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.

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.

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.

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.

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.

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 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.

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.

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.

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.