Genetic engineering technology serves as an effective method to shorten crop breeding cycles, specifically cultivate new crop varieties, and identify plant gene functions. Induced promoters are important tools in genetic engineering research, among which thermally inducible promoters being extensively utilized in plant molecular biology owing to the simple vector structure, convenient induction, and low cost. At present, the development of genetic engineering technology in rubber trees lags behind. Functional studies of target genes typically use constitutive promoters, which limits the progress of related work. In this study, rubber tree calli were treated by heat. Through transcriptome sequencing analysis, identified eight genes that were non-expressed or minimally expressed, but exhibited high level expression after heat induction in calli. After heat induced expression changes and specificity evaluation, two candidate genes HbHSP17.6C and HbHSP17.6B that specifically respond to heat treatment were identified. Further through nested PCR, we cloned the 1962 nt sequence upstream of the start codon of the heat shock protein gene HbHSP17.6C. Confirm that it is composed of a core transcription region and multiple cis acting elements, and is named pHbHSP17.6C. It is inferred that this promoter could be used for gene function research in rubber trees and other closely related plants, which is expected to provide new tool options for related research.

Banana is a typical respiration fruit. MaERF15 is a transcription factor located in the nucleus and has the effect of regulating postharvest ripening of banana fruits. MaACO8 is a key ethylene biosynthesis-ACC oxidase gene expressed at high levels during postharvest ripening of banana fruits. But the molecular interaction mechanism between the two has not been clarified. To explore the transcriptional regulation mechanism of ethylene response factor MaERF15 on the key genes of downstream ethylene synthesis was to provide a theoretical basis for the innovation of postharvest preservation technology of banana fruits. In this study, the promoter sequence of MaACO8 was isolated from banana DNA, and the promoter activity of MaACO8 was studied by bioinformatics analysis and GUS staining. Yeast monohybridization, EMSA, dual fluorescein reporter system and in vivo imaging system were used to study the interaction mechanism between MaERF15 and MaACO8 promoter. The results showed that there were 11 GCC-boxes in the promoter sequence of MaACO8 that bind to AP2/ERF transcription factors, which had strong priming activity. MaERF15 could specifically bind to the GCC-box of the MaACO8 promoter, activate the expression of MaACO8, promote the biosynthesis of ethylene, and regulate fruit ripening. The results further improved the theory of postharvest ethylene biosynthesis regulating fruit ripening of banana fruits, and would provide genetic resources and theoretical basis for the research and development of new technologies for storage and transportation tolerance breeding and maturity regulation of bananas, respectively.

Taking the chloroplast genomes of five coffea plants, namely Coffea liberica, C. canephora, C. arabica, C. eugenioides, and C. racemosa, as the research objects, a series of statistical and comparative analyses were carried out. The results demonstrated that the lengths of the chloroplast genomes varied from 154 751 bp to 155 189 bp, with C. arabica a possessing the longest genome and C. canephora having the shortest. The average GC content was determined to be 34.98%. Both C. liberica and C. arabica encoded 130 genes, while C. eugenioides had the largest number of genes, totaling 138, and C. racemosa had the least, with only 121. Upon comparing the border regions of the chloroplast genomes of the five coffee plants, it was observed that the directional sequence arrangements were consistent, thereby reflecting the high conservation of the chloroplast genome structure. The analysis of SSR sequences indicated that the five coffee plants exhibited a pronounced AT bias, and the types and quantities of SSRs differed among them. Through the analysis of nucleotide diversity variation sites, five segments with relatively significant nucleotide variations were identified, namely PetN-PsbM, accD, accD-PsaI, rpl16 and ndhF-rpl32. Furthermore, based on the combined analysis of the chloroplast genomes and the five highly variable nucleotide regions, a phylogenetic tree of 19 Coffea plants was successfully constructed, which shed light on their genetic relationships. This study can serve as a valuable reference for the identification of germplasm resources, the exploration of origin and evolution, as well as the hybrid breeding of Coffea plants.

The diversity of orchid labellum, a specialized petal, has great ornamental and biological value, but the formation mechanism has not been solved so far. APETALA3-3 (AP3-3) is a floral organ identity gene, which is related to the formation of orchid labellum, but there is no report on how it regulating the formation mechanism of orchid labellum diversity. In this project, wild type and DoAP3-3 overexpressing floral organs of Dendrobium officinale were used as the research objects to explore the formation mechanism from the perspective of transcription factor DoAP3-3 regulating downstream target genes through DAP-seq and RNA-seq joint analysis. The results showed that a total of 7 key candidate target genes, MADS6, NAC029, NAC054, WOX3, AS2, ERECTA, AG were identified, which may regulate floral organ development and floral morphogenesis development under the action of DoAP3-3 by specific regulation or interaction with other genes. The interaction between transcription factor DoAP3-3 and MADS6 was verified by yeast one-hybrid experiment, which further affecting floral morphogenesis development. This study would lay a foundation for preliminary analysis of the regulatory mechanism between DoAP3-3 and its target genes, and exploring the formation mechanism of highly specialized and diversified flower morphology in Orchidaceae.

Sucrose phosphate synthase (SPS) plays a crucial role in the sucrose synthesis process, and investigating the biological functions of the SPS family in durian (Durio zibethinus Murr.) can contribute to enhancing fruit quality. In the durian genome, 10 SPS members were identified and designated as DzSPS1 to DzSPS10. The results indicated that the average hydrophobicity coefficient was less than 0, with isoelectric points ranging from 5.70 to 6.68, suggesting that they are hydrophilic acidic proteins. Subcellular localization predictions primarily placed them on the cell membrane and nucleus. Analysis of conserved motifs within the gene family revealed variations in the number and distribution of motifs among durian SPS members, although all contained motif 3, indicating that motif 3 is a significant conserved domain within the durian SPS gene family. Gene structure analysis showed that durian SPS genes were structurally similar, containing 8 to 15 exons and 7 to 13 introns. Phylogenetic tree analysis demonstrated that durian SPS genes could be divided into two subfamilies, with subfamily Ⅱ comprising nine members and subfamily Ⅰ containing one member. Compared to SPS genes in horticultural fruit trees such as cacao and citrus, durian SPS genes exhibited closer phylogenetic relationships with Arabidopsis and rice SPS genes. Seven members of the durian SPS family shared high spatial structural similarity, with secondary structures predominantly consisting of α-helices and random coils. Cis-acting element analysis suggested that durian SPS genes may be readily induced by response elements related to light, low temperature, drought, and gibberellin. This study detected that the primary soluble sugars in durian fruit are sucrose, fructose, and glucose, with sucrose content significantly higher than that of fructose and glucose, and notable differences observed among different varieties. Fluorescence quantitative analysis revealed significant variations in SPS expression levels among different durian varieties, with the expression patterns of DzSPS3 and DzSPS7 correlating with changes in total sugar content between varieties, suggesting that DzSPS3 and DzSPS7 may be key members involved in sugar accumulation. By analyzing the structure and physicochemical properties of durian SPS genes and exploring the SPS accumulation characteristics in different varieties, this study would provide a reference for further investigation into the biological functions of the SPS family in durian.

The fruit of Aquilaria sinensis contains a class of tetracyclic triterpenoids known as cucurbitacins, which exhibit anti-inflammatory, hepatoprotective, and antitumor activities. Cytochrome P450s (CYP) are key enzymes in the biosynthesis pathway of cucurbitacins. The P450 genes for cucurbitacin synthesis in A. sinensis have not been extensively studied. In this study, a P450 gene (AsCYP131) was cloned based on A. sinensis transcriptome data. The complete open reading frame (ORF) of AsCYP131 gene was 1491 bp, encoding a protein of 496 amino acids with a molecular weight of 55.39 kDa. The theoretical isoelectric point (pI) of the protein was 7.65, with an average hydrophilicity coefficient of -0.053, and an instability index of 47.16, classifying it as an unstable protein. The protein contained 40 potential phosphorylation sites, and its secondary structure was predominantly composed of α-helix and random coil. The results of multiple sequence alignment and phylogenetic tree analysis showed that the protein encoded by the AsCYP131 gene clustered into a single unit with CsCYP, CmCYP, and ClCYP, which have been reported to be involved in the biosynthesis of cucurbitacins. The sequence of the functional structural domains at the C-terminal showed high consistency. At the same time, the expression levels of AsCYP131 in different tissues of A. sinensis detected by real-time fluorescence quantitative PCR (RT-qPCR). The results indicated differential expression levels of AsCYP131 across various tissues, including roots, stems, leaves, flowers, fruits, and seeds, with the highest relative expression observed in fruits. This study would serve as a valuable reference for the subsequent validation of the functional role of the AsCYP131 gene in cucurbitacin biosynthesis.

Fici Hirtae Radix, a Chinese herbal medicine, is prepared from the dry roots of Ficus hirta Vahl. This study aimed to provide theoretical and empirical support for the genetic diversity analysis, genetic map construction, and assisted breeding of F. hirta Vahl. by developing SSR molecular markers. Four typical leaves of F. hirta Vahl. were selected as the samples, and site feature analysis and molecular marker development were performed after transcriptome sequencing. A total of 16 851 SSR loci were identified from 34 375 transcriptome unigene sequences, distributed across 12 094 unigene sequences, resulting in a distribution frequency of 35.18%. The average frequency was one SSR locus every 2638 bp, with a density of 3.68 kb. Five distinct nucleotide motifs were observed, with the motif repeating six times being the most prevalent, constituting 20.92% of all SSRs, and typically less than 29 bp in length. Di-nucleotide repeats were predominant, followed by tri-and tetra-nucleotide repeats. (AG/CT)n was the most abundant repeat motif, representing 26.05% of all SSRs, while (AT/AT)n was the second most common, accounting for 18.69%. 100 EST-SSR primers were randomly selected to amplify target product using genomic DNA from four different leaf types of F. hirta Vahl. 89 primers exhibited polymorphism across the germplasms. Nine primer pairs, distinguished by the high definition and clarity, were selected to perform DNA amplification and construct DNA fingerprints for 31 specimens sourced from different regions. The average percentage of polymorphic bands observed across these primers was 72.04%. The substantial degree of polymorphism facilitated the unambiguous identification of each of the 31 germplasm samples, and robust DNA fingerprint profiles were successfully established for each specimen. This study demonstrated that SSR loci within the transcriptome of F. hirta Vahl. were rich in information and highly utilizable, offering valuable data support for future research endeavors.

In order to explore the characteristics and molecular regulation mechanism of high temperature albinism of tea variety Yaoqiu (YQ) and its molecular regulation mechanism, the effects of low temperature albinism on the shoot with one bud and two leaves of tea variety YQ in spring (YQC), summer (YQX), autumn albinism (YQQ) and autumn green (YQQL), and Baiye No. 1 (BY1H) in spring albinism (BY1HC), their biochemical components, and transcriptome sequencing were carried out on the new shoots in summer (BY1HX) and autumn (BY1HQ). The results of biochemical analysis showed that the total free amino acid content and tea polyphenols content of YQQ albino fresh leaves were lower than those of YQC green fresh leaves, and the difference of total free amino acid content was significant; while the total free amino acid content of BY1HC albino fresh leaves was significantly higher than that of BY1HQ green fresh leaves, and the tea polyphenols content was significantly lower than that of BY1HQ green fresh leaves. Cluster analysis revealed that the gene expression profiles of YQQ albino fresh leaves formed a distinct cluster. The comparison between YQQ and BY1HQ exhibited the highest number of differentially expressed genes. The new shoot leaves of YQ showed an albino phenotype induced by high-temperature stress in late summer and early autumn. This stress affected the structure of microtubules, cells, and subcellular components, leading to a reduction in the contents of amino acids and polyphenols. The three functional categories exhibiting the most significant gene enrichment were microtubule binding, movement of cellular or subcellular components, and non-membrane-bound organelles. Similarly, the top three pathways with the highest significance in gene enrichment were the flavonoid biosynthesis pathway, the starch and sucrose metabolism pathway, and the amino sugar and nucleotide sugar metabolism pathway. Through gene co-expression network analysis, modules exhibiting high expression levels were identified. Subsequently, the ten genes demonstrating the highest total connectivity (K value) were selected for further analysis and annotation. Notably, the functions of genes TGY042732 and the novel gene designated as novel.276 could not be predicted. These findings would provide a theoretical foundation for understanding the phenomenon of albinism in tea resources under conditions of elevated temperature.

The technology of secondary somatic embryo cyclic multiplication has realized the large-scale propagation of somatic embryo plantlets (self-rooted juvenile clones) of Hevea brasiliensis. This technology needs to cut the cotyledon embryo into 2 mm×2 mm pieces. A large amount of ethylene and reactive oxygen species (ROS) will be produced at the wound site, and much ethylene and ROS will also formed during culture process. Ethylene and ROS have adverse effects on somatic embryogenesis of H. brasiliensis. Silver nitrate (AgNO₃) is an ethylene inhibitor and also affects enzyme activity. In this paper, the effects of different AgNO₃ concentrations (0, 2.5, 5.0, 10.0, 15.0 mg/L) and different time (7, 14, 21, 28 days) on the embryo block browning and secondary somatic embryogenesis of H. brasiliensis were studied, and the phenotype and ploidy of regenerated plantlets were evaluated. AgNO₃ significantly reduced the browning of embryo blocks and the production of ROS. The effect of 5-15 mg/L was better than that of 2.5 mg/L, and the effect of 21 days treatment was better than that of the other three treatments. 2.5-15.0 mg/L AgNO₃ treated 7-28 days did not significantly increase the number of embryonic blocks, but the number of cotyledon embryos in 5.0 mg/L AgNO₃ treated for 21 and 28 days, 10.0 mg/L AgNO₃ treated for 21 days, and 15.0 mg/L AgNO₃ treated for 7-21 days were significantly higher than those in the control. The number of embryonic blocks was negatively correlated with browning, but not significantly, the number of cotyledon embryos was significantly negatively correlated with browning. The phenotype of regenerated plantlets from AgNO₃ treatments had no obvious difference compared with the control, and the chromosome ploidy was the same as the control. The results would provide technical support for improving the efficiency of secondary somatic embryogenesis in H. brasiliensis.

The study was aimed to breed new varieties of fresh-eating sweet potato with high yield and high quality to meet the market demand of fresh-eating varieties. A new fresh-eating variety Guishu No. 15 was successfully bred with Yuzishu No. 7 as the mother and Guiziweishu No. 1 as the father. The variety is spindle-shaped with purple skin and white heart. Guishu No. 15 is centralized and neat, with an average number of 5.10 storage roots per plant. The proportion of commodity sweet potato is high, with a medium and large storage roots rate of 94.20%. The cooked has excellent quality, with β-carotene 27.70 µg/100 g, anthocyanin 67.40 mg/100 g, soluble sugar 5.39%, reducing sugar 1.90 g/100 g, and protein 0.94 g/100 g. The average fresh storage roots yield, dry storage roots yield, and starch yield in the two-year regional trial was 30 303.00 kg/hm² 8187.90 kg/hm² and 5195.99 kg/hm², respectively, significantly increased by 11.95%, 23.10% and 27.81% compared to CK. Guishu No. 15 has good high and stable yield, excellent cooked food quality, and moderate resistance to Fusarium wilt, bactrium wilt, stem nematode, and root rot disease, which is suitable for planting in Guangxi and its similar ecological areas.

Rice (Oryza sativa L.) is one of the most critical staple crops worldwide, and enhancing its yield is fundamental to ensuring global food security. Shanlan rice, a prominent upland rice variety in the southern regions of China, particularly in the mountainous areas of central Hainan province, is highly valued by farmers for its strong adaptability, drought resistance, and superior stress tolerance. However, traditional Shanlan rice varieties often suffer from challenges such as excessive plant height, vulnerability to lodging, and yield instability, which restrict the broader application in modern agriculture. This study focused on four local Shanlan rice varieties: Wuzhishan Nandui Village Shanlan rice, Huangke Shanlan Nuo, Shanlan Nuo and Shanlan Hong. The varieties were subjected to mutagenic treatment using ethyl methanesulfonate (EMS). After treatment, superior mutants were selected through screening across M₁ to M₃ generations based on significantly reduced plant height and either stable or enhanced single-plant yield. The results revealed the successful induction of multiple dwarf, high-yield mutants in all four varieties via EMS mutagenesis. For instance, in Wuzhishan Nandui Village Shanlan rice (WZSNDCSLD2), plant height was reduced by 9.6%, while single-plant yield increased by 52.8%; in Huangke Shanlan Nuo (HKSLN31), plant height decreased by 11.5%, and single-plant yield rose by 46.0%; in Shanlan Nuo (SLN8), plant height was reduced by 15.4%, with a 37.0% increase in single-plant yield; and in Shanlan Hong (SLH6 and SLH9), plant height was reduced by 22.2% and 15.5%, respectively, while single-plant yield increased by 49.6% and 36.8%. The superior mutants also exhibited significant improvements in agronomic traits, including total grain number, spikelet number per panicle, filled grain number per panicle, thousand-grain weight and seed setting rate. The findings of this study demonstrate that EMS mutagenesis is an effective approach for improving both plant height and yield-related traits in Shanlan rice. This research would provide new genetic lines and a solid theoretical foundation for the genetic improvement and molecular breeding of Shanlan rice.

ITS molecular identification and mycelial antagonism experiments on 11 strains collected in the early stage, then screened and studied the biological characteristics of suitable strains for cultivation in tropical regions based on germplasm evaluation to promote the rapid development of Phallus rubrovolvatus industry in tropical regions. The strains collected were all P. rubrovolvatus, of which two strains were synonyms, resulting in a total of 10 different P. rubrovolvatus strains. In mycelial evaluation experience, the mycelia of strains 147, 160, H29 and L70 showed good growth and high degradability on brown sugar medium and rubber sawdust medium, and the mycelia were able to recover growth after stress at 10 ℃ and 35 ℃, making them suitable for off-season cultivation in tropical regions. In rubber forests, four strains were able to produce mushrooms, and H29 produced mushrooms neatly, good shape, storage resistance and high yield (750 kg/667 m²), making it suitable for on-site growing indusium. L70 strain produced more mushroom-eggs, short growth period and high yield (800 kg/667 m²), making it suitable for concentrated growing indusium of mushroom-eggs after harvesting. In the single factor experiment, the nutritional requirements of H29 and L70 mycelia were basically the same, the most suitable carbon sources were trehalose and starch, the most suitable nitrogen source was malt extract, the most suitable temperature was 25-28 ℃, and the most suitable pH was 4-5. In the orthogonal experiment, both strains showed the best growth in formula 4 (soluble starch, malt extract, 25 ℃, pH=4), demonstrating the results of the single factor experiment. Especially, in formula 6, the mycelia of both strains were whiter and denser, making it suitable for the preservation of P. rubrovolvatus. SPSS analysis showed that the influence degree of various factors on mycelial growth was as follows: nitrogen source>pH>carbon source>temperature (H29), nitrogen source>pH>temperature>carbon source (L70), with nitrogen source and pH having a greater impact. The study could provide reference for breeding, large-scale cultivation of P. rubrovolvatus, and the development of mushroom industry in tropical regions.

The mini-seedling graft method of Hevea brasiliensis is widely used in the breeding of high-quality rubber tree seedlings due to its advantages such as a short nursery period, low labor intensity, large number of seedlings per unit area, and well-developed main roots of seedlings. However, the seedlings of rubber trees budded in autumn and winter require more time for the scions to germinate after graft survival, and the grafted mini-seedlings grow weakly, which diminishes the advantages of the mini-seedling graft method. Therefore, it is crucial to find appropriate technical measures to improve the germination rate and growth rate of the seedling scions. In this study, the effects of grafting time and topping time on the sprouting and growth of scions in grafted seedlings of rubber tree were investigated, specifically focusing on the seedlings grafted in winter with the variety H. brasiliensis reyan879. Grafting time significantly affected the survival rate, sprouting rate, seedling height, and nursery release rate of the grafted seedlings (P<0.05), with seedlings grafted in November showing significantly higher survival, sprouting, and release rates than those grafted in October, while the seedling height at the two leaf-umbrellas was significantly lower for November-grafted seedlings. Topping time significantly influenced the height of the scions at the stage of two leaf-umbrellas, without significant impact on the survival rate, sprouting rate, withering rate, nursery release rate, or scion stem thickness. The interaction between grafting time and topping time did not significantly affect the survival rate, sprouting rate, withering rate, growth volume, and nursery release rate of the grafted seedlings. It is advisable to adopt a strategy of overwintering with the stalks for mini-rubber seedlings grafted in winter, and to perform topping from February to March after the beginning of spring in the next year, which could significantly shorten the time of budding, reduce the number of times the rootstock debudding, and ensure higher scion growth quality, and this timing aligned well with the planting period of the year, offering significant practical value for production. For seedlings with rootstocks that have reached two leaf-umbrellas, topping just above the first pair of true leaves did not affect the survival rate and could control the withering rate below 4%, demonstrating good technical stability. It is recommended that in practical production, the grafting and topping times for rubber tree seedlings should be strictly controlled to ensure the rootstock reaching an appropriate growth state before topping, and management measures should be adjusted as needed to achieve the best nursery results. The application of the findings would help improve the production efficiency of rubber tree seedling cultivation.

The present work aims to provide references for differentiated nutrient management of litchi cultivars, and enhance the cultivation promotion of the new quality cultivars via clarifying the differences in nutrient content, nutrient transfer capacity and nutrient accumulation in different parts of litchi fruits among the main and the new quality cultivars in South China. A total of 73 litchi fruit samples belonging to 25 main and new quality litchi cultivars were collected from 29 litchi orchards in South China. The contents of 12 nutrients in pericarp, flesh and kernel of litchi fruits were determined to compare the discrepancies in nutrient transfer and accumulation among cultivars. Further, the types of nutrient accumulation in litchi fruit were categorized through cluster analysis. The results show that, most cultivars of litchi had the highest K content in the pericarp and the flesh, whereas the highest N content were observed in the kernel. The average transfer factors of P, S, Fe, Cu and Zn from pericarp to kernel ranged from 1.09 to 1.58, with strong transfer ability. N, K, Mg, B and Mo had medium transfer ability, with the average transfer factors within 0.53-0.99. The average transfer factor of Ca and Mn was only 0.35 and 0.481 respectively, with relative low transfer capability. With regard to the transfer capability from pericarp to flesh, N, K, Mg, S, Fe, Zn, B and Mo were figured by average transfer factors of 0.49-0.87, and Cu and P by high average transfer factors (5.91 and 1.32). However, Ca and Mn were characterized by extremely low average transfer factors of 0.069 and 0.112, respectively. Among the 25 cultivars, the content of Ca, Mg and Mn in Xiantaoli peel was higher than that of all the other cultivars, which was 6.13 g/kg, 3.34 g/kg and 233.52 mg/kg, respectively. Moreover, the ability of the three elements transferring from peel to kernel or flesh was lower than that of all the other cultivars, leading to excess accumulation in the peel. The requirement of N and K in 25 litchi cultivars was categorized into seven types: low N and high K, medium N and low K, medium N and medium K, medium N and high K, high N and low K, high N and medium K, high N and high K. The accumulation of Ca, Mg, B and Mo was divided into three groups including the low-, medium- and high-types, respectively. Ca and Mn were difficult to transfer in litchi fruit, being an obstacle to the development of litchi fruit. Conclusively, the nutrient accumulation of litchi fruit is cultivar dependent, therefore, elaborate nutrient strategy for litchi can be made to meet the nutrient demand for fruit development. The fertilization strategy for the new quality varieties of litchi can be referred to the traditional cultivars belonging to the same nutrient requirement type.

The effect of gibberellin (GAs) on the fruit size of longan using the F₁ generation of a stable hybrid population, FD 52 (big-size fruit) and FD 114 (small-size fruit), which derived from the cross between ‘Fengliduo’ and ‘Dawuyuan’, were studied. Three concentrations of gibberellin (50 mg/L, 100 mg/L, and 150 mg/L) were applied to the inflorescences of small-fruit longan at four time points: 3 days before anthesis (-3 d), on the day of anthesis (0 d), 3 days after anthesis (3 d), and 6 days after anthesis (6 d). The endogenous GAs contents in the treatments were measured, and fruit quality traits were mature at the ripening stage. Additionally, the endogenous GAs content, cell size, and the number of cell layers in untreated large-fruit and small-fruit longan were compared. Results showed that exogenous gibberellin application significantly increased endogenous GAs levels and promoted fruit enlargement, with the most pronounced effect observed when 100 mg/L gibberellin was applied 3 days after anthesis. Early in fruit development, GA₄ was the predominant active gibberellin in longan fruit, with higher levels of GA₄, larger cell size, and more cell layers observed in big-size varieties compared to small-size ones. The findings suggest that GAs application and the differential accumulation of GA₄ along with cellular factors such as cell size and layer number, contribute to the variation in fruit size. This study would provide valuable insights for improving longan fruit size through the application of gibberellin in cultivation practices.

Melon is an important cash crop in Hainan, and its pollination is mainly hormone pollination, which is easy to cause fruit deformity and accompanied by different degrees of flavor and quality decline, affecting commodity rate and planting efficiency. Melon Jiyoumi 29 was used as the experimental material. Different artificial pollen combinations were used to pollinate to compare with hormone pollination. The growth status of plants and fruits, the internal quality of fruits and the activities of key enzymes for sucrose accumulation, and analyzed the effects of pollination on the growth of plants and fruits were studied. Different pollination methods had great effects on plant height, stem diameter and biomass, fruit weight and hardness, and the stem diameter and biomass and fruit weight treated with T₁ were significantly higher than those of the other treatments. The plant height and fruit hardness treated with CK were significantly higher than those of the other treatments. There were significant differences among different pollination methods on each index of melon fruit internal quality, and T₁ treatment had the best effect, and its soluble solids, soluble sugar, sucrose content, fructose content and glucose content were significantly higher than CK treatment. The activity of sucrose synthase (SS) treated with T₄ was relatively high during fruit growth and development. The sucrose phosphate synthase (SPS) in T₁ treatment maintained a high level during the fruit growth and development, and the acid invertase activity in T₁ and T₂ treatment reached the highest at the 40th day after pollination, which were 93.69 U/g and 88.54 U/g respectively. The treatment of T₁ (strong pollen vitality × high stigma receptivity) has the best effect on the growth and fruit quality of melon plants after artificial pollen pollination.

Taraxacum grypodon Dahlst. is an important medicinal and edible perennial herb. To study the effects of light intensity on the growth and secondary metabolites of T. grypodon can lay a foundation for revealing the formation mechanism of its secondary metabolites, and provide crucial reference for its subsequent comprehensive development and utilization, and also provide guidance for establishing high-quality and high-yield dandelion artificial cultivation system. In this study, four shading gradients (the light transmittance was 100%, 80%, 50%, 30%, respectively) were set up in the greenhouse to cultivate T. grypodon. At the time of harvesting, the growth related indicators were measured, and the sugar, flavonoids, total phenols, and lignin components in the aboveground leaves and underground roots were analyzed. 100% light transmittance was conducive to the growth and photosynthetic efficiency of T. grypodon. Under this light condition, leaf length, root length, aboveground and underground biomass were the highest (P<0.05), and the SPAD value of leaves was the largest. The total sugar and polysaccharide contents of leaves and roots were the highest when the light transmittance was 100%, and the total sugar content in roots was significantly higher than that in leaves (P<0.05), and the polysaccharide content in roots was significantly higher than that in leaves. The content of reducing sugar in leaves and roots both was the highest when the light transmittance was 50%. The content of reducing sugar in leaves and roots both had significant difference under different shading treatment. The flavonoids content in the leaves was significantly higher than that in the roots (P<0.05), and reached to the highest content in 100% light transmittance. The total phenolic content in leaves was significantly higher than that in roots (P<0.05), and reached to the highest at 100% light transmittance, but decreased significantly after shading. The lignin content in roots was significantly higher than that in leaves (P<0.05), and both reduced under shading. In conclusion, the flavonoids and phenols of T. grypodon are mainly accumulated in leaves, while total sugars and polysaccharides were mainly accumulated in roots. Sufficient light is more conducive to the accumulation of the metabolites and plant growth. Proper shading is beneficial to the accumulation of reducing sugar, reduces the content of total phenol and lignin, and increases the taste quality of T. grypodon. In production, both medicinal and edible quanlity should be taken into account, so the cultivation conditions of T. grypodon are suitable for no shaded or slightly shaded habitats.

Bletilla striata var. Alba is a variant of B. striata which possesses high ornamental and medicinal value. However, there have been no reports on its seed germination and propagation to date. In this study, using the seeds of B. Striata var. Alba as the experimental material, indoor seed germination tests and pot tests were carried out to investigate the effects of mycorrhizal fungi from different sources (MB-15, MB-18, MH1-E and YDLXB) on seed germination and seedling growth. The results demonstrated that various mycorrhizal fungi had different effects on promoting the germination of B. striata var. Alba seeds. Among them, the Sebacina fungus MB-18, derived from the roots of B. striata, exhibited an extremely significant promotional effect. Compared with the control treatment, the germination rate and seedling formation rate in the petri dish experiment increased by 10.76% and 20.55% respectively, while in the pot validation test was 36.95% and 355.78%, respectively. Moreover, when sown directly, the seeds of B. striata var. Alba could germinate, but the seedling formation process was hindered. However, compatible mycorrhizal fungi (MB-15, MB-18, MH1-E and YDLXB) effectively promoted the formation of seedlings. The results are of great significance for the germplasm conservation, large-scale seedling breeding and sustainable utilization of B. striata var. Alba.

Hyphal polarized growth in filamentous fungi requires tip-directed secretion of growth-related substances, and previous studies have shown that exocyst complex plays an important role in the processes of fungal secretion and polar growth. However, there are few researches on the hyphal polarized growth and pathogenic mechanism of obligate biotrophic fungi at present. Rubber tree (Hevea brasiliensis) is the most important source of natural rubber. Powdery mildew is one of the most serious diseases of H. brasiliensis, and its pathogen Erysiphe quercicola belongs to obligate parasitic fungi. In this study, EqExo70, a subunit of the exocyst complex, was identified in E. quercicola. The GFP labeled EqExo70 was expressed in the E. quercicola by electrotransformation method, and it was found that the protein showed fluorescence aggregation at the hyphal tip, suggesting that EqExo70 may be related to hyphal polarized growth. In addition, we silenced the EqExo70 by electroporating the reverse complementary sequence of EqExo70 into the E. quercicola, it was found that the pathogenic ability of E. quercicola decreased and the growth of hypha slowed down, suggesting that EqExo70 affects the pathogenicity of E. quercicola. The level of callose deposition and reactive oxygen species burst in H. brasiliensis significantly increased upon infection with the EqExo70-silenced strain, indicating that EqExo70 contributes to suppressing host immune response. The results indicated that EqExo70 is a key factor affecting pathogenicity of E. quercicola, and may be involved in the interaction with H. brasiliensis, as well as the hyphal polarized growth.

Cowpea Fusarium wilt caused by Fusarium oxysporum f.sp. tracheiphilum occurs in almost all cowpea growing areas, and the yield loss can be as high as 70% in major domestic producing areas such as Hainan. Currently, chemical control measures are the primary management strategy in China. The use of microbial biocontrol agents can reduce the application of agrochemicals and mitigate the risks of pesticide residues, and has been widely adopted for the management of soil-borne diseases. However, there is limited research on the use of multi-functional microbial consortia for the biocontrol of Fusarium wilt in cowpea. In this study, we screened highly efficient phosphate-solubilizing bacteria (PSB) using the molybdenum-antimony colorimetric method, and evaluated the synergistic effects of the selected PSB strain and the antagonistic Bacillus velezensis strain on cowpea growth and Fusarium wilt control. From 10 phosphate-solubilizing bacterial isolates, we identified B. cereus LMSY3PSB-2-2 (abbreviated as P) as a highly efficient PSB strain. The optimal ratio of the PSB strain P to the biocontrol strain B. velezensis X5 was determined to be 2∶1. Compared to the individual application of the PSB strain P or the biocontrol strain X5, the composite inoculum at this ratio significantly enhanced cowpea seed germination, plant growth, and root vigor. Under pot experiments, the composite inoculum achieved a 96% disease control effect against Fusarium wilt and increased the available soil phosphorus content by 19%. The results would provide a theoretical guide for utilizing the PSB strain P and the antagonistic strain X5 in a microbial consortium to promote cowpea growth and control Fusarium wilt, laying a foundation for the development of multi-functional composite microbial products to support sustainable agriculture.

Natural rubber (NR) is an important industrial material and strategic resource. Its composition, structure, and properties are influenced by factors such as the rubber tree cultivar and processing methods, leading to significant variations in quality stability. By studying the changes in particle size and molecular weight of natural rubber prepared through different centrifugation cycles, this research explored the effects on rubber composition and performance, which is crucial for obtaining high-quality rubber. In this study, two rubber cultivars, Reyan 73397 and PR107, were selected to investigate the impact of different centrifugation cycles on the particle size of latex, molecular weight, physicochemical properties of raw rubber, and vulcanized rubber properties. After centrifugation, the particle size of the latex from both cultivars increased with the number of centrifugation cycles, and the particle size distribution became more concentrated, with Reyan 73397 having a larger particle size than PR107. The molecular weight decreased, and the molecular weight distribution narrowed as the centrifugation cycles increased. With more centrifugation cycles, the ash content, gel content, nitrogen content, and Mooney viscosity of both cultivars decreased, the vulcanization time extended, but the resistance to storage hardening increased. However, the tensile strength and tear strength were reduced. The aging resistance of the vulcanized rubber from both cultivars decreased with the increase of centrifugation cycles. Furthermore, centrifugal treatment increased the glass transition temperature (T_g) of the rubber, enhanced its resistance to wet sliding, and increased the rolling resistance and heat build-up of the rubber.

The study was aimed to study the effects of exogenous ATP and rotenone treatment on chilling injury and sugar metabolism in cold-stored guava fruits. Post-harvest ‘Hongxiang’ guava fruits were treated with distilled water, 0.8 mmol/L ATP, and 0.2 mmol/L rotenone, respectively, and stored at (4±1)℃. During storage, the chilling injury index, commercial rate, sugar content, and sugar metabolism-related enzyme activity of the guava fruits were regularly determined. Compared with the control fruit, ATP treatment reduced chilling injury, increased the activities of sucrose monophosphate synthase (SPS), acid invertase (AI), and sucrose synthase synthesis direction (SSs) during the late stage of storage, decreased the activities of neutral invertase (NI) and sucrose synthase decomposition direction (SSc) during late-storage, inhibited the increase in fructose and glucose content during mid-storage, maintained the content of sucrose and total soluble sugar at a high level, and improved the cold resistance and commercial rate of the fruit. Rotenone treatment exacerbated chilling injury by simultaneously inhibiting the increase of SSS activity and SPS activity during the middle stage of storage, the decrease of AI activity, NI activity, and SSc activity during the middle and late stages of storage, accelerating the decomposition of sucrose, increased the content of fructose, reduced the total soluble sugar and reducing sugar, and resulted in a low commercial rate of the fruit. ATP treatment could enhance cold resistance in guava fruits, and the mechanism may be related to changes in sucrose and soluble total sugar content. However, rotenone treatment induced an imbalance in sugar metabolism and exacerbated chilling injury.

Sodium alginate (SA) edible composite film incorporated with different amounts of galangal essential oil (EO)/ curcumin (Cur) was prepared by solvent casting method and applied to fresh-cut pineapple in this study. The results showed that 0.3% EO could improve the thickness and thermal stability of the composite film, and reduce the water vapor penetration rate. SA-0.3%EO and SA-0.3% EO-Cur film groups had significant fresh-keeping effect on fresh-cut pineapple, while the control group showed obvious browning after three days of storage at 4 ℃. The fresh-cut pineapple in SA-0.3% EO-Cur group maintained the best appearance, followed by SA-0.3%EO group. When the storage time was extended to eight days, the weight loss of fresh-cut pineapple in the SA-0.3%EO coating group was the lowest (2.12±0.08)%, the total number of colonies (lgCFU/g) was 3.48±0.00, the number of molds and yeast (lgCFU/g) was 3.89±0.19 were the lowest. However, the appearance color of the SA-0.3% EO-Cur coated group was the best, and the antibacterial effect was second only to that of the SA-0.3%EO coated group, which was obviously better than the control group. However, when the EO content increased to 0.5%, the appearance of fresh-cut pineapple also showed browning and other quality deterioration, indicating that the concentration of essential oil would affect its preservation effect and have a negative impact on the quality of fruit. In conclusion, this study would provide a new idea for the development of a new edible film system, and provide data support and theoretical support for extending the shelf life of fresh-cut pineapple.

This study investigated the impact of different netting methods on the cowpea (Vigna unguiculata) industry. Specifically, it compared the degradation characteristics of three pesticides-matrine, spinosad, and difenoconazole-under two netting conditions (fully enclosed and semi-enclosed), the accumulation changes of pectin, cellulose, total phenols, and flavonoids, and analyzed the economic benefits of cowpea cultivation under the netting methods. The results indicated that under semi-enclosed netting conditions, the half-life of the pesticides was 1.13 days for matrine, 0.42 days for spinosad, and 1.96 days for difenoconazole. In contrast, under fully enclosed netting conditions, the half-life of the pesticides was 1.53 days, 0.83 days, and 2.51 days, respectively. Compared to fully enclosed netting, the degradation rate of the pesticides was significantly faster under semi-enclosed netting conditions. Regarding the accumulation of key substances, there was no significant difference in the contents of pectin [(15.88±2.025)mg/g] and cellulose [(1.75±0.128)mg/g] between semi-enclosed and fully enclosed conditions. However, total phenol content under semi-enclosed netting [(0.42±0.125)mg/g was 40.00% lower than that under fully enclosed netting [(0.70±0.091)mg/g], and flavonoid content [(6.08±2.509)mg/g] was 55.91% lower under semi-enclosed netting than under fully enclosed netting [(13.79±0.876)mg/g]. Economic analysis showed that considering field management, pest control investment, and market conditions, cowpea cultivation under fully enclosed netting yielded higher input and output compared to semi-enclosed netting. When the purchase price of cowpea reaches 5.11 yuan/kg (for fully enclosed netting) and 3.85 yuan/kg (for semi-enclosed netting), the profit and loss break even. This study would provide both theoretical and practical guidance for selecting appropriate netting methods for cowpea cultivation.

The residue of nitrogen fertilizer in soil is an important destination after nitrogen fertilizer application. Under tropical acidic soil conditions, it is hypothesized that the lack of carbon may further limit soil retention of nitrogen fertilizer in rubber plantation. A field micro-experiment utilizing ¹⁵N isotope tracer technology was conducted to investigate the soil nitrogen residual characteristics in rubber plantations with different nitrogen application levels (0 kg/hm², N₀; 100 kg/hm², N₁₀₀; 200 kg/hm², N₂₀₀; 400 kg/hm², N₄₀₀) under the addition of exogenous carbon (100 kg/hm²). The results showed that the soil residual rate of nitrogen fertilizer was 8.8%-17.6% in the first year and 6.6%-16.5% two years later after adding carbon. Notably, the residual rate of nitrogen fertilizer showing a downward trend was observed with the increasing of nitrogen application; compared with the treatment without nitrogen fertilizer, the lower nitrogen application level (100 kg/hm²) under carbon addition had a significant effect on enhancing both soil total nitrogen and organic carbon content. The 2-year field trial revealed that the residual rate under different nitrogen application with carbon addition was higher than that without such addition. Variance analysis showed that exogenous carbon addition had a significant positive effect on the residual rate of nitrogen fertilizer; and carbon addition could effectively enhance the soil retention of nitrogen fertilizer. In conclusion, the deficiency of soil carbon emerged as a critical factor contributing to the low nitrogen residue rates in rubber plantations; therefore, it is imperative to combine chemical fertilizers with organic fertilizers during the fertilization process in rubber plantations, while the nitrogen application rate remains moderate.