Rubber tree latex metabolic processes are regulated by a variety of mechanisms, among which ubiquitination modification is the most significant. The phloem protein PP2 belongs to the F-box protein family and is specifically highly expressed in latex, which may be involved in the regulation of latex regeneration. In this study, bioinformatics and expression pattern analysis were conducted on 17 F-box members of the HbPP2 gene identified in the genome of Hevea brasiliensis. The results revealed that the majority of proteins encoded by the rubber tree PP2 genes were unstable hydrophilic proteins with molecular weights ranging from 9.402 to 61.206 kDa. Phylogenetic analysis showed that the 17 HbPP2 genes in the H. brasiliensis could be divided into three subgroups (Subgroup Ⅰ, Subgroup Ⅱ, Subgroup Ⅲ), in which HbPP2 members were completely absent in subgroup I. Analysis of cis-acting elements revealed that the rubber tree PP2 gene family contained diverse functional elements involved in growth and development regulation, hormone response, and light response. Subcellular localization analysis indicated that PP2 proteins were primarily localized in chloroplasts or cytoplasm. Tissue expression analysis showed that, except for some members with tissue-specific expression, most members of the rubber tree HbPP2 family were expressed in various tissues. In latex, the expression levels of six genes, HbPP2-B1, HbPP2-B1.1, HbPP2-B10.1, HbPP2-A13.2, HbPP2-B13 and HbPP2-A15.1, were relatively high, but tapping treatment significantly upregulated the expression of HbPP2-A13.2 and HbPP2-B13. This study would provide preliminary insights into the physicochemical and expression characteristics of the HbPP2 family members in the H. brasiliensis, laying a foundation for further research on the functions of this genes family in rubber trees latex synthesis and metabolism.

Mango (Mangifera indica L.), as a typical climacteric fruit, undergoes ripening and senescence processes closely related to ethylene. Ethylene-responsive factors (ERF) play crucial roles in plant growth, fruit ripening and ethylene signaling transduction. Mango variety Guifei was used, MiERF20, 492 bp long and encoding 163 amino acids, was cloned and analyzed. Bioinformatics analysis revealed that MiERF20 was an unstable, hydrophilic protein without signal peptides or transmembrane regions, containing 25 phosphorylation sites and one AP2 conserved domain. The secondary structure was dominated by 40.49% irregular coils, 33.13% α-helices, 16.56% extensions and 9.82% β-rotations. Its secondary structure comprised irregular coils, α-helices, extended chains, and β-turns, consistent with AP2 domain features. MiERF20 showed 83.89% homology with ERF20 of Lacertidae pistachio. Subcellular localization indicated that MiERF20 was located in the nucleus and possessed transcriptional activation activity. Prokaryotic expression assays demonstrated that the protein could be inducibly expressed in a prokaryotic system. Real-time fluorescence quantification showed that MiERF20 was ethylene-inducible, suggesting its role in ethylene-regulated fruit ripening. This study would provide a foundation for further analysis of the functions and regulatory mechanisms of ERF transcription factors during postharvest fruit ripening.

Gene TFL1 belongs to the phosphatidylethanolamine binding protein (PEBP) family and is closely related to plant flowering regulation. To explore the functions of TFL1 gene in Dendrobium hybrid, based on the transcriptome data of floral in Dendrobium hybrid, a TFL1 gene was cloned and named DenTFL1. And the bioinformatic analysis protein structure and subcellular localization prediction, expression patterns analysis were done to explored the functional of DenTFL1. The results showed that the full length of DenTFL1 cDNA sequence was 522 bp, encoding 173 amino acids. Bioinformatics analysis showed that the molecular formula of DenTFL1 was C₈₇₀H₁₃₅₄N₂₄₆O₂₄₉S₆, the theoretical relative molecular mass of the protein was 19.43 kDa, and the theoretical isoelectric point was 7.82, and the protein was hydrophilic and structurally stable. Subcellular prediction showed that it was located in the cytoplasm, without signal peptide and transmembrane domain. The secondary structure was dominated by 61.85% of random curl, also contained 23.70% of the extended chain, 14.45% of α-helix. The three-dimensional structural model was basically consistent with the secondary structure. The conserved domain analysis showed that DenTFL1 had a conserved PEBP domain and amino acid sequence alignment and phylogenetic tree analysis showed that DenTFL1 was closely related to D. nobile and D. thyrsiflorum. The constructed protein network showed that DenTFL1 mainly interacted with AT5G63440, LFY, SOC1, AGL24, AGL8. Expression analysis showed that DenTFL1 was expressed in all tissues of different development stages of Dendrobium hybrid, and had the highest expression level in the stems of young and mature plantlet and the flower stalks, and had a lower expression level in the roots of young plantlet and the leaves and roots of medium plantlets. Moreover, it had a high expression in different development stage of inflorescence except 3.0 cm long inflorescence. It also showed high expression in 7.0 mm and 9.0 mm width floral bud and the tissues of fully open flower, but expressed lower in the tissues of early development stages of floral bud. The research could provide a reference for the flowering regulation of Dendrobium hybrid, and add relevant information for the study of TFL1.

Heat shock transcription factor (HSF) is an important regulatory factor that plays a crucial role in plant response to hot ambient temperature (HAT). High temperature stress has a serious negative impact on the flowering of passion fruit, therefore, studying the regulation of heat tolerance by HSF in passion fruit is of great significance. In this study, we identified 26 HSF genes on the genome of passion fruit using bioinformatics technology, named PeHSF1-PeHSF26. The genes could encode proteins of 100-1589 amino acids, with molecular weight 11 544.9-177 157.8 g/mol, and a theoretical isoelectric point of 4.25-10.80. The 26 genes were distributed on chromosomes 1, 4, 5, 6, 7, 8 and 9, and were divided into 10 subpopulations. The analysis of the whole genome replication event showed that ZX01G0033270, ZX01G0052790 and ZX01G0052980 were located within the genome duplications. The genes contained 1-12 introns and 2-13 exons, all contained HSF-DNA binding domains. RNA-seq analysis of Huangguo original species and Jinlingziguo HSF genes to HAT revealed that there were significant differences in the expression levels of genes, including ZX01G0002530, ZX01G0052790 and ZX01G0121040 in flower buds. The expression levels of candidate HSF genes were validated by RT-qPCR. Based on comprehensive analysis, it is supposed that the most ideal candidate HSF gene for passion flower response to high temperature stress was ZX01G0121040. The results would contribute to understand the function of HSF in response to high temperature stress during the flowering of passion fruit, and provide important genetic resources and theoretical basis for genetic improvement of passion fruit.

The total RNA of Aquilaria sinensis vitro roots was extracted using the EASYspin Plus Plant Rapid Extraction Kit after three consecutive generations of salt stress treatment, and sequenced using the HiSeq 2500 high- throughput sequencing platform, aiming at exploring the roles of miRNAs in the three generations of A. sinensis vitro roots under salt stress and the metabolic pathways that may be involved in the regulation, and providing references to reveal the mechanisms of A. sinensis. The miRNA expression profiles of the first, second and third generations were obtained by using the high-throughput sequencing platform and bioinformatics technology, and the differential miRNAs in the three generations of vitro roots were screened, and the target genes of the differential miRNAs were predicted, and then the target gene analysis was performed to obtain the miRNAs that might be involved in the secondary metabolites of A. sinensis and those that were related to the response to salt stress. The results showed that 508 known miRNAs and 764 new predicted miRNAs were detected in the first-generation samples; 444 known miRNAs and 673 new predicted miRNAs were detected in the second-generation samples; 904 known miRNAs and 1100 new predicted miRNAs were detected in the third-generation samples. A total of 59 differentially expressed miRNAs and 275 target genes were obtained from the three samples. The up-regulated miRNA target genes were mainly involved in flavonoid biosynthesis and glutathione metabolism, while the down-regulated miRNA target genes were mainly involved in phenylpropanoid biosynthesis, Plant hormone signal transduction, plant-pathogen interactions and other signaling pathways. The key miRNAs were selected for NR annotation, and it was found that miR8020-x and novel-m0628-5p might be involved in the synthesis of secondary metabolites in A. sinensis vitro roots, and miR7494-y, miR477-y, miR5185-y, miR7757-y, miR408-z, and novel-m0628-5p might be responded to A. sinensis vitro roots salt stress. In this study, we used high-throughput sequencing to obtain miRNA expression profiles of A. sinensis vitro roots under salt stress, and bioinformatics analysis to obtain miRNAs that may be involved in secondary metabolites of A. sinensis and those related to the response to salt stress. The results of the present study will help to enhance the understanding of the miRNA regulatory mechanisms of A. sinensis under salt stress conditions and provide a new pathway for the synthesis of secondary metabolites of A. sinensis.

Mulberry is a fruit tree with rich nutrition and dual functions of food and medicine, which is deeply loved by consumers. The fragrance is a significant factor in the sensory quality of mulberries, playing a crucial role in consumer purchasing behavior. Mulberry Baichang is a unique variety that emits a strong, creamy fragrance, which has enormous potential market value. However, the key metabolites and mechanisms responsible for the formation of this fragrance are still unclear. In this study, we utilized GC-MS and RNA-seq technology to examine the volatile organic compounds (VOCs) and gene expression in Baichang and Hongchang, which lacking a distinct fragrance. The results showed that 661 volatile metabolites were detected in both varieties. Most of these were found in higher relative amounts in Baichang, with 47 types being present only in Baichang, suggesting a rich composition of VOCs in this variety. A total of 312 metabolites were identified as differential metabolites; combining the sensory annotation information and relative content of VOCs, 70 candidate VOCs were annotated as being related to the formation of “sweet, waxy, coconut and oily” sensations. These could potentially be the key metabolites contributing to the unique aroma of Baichang. The relative odor activity value (rOAV) analysis revealed that 5-hexyldihydro-2(3H)-furanone (also known as γ-decalactone) was the key VOC contributing to the formation of the special aroma of Baichang. Using RNA-seq, 19 key structural genes related to ester synthesis were screened, including AAT, ACX, ALDH, CYP, EHL, FAD, HPL and LOX. The high expression levels of these structural genes in Baichang may contribute to the unique creamy aroma of this variety; however, the underlying mechanisms require further investigation. This study would provide insights into the aroma differences among different kinds of mulberries.

In order to select a new tobacco variety with excellent industrial and agricultural characteristics was selected, the tobacco variety Y87 was used as the control to compare and analyze the agronomic traits, ultrastructure, metabolites and post baking tobacco quality evaluation of four newly introduced tobacco varieties Y121, Y116, Y301 and Y119. The results showed that Y121 had relatively good field growth, complete chloroplast structure, and a large volume and quantity of osmium loving particles on the chloroplast membrane. Through metabolic pathway enrichment analysis, it was found that Y121 contained more organic acids such as succinic acid and phenylacetic acid, as well as fewer nicotine such as nicotine reducing and new tobacco alkaloids, which are beneficial for improving the aroma quality and safety of tobacco leaves. In addition, compared to other newly introduced varieties, the Y121 had better appearance quality, more coordinated chemical composition, higher sensory quality score, and is closer to Y87. The results would provide reliable technical support for the upgrading of varieties, which is conducive to the sustained and stable development of high-quality raw material production.

Biomass is a key factor in plant evolutionary adaptation and yield, and obtaining high-yield crop varieties is always a basic requirement for crop breeding. In this study, a mutant Mu with increased biomass was discovered during the tissue culture of Setaria viridis ME34, and the trait can be stably inherited to the next generation. Through the observation of the phenotype of S. viridis and statistical analysis of the agronomic traits of seedlings and adults, it was found that the biomass (fresh and dry weight) of the mutant seedlings and the adult plant height of S. viridis mutant was significantly higher than that of the wild-type plants, and the spike length and seed length were also significantly longer than those of the S. viridis wild-type plants, reaching a highly significant level. Transcriptome sequencing was performed on the leaves and stems of ME34 and Mu, and some genes were validated by RT-PCR. Differential expression gene analysis revealed that the genes related to nitrogen metabolism and regulation accounted for about 20% of the total differential genes. GO functional and KEGG enrichment analysis also revealed a close relationship between biomass and nitrogen metabolism and regulation. The DEGseq method was used to analyze the changes in the differentially expressed genes, and some related genes involved in nitrogen absorption, transport, assimilation, and reuse were obtained, such as nitrate transporter NRT, ammonium transporter AMT, nitrate reductase NR, nitrite reductase NiR, glutamate synthase GOGAT, NLP family transcription factors, and serine threonine protein kinase. Through the above research, important molecular basis and foundation are provided for the breeding work of crops such as foxtail millet.

Camellia oleifera is a significant woody oil tree species that is extensively cultivated in southern China. It displays a notable degree of diversity in phenotypic traits, such as fruit, leaf and tree shapes, etc.. In the present study, 100 C. oleifera seedling trees were collected and 33 phenotypic traits were subjected to the comprehensive evaluation. In the diversity analysis of quantitative traits, the coefficient of variation (CV) was ranged from 8.81% to 56.85%, with the number of flowers per unit area (NFPUA) exhibiting the greatest variability (56.85%), and the fruit shape index (FSI) demonstrated the least variability (8.81%). The diversity index of quantitative traits exhibited a range of 1.13 to 4.61, indicating a notable degree of genetic diversity in fruit and leaf traits. Cluster analysis classified the 100 germplasm accessions into five categories. The first category was characterized by dark fruit colour, a rounder fruit shape, and taller trees. The second category exhibited flattened fruit shape and heavier fruit weight with narrower tree cannopy. The third category was characterized by longer fruit shapes with heaviest single fruit weight, and smaller but denser tree canopies. The fourth category was distinguished by mainly round fruits, lighter single fruit weight, and larger leaf area. The fifth category exhibited elongated fruits with thicker peels and more opened tree canopy. Principal component analysis yielded 12 principal components, collectively accounted for 79.174% of the cumulative contribution rate, including traits such as fruit diameter, single fruit weight, and fresh seed weight. Based on the results of the principal component analysis, superior C. oleifera accessions were selected for further observation. This study demonstrated that C. oleifera germplasm resources in Hainan province exhibited a high level of phenotypic trait diversity. The research would provide a theoretical base for the genetic improvement of C. oleifera.

Based on 24 phenotypic traits, statistical analysis, correlation analysis, principal component analysis and systematic cluster analysis were carried out on 187 pepper hybrid combinations introduced from different ecological regions in China to screen out the best hybrid combinations of pepper suitable for planting in Jiangxi. The Shannon-Weaver genetic diversity index of 12 descriptive traits was ranged from 0.36 to 1.95, with an average of 0.82. The genetic diversity index of fruit shape was highest (1.95). The variation coefficient of 12 quantitative traits was ranged from 16.61% to 84.48%, and the variation coefficient of single fruit weight was the largest. The genetic diversity index was ranged from 0.67 to 2.08, with an average of 1.80. Correlation analysis showed that the correlation coefficient (r_s) between single fruit weight and fruit diameter was the highest, reaching 0.86. In addition, yield was significantly positively correlated with fruit diameter, fruit flesh thickness and single fruit weight. Principal component analysis simplified the 24 traits index into 3 principal components, and the cumulative contribution rate reached 69.164%. The cluster analysis showed that the 187 hybrid combinations could be divided into 5 groups at 8.10 Euclidean-distance, and there were significant differences in single fruit weight, fruit color, fruit shape and plant height among the groups. After comprehensive scoring, 10 excellent hybrid combinations suitable for planting in Jiangxi were selected. The above results would provide scientific basis for the comprehensive evaluation, selection and application of pepper hybrid combination.

To generate polyploid B. ochracea Schltr and find out the optimal induction condition, the seeds of diploid B. ochracea were treated with different concentration of colchicine solution under a range of treatment time. The results of the study suggested that the seeds treated with 0.25% colchicine solution for six days was effective in polyploid induction for B. ochracea, with a 35.66% survival rate of treated seeds and a 45% induction rate. The tetraploid gave a significant enhancement on various agronomic traits, including plant height, leaf number, leaf width, stem diameter, bulb length and root diameter. In addition, tetraploid B. ochracea showed increased stomatal aperture and decreased stomatal density. The tetraploid B. ochracea was generated in this study, which would provide technical support and basic material for improving the genetic traits of medicinal orchids.

Longan (Dimocarpus longan Lour.) is an important economic crop in tropical subtropical areas. Under normal circumstances, longan can become flowers only when induced by low temperature in winter together with appropriate measures to control the winter tips, but potassium chlorate, as the only known compound that can induce longan to become flowers in the opposite season, the anatomical process and physiological mechanism of the potassium chlorate-regulated flower formation are not clear, and the carbon and nitrogen nutrition is closely related to flower formation. Carbon and nitrogen nutrition are closely related to flower formation, therefore, analyzing the changes of carbon and nitrogen content of longan by potassium chlorate is also an important perspective to reveal the mechanism of flower formation. In this study, we used Shixia longan (Dimocarpus longan Shixia) as the test material, and induced the antiseasonal flower formation of longan by soil application of potassium chlorate to investigate the anatomical changes of the terminal buds of the antiseasonal longan during flower formation, and analyzed the changes in the C and N contents as well as the relationship between C/N and the development of the terminal buds. By observing the growth point of the terminal buds in the control group, which always showed a more pointed leaf bud state, the terminal buds after potassium chlorate treatment clarified the three stages of flower bud differentiation according to the changes in the morphology of the growth point: the stage of physiological differentiation of flower buds, the stage of inflorescence formation of flower buds, and the stage of floral organ formation. The carbon content of terminal buds treated with potassium chlorate showed a continuous increasing trend, while the carbon content of the control showed an increasing and then decreasing trend, the nitrogen content of both groups showed an increasing and then decreasing trend, and the C/N trend of the two groups showed a “stable-decreasing-increasing” trend. At the stage of flower bud physiological differentiation, the C/N content of terminal buds increased more than that of the control after KClO₃ treatment, while the N content of both groups did not change much. The C/N content of terminal buds increased from 22.82 to 23.41, while that of the control decreased from 22.82 to 22.63, showing a smooth trend in both groups. During the inflorescence formation stage of flower buds, the increase in total carbon content of terminal buds was smaller than that of the control, while the increase in total nitrogen content was larger than that of the control after potassium chlorate treatment; the C/N of terminal buds decreased from 23.41 to 17.65 after potassium chlorate treatment, while that of the control decreased from 22.63 to 20.29, and the decrease of terminal buds was larger after potassium chlorate treatment than that of the control. At the stage of inflorescence emergence, the whole carbon and nitrogen contents of terminal buds showed an increasing trend after potassium chlorate treatment, while the opposite was true for the control. The C/N of terminal buds increased from 17.65 to 21.44 after potassium chlorate treatment, while that of the control increased from 20.29 to 22.92, but the rate of increase of terminal buds was greater after potassium chlorate treatment than that of the control. This study reveals that a more than 21.47% increase in the C/N ratio of longan terminal buds is conducive to flowering. The application of potassium chlorate through soil leads to a continuous increase in total carbon content and an initial increase followed by a decrease in total nitrogen content in longan terminal buds, resulting in a significant rise in the C/N ratio, which is beneficial for the development of terminal buds towards floral formation.

Guangxi is the leading sugarcane production area in China. over 85% of the sugarcane is planted on non-irrigated dry land, and varying degrees of drought damage occur every year. Drought is the main limiting factor for sugarcane production in China. Tillering is one of the important traits affecting the yield of sugarcane. It is of great significance to study the effect of drought stress on the development of tillering buds at tillering stage. Guire 2 is a new sugarcane variety bred by our team with good drought resistance and strong tillering ability. In order to investigate the effects of drought stress on physiological indicators of sugarcane tillering seedlings and leaves at tillering stage, Guire 2 was used to conduct drought stress experiments at the early stage of sugarcane tillering. The experiment was set up with control (19%-25% soil absolute water content) and drought stress treatment by stopping irrigation. Samples were taken from the control group and treatment group at early drought stress (14%-15% soil absolute water content), middle drought stress (10%-11% soil absolute water content), late drought stress (6%-7% soil absolute water content) stages. The changes of antioxidant enzyme activity, MDA, osmoregulatory substances and endogenous hormone contents were measured by subordination function method. The correlation of the physiological indicators in sugarcane tiller shoots and leaves was analyzed, and the drought resistance of tiller shoots and leaves was evaluated. The results showed that drought stress increased the activities of peroxidase (POD), and superoxidate dismutase (SOD), and contents of proline (Pro), soluble protein, starch, sucrose and abscisic acid (ABA), especially in tiller shoots, the treatment group and the control group reached a significant difference, while the malondialdehyde (MDA) content remained at a similar level in sugarcane tillering seedlings and leaves during drought stress. Compared with leaves, drought stress significantly increased the activity of SOD and the contents of Pro, soluble protein and sucrose in tiller shoots. Correlation analysis showed that most significant correlations between the physiological indicators in sugarcane tiller shoots and leaves under drought stress were positive, and sucrose content, starch content, Pro content, IAA content and SOD activity were more significantly or extremely significantly correlated with other indicators. According to the comprehensive drought resistance coefficient and the average of subordinate function values of each index, the drought resistance of tiller shoots was stronger than that of leaves in sugarcane.

Lodging was one of the important limiting factors for high yield, high sugar content and mechanized harvesting of sugarcane, and it was also an urgent problem to be solved in sugarcane mechanized breeding. In this study, 24 reciprocal hybrids of 57NG208 and Nanjian chewing cane and PT43-52 (CK) were used as research materials. The plant height, basal stem diameter, middle stem diameter, brix, center of gravity height, single stem weight, the lodging resistance index, basal and middle stem diameter ratio and stem breaking force were measured. The correlation analysis, principal component analysis, membership function method and cluster analysis were used to comprehensively evaluate them. The results showed that the coefficient of variation of 9 indexes such as lodging resistance index and agronomic traits of 25 materials was between 11.57% and 30.80%, and the traits were obviously separated and the variation was abundant. The correlation analysis showed that the lodging resistance index was significantly positively correlated with brix, basal stem diameter, basal and middle stem diameter ratio, center of gravity height, single stem weight and stem breaking force, and negatively correlated with plant height and middle stem diameter. The results of principal component analysis showed that the cumulative contribution rate of the first three principal components was 75.7717%, which represented most of the information of lodging resistance of the tested materials. Cluster analysis showed that 25 materials could be clustered into three categories, and the results were consistent with the results of membership function evaluation. Among them, 13 materials in the first category had excellent lodging resistance and high comprehensive evaluation scores, especially Yunrui 12-9-45, Yunrui 12-9-5, Yunrui 12-38-32, PT43-52 and Yunrui 12-38-46. The lodging resistance index of the remaining germplasms was 3.00 except Yunrui 12-38-46, and the comprehensive evaluation E value was in the top 5, which should be used in the future improvement of lodging resistance.

Tea plants (Camellia sinensis) is an essential economic crop in China with significant genetic diversity. Polyploidization, a key driver in species evolution, plays a crucial role in enhancing the economic traits of tea plants, providing new avenues for breeding improved varieties. This study aims to explore the ploidy differences between diploid and triploid tea plants by investigating the morphological, physiological, biochemical and metabolic traits. Utilizing flow cytometry, we identified the chromosome ploidy of 165 tea germplasm resources and discovered 11 new triploid tea plant varieties. The 11 triploid varieties, along with 12 diploid varieties, underwent a comparative study focusing on bud, leaf and anatomical characteristics. The results revealed significant differences between diploid and triploid tea plants in several traits, including phenological period, bud weight, leaf area, stomatal size and stomatal density. Triploid tea plants generally exhibited later budding, significantly higher bud weight, larger leaf areas, and larger stomatal dimensions, but lower stomatal density compared to diploid varieties. As the buds and leaves are vital for tea quality, the morphological and physiological differences can influence tea production and its overall quality. Furthermore, metabolomic analysis using UPLC-MS/MS technology was conducted on the triploid variety Xilianno. 1 and its maternal diploid Fuding Dabai (CK). A total of 1203 differential metabolites were detected, with 170 showing significant variation, of which 81 were upregulated and 89 were down regulated. The most abundant metabolites were flavonoids, followed by amino acids and their derivatives. The triploid variety displayed enhanced levels of metabolites associated with improved antioxidant activity and other health-related properties. The study would provide novel insights into the morphological, physiological and metabolic differences between diploid and triploid tea plants, offering valuable references for genetic assessment and breeding strategies. The findings also emphasize the significance of polyploidy in improving tea plant resilience, yield and quality, which is critical for the sustainable development of the tea industry.

Partial replacement of chemical fertilizers with organic fertilizers is a key path for achieving zero growth in chemical fertilizers in tea gardens. Biochar, a new agricultural soil amendment, has positive effects in optimizing the soil microecological environment. Further understanding the effects of organic fertilizer substitution and biochar application on the soil aggregate stability and organic carbon accumulation in tea gardens, also the synergistic effects, can provide scientific basis for reducing fertilizer application, increasing efficiency, and carbon sequestration and emission reduction in tea gardens. Wet screening method was used to treat seven different fertilizers, namely no fertilization (CK), conventional fertilization (NPK), fertilizer and biochar application (biochar dosage 10 t/hm², NPK+BC10), 50% fertilizer+50% organic fertilizer (OM50), 50% fertilizer+50% organic fertilizer (OM50) combined with different amounts of biochar. The amount of biochar was 10 t/hm² (OM50+BC10), 20 t/hm² (OM50+BC20) and 40 t/hm² (OM50+BC40) for physical grading of soil aggregates. The distribution, structure and stability and the change of organic carbon content in different treated tea plantations were studied. Under the treatment of OM50+BC10, OM50+BC20 and OM50+BC40, the organic carbon reserves of aggregates increased to different degrees compared with the conventional fertilization control treatment. In contrast to the NPK and CK treatments, the replacement of 50% chemical fertilizer with different doses of biochar could significantly improve the organic carbon content of soil>2 mm and 0.25-2.00 mm granular aggregates. The increase rate was ranged from 23.96%-70.87% and 21.87%-49.27%, OM50+BC20 and OM50+BC40 had the most significant treatment effect. Geometric mean diameter (GWD) and mean mass diameter (MWD) in aggregate were in the order CK<NPK<NPK+BC10<OM50<OM50+BC10<OM50+BC20<OM50+BC40. The aggregate content and organic carbon content were the most significant in OM50+BC40 treatment. 50% organic fertilizer replacing 50% fertilizer, different amount of biomass carbon application could significantly increase tea garden soil aggregate, organic carbon content, promote tea garden soil aggregate stability and structure level. Organic fertilizer and biomass carbon is more conducive to improving the stability of soil aggregate and promoting the sequestration of organic carbon. OM50+BC20 and OM50+BC40 treatment showed significant results in improving the stability of soil organic carbon and soil aggregates in tea plantations. Without considering the cost effect, OM50+BC40 is a suitable fertilization scheme; otherwise, OM50+BC20 can be selected.

White-fruited pepper is a highly distinctive type of pepper in Zhejiang province. In order to determine the optimal nitrogen level for this variety, a facility cultivation experiment was conducted to analyze the effects of five different nitrogen treatments: 0 kg/hm², T₀; 150 kg/hm², T₁; 195 kg/hm², T₂; 240 kg/hm², T₃; 285 kg/hm², T₄, on the growth, development, quality and accumulation of nitrogen elements in white pepper plants. The results showed that the main stem height, plant height, canopy width, stem diameter, stem and leaf biomass and yield of peppers increased with the application of nitrogen. Notably, fruit width, single fruit weight and yield reached the maximum under the T₄ treatment, with increased of 36.27%, 76.30% and 32.16% respectively compared to the control, followed by T₃, while the T₃ treatment produced the longest fruits. Furthermore, the photosynthetic capacity of the pepper leaves improved with higher nitrogen application, with T₃ and T₄ treatments showing significantly better performance than the others. The quality of peppers was also influenced by nitrogen application. Nitrogen application also affected the quality of the pepper. The content of vitamin C and dihydrocapsaicin decreased with the increasing nitrogen levels, while the levels of capsaicin, total capsaicin and amino acids showed a trend of first increasing and then decreasing. Different nitrogen levels had a minor impact on nitrogen absorption in the roots, stems and fruits of peppers, but significantly affected nitrogen absorption in the leaves, with the T₂ treatment achieving the highest leaf nitrogen content. Through principal component analysis of the 10 indicators related to yield and quality, the optimal nitrogen application for white-fruited peppers is T₃ (240 kg/hm²).

Enhancing photosynthesis is the key to improving crop yield and quality. The interaction between agronomic traits, photosynthetic parameters, and variety yield and quality is not yet clear. In this study, 10 different mulberry varieties (Morus sp.) were taken as the research objects. Based on the morphological data such as leaf size, the number of leaves, the number of branches, etc., obtained through the statistics of our research group, the nutritional index data such as crude protein, and the measured photosynthetic parameters, we analyzed the correlations of specific parameters within each index through correlation analysis. And we utilized the structural equation model to analyze the influence mechanism and contribution potential of their agronomic traits, stomatal characteristics, and photosynthetic indexes on the yield and quality of mulberry leaves. There were significant differences in stomatal characteristics and photosynthetic indicators among different varieties, and Sha 2×Lun 109 exhibited good photosynthetic capacity and water use efficiency. There was a significant correlation between intercellular carbon dioxide concentration and leaf length, leaf width, and total calcium content. There was a strong positive correlation between stomatal length and width (r=0.833), and a positive correlation between crude protein content and leaf weight (r=0.660). The structural equation model indicated that the stomatal characteristics had a negative effect on leaf quality (R²=–0.75), while the intercellular carbon dioxide concentration had a negative effect on net photosynthetic rate (R²=-0.91). The intercellular carbon dioxide concentration and net photosynthetic rate directly affected leaf yield (R²=2.99 and 3.04, respectively), and leaf yield had a positive effect on leaf quality (R²=0.66). The research shows that mulberry varieties affect the net photosynthetic rate through stomatal characteristics and intercellular carbon dioxide concentration, which further affects the yield and quality of mulberry trees. Therefore, by regulating the parameters of mulberry stomata, the yield and quality of mulberry trees can be improved, which would provide a scientific basis for mulberry variety improvement and precision cultivation management, and has important practical significance.

In order to explore the effect of DNA methylation on drought hardening of different ploidy watermelon, mannitol was used to mimic drought stress in suspension cultured cells of different ploidy watermelon. The cell growth and resistance related physiological indexes were measured after stress, recovery and re-stress treatments. Meanwhile, the DNA methyltransferase inhibitor 5-azacytidine (5-AzaC) was used to explore whether methylation is involved in resistance regulation. The results showed that 5-AzaC could retard the growth, inhibit the extracellular alkalization, increase the content of malondialdehyde, bring down the content proline and the activity of protective enzymes such as SOD in all types of cells. Moreover, it caused the membrane permeability raising in diploid and triploid cells. Above results suggest that 5-AzaC can aggravate the osmotic stress injury and reverse the effects of drought hardening partially. Principal component analysis revealed that malondialdehyde content, proline content, PAL, CAT and APX activity could be used as the main evaluation indexes for evaluation the effect of drought hardening. This study would provide clues for mining the physiological indexes for evaluate the effects of stress hardening and the mechanism of DNA methylation involved in watermelon resistance regulation.

Helopeltis theivora Waterhouse belongs to the genus Helopeltis of the family Miridae of the order Hemiptera, and is one of the most important sap-sucking pests in the tropical tea plantations in Hainan, China. The nymphs and adults of H. theivora mainly damage by piercing and sucking in the young tissues of tea shoots, which causes the black brown spots that necrosis on the leaf and results in the reduction of tea yield and quality. The research on the H. theivora in Hainan tea region is still rare. In this paper, we first investigated the external morphological characteristics of H. theivora, then, the growth and development characteristics such as egg hatching, nymph molting, and adult emergence, as well as the behavioral characteristics including feeding, mating and oviposition were recorded and analyzed, respectively. The results showed that the egg of H. theivora was in a sausage shape, with two respiratory processes on the egg operculum at different length. The color of the freshly laid egg was white. It was then gradually transformed to the orange and ultimately exhibited the orange-red as it approached incubation. The nymphal stage was divided into 5 instars, the color of the freshly hatched nymph was orange-red, and then gradually turned to pale green and green. The adult H. theivora possessed a small head, an elongated beak, and two black compound eyes. The antennae presented filamentous, and the length was twice more than the body. The color of adult H. theivora was brown or yellowish brown. The duration of incubation of H. theivora was (53.25±9.00)min. The hatchability was very low while the rate of egg- hatching was only 69.9% under the laboratory conditions. The moulting of nymphs and the emergence of adults happened mainly on the back of leaves, hanging upside down, and the duration was (6.20±0.97)min and (8.40±1.33)min, respectively. Particularly, as approached to the molting and eclosion, the feeding frequency became significantly less and the activity became weaker. The H. theivora preferred to sucking the saps of the young leaves and stems of tea shoots, and the feeding time was mainly concentrated in the evening. The mating behavior of adults H. theivora mainly happened between 9: 00 and 10: 00 and between 17: 00 and 18: 00, and the duration of each mating was (117.75±18.70) min. In addition, when a female decided to refuse a male’s request for courtship, it generally rolled her abdomen inwards. The stage of the fertilized egg of H. theivora was short. During the oviposition, the female arched itsr abdomen, its head was downward, and the whole body was in a curvedly arched state. The oviposition site was mainly in the epidermis of the tender stems, while a small part of eggs was laid in the petiole and leaf vein. The egg stage was 6-8 days. The results of this study would provide a theoretical basis for the further study on the morphological identification and behavioral ecology of H. theivora in Hainan tea region.

Citrus medica is an older cultivated varieties of the genus Citrus and the parent or ancestor of Citrus fruits with significant commercial value. Due to its nutritional and medicinal values, C. medica occupies an important position in the citrus industry. The southwestern part of China is an important center for the origin and diversity of C. medica, and its cultivation has reached a certain scale. Citrus Huanglongbing (HLB) has been spreading for hundreds of years in the major citrus-producing areas in China. C. medica infected with HLB and healthy C. medica were used as the materials. Firstly, the symptoms of the leaves and fruits of C. medica infected with HLB were observed. Secondly, the distribution pattern of HLB in different tissue parts of C. medica was explored. Meanwhile, the tissue anatomical structures and multiple physiological indicators of C. medica infected with HLB and healthy C. medica were analyzed and measured through comparison. Through comparative observation, it was found that the leaves of C. medica infected with HLB showed typical symptoms such as yellowing, mottling and mosaic, and some branches presented symptoms of witches broom and abnormal flowering, but no “red nose fruit” was observed. The distribution of HLB in different parts of the same C. medica was uneven, with the highest content in the fruit pith, followed by the midrib of the old leaves, and HLB was not detected in the fibrous roots. In C. medica infected with HLB, the cells in the phloem, xylem, parenchyma and root were arranged irregularly, the phloem tissue was deformed and collapsed, and the thickness of the phloem of the taproot was significantly decreased compared with that of the healthy C. medica at the same period (P<0.05). No obvious starch grain accumulation was observed in each tissue section of C. medica infected with HLB, but when the starch content was measured, it was found that the starch contents in the old leaves, new leaves, taproot, fibrous roots and fruit pith of C. medica infected with HLB were all higher than those of the corresponding healthy tissues. The hydrogen peroxide content in each tissue of the diseased C. medica increased significantly (P<0.5), especially significantly accumulated in the young tissues (new leaves, fibrous roots) infected with HLB. Compared with healthy C. medica, the callose deposition phenomenon in the tissues of C. medica infected with HLB, especially in the main root and the midrib of the old leaves, was more obvious. The research results of this study could provide a theoretical basis for the relevant studies on exploring the characteristics of damage caused by HLB and the defense mechanism of citrus against HLB in the future.

Natural rubber in the storage, transport process of rubber molecular chain on the aldehyde group condensaion reaction, results in the plasticity initial value, mooney viscosity and other indicators gradually increased, plasticity retention rate gradually decreased, making it more difficult to increase the plasticizing and mixing processes of natural rubber, and reduces the oxygen aging resistance of the rubber. It is necessary to prepare natural rubber with constant viscosity to reduce the condensation of aldehyde groups in the molecular chain of natural rubber. Alkylhydrazine (OP) solution was used to soak natural rubber by microbial coagulation to analyse the effects of OP solution concentration and wet film soaking time on the physical and chemical indexes, vulcanization characteristics, physical and mechanical properties of natural rubber, plasticity initial value, plasticity retention rate and mooney viscosity hardening value of natural rubber during storage. The results showed that plasticity initial value and mooney viscosity of natural raw rubber increased first and then decreased with the increase of the concentration of OP solution, but the plasticity retention rate was opposite. During the accelerated storage process, the plasticity initial value and mooney viscosity of natural raw rubber soaked in different concentrations of OP solution increased, while its plasticity retention rate decreased. With the increase of OP solution concentration, the hardening value of plasticity initial value, plasticity retention rate and mooney viscosity gradually decreased. With the concentration of OP solution ≥0.5%, the hardening value of plasticity initial value and mooney viscosity were ≤5. The effect of wet film soaking time on the physical and chemical indexes of natural raw rubber and the hardening values of the plasticity initial value, plasticity retention rate and mooney viscosity was not obvious. Compared with the control sample P₀, the natural rubbers (P₇, P₈, and P₉) soaked in 0.5% concentration of OP solution had slightly higher torque difference values ΔM of their blends, the tensile strength and tear strength of vulcanized rubber increased by 4.5%–14.2% and 3.0%–8.5%, respectively. In addition, the soaking time of wet film had a significant effect on the torque difference ΔM of the rubber and the tensile strength and tear strength of the vulcanized rubber. OP solution had a good constant viscosity effect on natural rubber. 0.5% concentration of OP solution soaked natural rubber had excellent physical and mechanical properties, and the production process was simple, not causing the waste of constant viscosity agent and the pollution of the production workshop, surrounding environment, easy to large-scale promotion and application.

The study on the ecological suitability regionalization for jackfruit (Artocarpus heterophyllus Lam.) is of great significance for guiding its cultivation layout and digging its development potential, via utilization of environmental resources efficiently in tropical and subtropical regions. Based on the analytic hierarchy process (AHP) and GIS, this study constructed a suitability analysis model for jackfruit cultivation using four evaluation factors: temperature, precipitation, sunshine hours and soil index. The results of the regionalization are then validated in conjunction with previous research findings and the actual distribution of jackfruit, while further explore the spatial potential for jackfruit cultivation by integrating land use spatial data. The results indicate that the zones able to plant are primarily distributed in tropical and subtropical monsoon climate regions. The suitable zones for planting are mainly found in Hainan, southern Guangxi, southern Guangdong, parts of southern Yunnan and southern Fujian, where there is sufficient heat throughout the year, favorable wintering conditions, and a good combination of light, heat and water. Total plantable area for jackfruit in China is approximately 47.85×10⁴km², of which 22.71×10⁴km² is suitable for cultivating, comprising 8.89×10⁴km² of arable land and 182.05 km² of unused land. In comparison to previous research findings, this study expanded the amount of potentially viable arable land for jackfruit cultivation by about 58 times the existing cultivating area. Considering comprehensive land use, ecological environment, and policy support, jackfruit has a high potential for production in suitable and relatively suitable arable and unused land in China. Priority should be given to developing suitable planting areas in the southern regions of Guangxi and Yunnan. The study findings could provide scientific and analytic references for optimizing the regional layout and development planning of jackfruit cultivation in China.

Based on the data of rice growth period in Dongfang and Ledong, main producers for rice seed reproduction in Hainan, and the meteorological data from 1971 to 2020, the Penman-Monteith formula and crop coefficient method and the method recommended by the Soil Conservation Service of the United States Department of Agriculture were used to obtain the water requirement (ET_c), effective precipitation (P_e) and water deficit (D_w) of rice seed reproduction in field period and early, middle and late stage of field period. The change characteristics of water supply and demand of rice seed reproduction in the two regions were then analyzed. The 50-year average value of ET_c in field period of rice seed reproduction in Dongfang and Ledong was 400.2 mm and 322.3 mm, respectively, the mean value of P_e was 45.7 mm and 84.3 mm, respectively, and the mean value of D_w was 354.5 mm and 238.0 mm, respectively. The ET_c and D_w in field period of rice seed reproduction were mainly distributed in the middle and early stages, accounting for 72.4% to 85.2% of ET_c and D_w during the field period. The P_e in field period of rice seed reproduction was mainly distributed in the late and middle stages, accounting for 78.2% and 85.6% of P_e during the field period, respectively. In the past 50 years, the ET_c and D_w of rice seed reproduction in field period and all growth stages of field period in Dongfang showed an increasing trend (the increase in field period was significant), while the P_e showed a decreasing trend. The variation trend of ET_c, P_e and D_w of rice seed reproduction with time in Ledong was roughly opposite to that in Dongfang. In the past 50 years, the water shortage situation of rice seed reproduction in Dongfang was significantly worsening, while the water shortage situation in Ledong was easing to some extent but remained severe. Effective measures should be taken to mitigate the impact of climate change on the rice seed reproduction. In the past 50 years, the main reasons for the increase of ET_c and D_w during most growth stages of rice seed reproduction in Dongfang were the insignificant increase in high temperature and extremely significant increase in low temperature, or the insignificant increase in high temperature and sunshine hours. The main reasons for the decrease of ET_c and D_w during most growth stages of rice seed reproduction in Ledong were the insignificant decrease in sunshine hours, extremely significant decrease in average wind speed, or insignificant decrease in sunshine hours and insignificant increase in precipitation. The results of this study provide strong support for rational water use and scientific irrigation scheme for rice seed reproduction in Hainan province under the background of climate change.