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.

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.

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.

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.

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.

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.

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.

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.

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.