatment. The effects of each treatment on cassava yield and quality were in the order of T₂>T₃>T₁>CK. The photosynthetic capacity of cassava leaves in intercropping mode significantly increased, and the net photosynthetic rate (P_n) of cassava leaves in root tuber formation and expansion stage was significantly higher than that of monoculture treatment. The P_n of cassava leaves under T₂ treatment was significantly higher than that under other treatments, and the intercropping treatment had significantly higher intercellular CO₂ concentration (C_i), stomatal conductance (G_s) and transpiration rate (T_r) than those under monoculture treatment. With the growth of cassava plants, the activity of sucrase in soil showed a trend of decreasing first and then increasing, urease showed a trend of increasing first and then decreasing, while acid phosphatase and catalase showed a trend of decreasing gradually. The activity of sucrase, acid phosphatase and catalase in soil was significantly promoted by intercropping at different stages, but had little effect on urease activity. The activity of sucrase, acid phosphatase and catalase in soil of T₂ treatment was significantly higher than those of monoculture treatment at the expansion and maturity stages of cassava roots. In conclusion: Compared with cassava monoculture, cassava intercropping model improved cassava photosynthetic performance and soil fertility level, so as to improve the economic yield and quality of cassava. The optimal cultivation model with two rows of cassava intercropping and one row of melon with a distance of 0.7 m was suitable for the cassava intercropping model in Changsha.

The effects of soil compaction caused by the mechanical harvesting of sugarcane variety Guitang 42 on growth and the content of endogenous hormones of roots were studied. The results showed that at the seedling stage, the compaction of 0-50 cm soil layer in the planting row and in the inter-row space increased greatly in mechanically harvested plots compared to the manual harvesting (control), with the highest compaction occurring in the top 0-10 cm layer. There was no significant difference in the compactness of 0-30 cm soil layer in the planting row between mechanically and manually harvested plots, but the compactness of 30-50 cm layer in the inter-row space was significantly higher in the mechanically harvested plots than that in the control. Mechanical harvesting significantly reduced the plant growth rate, plant height, millable stalk number and cane yield by 42.0%, 19.4%, 26.1% and 36.9%, respectively, compared to the control. However, sucrose content in the mechanised crop increased by 1.40, 0.75 and 0.58 % compared with the control. There was no significant difference in plant height, stem diameter, millable stalk number and yield between RCC and control Rootmorphology, root dry weight and root length decreased by 9.12% and 10.72%, respectively, and total root surface area and total root volume significantly decreased, while there was no significant difference between mechanized compaction and control. The endogenous content of hormone IAA, GA₃ and ZR and the levels in relation to that of ABA (IAA/ABA, GA₃/ABA and ZR/ABA) in sugarcane roots grown in compacted soil decreased to varying degrees, compared to that of the control. The root ABA content significantly increased in compacted soil IAA, GA₃, IAA/ABA and GA₃/ABA were positively correlated with root dry weight, root length, plant height and millable stalk number, while ZR and ABA were negatively correlated. In conclusion, mechanical compaction significantly increased soil compactness of sugarcane field, and greatly decreased the growth and yield composition of sugarcane root system.

One genus and five species of vascular plants, Nepeta Linn. , Nepeta cataria Linn. , Keiskea sinensis Diels, Leptochilus ellipticus var. flexilobus (Christ) X. C. Zhang, Illigera rhodantha Hance, Scutellariafranchetiana Levl, were reported as new records to Fujian, China in this study. The voucher specimens were preserved in Museum of Fujian Bioengineering Vocational and Technical College.

This study aimed to investigate the mineral nutrient composition, improve the economic benefits of Ficus hirta Vahl (FH) planting and increase the feed source for the animal farming. The biomass and mineral elements content in leaf, stem and fruit of one-year and two-year-old FH plants intercropped with rubber tree and monoculture was analyzed in the study. The results showed that the aboveground biomass of FH ranged from 3.06 to 9.22 t/hm², which showing monoculture>intercropping, biennial>annual. Intercropping increased the leaf biomass of FH and decreased the stem biomass. Two-year-old intercropping FH plant was mainly fruit development and the fruit biomass was significantly increased by 99.64%. Aboveground plants of FH was rich in mineral elements. The content of mineral elements in leaves and fruits was higher than that in stems. Intercropping under the rubber plantation increased the contents of N, K, Mg, Mn, Cu and Zn, and reduced the contents of Ca and Fe. In the macroelements, the content of K was the highest and P content was the lowest. The ratio of Ca to P in leaves, stems and fruits was between 1.52 and 4.84. In the microelements, the content of Mn was the highest and Cu content was the lowest. The content of mineral elements in leaves and fruits of FH was higher than that in stems. The mineral nutrition of two-year plants was better than that of one-year plants. Intercropping under forests would change the mineral nutrition composition of plants. The FH plant was not suitable for feeding alone according to its mineral nutrient composition. But it could be used as a feed additive to replace part of roughage and save feed cost.