Litchi (Litchi chinensis Sonn.) is one of the most distinctive fruits in South China and is one of the pillar industries of rural economy in South China. At present, the cultivated area of litchi in China is more than 533 000 hm² and the output is more than 2.3 million tons, accounting for more than 80% of the total cultivated area and more than 65% of the total output in the world. The panicle of litchi is paniculate, terminal, generally composed of cymes, with a length of 10-40 cm and 200-1500 florets. Excessive number of florets will consume tree nutrition and affect litchi fruit setting. Therefore, reducing the number of florets by regulating branches is an effective measure to improve fruit setting. SUPPRESSOR OF MAX2 1-LIKE 7 (SMXL7) is an important component of strigolactone signaling pathway and a new inhibitor with dual functions. SMXL7 is involved in leaf morphology regulating and branch development in Arabidopsis and rice. In order to identify the regulatory factors involved in the panicle branch development in litchi, LcSMXL7 the homologous of arabidopsis SMXL7 was cloned, the sequence of LcSMXL7 was obtained from RNA-seq data and the gene sequence, physicochemical properties, evolutionary relationships, conserved domain, tissue expression pattern, subcellular localization and gene function were analyzed. The open reading frame of LcSMXL7 was 3408 bp length, encoding 1135 amino acids. LcSMXL7 protein contained two CLP domains and one AAA_2 domain. The molecular formula, molecular weight and theoretical isoelectric point of LcSMXL7 was C₅₄₂₉H₈₆₃₂N₁₅₃₀O₁₇₁₅S₃₈, 123.99 kDa and 5.96. The Instability index, aliphatic index and grand average of hydropathicity of LcSMXL7 was 46.38, 83.74 and -0.305, respectively. LcSMXL7 was highly expressed in stems, seeds and leaves, followed by panicle, male flowers and pericarps, while the expression was low in female flowers, pulp and roots. Phylogenetic tree analysis showed that LcSMXL7 was closely related to SMXL7 protein from woody fruit trees sweet orange and mango. Subcellular localization analysis showed that LcSMXL7 was located in the nucleus, suggesting that it may participate in the regulation of gene expression as a transcription factor. Transgenic results showed that overexpression of LcSMXL7 in Arabidopsis could significantly increase the number of branches, indicating that LcSMXL7 could positively regulate the development of branches in Arabidopsis. We clarified the LcSMXL7 protein characteristics, tissue expression pattern, evolutionary relationships, conserved domain, subcellular localization and gene function, which would build a foundation for elucidating the molecular mechanism of LcSMXL7 in branch development.

C2H2 zinc finger protein is one of the most common zinc finger proteins and widely found in eukaryotes. It plays an important role in plant growth and development, abiotic stress response to salt, low temperature and drought stress. In this study, the C2H2 amino acid sequence of Arabidopsis thaliana were used to blast with local BLASTP in the oil palm genome database and to predict the conservative domains, and to screen the C2H2 zinc finger protein family of oil palm. The physical and chemical properties, evolutionary relationships, chromosomal location, gene structure, conservative motif and promoter cis-elements were analyzed through bioinformatics softwares, the expression of EgC2H2 gene was analyzed by the transcriptome data and real-time fluorescence quantitative PCR under low temperature stress. A total of 73 C2H2 type zinc finger protein family members were identified from the genome of oil palm. The number of amino acids in EgC2H2 family was between 128 and 556, The molecular weight was between 14 176.73 and 58 983.30 Da, the isoelectric point was between 4.99 and 9.62, the instability index was between 38.84 and 86.01, and the gravy was between -1.154 and -0.226. Subcellular localization showed that the C2H2 gene family were localized in the nucleus. Phylogenetic tree analysis showed that EgC2H2 family members were divided into four subfamilies, most members of EgC2H2 family were classified into subfamily Ⅰ and subfamily Ⅱ, and the domains of the same subfamily members were highly consistent. Chromosome location results showed that EgC2H2 family members were unevenly distributed on the 16 chromosomes of oil palm. Analysis of promoter cis-elements showed that the EgC2H2 family contained many promoter cis-elements related to light response elements, plant hormones response elements and stress response elements. Transcriptome analysis showed that most EgC2H2 genes responded to low temperature stress, and most EgC2H2 genes were highly expressed in cold-tolerant materials and low expressed in cold-sensitive materials. qRT-PCR analysis showed that the expression level of EgC2H2-23, EgC2H2-11, EgC2H2-19, EgC2H2-17 and EgC2H2-21 was significantly up-regulated, and the expression level of cold-tolerant materials was significantly higher than that of cold-sensitive materials. It was speculated that the genes would play a key role in oil palm response to low temperature stress, and can be used as candidate genes for further study. This study would provide theoretical reference for further study on the functional analysis of C2H2 gene family in oil palm.

Hirschmanniella spp. are migratory endoparasitic nematodes which are parasitic in the root of rice. They are widely distributed in different types of fields and have become serious parasitic nematodes to rice. The plant-parasitic nematode Hirschmanniella mucronate is one of the most serious rice nematodes in Jiangxi, China. At present, breeding and planting other disease-resistant varieties is the most economical and effective measure to control the disease. The significant up-regulated OsECH1 gene was screened by transcriptome analysis of healthy susceptible rice 'Bawangbian' root tissues and susceptible rice 'Bawangbian' root tissues infected by H. mucronata. Phylogenetic analysis of OsECH1 and its homologous proteins showed that OsECH1 and other homologous proteins had the same structure, including the same conserved domain PLN02874. And OsECH1 belonged to the ECH protein family. Besides, five homologous genes were found in the genome of 'Nipponbare' group and OsECH1 was located in Chr1. The full length of OsECH1 was cloned and the recombinant expression vector was constructed by homologous recombination technique. Meanwhile, the transgenic rice was transformed by GV1301. RT-qPCR was used to analyze the effect of OsECH1 gene expression level on the infection of H. mucronate in rice. The results showed that overexpressing OsECH1 in rice could reduce the infection of H. mucronata, while silencing OsECH1 in rice could significantly increase the infection of H. mucronata. The results of subcellular localization of OsECH1 showed that the protein was expressed in nucleus. And the results of His-tag pull down demonstrated that the protein may interacted with five defence-related proteins. The five defense-related proteins belonged to vATP-synt_E protein family, Ricin-B protein family, catalase and B_lectin protein family respectively. Meanwhile, RT-qPCR results showed that OsECH1 had regulatory effects on the five proteins. The results would provide a basis for further understanding the function of OsECH1 gene, and for understanding the molecular mechanism of OsECH1.

Identification of heterozygote is a key step in the cross breeding of Lentinula edodes. A new ISSR technique (N-ISSR) was designed in this study based on discrimination between the two nucleus of the donor strain to identify quickly and accurately the authenticity of hybrid strains of L. edodes. The new ISSR was used to identify 40 hybrid strains which were from the Di-mon mating between dikaryon wild strain YX7 and spore monokaryons of cultivated strain 808, as well as microscopy observation combined with antagonistic test (MOCAT) and the traditional ISSR technique (T-ISSR) as the control. N-ISSR results showed 27 strains were confirmed to be true heterozygote as they possessed specific DNA bands from one of the nucleus of donor strain YX7, and the other 13 strains were confirmed to not be heterozygote. Among them, 11 strains were strain YX7 itself as they possessed both specific DNA bands from the two nucleus of strain YX7, and 2 strains were spore monocaryons of strain 808 as they had no any specific DNA bands of donor strain YX7. Compared with MOCAT, N-ISSR could thorough identify all the 27 heterozygote strains, which included the 19 strains identified as heterozygote, the 6 strains unable to be identified and 2 strains incorrectly identified as non-heterozygote by MOCAT. N-ISSR could identify all the 27 heterozyote stains and 13 non-heterozyote stains with simple primer, and could classify the heterozygote strains into two groups according to the type of nucleus received from the donor. On contrast, T-ISSR needed 4 primers to identify all the 27 heterozygote strains, and was unable to con firm the other 13 stains as non-heterozygote stains, and was unable to classify the heterozygote strains into two groups. In conclusion, N-ISSR was an effective tool to be used for fast, extensive and accurate identification of heterozygote and non-heterozygote strains of L. edodes, and would be a technical support for further study on the cross breeding and genetic analysis of L. edodes.

Sugarcane is an important sugar crop and energy crop. Evaluating the nutritional quality of sugarcane germplasm resources can systematically understand the nutritional value of sugarcane germplasm resources, and provide scientific basis for the development and utilization of sugarcane germplasm resources and breeding of new varieties. We carried out a study using 100 sugarcane germplasms, analyzed 14 nutritional indexes such as sucrose, reducing sugar, total free amino acid, polyphenol, mineral and protein in sugarcane juice, SPSS software was used for Principal Component Analysis (PCA) and Systematic Cluster Analysis (SCA) of nutritional quality traits. Results showed that there were differences in nutritional components among the 100 sugarcane germplasms and some nutrients had a significant correlation with each other. Sucrose content was negatively correlated with reducing sugar, protein, total free amino acid, fructose and glucose content, while protein content was positively correlated with total free amino acid and total polyphenol content. The content of fructose, glucose and sucrose was positively correlated with the content of P. Among mineral elements, Ca content and Fe content, Fe content and Cu content were positively correlated. The main factors affecting the nutritional quality of sugarcane germplasm were reducing sugar factor, protein factor, sucrose factor, Ca content factor and K content factor. The cumulative variance contribution rate of the common factors to comprehensive evaluation of sugarcane nutritional quality was 69.62%. SCA showed that the nutritional quality of the 100 sugarcane germplasms could be divided into 5 groups (European distance D=18.5). Group Ⅰcontained 77 resources, which had the highest sucrose content. Group Ⅱ contained 6 resources with higher Ca and Fe content. Group Ⅲ contained 2 resources, the average content of reducing sugar, protein, total free amino acid, total polyphenol, fructose, glucose, P, Na was high, and the average sucrose content and Fe content were low. Group Ⅳ contained 4 resources, which had the highest average total free amino acid content, higher average protein and total polyphenol content. Group Ⅴcontained 11 resources, with the highest average K content. The comprehensive evaluation of nutritional quality of the 100 sugarcane germplasms showed that the top 5 sugarcane varieties were 'Hetang 1', 'Dezhe 0978', 'Funong 40-95', 'Zhongzhe 45' and 'Yunzhe 06-193'.

In this study, 27 phenotypic traits of the floral organs of 135 Phalaenopsis varieties were observed and analyzed to provide a theoretical basis for the utilization of Phalaenopsis germplasm resources and the directional breeding of new varieties. 135 Phalaenopsis germplasm resources collected and preserved in the Fuzhou Branch of the New Plant Variety Testing Center of the Ministry of Agriculture and Rural Affairs were used as the test materials to collect data on 27 phenotypic traits of Phalaenopsis orchid organs and analyze the flower phenotypic traits. The distribution frequency, coefficient of variation, Simpson index and Shannon-Wiener index, and correlation, principal component and cluster analysis of quantitative traits were studied. The majority of butterfly orchid organs were violet petals, racemes, separated petals and no fragrance, which accounted for 31.85%, 60.74%, 79.26% and 84.44% of the corresponding description distribution frequencies respectively. The Simpson index and Shannon-Wiener index of the lobes in the lip were the highest, 0.992 and 7.047, respectively, and the diversity was the most abundant. The variation coefficient of quantitative traits ranged from 19.79% to 52.72%, of which the coefficient of variation of the number of inflorescences was the largest, which was 52.72%. Most of the main quantitative traits had extremely significant positive correlations. Principal component analysis extracted 3 quantitative traits as the representative traits for evaluating Phalaenopsis phenotypic traits, and calculated comprehensive scores. The top 3 were 'JB2312', 'Wanhuayanhuo' and 'Dongfanghong' respectively. The R-type cluster analysis showed that the 16 quantitative traits of Phalaenopsis could be divided into 4 categories, and the Q-type cluster analysis showed that the 135 Phalaenopsis varieties were divided into 5 major species groups. Our research indicates that the flower phenotypes of 135 Phalaenopsis varieties have rich genetic diversity.

The analysis of the genetic diversity of aromatic rice varieties and clarification of the genetic relationship of aromatic rice varieties can provide references for breeding high-quality aromatic rice varieties. 24 conventional aromatic rice varieties approved in Guangxi was used in the study. The genetic diversity of the varieties was analyzed by SSR fluorescence labeled capillary electrophoresis in this study. The results showed that a total of 170 alleles were detected by 48 SSR primers. The number of alleles (Na) varied from 1 to 9, with an average of 3.54. The range of effective allele number (Ne) ranged from 1 to 4.5534, with an average of 2.0736. The highest effective allele number was RM21, followed by RM481, RM493 and RM258. Four pairs of primers had high detection efficiency. Shannon's index (I) ranged from 0 to 1.7942 with an average of 0.7726. The variation range of polymorphic information content (PIC) ranged from 0 to 0.7541 with an average value of 0.3732, indicating that the 24 varieties had certain genetic variation. The genetic similarity coefficient of the 24 varieties ranged from 0.3299 to 0.9600, among which the genetic similarity coefficient of 'Sanxiang 628' and 'Nongxiang 32' was the lowest, indicating that the genetic basis difference of the two varieties was the greatest and the genetic relationship was the furthest. The genetic similarity coefficient of 'Wanxiang 696' and 'Guangliangxiang 2' was the greatest, indicating that the genetic basis difference of the two varieties was small and the genetic relationship was close. Cluster analysis showed that the 24 cultivars could be divided into three large groups and four subgroups at the similarity coefficient of 0.504. There were two varieties in theⅠcategory, 19 varieties in theⅡcategory and 3 varieties in theⅢcategory. CategoryⅡcould be divided into 4 subclasses at the similarity coefficient of 0.624, including 1 variety in Subclassⅰ, 14 varieties in subclass ⅱ, 3 varieties in subclass ⅲ, and 1 variety in subclass ⅳ. The results showed that there was a certain genetic diversity in the 24 varieties, but it was not rich enough. The DNA fingerprints of the 24 varieties were constructed in the form of digital coding. The results could provide references for breeding and identification of conventional aromatic rice varieties in Guangxi.

To gain insight into the genetic diversity and relationship of the tropic bioenergy plant physic nut (Jatropha curcas L.) in Yunnan, China, joint analysis of agronomic and molecular characters was performed in the present study, using different accessions collected from nine sources/geographical provenances in Yunnan. To investigate the population polymorphism, eight pairs of SSR molecular markers were developed by MISA program, and four of them with higher polymorphism were selected for PCR amplification using 95 DNA samples collected from nine populations. The results indicated that JC01 exhibited the best polymorphism (0.711). UPGMA clustering analysis suggested that Baoshan and Xishuangbanna might serve as the parents or origins of physic nut in Yunnan, which was partially related to the geographical origin of populations. Comprehensive investigations revealed among all examined biological traits of seeds or seedlings, the underground fresh weight (UFW) exhibited the highest coefficient of variation, with obvious separation among populations. Two individual seedlings with extreme variance in UFW (BNMH and CXYM) were selected for RAD-based genomic sequencing, while 2783 and 3033 contigs were assembled. Analysis of genome assembly data using GenomeScope revealed that both materials were diploid, and a total 22 756 valid SNPs were detected at the whole genome level using genome-wide association study (GWAS). High frequency-SNPs associated with UFW preferably located on LG9, and three candidate proteins were linked to the UFW trait. The results indicated that the physic nut germplasm collected from different regions of Yunnan exhibited a high level of genetic diversity and uniqueness, which should facilitate further studies on its molecular breeding.

In order to objectively select new rubber tree clones suitable for China's rubber planting environment, the yield and secondary characters of four introduced clones 'Reshi 09-5' 'Reshi 09-6' 'Reshi 09-7' and 'Reshi 09-10' were systematically identified and evaluated. The results showed that among the four clones, just 'Reshi 09-7' showed fast-growing, not yet in yield. Only 'Reshi 09-5' was close to the control in the first taping year and was lower in other years. The results of latex physiological characteristics showed that, according to good latex stability, fast latex discharge and high sugar utilization rate, 'Reshi 09-5' showed good rubber production potential, had higher thiol content and lower sucrose content than that of 'RRIM600', and there was no significant difference in dry rubber yield and initial speed of latex discharge between them. 'Reshi 09-6' had higher dry rubber content and plugging index, thicker original bark and more latex tubes number than 'RRIM600', and there was no significantly differences in initial flow rate and sucrose content between them. It was considered that the variety had good rubber production potential, but the metabolic intensity of latex was low. It had better potential in latex production, but a low metabolic intensity, so the production could be increased by stimulated tapping. The results of raw rubber properties, physical and mechanical properties, molecular weight and molecular weight distribution of vulcanizates of different varieties showed that there were some differences among the four clones. 'Reshi 09-5' showed the lowest in plastic initial value and Mooney viscosity, but the highest plastic retention rate. 'Reshi 09-6' showed the highest Mooney viscosity. According to larger weight-average molecular weight, 'Reshi 09-7' showed good physical and mechanical properties. In terms of stress resistance performance, 'Reshi 09-5' had the lowest wind damage collapse rate and 'Reshi 09-10' had the highest. The results of cold-resistant outpost data showed that under the condition of no cold injury in the control clone '93-114', the cold injury grade of 'Reshi 09-5' was 1.00, and that of 'Reshi 09-7' was 0.17. The comprehensive analysis results showed that the fast-growing traits of the four introduced clones were obvious. 'Reshi 09-6' had good rubber production potential. 'Reshi 09-5' had better wind resistance than 'RRIM600', 'Reshi 09-7' had good adaptability in cold damage. Among the four clones, 'Reshi 09-6' showed better performance in yield, girth growth, latex physiological characteristics and latex quality, and suitable to popularize and cultivate in same condition.

As one of the characteristic spice crops in tropical areas of China, the content of aroma components is the key index to identify the quality of Pandanus amaryllifolius Roxb. (Pa). Pa is suitable for planting under shade of Hevea brasiliensisr (Hb) forest in Hainan Island, China. However, the effect of Hb and Pa intercropping on the aroma component of the leaves of Pa has not been explored. Pot experiments were set up to compare the differences of soil physical and chemical properties and the types and content of aromatic composition in Pa leaves under intercropping and monoculture treatments. The intercropping mode significantly increased the soil bulk density by 13.63%, the content of soil alkali hydrolyzed nitrogen by 59.71%, the content of soil available phosphorus by 193.03%, the content of soil available potassium by 9.78% and the soil pH reduced by 1.00 (P<0.05). A total of 10 categories and 68 aroma components were detected in the intercropping and monocropping treatments. Compared with monocropping treatment, intercropping significantly decreased the number of ketones by 56.52%, furans by 14.29%, furanones by 33.33%, hydrocarbons by 20.00% and phenols by 28.57% (P<0.05). Although furans significantly reduced the content of aroma components by 65.28%, hydrocarbons by 20.88% and ketones by 69.00%, they significantly increased the content of alcohol by 31.50%, pyrrole by 597.56%, esters by 122.78% and furanone by 96.89% (P<0.05). The decrease of soil pH was the main reason for the reduction of ketones, furans, furanones, hydrocarbons and phenols. Intercropping indirectly increased the content of alcohols, pyrroles and esters and reduced the content of furans and hydrocarbons by reducing pH, while increasing soil available phosphorus and alkali hydrolyzable nitrogen. Pyrrole compounds were the main aroma components of Pa, thus the intercropping mode could significantly promote the quality of Pa. The results of this study would have a positive effect on the optimization and promotion of the Hb intercropping Pa mode, and also conducive to promoting the income increase of farmers and the sustainable development of related industries.

In order to promote the application of digital image processing technology in forest nutrition diagnosis and realize real-time monitoring of forest growth status and nutrient content, three prediction models of the total nitrogen content of young Aquilaria sinensis Lignum Resinatum based on image color and shape characteristics were constructed in this study, which provided a theoretical basis for nutrition diagnosis of young forest tree. Firstly, the optimal K value is determined according to the boundary distance and the size of the setting error, and the improved K-Means algorithm is used to extract the foreground image. Then, separate the three channels of R, G, and B of the foreground image and calculate the average value respectively. Then, the R, G, and B three channels of the foreground image are separated and the mean values are calculated respectively. According to the image color space conversion formula, the image is converted to HIS and Lab color space respectively, and the hue (H), saturation (S), brightness (I), brightness (L), red to green channel (a), yellow to blue channel (b), and a total of 9 color features are obtained. Find the minimum circumscribed rectangle of the foreground image, calculate the area (CA) of the foreground image, the area (RA), perimeter (RC), and rectangularity (RD) of the minimum circumscribed rectangle of the foreground image, and obtain four shape features in total. Finally, principal component analysis was performed on the color features, shape features, and color features + shape features, and the obtained three types of principal components were used as independent variables to construct a prediction model for the total nitrogen content of young A. sinensis, and the accuracy of the three models constructed was tested. Finally, the principal component analysis of color feature, shape feature, and color feature +shape feature was carried out respectively, and the three principal components obtained were used as independent variables to construct the prediction model of the total nitrogen content of young A. sinensis, and the accuracy of the three models was teste. The results show that improving the K value selection method can reduce the uncertainty of the K-Means clustering segmentation algorithm, enhance the segmentation efficiency of the algorithm, and achieve accurate segmentation of A. sinensis visible light images. The three models of the total nitrogen content of young agarwood constructed in this study had good prediction ability. The model accuracy based on single image parameters was basically the same, but the model based on shape features used fewer parameters and had higher relative modeling efficiency. The two-image parameter model uses more parameters than the single-image parameter model, but the fitting degree is better and the accuracy is higher. In practical applications, it can be selected according to different needs. In this study, different image features were used to build a total nitrogen model, which better realized the non-destructive estimation of the total nitrogen content of young trees, and provided a certain reference for precision forestry.

Sugarcane is an important sugar crop in the world, but the main sugarcane producing areas in China are hilly and dry slopes, and seasonal droughts occur frequently due to the uneven distribution of rainfall. Droughts do great harm to yield and quality and the sustainable development of sugarcane industry in China. The plant hormone abscisic acid (ABA) not only regulates plant growth and development, but also plays an important role in the physiological and biochemical responses of plants environmental stresses. In this study, we used sugarcane (Saccharum officinarum L.) variety 'Guitang 42' as the material to investigate the effects of exogenous ABA on leaf physiological characteristics and gene expressions under water stress condition in treatments control (normal irrigation), control+ABA, drought (stop irrigation), drought+ABA. The foliar application of 15 μmol/L ABA was sprayed twice in two days before drought stress given. The results showed that the changes of main physiological and biochemical parameters and gene expression in control+ABA treatment were not significantly different from those of the control. The leaf relative water content (RWC) was gradually decreased by drought treatment but it could maintain higher in drought+ABA treatment. The drought treatment could result in an increase in malondialdehyde (MDA) and hydrogen peroxide (H₂O₂) content, but the plants applied with ABA were found to resist the excessive accumulation of MDA. Drought stress significantly reduced the leaf chlorophyll content in sugarcane, but the exogenous ABA application decreased the degradation of chlorophyll, counteracted, at least in part, the decrease in quantum efficiency of PSII (ΦPSII). The expression of gene encoding 9-cis-epoxycarotenoid dioxygenase (NCED) for ABA biosynthesis, the genes encoding Δ1-pyrroline-5-carboxylate synthase (P5CS) for proline biosynthesis, and the antioxidant enzymes catalase (CAT), superoxide dismutase (SOD), ascorbate peroxidase (APX), peroxidase (POD) encoding genes was significantly increased in the leaf under water stress condition, following the significantly higher endogenous ABA content, proline content and CAT, SOD, APX and POD activities in water stress treatment as compared to the control. But exogenous ABA application under water stress could further enhance the expression of the genes, hence further improved the ABA content, proline content and related antioxidant enzyme activity. The results clearly suggests that the foliar ABA application could triggering the over expression of antioxidative defense system, and improve drought tolerance of sugarcane under water stress condition.

Artocarpus heterophyllus is popular for its sweet fruit and has a very promising market, but conventional seed propagation makes it difficult to maintain its excellent traits and the grafting method has a very low survival rate. The technique of tissue culture and rapid propagation has been widely used in the propagation of many rare and valuable plants, but there are no reports of its application in the production of A. heterophyllus. In the process of tissue culture, it was found that the stem tip of A. heterophyllus was severely browned, which led to the difficulty of establishing asexual reproduction system. In order to effectively investigate the measures to overcome the browning, this experiment took the stem tips of A. heterophyllus 'Haida 2' as the explants and inoculated them into different concentrations of PVP medium after low-temperature pretreatment at different lengths for primary culture, the browning rate and germination rate were calculated after 15 d, and PPO activity, total phenol and total flavonoid content were determined to explore the inhibition of different concentrations of PVP on browning in stem the tip tissue culture of A. heterophyllus after low-temperature pretreatment. The results showed that the browning rate of A. heterophyllus explants was the lowest and the germination rate was the highest after 12-24 h low-temperature treatment of stem tip and then in 1/2MS medium supplemented with 2.0 g/L PVP. The experimental results showed that this method was beneficial to the proliferation of A. heterophyllus explants. The purpose of this experiment is to promote the establishment of technique of tissue culture and rapid propagation for A. heterophyllus, with a view to providing a theoretical basis for the construction of the A. heterophyllus seedling breeding technology system and its industrial production demonstration.

Eucalyptus urophylla × E. grandis is a hybrid of Eucalyptus grandis (♂) and Eucalyptus urophylla (♀). It has the advantages of rapid growth, straight trunk, high yield, short rotation period, easy to germinate, strong adaptability and so on. So it has become the main cultivated tree species in the key forest areas, important commercial timber forest bases and forest products industrial bases of Yunnan Province. Due to its endogenous plant growth inhibitors, the disposal of wood processing residues has not yet been effectively solved. In this study, urea, manure from chicken and sheep, EM bacteria and enzyme bacteria were added to Eucalyptus bark for decomposing fermentation to promote the degradation of its endogenous inhibitors, making it an organic substrate with similar physical and chemical properties to peat. In order to reveal the effects of three levels of decomposed Eucalyptus bark (raw/40-day/60-day) compounding with three volume ratios (10%, 20% and 30%) of perlite on the enzymatic activity at plant seedling stage, four crops (Lycopersicon esculentum, Brassica oleracea, Lactuca sativa and Moringa oleifera) were cultivated in a greenhouse using the two-factor and three-level experimental design. After 6-8 weeks of growth, the activity of six enzymes associated with carbon and nitrogen metabolism (SS, SPS, Rubisco, GS, GOGAT, NR) in the leaves was determined. The results showed that the decomposition level and the proportion of perlite had the extremely significant interaction on the SPS activities of L. esculentum, B. oleracea and L. sativa (P<0.01). On the whole, the activity of enzymes related to nitrogen metabolism was more affected by the decomposition level than those related to carbon metabolism. The enzymatic activity of the three vegetables in 60-day-decomposed Eucalyptus bark were significantly higher than those in the control peat, raw Eucalyptus bark and 40-day-decomposed Eucalyptus bark (P<0.05). Among them, the enzyme activity of L. sativa in compound 30% perlite was significantly higher (P<0.05). In addition, the enzymatic activity of the three vegetables in 40-day-decomposed Eucalyptus bark compounding with 20% perlite were significantly higher than those in peat (P<0.05). The enzymatic activity of M. oleifera in peat was significantly higher than that in Eucalyptus bark substrate (P<0.05), and that in raw Eucalyptus bark was significantly higher than that in decomposed Eucalyptus bark. Besides, the mechanism of endogenous compounds in Eucalyptus bark influence on the activity of enzymes related to carbon and nitrogen metabolism during plant growth needs to be further studied.

Gynostemma pentaphyllum is an important medicine-food homology plant. It enjoys the reputation of 'Southern ginseng' as it contains compounds of ginsenosides. As wild resources of G. pentaphyllum depleted gradually, artificial introduction and cultivation of G. pentaphyllum has become an inevitable trend. However, due to soil irrigation, fertilization, and pesticide use, problems such as unstable quality of medicinal materials and excessive heavy metal content in G. pentaphyllum occur from time to time, which seriously affects its standardized cultivation and the quality and safety of medicinal materials. Hydroponic production has the advantages of short cycle, high yield, no continuous cropping obstacles, and can effectively avoid heavy metal pollution, so it is widely used in the production of various Chinese medicinal materials. In this study, G. pentaphyllum seedlings were treated with different nutrient solution, temperature, light intensity and photoperiod. After that, growth characteristics and accumulation of total saponins of G. pentaphyllum were examined to obtain the most suitable hydroponics conditions, and thus provide reference and technical support for the large-scale production and organic cultivation of G. pentaphyllum. The results showed that Japanese Yamzaki formula with pH value 6.0 was the best nutrient solution for hydroponics of G. pentaphyllum. Correlation analysis showed that under different nutrient solution conditions, the total saponin content of single plant was highly positively correlated with plant height, leaf length, leaf width, number of leaves, fresh weight per plant and dry weight per plant, indicating that the cultivation of high-biomass plants was the key of the cultivation of high-quality plants of G. pentaphyllum. Under variable temperature of 20 to 30 ℃, photoperiod of 10 to 14 hours of light per day, and light intensity of 100 μmol/(m²·s), seedlings of G. pentaphyllum grew well and the total saponin content of the dry samples exceeded 3%, which was higher than the existing standards. This study would provide a scientific basis for the realization of double precise control of production and quality of G. pentaphyllum, and lay the foundation for the future research on large-scale production and quality standards of it.

Praxelis clematidea (Griseb.) is one of the most important invasive plants in China, which is continuously spreads with the increasingly serious nitrogen deposition in terrestrial ecosystem. The objective of the study was to reveal the responses of growth characteristics and accumulate the basic data for formulating corresponding prevention and control strategies using simulated nitrogen deposition. The growth characteristics such as root and plant length, leaf number and leaf area, root characteristics, biomass and its distribution and chlorophyll content in 45 days with four nitrogen deposition levels (control of 0, low nitrogen group of 40 kg/hm², medium nitrogen group of 60 kg/hm², high nitrogen group of 80 kg/hm²) compared with the 90 days were measured respectively. The results showed that the developmental ability was significantly improved in both growth periods (P<0.05) with the increase of nitrogen deposition level. Compared with N₀, the root length and plant height increased by 44.38% and 60.89% after N₃ culture for 90 days. The number of leaves and leaf area increased by 122.78% and 119.32%, and the growth rate of total root length, root surface area, root volume and root mean diameter was 56.04%, 42.36%, 59.38% and 61.54%. At 45 d, compared with the control group, total biomass of N₁, N₂ and N₃ increased by 37.50%, 81.25% and 106.25%, and the corresponding data at 90 d was 23.81%, 61.90% and 80.95%, respectively. Further comparison of the biomass distribution characteristics with different nitrogen concentrations at 45 d and 90 d showed that the different concentrations of nitrogen had inhibitory effects on RBR and R/S, and the inhibitory effect of low concentration nitrogen and early growth stage was stronger than that of high concentration nitrogen and late growth stage (P<0.05). However, it showed that a promoting effect on LBR and SBR was stronger under high-concentration nitrogen treatment and in the late growth stage of Stinkweed (P<0.05). When potted for 45 days, the content of chlorophyll a in the high nitrogen group (N₃) was increased by 131.69% compared with the control group (N₀), and the increase in chlorophyll b was 787.50%. Chlorophyll a and chlorophyll b increased by 82.45% and 314.29% respectively in potted plants for 90 days. It shows that the chlorophyll synthesis ability has strong tolerance to the heterogeneous environment represented by high nitrogen levels. At the early stage of growth (45 d), the positive feedback effect on moderate-level nitrogen deposition (N=60 kg/hm²) was strong. However, with the extension of the growth period (90 d), the adaptability to high levels of nitrogen deposition (N=80 kg/hm²) was significantly improved. The result proves that the aggravation of nitrogen deposition is beneficial to its growth.

Internal browning (IB) seriously restricts the development of pineapple industry. Its occurrence is mainly from excessive reactive oxygen species (ROS) causing membrane damage, which breaks the original compartmentalization between plastid polyphenol oxidase (PPO) and phenolic substrates in vacuoles. It polymerizes into quinones after contact with oxidation. The antioxidant clearance system is able to remove excess ROS and maintain the dynamic balance of ROS in the body. In early time, our laboratory used ascorbic acid (AsA) which can effectively delay the deterioration of IB of 'Pairs' pieapple. But the reaction mechanism of AsA is not clear. Ascorbate peroxidases (APX, EC1.1.11.1) are heme-binding enzymes that reduce hydrogen peroxide (H₂O₂) to water using AsA as an electron donor. It is involved in various developmental physiological processes and stress responses in plants. In this study, we selected six APX genes with AsA as the substrate in pineapple to analyze the occurrence process and the ascorbate transcript level changes after the AsA treatment. AcAPX1 was significantly upregulated at 9 d and 12 d after AsA treatment and was significantly different from the control group. It showed that AsA significantly enhanced the AcAPX1 expression. Correlation analysis showed that the incidence index of black heart disease was significantly positively correlated with the AcAPX1 expression level. It is speculated that this gene may play an important role in AsA delaying IB with pineapple. To further explore the mechanism of action, AcAPX1 was cloned from the pineapple pulp. The physicochemical properties and protein domain were analyzed by bioinformatics analysis. The results showed that the open reading frame length was 753 bp, encoding 250 amino acids. The predicted molecular weight of the protein was 27.410 87 kDa, and the theoretical isoelectric point was 5.52. There was no transmembrane helix region, which was a stable hydrophilic protein. Amino acid sequence alignment analysis showed that AcAPX1 of pineapple shared more than 85% homology with papaya, banana, coconut and oil palm. The functional domain analysis of AcAPX1 showed that it had heme binding sites, K⁺ binding sites and substrate binding sites (superfamily: cl00196), belonging to the members of the plant peroxidase superfamily. Cloning of AcAPX1 is of great significance for studying the molecular mechanism of its antioxidant capacity in pineapple and the control of internal browning. This study would lay a foundation for further exploring the molecular mechanism of pineapple AcAPX1 involved in AsA clearing ROS and delaying the deterioration of internal browning.

Thielaviopsis paradoxa is harmful to almost all palm plants, among which stem bleeding of coconut is the most serious, and no effective and safe control method is available. Among the biocontrol bacteria screened in the early stage of this study, Pseudomonas aeruginosa wrj-2-5 and Alcaligenes faecalis brj-21 were proved to have biocontrol potential against T. paradoxa. In order to determine the specific inhibitory effect of P. aeruginosa and A. faecalis on T. paradoxa, T. paradoxa was used as the target strain to determine the bacteriostatic effect, indoor control effect and fermentation conditions of the biocontrol strains wrj-2-5 and brj-21. The results showed that wrj-2-5 and brj-21 both had a bacteriostatic rate of more than 70% against T. paradoxa. In vitro experiment found that the two bacteria still had good bacteriostasis. The lesion area of the treatment group was significantly smaller than that of the control group. Earlier inoculation would lead to better effect. In addition, the strains had strong inhibitory effect on other pathogenic bacteria of coconut leaf spot, fruit rot, gray spot and heart rot. The optimal fermentation condition of wrj-2-5 was rotation speed 180 r/min, temperature 28 ℃, culture time 36 h, initial pH value 6.0-8.0, and inoculum amount 8%. The optimal fermentation condition of strain brj-21 was inoculum amount 8%, the initial pH value 6.0-8.0, rotation speed 180 r/min, temperature 28-32 ℃, and incubation time 24 h. In conclusion, wrj-2-5 and brj-21 have good control effects on the stem bleeding of coconut and fruit rot of coconut caused by T. paradoxa. They also have a certain inhibitory effect on the pathogens of other coconut diseases, which would provide an important reference for the green and biological control of T. paradoxa.

To select suitable slow-release fertilizers for sugarcane productions the endophytic bacterial community structure in the stems of sugarcane under different slow-release fertilizer applications were analyzed. Based on high-throughput sequencing techniques, the endophytic bacterial community structure in the stems of sugarcanes among conventional fertilization (CK) and different slow-release fertilizers (A-F treatments) were analyzed. In comparison with CK, the diversity of the endophytic bacteria in the stems of sugarcanes was significantly increased by adding long- acting agent (235 g/t) and synergist (3 g/t and 18 g/t), but the richness of the endophytic bacteria in the stems of sugarcanes was not significantly improved by slow-release fertilizer applications except adding long-acting agent (235 g/t) treatment C. Meanwhile, Herbaspirillum was the specific endophytic dominant bacterial genus in CK. Sporocytophaga and Cellvibrio were the unique endophytic dominant bacterial genera in the slow-release fertilizer adding long-acting agent (125 g/t) treatment A. However, no specific endophytic dominant bacterial genera could be found in the slow-release fertilizer adding long-acting agent (150 g/t) treatment B. Norank_f__SC-I-84, norank_f__Neisseriaceae, norank_f__JG30-KF-AS9 and Massilia were the specific endophytic dominant bacterial genera in the slow-release fertilizer adding long-acting agent (235 g/t) treatment C. Brevundimonas, Enterobacter, Staphylococcus were the unique endophytic dominant bacterial genera in the slow-release fertilizer adding synergist (3 g/t) treatment D. Cloacibacterium was the specific endophytic dominant bacterial genus in the slow-release fertilizer adding synergist (8 g/t) treatment E. And unclassified_f__Burkholderiaceae, Paenibacillus, Allorhizobium-Neorhizobium-Pararhizobium-Rhizobium, Corynebacterium_1, Chryseobacterium were the specific endophytic dominant bacterial genera in the slow-release fertilizer of adding synergist (18 g/t) treatment F. Furthermore, the functions of the endophytic bacteria in the stems of sugarcanes did not show significantly different between CK and applications of slow-release fertilizer treatments. In comparison with CK, the diversity of the endophytic bacteria in the stems of sugarcanes was significantly increased by adding longacting agent (235 g/t) and synergist (3 g/t and 18 g/t), but the richness only could be significantly improved by application with slow-release fertilizer adding with long-acting agent (235 g/t) treatment C. Except of slow-release fertilizers +long-term agent (150 g/t) treatment B, specific endophytic bacterial genera in the stems of sugarcanes all could be detected under slow-release fertilizer applications. Although the whole functions of the endophytic bacteria in the stems of sugarcanes were not significantly altered by slow-release fertilizer applications, higher stress resistant abilities could be concluded in sugarcanes under most of slow-release fertilizer applications (B-F treatments). Among them, the highest promotion and stress resistant effect on sugarcanes growth was the slow-release fertilizer + 235 g/t long-acting agent treatment (C) according to the composition and function of endophytic bacteria in stems of sugarcanes.

Low-ammonia concentrated natural rubber latex (CNRL) can alleviate the ammonia contamination problem caused by high-ammonia CNRL to a certain extent, and is gaining wider and wider application in a variety of CNRL products. In this study, four CNRL preservatives, BCT-2, HY, HM and LS, were used to prepare low ammonia CNRL, and the differences between the performances of low ammonia CNRL in different preserved systems were investigated by comparison with high ammonia CNRL. The results showed that the four preservation systems had good effect on the preservation of low ammonia CNRL, and all of them could meet the requirements of GB/T 8289—2016 national standard. Among them, the low ammonia CNRL preserved by BCT-2 had the lowest volatile fatty acid value (VFA No.), but the viscosity value was the highest, the lowest mechanical stability (MST); in addition, the average particle size of rubber particles was higher; the thermal stability and zinc oxide mechanical stability (ZST) were lower; the dry rubber film strength was higher. The low ammonia CNRL preserved by HY had the lowest VFA No., the lowest viscosity, highest MST and thermal stability; the fastest pre-cure speed; pre-cure latex with the lowest viscosity, highest MST and thermal stability; higher strength of vulcanized rubber film. HM preserved low ammonia CNRL with lower viscosity; higher MST and good stability; the lowest dry rubber film strength; the slowest pre-cure speed. LS preserved low ammonia CNRL with higher VFA No. and higher viscosity value; lower MST and poor stability; the smallest rubber particle size; the highest concentrated latex dry rubber film and vulcanized rubber film strength; the best dry rubber film thermal stability. Contrast analysis showed that HY and LS saved better overall performance of low ammonia CNRL, where HY low ammonia CNRL was suitable for the production of foam products, adhesives, etc., while LS low ammonia CNRL was suitable for the production of gloves, balloons and other pure rubber impregnated products.

The trunks of ten-year-old Aquilaria sinensis trees were filled with high-pressure nitrogen gas and treated every 7 and 15 days for 3 consecutive months. The wood discoloration area was observed and measured, the content of alcohol-soluble substances was detected, and the chemical composition and relative content of the agarwood were analyzed by GC-MS at 7 and 10 months after treatment. The effect of nitrogen gas filled on the agarwood formation was discussed, which would provide a feasible induction method for artificial agarwood formation. The results showed that nitrogen treatment significantly increased the longitudinal discoloration length and transverse discoloration width of wood trunks, and the results of the treatment filled with nitrogen gas every 7 days (N₇) were better than that of the treatment filled with nitrogen every 15 days (N₁₅). Ten months after N₇ treatment, the discoloration area was the largest, and the length of agarwood zone and total discoloration zone in both longitudinal and transverse direction were significantly longer than those of N₁₅ and CK₁. Inflating nitrogen treatment could significantly increase the content of alcohol-soluble substances and agarotetrol, and the content of agarwood zone was higher than that of transition zone. The content of alcohol-soluble substances and agarotetrol in agarwood area increased by 14.04% and 28.47% compared with that of N₁₅ and CK₁, respectively, and the content of agarotetrol was 0.12%, which significantly higher than that of N₁5 and CK₁, seven months after N₇ treatment. The content of alcohol-soluble substances and agarotetrol in each treatment increased with the increase of treatment time. Ten months after N₇ treatment, the content of alcohol-soluble substances and agarotetrol in agarwood zone was 19.37% and 0.30% respectively, which was noticeably higher than that of N₁₅ and CK₁. The content of alcohol-soluble substances and agarotetrol in N₁₅ treatment increased by 9.42% and 51.50% respectively, compared with CK₁. The volatile component of agarwood in N₇ treatment was the highest, which was rich in 25 terpenes, 5 chromones and 8 other compounds, and the total relative content of terpenes and chromones reached 66.09%, significantly higher than that of N₁₅ and CK₁.

In this paper, three types of green coffee oil microcapsules were prepared by complex coacervation using the combination of gum arabic (GA) with soybean isolate protein (SPI), whey isolate protein (WPI) and sodium caseinate (SC) as wall materials, respectively. The turbidity, infrared spectral characteristics, apparent morphology and fluorescence co-localization of the wall materials were analyzed by combining different characterization techniques; the encapsulation efficiency, morphology, particle size, structural characterization and thermal stability of the three green coffee oil microcapsules were compared. Gum arabic and different proteins formed complexes through electrostatic interactions, which can be used as a new wall material for encapsulating green coffee oil. Infrared spectral analysis showed that the three wall materials could encapsulate green coffee oil better. The encapsulation rate in a descending order was SPIGA-GCO (69.26%), SCGA-GCO (58.69%), WPIGA-GCO (52.57%). The microstructure of green coffee oil microcapsules had a flat surface without obvious cracks, among which the oil droplets were more uniformly distributed in SPIGA-GCO. DSC analysis showed that the thermal denaturation temperature of microcapsules was higher (103.93-108.33 ℃), with good thermal stability. The results showed that the performance of SPIGA-GCO microcapsules was significantly better than the microcapsule products prepared from the other two wall materials. This study would provide technical support for the development of stable and effective green coffee oil microencapsulated products, and also provide a theoretical basis for the high value utilization of green coffee oil.