The effects of NPK fertilizer applying on the properties and molecular weight of natural rubber were studied using an orthogonal test design on the eight years PR107 rubber trees. Different types and levels of fertilization had a significant effect on dry rubber content. The optimum combination of dry rubber content was urea 300 g/plant, calcium superphosphate 250 g/plant, and KCl 75 g/plant. The optimum combination of P0 was calcium superphosphate: 375 g/ plant, KCl 25 g/plant, and that of mooney viscosity was calcium superphosphate 250 g/plant, KCl 25 g/plant, but none of urea for both of them. The optimum combination of PRI was urea 200 g/plant, calcium superphosphate 375 g/plant, and KCl 50 g/plant. Fertilization also had a significant effect on the molecular weight of rubber, and the optimum combination of Mn was calcium superphosphate 125 g/plant, KCl 25 g/plant, but none of urea. The optimum combination of Mw and Mv was urea 300 g/plant, calcium superphosphate 250 g/plant, and KCl 25 g/plant. When producing rubber or latex products, suitable planting environment and fertilization measures could be chosen to produce raw materials according to the requirements of different products.
The soil fertility of Coffea arabica L. was analyzed by massive data of soil sampled in six main producing regions in Yunnan Province during 2015-2018, and compared with the data obtained during the second national soil survey to explore the laws and causes of the variation of the soil fertility. Presently, the soil fertility of C. arabica L. in Yunnan was pH 4.5-5.5 or 5.53 on average, organic matter 32.68 g/kg, alkalystic N 128.77 mg/kg, available P 18.01 mg/kg, and available K 138.31 mg/kg. The soil fertility had significant difference in different altitudes. pH and the content of alkalystic N decreased, the content of soil organic matter and available P increased, and the content of available K increased first and then decreased with the increase of altitude. Compared with the results from the second national soil survey, the soil pH, the content of organic matter, alkalystic N and available K decreased while available P increased significantly. The soil fertility varied significantly due to long-term frequent tillage and large application of chemical fertilizers in suitable areas. It is suggested that the application amount of phosphate fertilizer should be controlled, and the returning of coffee straw and peel to the field should be promoted to achieve the balance of supply and demand for nutrient.
To screen cold tolerance of wild sugarcane germplasms, and to explore the relationship between cold tolerance with original altitude and latitude, the comprehensive evaluation of cold tolerance of clones of Saccharum spontaneum L. from different habitats were performed. After low temperature stress at seedling stage, seven physiological indexes of 40 S. spontaneum clones samples were evaluated using cluster analysis, fuzzy membership function analysis and correlation analysis. Compared with the control group, the contents of Pro, MDA, PMP and SP in the stressed clones increased, in which the content of Pro was the highest by increasing 43.81%. The contents of Chl, SOD and POD decreased, moreover the content of Chl decreased the greatest by 35.01%. The coefficients of variation of Chl, Pro and SOD increased in different degrees, and the biggest increase was found in Chl, which was 1.76 times of the control. The result of correlation analysis showed that the cold tolerance of the 40 S. spontaneum clones was significantly positively correlated with the altitude and latitude of the habitats by correlation coefficients, which was 0.867 and 0.686, respectively. All the 40 S. spontaneum clones were divided into three categories according to the cold tolerance using fuzzy membership function and cluster analysis, in which 10 clones showed high cold tolerance, 19 clones showed medium cold tolerance and 11 clones were cold sensitive. The results showed that there were significant differences in cold tolerance among S. spontaneum clones collected from different habitats, and the membership function of cold tolerance was positively correlated with altitude and latitude, namely the clones collected from high altitude and high latitude had stronger cold tolerance than that collected from low altitude and low latitude habitats. It indicated that latitude is the main factor for the cold tolerance of S. spontaneum clones collected from the same altitude, and altitude is the main factor for the cold tolerance of S. spontaneum clones collected from the same latitude. This work would provide the scientific basis for the further utilization of S. spontaneum clones in sugarcane cold tolerance breeding.
The aim was to investigate the optimum nitrogen (N) fertilizer application for different sugarcanes varieties to conserve resources and reduce pollution. Using three main local sugarcanes varieties, ROC22, LC5136, and YT236, for experiments, 5 levels of N fertilizers quantities were set to study the effects of N fertilizer application on different sugarcanes varieties. The results showed that: (1) The weight of stem and yield of all three sugarcanes varieties increased with N fertilizers increased, followed by no significant change. The best application rate for ROC22 and LC5136 was 351.9 kg/hm 2, while that for YT236 was 234.6 kg/hm 2. The yield of ROC22 was the highest, which was more than LC5136 and YT236 for 8.6% and 40%, respectively. (2) The sugar yield of LC5136 and YT236 increased with increasing N fertilizer, followed by leveling off. The sugar yield of ROC22 with N application of 351.9 kg/hm 2 was significantly higher than no N application, but no obvious difference for different N applications. The average sugar yield of ROC22 was 20% and 57% higher than that of LC5136 and YT236. (3) The effect of N application on three sugarcanes varieties was different. With increasing N application, the use efficiency of N fertilizer of ROC22 and YT236 showed decreasing trend, reaching highest efficiency at 117.3 kg/hm 2. The use efficiency of N fertilizer of ROC22 was 10% higher than that of LC5316 and YT236. Considering the yield of sugarcanes, yield of sugar, and use efficiency of N fertilizer, the optimum N fertilizer application for ROC22 and LC5136 was 351.9 kg/hm 2, while that of YT236 was 234.6 kg/hm 2. The growth of ROC22 in the study area was obviously better than LC5136 and YT236.
The top 0-20 cm soil and the 20-40 cm soil with 1 m, 2 m and 3 m distance from walnut trunk of tea tree-walnut intercropping gardens aged 6 years, 10 years, 15 years and 30 years in Changning, Baoshan City were used to determine the soil pH, organic matter, alkali-hydro nitrogen, available phosphorus and available potassium, exchange of exchangeable calcium and magnesium content. The soil pH value of the intercropping tea garden increased with the extension of walnut tree planting time. The soil pH value of the walnut tree planted for 30 years was close to or greater than 7.0. The contents of soil organic matter, alkali-hydrolysis nitrogen and rapidly-available phosphorus in the intercropping tea garden with intercropping life of 30 years were significantly lower than those in the single-cropping tea garden. With the extension of intercropping years, the content of available potassium, exchangeable calcium and exchangeable magnesium in the intercropping tea garden was higher than that in the single-cropping tea garden. The above results indicate that walnut tree has obvious allelopathy inhibition on tea trees, which leads to the failure of tea tree growth and the decline of tea quality. Therefore, it is not suitable to have the two intercropped or use walnut trees as the shade trees to tea.
The effect of silicate (Si) on the growth and nitrogen (N) nutrition of three banana varieties with normal (200 mg/L) and higher (400 mg/L) nitrogen supply level through sand culture experiments was studied. The biomass of shoots and roots, root activity, concentration of nitrate, total nitrogen and silicon, and the distribution ratio in roots and shoots were changeable by adding silicon. The three banana varieties tested had different responding characteristic. N metabolism had interreaction with Si. Adding silicon increased or reduced markedly the change extent, but among two nitrogen supply levels the change trend had no significant difference. Root activity of ‘Brazil’ banana at normal, ‘Baodao’ and ‘Weiliansi’ banana at higher nitrogen supply level increased distinctly by 46.0%, 38.4% and 186% compared with the control treatment respectively after adding silicon. The ratio of total N concentration in roots to that in leaves of ‘Brazil’ banana reduced markedly after adding silicon, while the ratio of roots to that in pseudo stems of ‘Baodao’ and ‘Weiliansi’ banana at normal nitrogen supply level increased. Silicon concentration in leaves of three banana varieties tested increased by 17.6%-102.3% after adding silicon compared with the control treatment. By adding silicon the change of silicon concentration in roots and that in pseudo stems were related to N supply level and banana varieties respectively. In roots N concentration showed significant linear relationship with silicon concentration at higher nitrogen supply level with no silicon supply.
To study the binder content on the compressive performance of fertilizers and the nutrients leaching characteristics, the contents of different binder were used 0%, 2%, 4%, and 6%, respectively. The nutrient leaching characteristics of fertilizers with binder and common fertilizer with the same ratio of nutrients were measured by the method of soil column leaching test under room condition. And the compressive performance of the manure bars was also measured by a universal testing machine. The results showed that the positive and lateral compressive strength of fertilizer rods could be promoted with higher binder contents. Meanwhile, the nitrogen and potassium leaching rates could be reduced using the fertilizer rods. The total nitrogen leaching rates of fertilizer rods with contents of 0%, 2%, 4%, and 6% binders decreased by 6.21%, 10.52%, 15.83%, and 22.15%, respectively, and the total potassium leaching rates of fertilizer rods with contents of 0%, 2%, 4%, and 6% binders also decreased 26.69%, 50.70%, 55.50%, and 61.79%, respectively. It showed that the the compressive performance of fertilizer rods could be improved using binder, and the fertilizer rods with binder addition had the effect on delaying the release of nutrients in soil, and extended fertilizer nutrient release cycle. It would provide a theoretical basis for the related research on the special slow-release fertilizer for fruit trees in the tropical region.
In order to investigate the effect of sugar metabolism on the somatic embryogenesis of litchi, embryonic callus of ‘Dadingxiang’ and ‘Xinqiumili’ were inoculated on TD medium, respectively, and the embryonic callus of ‘Xinqiumili’ was inoculated on TX medium. Contents of starch, sucrose and other sugar components and activities of the metabolism-related enzymes were compared among the three embryonic cultures. The results showed that starch content on TD and TX medium in ‘Xinqiumili’ were lower than that in ‘Dadingxiang’ during somatic embryogenesis. All the glucose and fructose content were similar, but glucose and fructose contents in ‘Dadingxiang’ was higher than that in ‘Xinqiumili’, while sucrose content in ‘Xinqiumili’ was higher than that in ‘Dadingxiang’. The activity of amylase and β-amylase in ‘Xinqiumili’ were higher than that in ‘Dadingxiang’, but the α-amylase activity in ‘Xinqiumili’ and ‘Dadingxiang’ were similar. The activity of sucrose synthase and acid invertase on TD medium in ‘Xinqiumili’ were higher than that in ‘Dadingxiang’, but neutral invertase activity in ‘Dadingxiang’ was higher than that in ‘Xinqiumili’, and also the dominant by neutral invertase on TX medium in ‘Xinqiumili’. Through converted the starch into the sucrose by amylase, sucrose synthase and invertase in ‘Xinqiumili’ was provided material energy for somatic embryogenesis, while high neutral invertase activity and low amylase activity in ‘Dadingxiang’ can not accumulation of sucrose, maked the efficiency of somatic embryogenesis in ‘Dadingxiang’ was lower than that in ‘Xinqiumili’.
The stems and leaves of different maturity at the seedling stage of high sugar (GT35) and low sugar (B8) sugarcane were used as the materials, and the contents of sucrose, glucose and fructose were measured using high performance liquid chromatography (HPLC), to analyze the correlation and difference between sucrose metabolic enzymes and sugar accumulation in high and low sugar sugarcane. The sucrose content in the leaves was positively correlated with the activity of sucrose phosphate synthase (SPS) and sucrose synthase in the synthesis direction (SS-s). The hexose content in the stem was positively correlated with the activity of neutral/alkaline invertase (NI), the sucrose content in the stem was positively correlated with the activity of SPS, and the activity of sucrose synthetase in the cleavage direction (SS-c), soluble acid invertase (SAI) and cell wall-bound invertase (CIN) was negatively correlated. Sucrose content in the stem of GT35 was significantly higher than that of B8, and sucrose content in the leaf was significantly lower than that of B8. The SPS activity in stems and SS-s activity leaves of GT35 were significantly higher than that of B8, while the SS-s and SS-c activity in GT35 stems was lower than that of B8, but only the SS-c activity in young stems of GT35 was not significantly lower than of B8. It indicates that high SS-s activity in leaves, high SPS activity in stems, low SS-s and SS-c activity in stems may be important factors for regulating sucrose accumulation in high-sugar varieties of sugarcane at seedling stage.
To provide references for rational cultivation and improvement of resistance of strains, the growth and physiological characteristics of two-year-old Camellia azalea at 0, 30%, 50% and 80% shading levels were investigated. The relationships between light intensities and growth and physiological characteristics were analyzed. The results showed that with increasing shading rate, the plant height, ground diameter, crown width, branch number, survival rate, root dry weight, stem dry weight, leaf dry weight and total dry weight of C. azalea increased to a certain extent, with all of them being at the highest level under the 50% shading condition. With the increasing shading intensity, the MDA content, and SOD and POD activities in leaves decreased, then increased, and finally reached the lowest level under the 50% shading condition. However, the content of free amino acids in leaves trended to decrease gradually. Therefore, moderate shading treatment helped the growth of C. azalea seedlings, with 50% shading as the best planting effect.
The disease index and 15 physiological and biochemistry indexes of 19 green stem pakchoi cultivars were measured and analyzed by multivariate statistical analysis methods such as principal component analysis, cluster analysis and regression analysis to evaluate the genetic diversity of heat-resistance evaluation system of green stem pakchoi. The 15 indexes were grouped into 6 principal components with cumulative contributive rate 83.179% by principal component analysis. The varieties were divided into 3 categories based on cluster analysis of comprehensive evaluation of heat resistance would. Qing 11, Qing 16, Qing 13, Qing 9, Qing 18 were in the first category, Qing 19, Qing 4, Qing 7, Qing 5, Qing 14, Qing 12, Qing 15, Qing6, Qing 2 was in the second category, and Qing 10, Qing 8 Qing 1, Qing 3, Qing 17 was in the third category. The mathematical model for evaluating the heat tolerance of green stem pakchoi was established by stepwise regression analysis; D=-0.349-0.063×(RR)+0.163×(FW)+0.222×(SI)+0.394×(TC)+ 0.033×(AA)+0.137×(Pr)+0.159×(SS)-0.091×(CII). Combined with field identification results, Qing 13, Qing 11, Qing 9, Qing 16 and Qing 18 can be planted in Hainan in summer and autumn.
The NAC (NAM/ATAF/CUC) transcription factor gene family was widely distributed in terrestrial plants and plays an important role in the regulation of growth and stress responses. The preliminary research about the role of this gene family on the cassava against bacterial blight was carried out in our lab. Two genes, MeNAC29 and MeNAC30, were cloned from cassava cDNA by RT-PCR, the different expression changes between resistant and susceptible cassava germplasms infected by Xanthomonas axonopodis pv. manihotis (Xam) were also quantified by qRT-PCR. The results showed both MeNAC29 and MeNAC30 contain three exons, two introns, and conserved NAM domain. The length of MeNAC29 gene’s ORF was 888 nt, which encode 295 amino acids, while the MeNAC30 gene’s ORF was 870 nt and encode 289 amino acids. Compared with susceptible cassava germplasms, both two genes’ expression was significantly increased in the resistant cassava germplasms - Xanthomonas axonopodis pv. manihotis interaction, which showed they are involved in resistance response of cassava to bacterial blight.
The SSR fingerprint map and genetic diversity of 68 rambutan (Nephelium lappaceum L.) accessions were studied using 10 pairs of selected polymorphic SSR primers. The results indicated that all the primers showed polymorphism, and 20 polymorphic alleles were revealed and the average polymorphic information content (PIC) was 0.393. The genetic similarities among accessions ranged from 0.290 to 0.664, on which a phylogenetic tree showing the relationship among the accessions was constructed. A strategy of combining primer pair with distinct alleles for fingerprint construction was developed and applied to the 68 cultivars. The DNA fingerprinting provides a technical reference for the varieties identification and molecular breeding in rambutan.
Using terminal buds and stems with axillary buds as the explants, the technology of tissue culture and rapid propagation of standard cut chrysanthemum ‘Baishan’ was studied. The best sterilization conditions of apical bud explants and axillary buds was 75% alcohol 30 s+0.1% HgCl2 for 3 min and 4 min. The best primary culture medium of ‘Baishan’ was MS+6-BA 1.0 mg/L+NAA 0.1 mg/L with the best inducing effect rate 100% and average single bud induction 1.69. The optimal proliferation medium was MS+6-BA 1.5 mg/L+NAA 0.15 mg/L with multiplication coefficient 3.05, effective rate of bud 65.26% and average height 3.22 cm cultivated 30 d after. The 1/2MS medium supplemented with NAA and IBA could induce rooting in bottles, and the rooting rate was 100%. It could root outside bottles. The buds was inserted into the substrate after 5 minutes of immersion in the NAA solution, and the rooting condition was good. The results could be applied directly for production popularization of ‘Banshan’. The results could provide theoretical and technical guidance for the large-scale promotion and industrialization of ‘Baishan’ and standardized production of seedlings.
Rapid propagation in vitro of Codiaeum variegatum ‘Golden Queen’ was studied using apical buds and stem segments with axillary buds as the explants. Establish a research system for the rapid growth of the ‘Golden Queen’ to provide theoretical basis and technical support for the factory production of the ‘Golden Queen’. The optimum conditions for the surface disinfection of the explants was disinfected first by 75% of alcohol for 30 s and then by 0.1% mercuric chloride for 10 min, which resulted in a pollution rate of 25.2% and a high survival rate of 72.77%. The best primary culture medium was MS+6-BA 2.0 mg/L+IBA 0.2 mg/L, on which the bud induction rate was 3.75. The best medium for proliferation was MS+6-BA 1.0 mg/L+ NAA0.2 mg/L, on which the proliferation coefficient was 10.77. The most suitable medium for rooting was 1/2MS+ IBA 1.5 mg/L, on which the rooting rate reached 100%. The optimum medium for transplanting the in vitro seedlings was peat, sand, and vermiculite at the ratio 3:1:1, respectively, on which the survival rate was 90%.
This study aimed to survey the population of dematiaceous hyphomycetes from decay branches from a subtropical forest in Xishui National Nature Reserve in Guizhou. A newly recorded genus from China—Dwayabeeja was identified on the morphological and micorscopicic characterstics by consulting relevant data and literature. The examined specimens are deposited in the Mycological Herbarium of Zunyi Normal University (HMZNC).
In order to identify the pathogen of leaf spot disease on Nelumbo nucifera Gaertn. and to study the biological characteristics, the samples of Corynespora leaf spot on lotus roots were collected from a lotus root field in Haikou, Hainan. The results showed that the pathogen was Corynespora cassiicola (Berk.& Curst.) Wei, the optimum temperature for mycelial growth was 25?30 ℃, and 28 ℃ was the most suitable temperature. The suitable pH was 6-9 and the best pH was 7. The mycelium of C. cassiicola grew well on the medium with anhydrous dextrose and D-xylose as the carbon sources. Peptone and beef extract was the best nitrogen source. Light had little effect on the pathogen.
In order to explore its application prospect in sugarcane field in Guangxi, the weed controlling spectrum, herbicidal activity and safety of sulfentrazone to sugarcane were tested under greenhouse conditions. The results showed that sulfentrazone displayed good controlling effect on the common grasses, broadleaf weeds and sedge weeds in sugarcane. The fresh weight control effect was higher than 90% to Echinochloa colonum, Eleusine indica, Digitaria sanguinalis, Cyperus rotundus, Amaranthus viridis and Solanum nigrum as the treatment dose was 70 g/hm 2 while the fresh weight control was higher than 80% to Rottboellia cochinchinensis, Oxalis corymbosa and Cynanchum chinense. Sulfentrazone howed higher herbicidal activity against E. colonum, E. indica, D. sanguinalis and C. rotundus than diuron. The selectivity index between ‘Xintaitang 22’ (a sugarcane variety) and E. colonum, E. indica, D. sanguinalis, C. rotundus was 2.04, 2.67, 2.95 and 2.25, respectively, which was much higher than that of diuron with corresponding selectivity index of 1.74, 1.68, 1.80 and 1.24, respectively. The selectivity index between ‘Guitang 46’ (another sugarcane variety) and the weed species mentioned above was similar to that of ‘Xintaitang 22’. This study indicated that sulfentrazone had a good control effect on a variety of major weeds in sugarcane fields and it was safe to the two sugarcane varieties that planted in large-scale in Guangxi. Therefore, it could be used as one of the alternative agents for pre-emergence herbicides in sugarcane fields.
The color changes of thermally modified rubber wood, which was treated at 155 ℃ and 185 ℃ for 2 and 6 h, and 215 ℃ for 2 h respectively, were analyzed using the CIE L *a *b * color space. Changes in chemical structure of the wood samples were analyzed by UV-visible spectrophotometer (UV-Vis) and Fourier transforms infrared spectroscopy (FTIR). The results showed that the color of rubber wood became orange and then approached dark brown, and the light value L * decreased steadily. The parameter C * increased at the beginning of thermally modified treatment and then went down rapidly. The parameter ΔE * showed a positive correlation with the modification degree, and treatment temperature played a more important role in the change of wood color compared with treatment time. A significant increase emerged in the 350-550 nm in UV-Vis spectra of heat-treated rubber wood above 185 ℃, indicating the generation of chromophoric groups. According to FTIR spectra, the content of lignin increased as hemicellulose and cellulose degraded at high temperature; and the loss of syringyl units or breaking of aliphatic side-chains could be inferred from a shift of maximum absorption from 1507 cm -1 to approximately 1511 cm -1 due to decrease of methoxyl groups. The cleavage of acetyl groups was considered to be detected in FTIR spectra in the samples treated at 155 ℃ for 2 h.
A method was established for the simultaneous determination of imidacloprid and β-cypermethrin residues in bananas. The samples were extracted with 1% of acetic acid-acetonitrile, cleaned by PSA and GCB. Gradient elution separation was carried out with methanol and 2 mmol/L ammonium acetate solution as the mobile phase. The samples were determined using electrospray positive ionization (ESI +) with multiple reaction monitoring (MRM) and then quantified by the matrix-matched external standard method. The results showed that the correlation coefficient r was > 0.9991, when the concentration ranged from 0.001 to 0.1 mg/L. The limit of detection (LOD) was 1 pg and the limit of quantification (LOQ) was 0.01 mg/kg. The recovery of imidacloprid and β-cypermethrin in banana was from 84.91% to 104.78% and the relative standard deviation (RSD) was from 1.23% to 9.69%. The method is simple, sensitive and reproducible for the determination of imidacloprid and β-cypermethrin residues in bananas.
The effects of different concentrations of chitosan treatment on the physiological attributes, nutritional quality and storage behavior of harvested ‘Jianyang Tangelo’ fruit during storage at (10±1)℃ were investigated. Compared with the control ‘Jianyang Tangelo’ fruit, chitosan treatment could reduce fruit respiration rate, delay the increase of pericarp cell membrane permeability, suppress the decrease of hue angle value of fruit surface, maintain higher contents of total soluble solids (TSS), titratable acidity, total sugars, vitamin C and carotenoid in the pulp of ‘Jianyang Tangelo’ fruit. In addition, chitosan treatment reduced fruit weight loss and fruit decay, kept higher rate of commercially acceptable fruit. Among the treatments, the fruits treated with chitosan diluted by 500 times showed the best quality, since the rate of commercially acceptable fruit maintained higher than 95%, the disease index kept lower than 0.1, the low water phenomenon of juicy cell was almost not observed and the weight loss rate could be controlled under 5%. The optimal chitosan treatment for ‘Jianyang Tangelo’ fruit was the 1:500 (Vchitosan: Vchitosan+water) dilution, which might be a pro mising method for keeping quality and prolonging shelf-life of harvested ‘Jianyang Tangelo’ fruit.
In order to remove the pigment of seed cake protein from Camellia Oleifera, the protein extract was treated with 4% (V/V) hydrogen peroxide at 40 ℃ for 1 h, and a better decolorization effect was obtained. However, the effect of decolorization with hydrogen peroxide on the function and structure of the protein was worthy of discussion. The changes of protein structure and function before and after decolorization were studied by measuring denaturation temperature, surface hydrophobicity and sulfhydryl content, analyzing infrared spectrum, X-ray diffraction peak and microstructure, etc. Decolorization with hydrogen peroxide caused the surface hydrophobicity increased, the sulfhydryl content decreased, and the disulfide bond content remained basically unchanged, and the chemical bond strength weakened. But the basic skeleton, the microstructure, the position and intensity of the X-ray diffraction peak of C. sinensis were basically the same. The heat denaturation temperature increased, the isoelectric point did not change, but the solubility, emulsifying properties, emulsion stability, foaming ability and foam stability of protein decreased, and oil and water holding capacity increased. The results showed that the decolorization of hydrogen peroxide did not significantly affect the protein structure, but its funct-ional properties were affected.
In order to study on volatile components under four different preprocessing models, fresh fruit samples from Gongshan, Yunnan were dried by natural drying, 55 ℃ baking, lyophilization drying and smoking drying, respectively. The dried fruit was separated into pericarp and kernel, grounded and extracted with n-hexane, and the extraction was analyzed by GC-MS. 53 components were detected at present research. Higher content and more compound types were found in the smoking drying treatment of pericarp and kernel than that of the other three treatment groups, indicating that the components of pericarp and kernel after smoking drying treatment became rich and complex. In addition, the relative content of the same compound in the kernel was significantly higher than that in the pericarp in all four treatments. Although the pericarp had more compound types, the relative content of the same compound was generally not high. The results would provide a certain technical reference for the later processing, preservation and application of grass fruit.
To reveal the dominant cell metabolites, as well as their contents, including carbohydrates, lipids, proteins, chlorophyll and carotenoid of two newly isolated microalgae (Desmodesmus sp. QL96 and Desmodesmus sp. QJ74). Two microalgae were collected at the dedicated culture time, the cells were lyophilized, ground and resuspended to prepare a cell lysate, and then subjected to stepwise extraction and fractionation to detect the content of the cell metabolite obtained in each extraction step. The results showed that the protein content of Desmodesmus sp. QL96 and Desmodesmus sp. QJ74 reached up to 71.68% and 62.14% of the cell dry weight which were grown in the BG11 medium for 30 days, respectively. The contents of other cell metabolites were much lower, none exceeding 20% of the cell dry weight. Compared to other microalgae in literatures, Desmodesmus sp. QL96 is the most protein abundant microalgae and deserves further study, including protein expression patterns and protein-sourced product development.
Residue experiments of 4% bifenthrin suspending agent in litchi were conducted in this study. The acute and chronic dietary exposure risks to different subgroups of Chinese and the environment risks to non-target organism earthworm were assessed according to the results of the experiments. Results showed the half life of bifenthrin in litchi and soil was 2.6-6.9 d and 11.5-13.8 d, respectively, the acute and chronic dietary exposure risks to different subgroups were low after spraying at the dosage of 1000 times for twice with 10 d intervals and PHI of 21 d, and the environment risks to non-target organism earthworm were also low.
CiteSpace was adopted for document co-citation analysis on literatures of natural rubber included by Web of Science from 1988 to 2017. Based on the analysis, research frontier, intellectual foundation and evolution course of this domain were presented in visualization mapping, expecting to provide a scientific base for government decision and industrial development. The results showed that the research frontier was formed on latex allergy, latex-fruit syndrome and natural rubber biosynthesis at early stage, on styrene butadiene rubber or natural macromolecular compounds/ natural rubber nanocomposite at medium term stage, and on nanoparticle/natural rubber nanocomposite, strain-induced crystallization and rubber elongation factor at present stage. The evolution can be divided into four stages: establishment of the research object, development of research instruments or tools, formation of research points sustained by the newly developed techniques and the transferring to knowledge.
The Illumina Miseq 16S rRNA high-throughput sequencing technology was used to study the bacterial community structure and diversity of two group soil samples with and without paclobutrazol treatment, respectively, from a mango orchard in Ledong, Hainan. A total of 3586 operational taxonomic units (OTUs) in two groups were obtained, which were classified as 38 phylums, 89 classes, 195 orders, 378 families, 673 genera and 1353 species. The results of the analysis of Alpha diversity showed that soil bacterial richness index was significantly higher in the paclobutrazo-treated soils, however compared with the soils without paclobutrazol treatment, the bacterial diversity was significantly decreased. The principal component analysis indicated that the community structure of soil bacteria was affected by paclobutrazol. The quantities of Proteobacteria and Planctomycetes were significantly increased in the paclobutrazol-treated soils, however, those of Actinobacteria and Firmicutes were significantly decreased. The PICRUSt analysis showed that the functional gene families were mainly related to 43 sub-functions including the cell growth and death, carbohydrate metabolism, biosynthesis of secondary metabolites, amino acid metabolism, and so on. The total metabolic capacity of soil bacteria could be reduced after treated with paclobutrazol. Therefore, the application of paclobutrazol can reduce the diversity of soil bacteria, and it also has some impacts on the relative abundance and functions of soil bacteria.
In this paper, the aboveground biomass allocation ratio and regional distribution of three species of plantation tree species (Acacia mangium, Hevea brasiliensis and Eucalyptus spp.) were investigated in seven cities and counties in Hainan Island. The proportion of aboveground total biomass allocation of the three species of plantations was basically followed by dry wood > branches > leaves > dry bark, and the trunk dominates. Based on the consistent diameter of breast diameter, the total biomass of plantation trees in different regions of the tropics was significantly different. The total biomass of A. mangium was between 51.06-179.25 kg, and the value in Baisha was the largest. The total biomass of H. brasiliensis was between 48.42-173.15 kg, the value in Lingshui was the largest. The total biomass of Eucalyptus spp. was between 43.06-228.11 kg, and the value in Danzhou was the largest. The proportion of biomass allocation in the same tree species in different cities and counties was very different. The trunk biomass of A. mangium, H. brasiliensis and Eucalyptus spp. was 48%-78%, 35%-78% and 48%-85% of the aboveground biomass respectively. Greater contribution of tree trunk biomass resulted in higher aboveground biomass. The results of this study would provide basic data for rational management of plantation resources in tropical areas.
The investigation of wall plants on eight traditional volcanic villages in Northern Hainan Island was carried out to determine the species diversity and ecological significance. 88 species from 77 genera of 43 families were recorded, consisting of 8 ferns and 80 angiosperms. Among them, 68 plants were native species (including two endemic species and one endangered plants), accounting for 77.27%. Five plants were cultivars (accounting for 5.68%), one plant was naturalized species (accounting for 1.14%), four plants were escaping species (accounting for 4.55%), and 10 plants were exotic invasive species (accounting for 11.36%). The proportion of woody plants and herbaceous plants was 43.18% and 56.82% respectively. There were 79 tropical species, accounting for 89.77% of the total plants. It was also found that the walls of volcanic villages had important ecological functions, which could well preserve the native species and avoid their loss due to agricultural production. Therefore, in the practice of traditional village protection and rural tourism, it was necessary to protect and utilize these wall plants reasonably, so as to achieve the balance between the protection of ancient buildings and biodiversity.
