HSP90 is a key component in maintaining intracellular homeostasis, and it controls multiple cellular processes by regulating the maturation, stability, activity and turnover of its substrates. Rubber tree (Hevea brasiliensis Müll. Arg.) is an important source for the production of natural rubber, which has thousands of industrial uses and a high socioeconomic value. Using PCR technique, an HSP90 family member gene, named HbHSP90.6 gene (GenBank accession number: OP375588), was cloned from rubber tree variety Reyan73397 latex, and the sequence analysis showed that its coding region (CDS) was 2112 bp. Physicochemical analysis showed that its relative molecular weight was 80 774.85 Da, isoelectric point was 5.04, instability coefficient was 38.98, and total average hydrophilicity was -0.610, presumably HbHSP90.6 protein is a stable hydrophilic protein. The results of conserved structural domain analysis and multiple sequence alignment showed that HbHSP90.6 contained a structural domain of PTZ00272 and a highly conserved MEEVD motif, which is a member of the HSP90 family. Phylogenetic analysis showed that HbHSP90.6 clustered with Arabidopsis AtHSP90.1 (NM_124642.4) and rice OsHsp90-1 (LOC_Os04g01740) with 92.34% and 86.44% homology, respectively. Tissue expression analysis showed that the gene expression of HbHSP90.6 gene in latex was significantly higher than that in root, flower, branche, stem and leaf, and the expression of HbHSP90.6 gene in latex reached 283-fold relative to flowers, presumably the HbHSP90.6 gene may be involved in intracellular transport of latex tubes and regulation of latex metabolism. Mechanical wounding treatment in latex significantly upregulated the expression of HbHSP90.6 gene by 19 fold compared to the pretreatment pair, and it is hypothesized that HbHSP90.6 gene is involved in mechanical wounding regulated physiological and metabolic activity responses in rubber trees. The expression of HbHSP90.6 gene reached the highest level at 6 h of treatment with the phytohormones ethephon, jasmonic acid and 3-Indoleacetic acid, which were 45 fold, 17 fold and 6 fold higher than before treatment, respectively. The expression of HbHSP90.6 gene was significantly upregulated at 12 h after brassinosteroids treatment, reaching 50 fold of the pretreatment expression, presumably the HbHSP90.6 gene is involved in phytohormone mediated transcriptional regulation. Subcellular localization was performed by constructing a 35S::HbHSP90.6::GFP fusion expression vector, and the results showed that the HbHSP90.6 gene was localized in the cytoplasm and nucleus, which was consistent with the predicted results of subcellular localization. The results of this study would provide a thorough basis for elucidating the molecular mechanisms of HbHSP90.6 gene in plant hormone signaling-regulated stress and latex metabolism in rubber trees.

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.

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.

The enlarged corm of Chinese water chestnut (Eleocharis dulcis) is the main edible part, and the related genes involved in the regulation of the corm enlargement process remain unclear. COL5 (CONSTANS-Like 5) gene is a member of COL gene family, which may play an important role in the development of plant storage organs. The transcript fragment with high homology to COL gene in other plants was screened from the Chinese water-chestnut transcriptome databases and cloned its cDNA sequence and full-length DNA, and then the bioinformatics analysis and spatiotemporal expression pattern analysis were analyzed to study the expression pattern and possible role of Chinese water-chestnut COL5 during corm enlargement. The results showed that the cloned COL5 gene related to Chinese water-chestnut enlargement had an ORF of 1017 bp, encoding 338 amino acids, and the DNA sequence was 1275 bp, containing an intron of 257 bp, which was named CwCOL5 (ON934922). Bioinformatics analysis showed that the CwCOL5 protein with the formula C₁₅₉₂H₂₅₁₅N₄₇₇O₅₀₈S₁₇, the relative molecular weight of the predicted protein was 37 010.39 Da, and a theoretical isoelectric point of 5.89. The total average hydrophilic value (gravy) was -0.462, the instability coefficient was 45.63, which was a hydrophilic unstable protein. There were 31 phosphosites, no transmembrane structure, and no signal peptide, and additionally subcellular prediction analysis showed that it was located in the nucleus. CwCOL5 contained two B-box Zinc fingers and a highly conserved CCT domain. Phylogenetic analysis showed that CwCOL5 was closely related to the COL protein of Nelumbo nucifera and Arabidopsis. The results of PCR showed that CwCOL5 had a high expression in the leaves and water-chestnut peel, and the expression of CwCOL5 increased rapidly in the early stage of corm enlargement. The CwCOL5 gene belongs to a typical transcription factor family of zinc finger protein, and the gene may be involved in the process of corm enlargement of Chinese water-chestnut. In this study, COL5 gene was cloned from the corm of Chinese water-chestnut and its expression pattern was analyzed, which would provide a theoretical basis for molecular mechanism of plant corm enlargement.

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.

A new recorded plant of Asteraceae, Porophyllum ruderale (Jacquin) Cassini was reported in Hainan which could be used as a spice. This paper introduced the biological characters, origin and distribution of P. ruderale, and evaluated the ecological invasion risks, and analyzed the value of being a spice plant, which could provide references for the prevention, control as well as the development and utilization of spice resources on the exotic species in Hainan province.

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.

To lay a foundation for the scientific evaluation of the ornamental traits of Primulina, 40 species of the Primulina were used as the experimental materials. The analytical hierarchy process was applied and four first-level indicators including foliage traits, flower traits, plant characteristics and cultivation performance to construct the constraint hierarchy were selected, then 14 secondary indexes including leaf shape, leaf pattern, leaf color, flower color and pattern, corolla size, flower quantity, flowering period, leaf arrangement, plant type compactness, peduncle shape, cultivation difficulty, pest and disease were selected to construct a comprehensive evaluation system for the ornamental traits of Primulina. The results showed that among the four first-level indexes, the weight of cultivation performance was 34.0%, which is the highest, followed by plant characteristics (26.6%), flower traits (24.0%), and foliag traits (15.4%). Among the 14 second-level indexes, the weight of cultivation difficulty, peduncle shape, leaf pattern and leaf arrangement on the ornamental value of Primulina all exceeded 10.0%. The weight of cultivation difficulty was 17.2%, which is a key indicator affecting the ornamental value of Primulina. According to the established scoring criteria, 40 species of Primulina were assigned, combined with the weight to calculate the scores, and divided into three grades: Grade Ⅰ (score over 3.5), 10 species with high ornamental value; Grade Ⅱ (score 3.0-3.5), 20 species with medium ornamental value; Grade Ⅲ (score below 3.0), 10 species with low ornamental value. Among them, the species rated as high ornamental value (Grade Ⅰ) are: P. Cleopatra, P. Snow Angel, P. guizhongensis, P. Stardust, P. qintangensis, P. Blue Mood, P. liujiangensis, P. hochiensis var. rosulata, P. Flying Wings and P. macrorhiza, these 10 species of Primulina are easy to cultivate and have outstanding performance in flower viewing, foliage and plant types, which can be used as excellent hybrid parents to participate in breeding, and can also be directly promoted to the market; the species classified as low ornamental value (Grade Ⅲ) are often difficult to cultivate, with poor stress resistance, and peduncle shape are poor, lack of characteristic flower color and pattern. The 40 species of Primulina are divided into 5 categories according to their ornamental values by cluster analysis, and the species with complementary traits can be selected as parents to produce better hybrid varieties.

Tropical crop germplasm resources are an important basis for the development of tropical agricultural science and technology in China. In order to fully implement the protection and utilization of tropical crop germplasm resources, and promote the high-quality development of the tropical crop industry. This study elaborates in detail on the collection and preservation of tropical crop germplasm resources, the construction of germplasm resource nurseries (libraries), and the innovative utilization of germplasm resources in China. According to the development status and long-term positioning, the problems at the current stage were point out, and corresponding opinions and development suggestions were put forward.

Information management of germplasm resources is the only way to improve the efficiency of germplasm resource management, sharing is an important means to activate the utilization value of preserved germplasm resources and realize the multiplier effect of seed industry, benefit distribution in sharing activities is the original incentive to promote germplasm resource sharing, and benefit ownership certificate is the key basis for benefit distribution. At present, the management of tropical crop germplasm resources is faced with the following problems: decentralized management of resource flow business chain; distortion of information data of resources and business chain; lack of evidence chain of credible benefit distribution of resources. To solve these problems, based on block chain technology, we put forward a kind of block chain system for tropical crop germplasm resources management to solve the problem of information asymmetry, by using decentralization, tamper-resistant, marks keeping in whole process, traceability, collective maintenance, and transparency, so as to realize the many relevant institutions of tropical crop germplasm resources and link collaboration trust and consistent action, effectively address the above issues and challenges. The system can keep marks processed and trace back to source, in full life cycle of tropical germplasm resources, laid the foundation for the combination of agriculture and computer agriculture, and resource traceability issues research. It is of great significance to the efficient management of tropical crop germplasm resources and the mining of potential value.

Rubber tree is the most important cultivated rubber-producing plant, and the tapping of trunk is the only way to obtain natural rubber from the laticifer in the bark currently. The characteristics of latex flow after tapping determine the latex yield, but the mechanism of latex flow is not yet completely clear. The turgor pressure of bark is the main initial driving force for latex flow, and the content of lignin, as the main component of cell wall, is closely related to the turgor pressure. At present, the study on the lignin content in bark of rubber tree is deficiency, among which the analysis of lignin content by morphological structure is lack. Using the bark of RY8-79 and PR107 mature tree as the research materials, paraffin sections were prepared, and the lignin in the bark was stained and localized by Wiesner reaction, Mäule reaction, and safranin staining combined with fluorescence, respectively. The results showed that both Wiesner reaction and Mäule reaction could stain the lignin component of the parenchyma cell wall, but difficult to distinguish different strains and tissues for the light color. The light purplish red of lignin in the parenchyma cell could be observed after safranin staining, but it was also difficult to distinguish different tissues and strains. The obvious red fluorescence of lignin tissue could be observed after safranin staining combined with 546 nm green light excitation, and there was significant difference among different cell types and strains. The lignin fluorescence of parenchyma cell in RY8-79 was significantly weaker than that in PR107, indicating that the content of lignin in RY8-79 was lower than that in PR107. Iodine-bromine staining showed that the distribution of secondary laticifer was consistent with the distribution of lignin with strong fluorescence, indicating that the lignin content of secondary laticifer and its surrounding parenchyma cells increased significantly, especially in PR107. In addition, Wiesner and Mäule reaction needed dangerous chemical reagents such as phloroglucinol, hydrochloric acid and potassium permanganate (KMnO₄), respectively, and the reaction time was not easy to control for slices falling off from slides and cell wall damage. By comparison, the reagents used for safranin staining combined with fluorescence observation were safe and non-toxic, and the structure of cell in bark could maintain intact easily. According to the comprehensive analysis of different methods, for the excellent clarity of lignin as well as safety and simplicity of operation, safranin staining combined with fluorescence observation is the most suitable method for lignin location in parenchyma cell of rubber tree bark.

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.

In order to provide theoretical and practical basis for the effective molybdenum deficiency control measures and rational application of molybdenum fertilizer, field investigation, morphological diagnosis, leaf nutrients content determination and spraying test of ammonium molybdate were carried out in navel orange (Citrus sinensis Osbeck). Further, navel orange leaves with different degrees of chlorisis were collected to measure photosynthetic pigment concentration, photosynthesis rate, chlorophyll fluorescence parameters and photosynthetic product concentration. For normal, slight chlorisis and severe chlorisis leaves, the concentration of nitrogen, potassium, magnesium and born were all in optimum range, zinc and calcium content were no significant difference. The molybdenum content of slight chlorisis and severe chlorisis leaves were lower than that of the threshold value of molybdenum deficiency (0.10 mg/kg), and decreased significantly than the normal leaves. Spraying 0.05% ammonium molybdate significantly reduced the symptoms of chlorisis, indicating that the yellowing leaves of navel oranges in the test orchard was caused by molybdenum deficiency. Molybdenum deficiency symptoms of navel orange were with nearly round and bright yellow waterlogged spots or patches on the new leaves, and the leaves were distorted with the edge leaf rolled up or inward. Photosynthetic pigment concentration, activity of RUBP carboxylase, potential activity (F_v/F_o), maximum photochemical efficiency (F_v/F_m), electron transfer efficiency (ETo/RC) and quantum yield (ETo/CSm) of PSⅡ reaction center decreased significantly with molybdenum deficiency, while the heat dissipation coefficient (DIo/RC) increased significantly. Molybdenum deficiency significantly decreased the photosynthetic rate (P_n), soluble sugar and sucrose contents, indicating molybdenum deficiency will decrease the photosynthesis of navel orange.

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.

The purpose of the paper is to investigate the physiological and biochemical mechanism of drought and low temperature stress in Sophora davidii seedlings. S. davidii seedlings were used as the experimental materials to evaluate the changes of anti-oxidant protective enzyme activities, membrane injury indexes, osmotic adjustment substances in leaves under increasingly severe drought in natural conditions, and late artificial low temperature treated, with pot experiments. The results showed that the relative water content of leaves decreased significantly with the increase of drought time, and the growth could be restored 2 days after rehydration. Moderate drought was beneficial to the accumulation of photosynthetic pigments, but the content of synchromes decreased in severe drought. Superoxide dismutase (SOD), peroxidase (POD) and catalase (CAT) activities first increased and then decreased with prolonged drought stress. The peak activity of SOD and POD was 458.85 U/g and 5.30 U/g, respectively on the 8th day, which was 142.53% and 68.25% more than CK respectively. Malondialdehyde (MDA) showed a slow increase with the prolonged drought stress, the peak value was 6.20 mmol/g FW on the 15th day, which was 108.75% higher than that of CK. Osmotic adjustment substances such as proline increased first and then decreased with prolonged drought stress, the peak value was 459.67 mg/g on the 10th day, which was 226.45% higher than that that of CK. Under drought stress and low temperature, photosynthetic pigment content of S. davidii leaves decreased significantly, and the changes of three protective enzymes activities (SOD, POD and CAT) increased first and then decreased, which were similar to those under drought stress. Malondialdehyde (MDA) and proline (Pro) showed increase gradually when cold stress continued. Three protective enzymes could play inter-coordinating roles at different stress stages for drought resistance and cold tolerance of S. davidii. The study revealed that S. davidii positively responded to stress through improved antioxidant enzyme activity and the accumulation of osmotic adjustment substances as proline, which could help to reduce reactive oxygen to the membrane damage. Drought stress could improve the adaptability to low temperature, which may be related to the enhancement of protective enzyme system and osmotic regulation ability.

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 this study, potassium hydroxide (KOH), ammonia, sodium dodecyl sulfate (SDS) and potassium laurate were added to NRL to study the effects of different stabilizers on the stability of NRL. The results showed that KOH could quickly increase pH value of NRL, maintain the viscosity of fresh latex, improve the mechanical stability (MST) of fresh latex, especially when the dosage exceeds 0.3%. But KOH would increase the viscosity of concentrated natural rubber latex (CNRL), lead to the thickening of the CNRL. It had no obvious effect on improving MST and the mechanical stability (ZST) of the concentrated latex. KOH could significantly improve the thermal stability of the CNRL, significantly improve the particle size of the rubber particles. When the dosage of ammonia was low, pH value of NRL could quickly increased, but when the dosage was high, the effect of improvement was not obvious. Aammonia could stabilize the viscosity of fresh latex, increase MST of fresh latex, but when the dosage exceeded 0.2%, the increase was no longer obvious. At the same time, ammonia could maintain the fluidity of CNRL and stabilize the viscosity value. Ammonia had no obvious effect on improving MST, ZST and thermal stability of CNRL, it had no obvious effect on the particle size of latex rubber particles. SDS would increase the viscosity of the fresh latex, resulting in the thickening of the fresh latex, but it could maintain the fluidity of the CNRL and inhibit the viscosity increase. It could slowly increase MST and ZST of CNRL. Increasing the average particle size of rubber particles also had a certain effect. Potassium laurate would increase the viscosity of fresh latex, resulting in thickening of fresh latex, at the same time, it would also cause CNRL to thicken slowly. Potassium laurate could also rapidly increase MST and ZST of concentrated latex, and cause CNRL to heat up the stability decreases rapidly. It also had a certain effect on increasing the average particle size of rubber particles, but when the dosage exceeded 0.3%, the particle size would also decrease. Therefore, the type and dosage of stabilizers need to be controlled during the production of CNRL.

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.

To explore the effect of the extract from Camellia oleifera cake on the postharvest disease resistance of pitaya, pitaya Zihonglong was sprayed with different concentrations of C. oleifera cake extract before harvest. The fruits were stored at (10±0.5)℃ and 90%-95% RH after harvest. The changes of physical and chemical properties, nutritional components, reactive oxygen species (ROS) metabolism and defense-related enzyme activities of pitaya fruits after harvest were analyzed, and the correlation between each index and comprehensively scores were analyzed. The results indicated that the preharvest spraying extract from C. oleifera cake could effectively reduce the decay index (DI) of pitaya fruit. The respiratory rate (RR) and ethylene release rate (ERR) of pitaya fruit were effectively inhibited by C. oleifera cake extract at the later storage period. Pitaya fruit treated with C. oleifera cake extract effectively delayed the decrease of ascorbic acid (AsA) content, and increased the activities of catalase (CAT), superoxide dismutase (SOD) and other antioxidant enzymes, effectively promoted the metabolism of hydrogen peroxide (H₂O₂) in fruit, reduced the H₂O₂ content, and effectively removed the ROS accumulation during the fruit physiological metabolism. Meanwhile, the C. oleifera cake extract effectively increased the activities of defense-related enzymes such as phenylalanine ammonialyase (PAL), peroxidase (POD), polyphenol oxidase (PPO), β-1,3-glucanase (GLU) and chitinase (CHI) in pitaya fruit, thus improving its disease resistance. Correlation analysis founded that pitaya fruit DI was closely related to the ROS accumulation and membrane lipid peroxidation. Decreasing oxidative stress and maintaining the integrity of cell membrane were the basis for improving the disease resistance of pitaya fruit, and enhancing the disease resistance of pitaya fruit was helpful to reduce decay. Comprehensive evaluation showed that the comprehensive score of pitaya fruit preharvest spraying with 1.00% C. oleifera cake extract was the highest, indicating that its treatment effect was the best. In conclusion, preharvest spraying with 1.00% C. oleifera cake extract could maintain quality of pitaya fruit by improving the antioxidant and disease resistance. The results provide a theoretical reference for the application of C. oleifera cake extract in the postharvest storage and preservation of pitaya.

This paper reported the density, pH value, starch content, soluble protein content, anatomical structure and volatile components of the wood of Humbertia madagascariensis Lam. (HM), which is an endemic species in Madagascar. Methods for determination of wood density (GB/T 1933—2009), determination of wood pH (GB/T 6043—2009), anthrone colorimetric method, coomassie brilliant blue method, wood anatomy method and gas chromatography mass spectrometry (GC-MS) were used to determine the above contents. The results would provide a basis for the research on the wood identification, plant conservation, processing and utilization. The wood basic density of HM was 1.684 g/cm³, and it sank in water test. The wood pH value, starch content and soluble protein content of HM was 6.78, 10.953 mg/g and 0.271 mg/g respectively. The macroscopic structure of HM wood was yellowish-brown, glossy, with the smell of "citrus and sandalwood", diffuse-porous wood with large pore, with white to golden yellow tyloses inside and at the edge especially obvious on the tangential section, wood ray with clear, uniform and fine on the cross section, stripes obviously and densely distributed on the radial section, threadlike, ripple marks slightly visible on the tangential section. The microscopic structure of HM wood was elliptic or round pores, with 3-5 pores per square millimeter, dispersed and solitary vessels containing golden gum inside and at the edges of the pores, non overlapping and homogeneous uniseriate wood rays, with 7-9 wood rays per millimeter, large, mostly elliptic or oblong wood ray cells usually without gum, square cell ray recumbent with 3-7 layers, obvious numerous and regular longitudinal arrangement elliptic crystalson the outside of vessels and in the fibrous tissue on the three sections. GC-MS analysis indicated that the main components were fatty acids (88.81%), followed by lipids (8.12%) and terpenes (0.94%). The highest content of the compound was n-hexadecanoic acid (47.32%), followed by octadecanoic acid (38.79%). It also contained a small amount of unsaturated fatty acids, such as (Z,Z)-9,12-octadecadienoic acid (0.23%) and oleic acid (0.61%), which be speculated may related to "citrus and sandalwood" smell from the wood of HM.

To clarify the adaptability of Eotetranychus sexmaculatus in different main rubber strains in rubber planting areas in China, the development and reproduction of E. sexmaculatus in six rubber strains, Reyan 73397, Reyan 72059, Reken 628, Dafeng 95, PR107 and RRIM600, were observed by biological methods, and the experimental population life table was established. The results showed that different rubber strains had significant effects on the development and reproduction of E. sexmaculatus. The whole generation duration of E. sexmaculatus was the shortest in RRIM600 strain and the longest in Reken 628, which was 10.93 d and 12.82 d, respectively, followed by Reyan 73397, Reyan 72059 and PR107, with no significant difference. The juvenile survival rate of Dafeng 95 strain was the lowest, only 65.00%, and there was no significant difference among other strains. The large number of fecundity per female was the largest when feeding on RRIM600, which were 18.38 eggs. PR107 strain was the most unfavorable to the survival and reproduction of adult mites, and its life span and spawning period were also the shortest. There was significant difference in the sex ratio of F₁ generation of E. sexmaculatus on different rubber strains and the female rate of Dafeng 95 was the highest, which was 78.67%. Through the establishment of population life table for parameter analysis, the intrinsic rate of increase and finite rate of increase of E. sexmaculatus were the largest in RRIM600, and the lowest in Reyan 73397, followed by Reyan 72059, Reken 628 and PR107, which was no significant difference among the Reyan 72059, Reken 628 and PR107. The double population time was the shortest in RRIM600, while was the longest in Reyan 73397, followed by Reyan 72059, Reken 628 and PR107. In a comprehensive view, it showed that E. sexmaculatus had a high fitness when feeding on RRIM600 and a low fitness on PR107.

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.

The aim of this study was to investigate the effects of pitaya stem polysaccharide (PSP) on the cellular immune function in mice with cyclophosphamide induced immunodeficiency. In this study, the toxicity of pitaya stem polysaccharide was evaluated, and the immune function of mouse cells was evaluated by detecting the proliferation ability of mouse lymphocytes induced by mitogen, calculating the body weight, spleen index, spleen immune count and blood cell count of mice. PSP had no inhibitory effect on the survival rate of lymphocytes. PSP-1 and PSP-2 had the same proliferation effect on T lymphocytes, but had no obvious effect on B lymphocytes. In the immunocompromised mouse model, the splenic index and blood cell count of mice treated with PSP were alleviated, and the effect was better in the high-dose group, but the enhancement of whole splenic immune cells was not obvious. The results showed that PSP-2 may be the active component of PSP-1 to exert immune function, T lymphocytes are the main effector cells, and the immune function of dragon fruit stem polysaccharide is mainly achieved by promoting lymphocyte proliferation.