Sweet potato (Ipomoea batatas) is a globally significant food and functional crop, with its purple-fleshed varieties drawing particular attention due to the high anthocyanin content. Anthocyanins not only give the tubers distinct color but also possess antioxidant, anti-inflammatory, and disease-preventive physiological functions, making them highly valuable in the development of health foods. However, the biosynthesis of anthocyanins is regulated by a multi-level network, and the role of bHLH transcription factors in sweet potatoes has not been fully elucidated. This study focused on the sweet potato gene Tai6.33665, aiming to clarify its molecular characteristics, subcellular localization pattern, and regulatory role in anthocyanin accumulation, providing a theoretical basis for molecular breeding of high-anthocyanin sweet potato varieties. Using purple-fleshed sweet potatoe (PFSP) and white-fleshed sweet potatoe (WFSP) as materials, the study analyzed the protein structure and evolutionary relationship of Tai6.33665 through bioinformatics, detected the gene expression pattern using qRT-PCR, constructed a Tai6.33665-GFP fusion vector for transient transformation in tobacco, determined the subcellular localization using laser confocal microscopy, and analyzed the correlation between gene expression and anthocyanin content and the miRNA interaction mechanism. The results showed that the protein encoded by Tai6.33665 had a typical bHLH domain and was highly homologous to anthocyanin synthesis regulatory factors. Its expression level was significantly negatively correlated with anthocyanin accumulation (P<0.05), and it was targeted and inhibited by ib-miR52. Subcellular localization indicated that the protein was located in the endoplasmic reticulum, suggesting that it might indirectly regulate metabolism through post-translational modification or the endoplasmic reticulum pathway. This study confirmed that Tai6.33665 acted as a negative regulator of anthocyanin biosynthesis in sweet potatoes, and its function depended on subcellular localization specificity and miRNA-mediated post-transcriptional regulatory networks. This discovery not only enriches the theoretical framework of plant secondary metabolism regulation but also provides a dual-track strategy for molecular breeding by targeting knockout of Tai6.33665 or overexpression of ib-miR52 using CRISPR/Cas9, the genetic limitations of anthocyanin accumulation could be overcome, and new high-anthocyanin sweet potato varieties could be developed. Future work would focus on elucidating the interaction mechanism between the gene and MYB/WD40 proteins, as well as the regulatory pathway of its transcriptional activity by endoplasmic reticulum localization.

Phytophthora capsici is a damaging pathogen with a wide host range, causing devastating diseases such as root rot, stem rot, leaf and fruit rot in plants from diverse families like Solanaceae, Cucurbitaceae, and Legumes. The diseases pose a significant threat to the sustainability of related agricultural industries. In this study, we identified a key RXLR effector, Pc13306, from the RXLR effector repertoire of P. capsici. The coding region of Pc13306 comprised 888 nucleotides, encoding 295 amino acids, with a conserved RXLR motif residing at positions 34-37 in the N-terminal region. Utilizing a yeast secretion system, we confirmed that the signal peptide of Pc13306 exhibited robust secretory activity. Quantitative real-time PCR (qRT-PCR) analysis revealed that Pc13306 was specifically upregulated during the late stages of P. capsici infection. Through agrobacterium-mediated transient transformation of Nicotiana benthamiana Pc13306 was demonstrated to significantly enhance lesion expansion and pathogen biomass accumulation, thereby improving infection efficiency. Moreover, Pc13306 induced reactive oxygen species (ROS) bursts and hypersensitive response (HR). Further exploration into the regulatory mechanism of Pc13306 in plant immunity revealed that it activated the salicylic acid (SA) signaling pathway and autophagy processes. Notably, Pc13306 markedly upregulated the expression of core genes involved in pattern-triggered immunity (PTI), indicating its role in modulating plant immune responses. The findings would provide insights into the interaction mechanisms between P. capsici and its host, and facilitate the development of targeted disease control strategies focusing on effectors.

Alpinia oxyphylla Miq. renowned as one of the "Four Great Southern Medicinal Herbs" of China, possesses modern pharmacological activities including antioxidant, anti-inflammatory, neuroprotective, and anti-tumor effects. However, with its wild resources increasingly depleted and cultivated plants facing pressures from pests, diseases, and climate change, there is an urgent need to enhance germplasm quality and stress resistance through biotechnological approaches. This study aimed to analyze the codon usage bias in the chloroplast genome of A. oxyphylla Miq. providing a theoretical basis for its subsequent applications in genetic engineering and synthetic biology. Fifty-one high-quality protein-coding sequences from the A. oxyphylla chloroplast genome were screened based on multiple filtering criteria. Codon usage characteristics were analyzed using CodonW 1.4.2 software combined with the online platform CUSP. There existed significant A/U-ending preference. The GC content showed a decreasing gradient (GC₁=45.69%>GC₂= 38.79%>GC₃=27.50%), with 90.6% of the preferred codons (RSCU>1) ending in A/U. There existed overall weak codon usage bias. The mean effective number of codons (ENC) was 46.56 (67.78% of genes had ENC>45), and the mean codon adaptation index (CAI) was 0.17. Natural selection dominated codon evolution. Neutrality plot analysis showed no significant correlation between GC₁₂ and GC₃. The actual values significantly deviated from the expected curve in the ENC-plot. The PR2-plot revealed a bias at the GC₃ position favoring A>T and C>G. Ten optimal codons were identified. This study is the first to reveal the conserved A/U-ending preference and the multifactor synergistic regulatory mechanism dominated by natural selection in the A. oxyphylla chloroplast genome. The identified optimal codons could serve as key elements for chloroplast genetic engineering in A. oxyphylla. Directional optimization of codon usage in exogenous genes (e.g., genes encoding enzymes for medicinal compound synthesis) using the codons is expected to enhance the expression efficiency, providing technical support for A. oxyphylla quality improvement and stress-resistant breeding.

Six mango varieties (Guiqi Mang, Tainong Mang, Guifei Mang, Jinhuang Mang, Ivory Mang, and Jade Mang) mainly planted in Baise were selected as the research objects, and 22 quality indicators (including appearance quality, internal quality.) were analyzed. The results indicated that the coefficient of variation for indexes such as single fruit weight and fruit shape index exceeded 10% among different varieties in appearance quality. For intrinsic quality, Guiqi mango performed optimally in sweetness-related indexes (TSS, total sugar, soluble sugar) and flavor coordination (solid-acid ratio, sugar-acid ratio), with the highest Vc content reaching 36.6 mg/100 g, while Tainong mango had the lowest Vc content at 28.7 mg/100 g. Yumang mango had the highest contents of phenolic substances (4.33 mg/100 g) and flavonoids (1.12 mg/100 g). Guifei mango and Yumang mango had relatively high protein contents, both at 1.0 g/100 g. Further analysis indicated that there existed both relative independence and close correlation among multiple quality index variables of mango. The 5 principal components extracted by principal component analysis accounted for 100% of the information of the above indexes, and the comprehensive quality ranking was as follows: Yumang mango>Guiqi mango>Tainong mango>Xiangya mango>Guifei mango>Jinhuang mango. Systematic clustering classified the 22 quality indexes into 3 categories: bioactive components (e.g., vitamins, flavonoids), fruit flavor characteristics (e.g., sugar-acid related indexes), and mineral elements (e.g., potassium, calcium). The results revealed the characteristic differences in fruit quality among the main mango varieties in Baise, and suggested that principal component analysis and systematic clustering analysis could be applied to simplify the evaluation of mango fruit quality.

10 inflorescence traits of 200 domestic and international Macadamia germplasms in the Jinghong Macadamia Germplasm Repository of the Ministry of Agriculture and Rural Affairs were evaluated using QGA Station combined with different genetic distance metrics, clustering methods, sampling strategies, and sampling proportions to conduct a core macadamia collection construction. The optimal methodology for core collection development was identified as “Mahalanobis distance+multi-clustering deviation sampling+centroid clustering method+15% sampling proportion”, resulting in a core collection comprising 30 accessions. The mean difference percentage, variance difference percentage, range coincidence rate and variation coefficient change of core collection and original collection was 0.00%, 90.00%, 99.31% and 150.08%, respectively. No significant differences in trait means were detected between the core and original collections (T-test). The variances of all traits in the core collection exceeded those of the original collection, with 9 traits showing statistically significant differences. While genetic diversity indices slightly decreased, the conformity rate for all traits remained above 80%. Principal component analysis (PCA) demonstrated that the cumulative variance contribution rate of the first three principal components was 74.118% and 84.350% for the original and core collections, respectively, with congruent geometric structures in their PCA scatterplots. Correlation analysis further confirmed that trait relationships in the core collection closely mirrored those of the original collection. The core collection comprised 8 Australian accessions, 10 Hawaiian accessions, 9 China Yunnan accessions, and 3 accessions of special types, exhibiting a degree of geographic representativeness. Analyses using both cluster analysis and PCA on the core collection revealed that domestic and foreign accessions were distinguishable to a certain extent based on the inflorescence phenotypes. The Macadamia core collection developed in this study, based on inflorescence phenotypic traits, effectively represents the genetic diversity of the original collection and would provide a robust foundation for future research on Macadamia genetic resources.

It aimed to establish and optimize an efficient tissue culture rapid propagation system for Dendrobium Reke Xiamo to address the inefficiency and high cost associated with its traditional propagation methods. By systematically screening the concentration ratios of cytokinin (6-BA) and auxin (NAA), the addition of potato powder, and rooting medium formulations, an efficient and stable tissue culture rapid propagation system was successfully developed. The experimental results showed that the combination of 6-BA at 3 mg/L and NAA at 0.5 mg/L in MS medium was the optimal shoot induction medium, with the highest shoot induction rate achieved when 80 g/L of potato powder was added. The proliferation medium consisting of 6-BA at 2 mg/L and NAA at 0.5 mg/L resulted in an average proliferation coefficient of 5.63. During the rooting stage, the combination of NAA at 0.5 mg/L and IBA at 0 mg/L yielded the most significant results. By establishing a stage-specific precise hormonal regulation system (induction-proliferation-rooting), the propagation bottleneck was successfully overcome, and the proliferation coefficient increased by over 30%. This technical system would provide reliable technical support for the scaled production and commercialization of Dendrobium Reke Xiamo.

The identification and evaluation of superior germplasm are the foundation for the research on germplasm resources and breeding utilization. 45 citronella grass resources from Hainan, Fujian, Guizhou, Yunnan and other regions were assayed to evaluate the essential oil content. The agronomic traits, essential oil content and main components of essential oil of the resources at different cutting stages were analyzed in Kunming. The results showed that there were significant differences in total grass length, leaf length, leaf width, biological yield and essential oil content among different cutting periods and different materials. Correlation analysis between characteristic traits and essential oil content revealed that the essential oil content was significantly negatively correlated with leaf length and significantly positively correlated with leaf width. Systematic cluster analysis based on agronomic traits and essential oil content divided the resources into 5 groups. The Ⅰ group contained 36 materials, and all materials were identified as Cymbopogon citra=tus, The Ⅱ group had 4 materials, all in Cymbopogon winterianus. Cymbopogon caesius and Cymbopogon hamatulus were individually clustered into the Ⅳ and Ⅴ groups, respectively. A standard for identifying and grading superior germplasm oriented towards essential oil yield was established, and the 45 resources were divided into three grades, including 6 in the first grade, 18 in the second grade and 21 in the third grade. In addition, the analysis of essential oil content and main components of 16 germplasm in Yuanmou test region at 6 different periods showed that the accumulation of essential oil did not increase with the extension of planting time, and the contents of main components in essential oil also varied in different periods. Geraniol reached the highest value in January; Linalool had the highest content in March; Geranyl acetate peaked in September; Citronellyl acetate had the highest content in January, and β-myrcene was the highest in May. This study would provide a scientific basis for the identification and evaluation of superior citronella grass germplasm, breeding utilization, and the production and utilization of high-quality and high-yield raw materials.

The study developed a new fresh-eating sweet potato variety Guishu No. 13 and established its virus-free seedling breeding technology system to meet the market demand for fresh-eating sweet potato varieties and healthy seedlings. Guishu No. 13 was bred from seeds by open pollinated using Guizhu No. 10 as mother. The variety has purple red skin, orange yellow flesh, and a high rate of medium to large storage roots. The content of β-carotene, protein and reducing sugar was 1790 mg/100 g, 1860 mg/100 g and 1200 mg/100 g, respectively. In the production experiment, the starch storage roots yield was 29 786.40 kg/hm² and starch yield was 4675.10 kg/hm², which increased by 5.52% and 17.52% respectively compared to Guishu No. 2 (CK). Guishu No. 13 has moderate resistance to Fusarium wilt, black rot, and stem nematode. The best culture medium for callus differentiation and germination rate of Guishu No. 13 was MS+0.10 mg/L NAA+1 mg/L 6-BA and MS+0.20 mg/L NAA+2 mg/L 6-BA, respectively. Guishu No. 13 has good yield and stability, high fresh storage root yield, and the establishment of a virus-free breeding system would lay the foundation for the development and application of the Guishu No. 13.

The study determined quality indexes including single fruit mass, longitudinal and transverse fruit diameter, peel thickness, edible rate, soluble solids and titratable acid of 51 pomelo accessions to analyze the fruit quality characteristics of different pomelo germplasm resources and establish a comprehensive evaluation system. Correlation analysis and principal component analysis were employed to comprehensively evaluate the fruit quality. The fruit longitudinal diameter ranged from 64.00 to 191.00 mm, with transverse diameter measured between 76.00 and 170.90 mm. Fruit shape index values varied from 0.82 to 1.35, while single fruit mass spanned 220.00 to 1750.00 g. Peel mass was recorded between 50.00 and 996.00 g, with edible rates from 19% to 81%. Peel thickness measurements showed variation from 4.00 to 39.67 mm. Segment number per fruit was 10‒20, soluble solids content ranged 4.50%-10.90%, and titratable acid level was 0.13%‒2.96%. The solid-acid ratio varied between 2.70 and 41.70, with number of seeds ranging from 0 to 224. It indicated that the phenotypic diversity of pomelo germplasm resources in Hekou, Yunnan was rich. Pearson correlation analysis revealed that longitudinal diameter exhibited significant positive correlations with fruit shape index and single fruit mass. Transverse diameter showed extremely significant positive correlations with single fruit mass and peel mass. Significant negative correlations were observed between edible rate and peel thickness, titratable acid and solid acid ratio. Cluster analysis grouped the resources into approximately four categories, with each group displaying substantial difference in both external appearance and internal quality. By principal component analysis (PCA), the 13 traits were integrated into 4 principal components, and the contribution rate of the first principal component was 31.614%. The longitudinal diameter, transverse diameter, single fruit mass and peel mass contributed more. The contribution rate of the second principal component was 16.842%, which was based on edible percentage, number of segments and soluble solid. The contribution rate of the third principal component was 15.397%, and the contribution rate of titratable acid was larger. The contribution rate of the fourth principal component was 14.686%, which was based on the number of seeds. After fruit quality analysis and comprehensive evaluation, Yunqing 1, Green peel and red flesh Pomelo, Huangjin pomelo, Guanxi red flesh pomelo, Dongshizao Pomelo, and Wanbai Pomelo demonstrated superior comprehensive quality and were recommended as candidate materials for main cultivars or breeding parents in Hekou, Yunnan.

1-year-old and 5-year-old Alpinia galanga intercropped under rubber forests was used to understand the photosynthetic physiological characteristics of Alpinia galanga in rainy and dry season, explore its growth adaptability and growth habits, and provide a theoretical basis for its popularization under rubber forests. There were significant differences in photosynthetic parameters between 1-year-old and 5-year-old plants. The net photosynthetic rate (P_n) and transpiration rate (T_r) of 1-year-old plants were higher than those of 5-year-old ones, and T_r was higher in rainy season than in dry season, indicating drought tolerance and stronger photosynthetic capacity in seedlings. There existed differences in light response curve parameters. Light saturation point (LSP) and light compensation point (LCP) of both age groups were between those of heliophytes and sciophytes, confirming shade tolerance. LSP and apparent quantum efficiency (AQE) were higher, while LCP was lower in the dry season, further indicating drought tolerance. The maximum photochemical efficiency (F_v/F_m) was slightly higher in the dry season, suggesting stronger photosynthetic capacity. Contents of chlorophyll a, chlorophyll b, total chlorophyll, and Chl a/b ratio were higher in the dry season, indicating more favorable growth conditions. The 5-year-old plants had thicker upper epidermis and higher palisade-spongy ratio, adapting to shade and drought under rubber forests. The spongy tissue thickness exceeded that of palisade tissue in both age groups, confirming shade tolerance. In conclusion, Alpinia galanga is shade/drought-tolerant with high weak-light utilization. This indicates that dry season conditions and appropriate shading (shading degree of 40%-80%) are more conducive to the growth of Alpinia galanga.

A field split plot experiment of pineapple was carried out from 2023 to 2024 to explore the effects of nitrogen fertilizer postponing and magnesium fertilizer coupling on the growth and development, yield and quality of pineapple and to provide practical reference for scientific fertilization management of pineapple. The main area was magnesium application rate, namely MgO 0 kg/hm² (M₀), MgO 37.5 kg/hm² (M₁) and MgO 75 kg/hm² (M₂). The sub-area was conventional nitrogen application treatment (N₁) and nitrogen fertilizer postponing treatment (30% of nitrogen fertilizer in slow growth period and flowering period was postponed to rapid growth period and fruit enlargement period, respectively) (N₂). The leaf number, leaf area index, chlorophyll content, dry matter accumulation, yield and quality indexes of pineapple were measured during the key growth period of pineapple. The results showed that compared with N₁, N₂ could significantly increase the contents of chlorophyll a and chlorophyll b in pineapple leaves at mature stage, and increase the number of leaves and leaf area index of pineapple at red stage. Compared with N₁, the dry matter quality and yield at maturity stage increased by 9.40% and 7.65%, respectively, and the vitamin C content and soluble sugar content of fruit were also significantly higher than those of N₁ (P<0.05)_, while the difference in yield was not significant. Similarly, compared with M₀ and M₂ treatments, M₁ treatment could significantly increase the contents of chlorophyll a, chlorophyll b and carotenoids in leaves, and the leaf number and leaf area index of pineapple at the red stage of flowering increased significantly, thereby improving the dry matter quality and yield at the mature stage, and the difference was significant (P<0.05). The fruit dry matter distribution rate, soluble sugar content, soluble protein content, vitamin C content and sugar-acid ratio under M₁ treatment were significantly higher than those under M₀ and M₁ treatments (P<0.05). Interaction effect analysis revealed that N₂M₁ treatment could increase the content of chlorophyll a, chlorophyll b and carotenoid in pineapple compared with other treatments, and then the number of leaves, leaf area index and dry matter quality increased significantly. Yield increased significantly by 19.43%, 17.39%, 10.07% and 24.96% compared with those of N₂M₀ (P<0.05), N₁M₂, N₁M₁ and N₁M₀, respectively, but not significantly different from that of N₂M₂. The fruit shape index, vitamin C, soluble sugar, soluble protein content and sugar-acid ratio of pineapple fruit treated with N₂M₁ were higher than those of other treatments, and there was a significant difference between N₂M₁ and N₁M₀ (P<0.05). Correlation analysis showed that pineapple yield was significantly positively correlated with leaf number, leaf area index, dry matter accumulation, chlorophyll b content, vitamin C, soluble sugar and soluble protein. There was a significant negative correlation with titratable acid content. N₂M₁ treatment can significantly increase the number of leaves, leaf area index and photosynthetic pigment content of pineapple plants, increase fruit dry matter distribution, thereby increasing pineapple yield and effectively improving fruit quality. Therefore, N₂M₁ could be recommended as the best model for fertilization management of pineapple in tropical regions.

The present study investigated the ameliorative effects of 5-aminolevulinic acid (5-ALA) on muskmelon seedlings subjected to saline-alkali stress. Using the melon variety Zhongbao No.1 as the test material, under pot cultivation conditions, the study investigated the effects of root application of five different concentrations (25, 50, 100, 150, and 200 mg/L) of 5-ALA on the growth changes, photosynthetic pigments, reactive oxygen species (ROS) accumulation, osmotic adjustment, and antioxidant system of melon seedlings under 150 mg/L mixed salt-alkali stress. The results showed that under saline-alkali stress, exogenous 5-ALA at appropriate concentrations (100, 150 mg/L) significantly increased plant height, stem diameter, leaf length, leaf width, and leaf area of muskmelon seedlings. It also increased the contents of photosynthetic pigments and soluble sugars, proline content was reduced but still remained higher than that of CK, and significantly reducing both MDA content and O^2- generation rate. Furthermore, the activity of antioxidant enzymes, specifically SOD, CAT, APX, and GR, along with GSH content, exhibited elevation. Although POD activity showed a decrease, it maintained significantly higher levels compared to the control treatment (CK). In addition, TOPSIS comprehensive evaluation analysis was conducted on different exogenous 5-ALA treatments based on all the above measurement indicators, and the results showed that SA₁₅₀ treatment ranked first. Therefore, exogenous 5-ALA at a concentration of 150 mg/L exhibits the optimal effect in alleviating saline-alkali stress in muskmelon seedlings, which would provide a theoretical foundation for the cultivation of crops under saline-alkali stress conditions.

Reasonable fertilization is of great significance for increasing the yield of oil-tea Camellia, and the application of bio-organic fertilizers is superior to the current practice of using farm manure as the main fertilizer for oil-tea Camellia in many aspects. In order to develop and value the specialized bio-organic fertilizers suitable for the soil conditions of oil-tea Camellia plantations in tropical regions, the nutrient contents of oil-tea Camellia leaves, the physical and chemical properties, and enzyme activities of oil-tea Camellia forest soil were determined. The results showed that the application of bio-organic fertilizers and conventional compound fertilizer could significantly increase the water content, relative chlorophyll content (SPAD value), and nutrient elements of oil-tea Camellia leaves. The soil moisture contents and field capacities of different fertilization treatments were higher than those without fertilization, but there were no significant differences in soil bulk density and porosity between the treatments and the control group. All four types of bio-organic fertilizers could increase the contents of soil organic matter, alkaline nitrogen, available phosphorus, available potassium, and soil enzyme activity in different soil layers. T₁ and T₄ bio-organic fertilizer improved the chemical properties of oil-tea Camellia soil more, which is of great significance for the targeted improvement of the fertility and available potassium content of Hainan oil-tea Camellia forest land. The results would provide data for screening specialized bio-organic fertilizers suitable for tropical oil-tea Camellia, laying a scientific foundation for the subsequent large-scale application of bio-organic fertilizers for tropical oil-tea Camellia.

The study was aimed to clarify the effects of different bag types on fruit quality and postharvest storage of Dongshizao pomelo, and screen suitable bag types to provide reference for production and application. In this study, 23-year-old Dongshizao pomelo trees were used as the experimental material, fruit without bagging was used as the control group, fruit bagging was carried out with 8 types of bags, including 60-mesh nylon mesh bag, 80-mesh nylon mesh bag, unilateral polyethylene-paper bag, white nonwoven bag, green-single-layer bag, white-single-layer bag, single-layer bag with yellow outside and black inside, double-layer bag with yellow outside and black inside. Fruit quality difference between harvest and post-harvest storage was compared, and comprehensive evaluation was carried out by the subordinative function method. The results showed that the white-single-layer bag significantly increased the single fruit weight by 47.86%, double-layer bag with yellow outside and black inside significantly decreased the pericarp thickness by 28.19%, and the total soluble solids (TSS) content of fruits with single-layer bag with yellow outside and black inside was significantly decreased. The titratable acid (TA) content of fruits with unilateral polyethylene-paper bag, single-layer bag with yellow outside and black inside, double-layer bag with yellow outside and black inside were decreased. While the single-layer bag with yellow outside and black inside, double-layer bag with yellow outside and black inside were significantly improved the TSS/TA rate by 19.71% and 34.40%, respectively. At harvest, the comprehensive evaluation of fruit quality revealed that fruits bagged with the double-layer bag with yellow exterior and black interior achieved the highest score (0.56), followed by those with the single-layer bag of the same design (0.55), both outperforming the unbagged control (0.50) and white single-layer bag (0.49). During postharvest storage, the fruit weight loss rate generally increased with storage duration, except for one transparent paper bag treatment, and peaked on the 45th day of storage. Throughout the storage period, significant differences were observed in various fruit quality indices, including edible rate, juice yield, soluble sugar, soluble protein, TSS, and TA content, with fluctuations influenced by bag type. Regardless of treatment, the inherent quality indices of the fruit pulp exhibited significant variability rather than a simple upward or downward trend. The bagged fruits also displayed a distinct ‘returned acidity’ phenomenon, with the timing and intensity of this phenomenon influenced by the type of bag used. The comprehensive evaluation of postharvest storage quality showed that the average comprehensive score of fruits bagged with the white single-layer bag gradually increased with extended storage time, reaching the highest average score (0.65) among all treatments, with the smallest coefficient of variation (5.14%). In conclusion, while fruits bagged with the single-layer and double-layer bags with yellow exterior and black interior demonstrated superior comprehensive quality at harvest, they exhibited greater quality fluctuations and poorer storage stability. Conversely, although the initial harvest quality of fruits bagged with the white single-layer bag was slightly inferior to the control, this treatment exhibited the smallest variation range in storage quality, coupled with the highest overall storage quality and stability. Therefore, the white single-layer bag is recommended as the primary bagging option for the production and cultivation of Dongshizao pomelo, offering a balanced approach to optimizing both fruit quality and postharvest storage performance.

The study aimed to find non-toxic and pollution-free post-harvest prevention and treatment methods replacing chemical fungicides to enrich the resources of mango stalk rot antagonist bacteria. Botryodiplodia theobromae Pat. and Phomposis mangiferae Ahmad were used as the indicator fungi, and actinomycetes with antagonistic effects on stalk rot fungi were isolated and screened from the rhizosphere soil of mango trees by the plate dilution and dual culture method. The classification status, live prevention effects, and the antimicrobial mechanism were preliminary studied. Antagonists A2, B85 and D16 were selected, which had antimicrobial effects and good genetic stability against both Botryodiplodia theobromae Pat. and Phomposis mangiferae Ahmad, and had inhibitory effects on Colletotrichum gloeosporioides, Pestalotiopsis mangiferae, Alternaria alternate and Botrytis cinerea, with a wide antifungal spectrum. In the live test, on the 3^rd day after inoculation, there were no significant differences in the diameter of the fruit lesions treated with antagonist strains A2, B85 and D16 (8.58, 8.50, 7.83 mm) and the imimerine-treated group (6.33 mm), but significantly lower than that of the control group (20.58 mm). Strains A2 and B85 were identified as Streptomyces malaysiensis, and D16 was Streptomyces lydicus. Strains A2, B85 and D16 inhibited the occurrence of pedicle rot by producing active substances with antimicrobial effects, inhibiting spore germination of dipodol, nutritional competition, and improving the activity of fruit SOD, POD and CAT. Among the three antagonistic strains, the D16 could also produce volatile organic compounds with antimicrobial effects to inhibit the occurrence of pedicle rot fungi. The three strains had certain antagonistic effects on pedicle rot bacteria and could be further studied.

Banana anthracnose, caused by Colletotrichum musae, is a major postharvest disease that threatens fruit quality and banana industry sustainability. Phospholipase (PL) plays dual roles in plant disease resistance and pathogen metabolism, acting as a key enzyme in defense responses and as a virulence factor for pathogenic fungi.. Previous studies have shown that PL inhibitors can help maintaining membrane stability under stress conditions. In this study, the inhibitory effects of three PL inhibitors, i.e. quinacrine dihydrochloride (QU), neomycin sulfate (NE), and n-hexanol (Hex), on C. musae were evaluated through in vitro antifungal assays. Results showed that all three inhibitors significantly suppressed mycelial growth and spore production of C. musae. The half-maximal inhibitory concentrations (IC₅₀) for mycelial growth were 1.00 mmol/L (QU), 5.00 mmol/L (NE), and 8.80 mmol/L (Hex). Enzymatic activity assays revealed that QU significantly inhibited both PLA activity in C. musae and banana peel tissues, NE primarily suppressed PLC activity in banana peel, whereas Hex markedly reduced PLD activity in C. musae. Moreover, the appropriate concentrations of the inhibitors (2.00 mmol/L QU, 3.00 mmol/L NE, and 13.20 mmol/L Hex) effectively controlled the development of banana anthracnose. The findings suggested that QU, NE, and Hex suppressed banana anthracnose through distinct mechanisms involving interference with host-pathogen interactions. This study would provide a theoretical basis for the green control of postharvest banana diseases via the targeted regulation of phospholipase activity.

Cymbidium mosaic virus (CymMV) and Odontoglossum ringspot virus (ORSV) are common viruses in Phalaenopsis production, and monitoring CymMV and ORSV of in vitro seedlings is the foundation of high-quality and healthy seedling production in Phalaenopsis. In this study, 20 Phalaenopsis cultivars were used as the research objects. Two batches of in vitro seedlings selected from the production line with 10-month intervals between the subculture proliferation cycles, were investigated for CymMV and ORSV through RT-PCR (reverse transcription polymerase chain reaction) and RT-qPCR (real time quantitative polymerase chain reaction) at the same time. RT-PCR results showed that the positive rate of CymMV in the first and second batch was 25% and 20%, respectively, and the positive rate of ORSV was both 15% in the two batches. RT-qPCR results showed that the positive rate of CymMV in the first and second batch was 100% and 91.67%, respectively, and the positive rate of ORSV in the two batches was 50% and 25%, respectively. Comparing with the first batch, CymMV content of 16 cultivars and ORSV content of 9 cultivars decreased in the second batch, but ORSV content of Phalaenopsis Sogo Yukidian V3 increased significantly, which increased from negative to 6.85×10⁵-8.50×10⁵ copies/μL. The results indicated that CymMV and ORSV widely existed in in vitro seedlings of Phalaenopsis, and the content varied with different batches. The cultivars detected as the negative also faced the risk of virus content increase. Thus, CymMV and ORSV should be investigated regularly in the production of in vitro Phalaenopsis seedlings to ensure the high-quality seedling source for Phalaenopsis industry.

Natural rubber latex serves as the primary raw material for various products, including medical gloves, condoms and tires. Enhancing its formulation can effectively reduce production costs, improve product performance, and enhance the competitiveness of manufacturing industry. In this study, a spherical symmetric design method was employed to optimize the rubber compound formulation. Sulfur, zinc oxide, accelerator UH-301 and antioxidant WSL were selected as key components for the formulation. The investigation focused on three comprehensive indicators: elongation at break, tear strength and tensile strength. The indicators were analyzed through hypothesis modeling, regression analysis and programming solutions to determine the optimal formulation. The vulcanization characteristics and mechanical properties of both the optimized formula and the basic formula for latex vulcanization were tested. The results indicated that the optimized formula (sulfur: 1.50 phr, zinc oxide: 0.25 phr, accelerator UH-301: 0.40 phr, antioxidant WSL: 1.36 phr) was obtained via regression analysis, with an estimated comprehensive strength of 1.2891. Verification tests confirmed the feasibility of the mathematical model constructed using the spherical symmetrical design method. Comparing the optimized formula with the basic latex vulcanization formula revealed that the former significantly outperformed the latter in vulcanization rate and physical-mechanical properties. Specifically, the tensile strength of the vulcanized rubber film with the optimized formula reached 32.2 MPa, an increase of 212.4%, while the tear strength reached 60 kN/m, an increase of 180.1%. The findings further demonstrate the practical application value of the optimized rubber compound formulation and would provide a solid foundation for enhancing the performance of natural latex rubber films.

Ammonia preservation and acid solidification are key steps in natural rubber (NR) processing, but there is still a lack of systematic research on the influence on the structure and properties of NR. In this paper, the same batch of fresh latex was treated with 0%, 0.05%, 0.20% ammonia and two solidification methods(acid solidification, biological solidification) to prepare samples. The effects of ammonia preservation and acid solidification on the structure and properties of NR were comprehensively evaluated from the aspects of molecular structure, composition, intrinsic properties, and the mechanical performance of both unfilled and carbon-black-filled vulcanizates. It was found that ammonia preservation led to a decrease in weight-average molecular weigh, the initial plastic value and Mooney viscosity of the acid-solidified samples, whereas the properties remained largely unaffected in biologically solidified counterparts. The addition of ammonia exerted minimal influence on the mechanical properties of unfilled vulcanizates, but significant effects emerged in carbon-black-filled systems. Acid-solidified samples demonstrated higher fatigue temperature rise, while biologically solidified samples showed decreased tensile stress and tear strength. The solidification mode profoundly impacted the molecular structure, chemical composition, intrinsic properties, and mechanical performance of NR. Compared to biological solidification, acid-solidified rubber exhibits higher nitrogen, free fatty acid content and weight-average molecular weight. Furthermore, acid-solidified samples displayed lower initial plasticity and Mooney viscosity. The solidification method significantly affected the properties of both unfilled and carbon-black-filled vulcanizates. Compared to biological solidification, acid-solidified samples exhibited slower cure rates and higher fatigue temperature rise. The results showed that ammonia preservation of fresh latex and subsequent solidification with acid could affect the important components and intrinsic properties of NR, and had a significant impact on the dynamic properties such as fatigue temperature rise and permanent deformation, especially in carbon-black-filled vulcanizates. However, by comparing with the imported RSS, the preservation of fresh latex with ammonia and the subsequent solidification with acid were not the only reasons causing the performance of domestic NR to be worse than that of imported NR and differences in processing maybe the other causes. This work not only reveals the reason of the performance difference between domestic and imported NR products, but also would provide technical support for optimizing the production management of special rubber park.

Coconut water is sterile in the interior cavity of the coconut fruit. However, once the coconut is opened and repackaged, the coconut water beverage may become a breeding ground for bacteria and fungi, leading to the production of harmful mycotoxins. This study aimed to detect the usage of preservatives and sweeteners, also the levels of the common carcinogenic contaminant benzo[a]pyrene and harmful mycotoxins in bottled coconut water sold on the market. By using national standard methods, no preservative such as benzoic acid and sorbic acid, no sweetener sodium saccharin, and no contaminant benzo[a]pyrene were detected in this batch of coconut water beverages. This study also investigated the level of mycotoxins in bottled coconut water stored at low temperatures (4‒8 ℃) for 21 days. No zearalenone (ZEN) or deoxynivalenol (DON) was detected in the coconut water stored at 4‒8 ℃ for 21 days. During monitoring, the response signal for aflatoxin B₁ (AFT B₁) in one of the samples had an increasing trend with prolonged storage time but the level did not exceed the quantitative limit specified in the national standard method. Electron microscope observation of the bottled coconut water stored at low temperatures revealed a large number of moving microorganisms in 1‒3 days, with the aerobic plate count increasing exponentially. After 21 days of low-temperature storage, infrared spectra showed new characteristic absorption peaks, indicating that the coconut water had undergone qualitative changes. It is recommended that bottled coconut water from freshly cut coconuts should be consumed on the same day.

The effects of exogenous ethylene (ETH), 1-methylcyclopropene(1-MCP) and a combined ETH+1-MCP treatments on fruit storage quality and physiological changes were evaluated to investigate the effects of ethephon on the fruit appearance color and internal quality during the ripening process of mangoes Hongguifei. The results showed that compared with the control, both ETH and ETH+1-MCP treatments significantly accelerated the decline in fruit firmness, titratable acid, chlorophyll, flavonoids, total phenolics, and ascorbic acid content, increased cell membrane permeability, and promoted in a^* color value, total soluble solids (TSS) in the early stage of storage, and carotenoid. Among the treatments, the ETH+1-MCP group showed the highest level of TSS and carotenoids while 1-MCP group effectively delayed the loss of nutrients and firmness, and inhibited chlorophyll degradation in the fruit peel. Further analysis of the metabolomes of the CK and ethylene treatment groups revealed 140 different metabolites, among which 88 were upregulated and 52 were downregulated. The content of flavonoids in the fruits of the ETH treatment group was significantly lower than that of the control group, indicating that the ETH treatment accelerated the degradation of flavonoids. This study revealed the metabolic mechanism of ETH in promoting the ripening and quality formation of mangoes, which would provide a theoretical basis for in-depth research on the mechanism of post-ripening quality changes in mangoes.

Biogenic volatile organic compounds (BVOCs) are important secondary metabolites released by forest plants, playing a crucial role in plant growth, development and environmental regulation. This study focused on rubber trees (Hevea brasiliensis) widely cultivated in Hainan Island. Using dynamic headspace sampling coupled with thermal desorption-gas chromatography-mass spectrometry (GC-MS), we systematically analyzed the emission characteristics of BVOCs and the environmental influencing factors across rubber trees of different stand ages (5, 15, 20 and 25 years). The diurnal variation of BVOCs exhibited a unimodal curve, with peak emissions concentrated between 10:30 and 13:00. BVOC emission rates decreased significantly with increasing stand age (5 years >15 years >20 years >25 years), and emissions during the rainy season were significantly higher than those during the dry season. The diversity of monoterpenes (MTs), other terpenes (OTs) and oxygenated volatile organic compounds (OVOCs) decreased with stand age, while sesquiterpenes (STs) remained stable. BVOC emissions showed significant positive correlations with net photosynthetic rate, transpiration rate, and light intensity (P<0.05), with light intensity being the primary influencing factor. The effects of air temperature and humidity on BVOC emissions increased with stand age. This study elucidated the age-related effects and seasonal dynamics of BVOC emissions in rubber plantations, providing a scientific basis for assessing the ecological and environmental impacts of tropical artificial forests.

The maize leaf area index (LAI) is a key parameter for reflecting growth and yield of maize, and the pollination stage being crucial for determining ear kernel number and yield. This study aimed to identify an effective inversion method to accurately estimate the LAI of Nanfan maize at pollination stage. Nanfan maize at pollination stage was used as the study subject. Canopy reflectance data were acquired using a ULTRIS X20 PLUS hyperspectral imager mounted on a Jingwei M300RTK quadrotor UAV platform. Based on correlation analysis, 28 LAI-sensitive vegetation indices were selected. Two traditional empirical models, univariate linear regression (ULR) and multiple stepwise regression (MSR), and four machine learning models, partial least squares regression (PLSR), random forest regression (RFR), support vector regression (SVR) and back propagation neural network (BPNN) were employed to construct LAI inversion models. The prediction accuracy of different vegetation indices and regression algorithms was compared, and the optimal inversion model was selected for accurately predicting the LAI status of Nanfan maize at pollination stage. Most vegetation indices exhibited highly significant correlations with LAI (P<0.01). Compared to univariate regression, multivariate regression models provided higher prediction accuracy. Among them, RFR, MSR and PLSR models achieved the highest R² values, with coefficients of determination (R²) of 0.96, 0.85 and 0.80 and corresponding root mean square errors (RMSE) of 0.18, 0.35 and 0.41, respectively. By analyzing the correlation and sensitivity between hyperspectral data and maize LAI, and employing vegetation indices calculated based on hyperspectral information combined with regression algorithms, this study successfully developed a reliable LAI inversion model, and established a spatial distribution of Nanfan maize LAI at pollination stage based on the RFR model with the best inversion effect. The model would provide both theoretical support and technical guidance for LAI estimation and field monitoring of Nanfan maize growth and development.

This study aimed to study the effects of long-term grass planting on soil fertility, enzyme activity and microbial diversity in tropical latosol soil, providing theoretical and technical support for improving the fertility and amelioration of tropical latosol soil. Using clean tillage as the control and three grass-planting treatments were established: Reyan No. 2 Stylosanthes (Re) and Ubon Stylosanthes (Ub) and natural grass (NG). Soil samples from 0‒20 cm and 20‒40 cm layers were collected to measure soil organic matter, pH, nitrogen, phosphorus, potassium and related enzyme activities. Utilizing a high-throughput sequencing platform to analyze soil bacterial and fungal communities, and investigating the effects of long-term orchard grass cultivation on the physical and chemical properties, enzyme activity, and microbial diversity of latosol soil. Five years of grass cultivation significantly increased soil organic matter, total nitrogen, and alkali-hydrolyzed nitrogen. with higher levels in Reiyan No. 2 and Ubon treatments compared to natural grass. Natural grass significantly increased total phosphorus in the 0‒20 cm layer, while Stylosanthes treatments significantly enhanced total phosphorus in the 20‒40 cm layer. Long-term grass planting significantly increased urease, acid phosphatase, and sucrase activities in both soil layers, with no notable effect on catalase activity. The Stylosanthes treatments showed higher urease, acid phosphatase, and sucrase activities than natural grass. Correlation analysis revealed that acid phosphatase, urease, and sucrase were extremely significantly positively correlated with organic matter, total nitrogen and alkali-hydrolyzed nitrogen. Acid phosphatase was significantly positively correlated with pH, while catalase only correlated significantly with organic matter, alkali-hydrolyzed nitrogen. Long-term grass cultivation, particularly the Ubon treatment, increased bacterial OTUs numbers in the 20‒40 cm layer. Grass cultivation altered bacterial and fungal community compositions. The dominated bacterial phyla were Acidobacteria, Chloroflexi, Verrucomicrobia and Proteobacteria. In the 0‒20 cm layer, grass cultivation increased the relative abundances of Acidobacteria, Verrucomicrobia and Proteobacteria but reduced Chloroflexi. For fungal, Ascomycota, Basidiomycota and Mucoromycota were dominant. Grass cultivation decreased Ascomycota abundance while increasing Mucoromycota. Soil environmental factors significantly influenced microbial communities. Acid phosphatase, organic matter, urease and pH were key drivers of bacterial community changes, whereas organic matter, total nitrogen, alkali-hydrolyzed nitrogen, sucrase and urease primarily shaped fungal community structure. Long-term grass cultivation in orchards, particularly Stylosanthes, significantly increased the organic matter, total nitrogen, and alkali-hydrolyzable nitrogen content in latosol soil. It also enhanced the activities of soil urease, acid phosphatase, and invertase enzymes. Furthermore, it altered the community structure and diversity of both soil bacteria and fungi, thereby effectively improving soil fertility and ameliorating the soil micro-ecological environment.