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.

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.

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.

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.

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.

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.

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.

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.

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.

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.