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.

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.

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 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.

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.

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.

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.

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.

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.