The influence of root exudates on neighboring plants is one of the important factors determining the coexistence status of plants and their neighbors. This study aimed to explore the effects of the root exudates of Stylosanthes guianensis and cultivation substrates on the growth and physiological characteristics of Hevea brasiliensis seedlings. We cultivated H. brasiliensis seedlings with distilled water, sterilized vermiculite, and soil as cultivation substrates, and compared the differences in biomass accumulation and distribution, aboveground and underground morphological characteristics and physiological characteristics of H. brasiliensis when they respectively were irrigated with nutrient solutions containing the root exudates of S. guianensis and containing their own root exudates. The results showed that in soil culture and distilled water culture, the aboveground biomass, underground biomass, total biomass, primary lateral root number, chlorophyll content, carotenoid content, soluble carbohydrate content and root vitality of H. brasiliensis seedlings under the treatment of S. guianensis root exudates were significantly higher than those under the treatment of their own root exudate (P<0.05), except for the difference of root-shoot ratio, plant height and root length. Moreover, except for root vitality, the increase extent of the indexes was distilled water culture > soil culture. The malondialdehyde (MDA) content of S. guianensis root exudate treatment was significantly lower than that of H. brasiliensis root exudate treatment (P<0.05). When cultured with sterilized vermiculite, there were no significant differences in biomass index, morphological index and MDA content of H. brasiliensis seedlings treated with root exudates of two kinds of plants, but chlorophyll content, carotenoid content, soluble sugar content, and root vitality were significantly increased under root exudates of S. guianensis treatment (P<0.05). The comprehensive evaluation of membership function of H. brasiliensis seedlings cultivated in the substrates under the treatment of root exudates of S. guianensis was higher than that of their own root exudates, and the comprehensive evaluation of cultivation substrates under the treatment of the same root exudates was vermiculite culture > distilled water culture > soil culture. It indicates that the root exudates of S. guianensis can significantly improve the physiological function of H. brasiliensis seedlings and promote their growth, but the response of H. brasiliensiss to root exudates is significantly affected by the cultivation substrate.

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.

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.

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.

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.

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.

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.

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.

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 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.