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.

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.

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.

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 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.

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.

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.

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.

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.