Ocimum gratissimum is widely utilized due to its significant medicinal and culinary value. However, substantial variations in volatile components and medicinal metabolite content exist among different germplasms, influenced by geographical origin, cultivation conditions, and environmental factors. The variations directly impact the stability of pharmacological efficacy and industrial-scale production. To address this, the present study employed an integrated metabolomics and transcriptomics approach to systematically investigate the aroma profiles, metabolite composition, and regulatory mechanisms of two distinct O. gratissimum germplasms (G096 and G134). Sensory evaluation confirmed that both accessions exhibited a characteristic clove-like aroma. Metabolomic analysis identified 1094 volatile metabolites, with 784 showing significant differential accumulation between the two germplasms. Correlation analysis between differential metabolites and sensory attributes revealed that eugenol was the key metabolite responsible for the distinctive flavor of O. gratissimum. Transcriptomic profiling identified 54 936 differentially expressed genes (DEGs), including 27 220 upregulated and 27 716 downregulated genes. Through metabolic pathway prediction, a biosynthetic pathway for eugenol in O. gratissimum was constructed, identifying PAL, C4H, 4CL, HCT and C3'H as critical regulatory genes governing eugenol biosynthesis. This study would not only elucidate the biosynthetic mechanism of the primary flavor compounds in O. gratissimum, but also provide a crucial molecular theoretical foundation for quality improvement and standardized production. The findings would hold significant scientific and practical value for advancing the industrial development of O. gratissimum.

Flg22 is an artificially synthesized 22-amino-acid peptide derived from the conserved N-terminal region of bacterial flagellin, playing a crucial role in regulating plant immune responses. Due to the high cost of artificially synthesized flg22 short peptides and limitations for large-scale application, this study aimed to determine the suitable conditions for prokaryotic induction expression of the flg22 protein and to verify its function, thereby determining whether it could replace the commercially used flg22 short peptides. In this study, the pET32a-flg22 prokaryotic expression vector was synthesized, and we then compared protein expression efficiency under induction at 28 ℃ and 37 ℃. Additionally, we detected the dynamic burst of reactive oxygen species (ROS) in cassava treated with flg22 peptides and flg22 proteins at different concentrations to validate the functions. The results indicated that 28 ℃ was the optimal induction temperature for inducing flg22 protein expression. ROS measurements showed that within a specific concentration range, the peak intensity of ROS increased with the increase in flg22 protein concentration. Furthermore, after spraying cassava leaves with 60 μg/mL and 600 μg/mL of flg22 recombinant proteins, as well as 2.27 μg/mL of flg22 peptides, for three days, we inoculated plants with the pathogen Xam (Xanthomonas axonopodis pv. manihotis, Xam). Compared to treatment with sterile water, both flg22 protein and flg22 peptide treatments showed significant antibacterial effects against Xam in cassava plants, with the 60 μg/mL and 600 μg/mL flg22 protein treatments showing notably stronger antibacterial activity than the flg22 peptide. The results preliminarily identified the prokaryotic expression conditions of flg22 recombinant protein and verified that its function in inducing plant defense responses is consistent with that of the peptide, providing a theoretical basis for substituting commercial peptides with flg22 recombinant protein.

High yield with cold resistance clones is the core objective of rubber tree breeding in Yunnan. In this study, the cold-resistant clone GT1, which exhibits strong tolerance to radiative chilling injury, was selected as the female parent, and the widely cultivated fast-growing, high-yielding variety Yunyan 277-5 was used as the male parent. Through artificial isolated pollination, hybrid offspring were obtained. After a sexual family trial, individual plants with potentials were selected from the progeny population and entered into small-scale and large-scale clone comparative trials. This process led to the selection of an excellent clone, Yunyan 76-235, which is characterized by high yield and fast growth with the cold resistance and latex production type comparable to the clone RRIM600. Thirty years of systematic evaluation demonstrated that Yunyan 76-235 exhibits rapid early growth, with an average annual girth increment of 6.0 cm by the 6^th year after planting in the primary trial area, which is 115.4% of the clone RRIM600. It also shows high yield of dry rubber, with an average annual dry rubber yield per tree of 2.64 kg in years 1-5 of tapping in the small-scale clone comparative trials, representing 149.26% and 168.54% of the RRIM600 and GT1, respectively. In the large-scale clone comparative trials, the average annual rubber production per tree in years 1-13 of tapping was 4.6 kg, which is 140.12% of the RRIM600. Its cold resistance is stronger than that of RRIM600 but weaker than that of GT1 and Yunyan 77-4. The successful breeding of clone Yunyan 76-235 enriches the genetic resources for rubber cultivation in areas of Yunnan where prone to mild and moderate cold damage, providing variety support for the development and enhancement of the local rubber industry.

To establish a regeneration system for somatic embryo-derived plants from the anthers of the triploid rubber tree clone Yunyan 73-46, this study utilized anthers as explants and employed an orthogonal experimental design to examine the effects of various hormone combinations on callus and somatic embryo induction efficiency. Furthermore, the morphological characteristics and differentiation capacity of callus under different culture duration were analyzed. Hormones were crucial for callus induction. In the absence of hormones, anthers failed to dedifferentiate and underwent browning and necrosis after 10d. In media containing 2,4-D, NAA, KT and TDZ, anther dedifferentiation to produce callus occurred with induction rates ranging from 15% to 91.56%, with a mean of (69.41±30.37)%. The impact of 2,4-D, NAA, KT and TDZ on callus induction rate and subsequent somatic embryogenesis rate were all highly significant (P<0.01), with the order of influence being 2,4-D>TDZ>NAA>KT. The optimal combination identified through comprehensive screening was 2,4-D 1.0 mg/L+NAA 0.8 mg/L+TDZ 0.02 mg/L. Upon verification, the callus induction rate and subsequent somatic embryogenesis rate was (86.15±1.53)% and (14.46±0.89)%, respectively, marking significant improvements of 2.31% and 5.40% over the best experimental combination (G7). The somatic embryogenesis capacity of this clone was generally low, with somatic embryo formation rates ranging from 6.91% to 19.31%, with a mean of (10.58±3.95)%. The effects of 6-BA, ABA, NAA and KT on somatic embryogenesis rate were highly significant (P<0.01), with the order of influence being ABA>6-BA>NAA>KT. The optimal combination was 6-BA 0.4 mg/L+ABA 0.2 mg/L+NAA 0.2 mg/L+KT 0.2 mg/L (M9), achieving a somatic embryogenesis rate of (19.31±0.60)%, which was significantly higher than other treatments. The optimal culture duration for callus was determined to be 55 d, which exhibited superior growth status without browning and the strongest somatic embryo differentiation capacity. The somatic embryogenesis rate was (30.83±1.67)%, the cotyledonary embryo formation rate was (18.33±0.83)%, and the average number of somatic embryos was (0.63±0.03), all of which were extremely significantly higher than those at other culture durations. By optimizing the hormone ratios during callus induction and somatic embryogenesis stages of Yunyan 73-46 anthers, coupled with adjusting the duration of callus induction culture, the production efficiency of anther-derived somatic embryo plantlets can be significantly enhanced. This approach would provide technical support for establishing a large-scale propagation system of somatic embryo plantlets for triploid rubber tree clones.

Date palm (Phoenix dactylifera) is a key economic crop in arid and semi-arid regions, which possesses ecological functions of sand fixation and water conservation, economic value driven by deep processing, as well as profound religious and cultural significance. This paper reviews the research progress in its genetic breeding from the following aspects. In germplasm resources, core germplasm banks have been established by institutions such as King Faisal University of Saudi Arabia, the National Plant Gene Bank of Iran, and the Chinese Academy of Tropical Agricultural Sciences. The institutions preserve germplasm resources by combining technologies like smart irrigation and cryopreservation, while molecular marker technologies including SSR and SNP have been applied to reveal genetic differences among date palm varieties. In breeding methods, traditional selection and hybrid breeding have laid the foundation for date palm breeding. Modern biotechnologies such as high-throughput sequencing, somatic embryogenesis, and CRISPR/Cas9 have accelerated the process of precision breeding. The current core challenges in date palm breeding include difficulty in early sex identification due to dioecy, a complete growth cycle exceeding 10 years, highly heterozygous genome, and lagging molecular research. Future breeding efforts should focus on developing varieties resistant to abiotic stresses such as hot temperature, drought and salinity-alkalinity, preventing and controlling pests and diseases including red palm weevil, Fusarium spp., and leaf spot disease, and optimizing fruit yield and quality. Meanwhile, it is necessary to deepen research on genetic mechanisms, break through bottlenecks in gene editing technology, and strengthen international exchange and cooperation of germplasm resources, to promote the sustainable development of the global date palm industry.

Determining the appropriate nitrogen application rate for Ficus hirta Vahl. is one of the key cultivation techniques for establishing an efficient and ecological "rubber-Ficus hirta Vahl." agroforestry system. This study evaluated five nitrogen application treatments, 0, 150, 225, 300 and 375 kg/hm² (denoted as CK, N₁₅₀, N₂₂₅, N₃₀₀ and N₃₇₅), and conducted a comprehensive analysis of the suitable nitrogen rate from the perspectives of productivity, resource use efficiency, and ecological footprint. The results showed that, compared with the CK treatment, nitrogen application significantly increased the yield, biomass, and economic benefits. Among the treatments, N₂₂₅ and N₃₀₀ performed the best, achieving a yield of 15 438 and 15 150 kg/hm² and an economic benefit of 60 950 and 57 555 yuan/hm², respectively (P<0.05). Compared with CK, nitrogen application significantly improved solar utilization efficiency by 59.1%-76.9%, but significantly reduced carbon efficiency by 46.2%-73.7%. The partial factor productivity from applied nitrogen also decreased significantly with increasing nitrogen application (P<0.05). N₁₅₀ exhibited the best overall performance in resource use efficiency, followed by N₂₂₅. Similarly, N₁₅₀ showed the best overall performance in terms of carbon and nitrogen footprints, followed by N₂₂₅. Nitrogen uptake in Ficus hirta Vahl. across different treatments ranged from 117.8 to 174.0 kg/hm², with the CK and N₁₅₀ showing higher nitrogen uptake than nitrogen input. Taking into account the productivity, resource use efficiency, ecological footprint and sustainability of nitrogen supply, this study concludes that N₂₂₅ is the suitable nitrogen application rate for establishing an efficient and ecological "rubber-Ficus hirta Vahl." agroforestry system.

To identify periods of oxygen deficiency in the root zone of pineapples, understand the mechanisms of oxygen changes, and provide sufficient response time for oxygen-enriching irrigation technology management and soil regulation to address abnormal fluctuations in oxygen content in the root zone, this study utilized a soil oxygen diffusion-consumption coupling mechanism constructed based on the Monte Carlo method. In model construction, the study fully considered soil oxygen diffusion, root respiration, and microbial oxygen consumption processes. Using parameter perturbation and uncertainty sampling, the model incorporated measured boundary conditions and depth-stratified initial concentration settings. Combined with multi-layer soil profile monitoring data, the model established a simulation system for oxygen content changes at depths of 10-40 cm in three typical soil types (loam, sandy soil, and clay). Finally, the model was validated using field trial data from spring 2025. The results showed that the model demonstrated strong predictive capability under various soil and depth conditions (R²>0.95, with the lowest RMSE of 0.214 mol/m³). The error distribution fluctuated slightly with increasing depth but remained within an acceptable range overall. Further analysis revealed that the model successfully identified periods prone to oxygen deficiency within 3-12 hours after irrigation or rainfall events. In oxygen deficiency identification, the model achieved over 90% accuracy in determining responses below the critical concentration (1.5 mol/m³). The above results validate the effectiveness of the constructed model in simulating root zone oxygen dynamics and providing risk warnings, aiming to provide a theoretical basis and predictive foundation for intelligent oxygen management in pineapple fields.

The study was aimed to solve the problems of relatively extensive cultivation and low soil quality of Pandanus amaryllifolius that restrict the improvement of yield and quality. Different ratios of biochar combined with mushroom residue were used to improve the soil, clarify its yield-increasing effect and mechanism, and to provide technical support for efficient cultivation of Pandanus. Under basic fertilization, four treatments were set up, 800 kg/hm² mushroom residue (MD), 800 kg/hm² mushroom residue + 1600 kg/hm² biochar (MDB1), 800 kg/hm² mushroom residue +3200 kg/hm² biochar (MDB2), and no mushroom residue or biochar added (CK). A field plot experiment was conducted to study the effects of different treatments on plant growth and yield, soil physicochemical properties and microbial community structure of Pandanus. Compared with CK, the yield increase effect of mushroom residue alone (MD) did not reach a significant level, while the biochar combined application treatments (MDB1, MDB2) significantly increased the fresh leaf yield of P. amaryllifolius. This was related to the significant increase in leaf SPAD value and net photosynthetic rate of MDB1 and MDB2, which significantly increased the average fresh leaf weight, but there was no significant difference in yield between MDB1 and MDB2 treatments. Soil nutrient results showed that compared with CK, MD, MDB1 and MDB2 all significantly increased soil pH and available potassium content, but MD treatment significantly reduced soil organic matter, alkali-hydrolyzable nitrogen and available phosphorus content, which may be related to the utilization of soil organic matter by a large number of organic matter-decomposing microorganisms in the mushroom residue leading to nutrient consumption, while the combined application of high-dose biochar (MDB2) alleviated this effect, thus increasing organic matter content and alkali-hydrolyzable nitrogen content. PCA analysis based on soil bacterial OTUs found that there were significant differences in community structure among different treatments. Compared with CK, MD soil bacterial Shannon diversity index decreased and Simpson dominance index increased, while MDB1 and MDB2 significantly improved soil bacterial diversity. Compared with MD, they significantly increased beneficial plant growth-promoting bacteria such as Pedomicrobium, Streptomyces, MND1, Nocardioides and Pseudomonas. RDA analysis showed that soil alkali-hydrolyzable nitrogen was the main environmental factor affecting bacterial community structure. In summary, although mushroom residue application alone has yield-increasing potential, its effect on soil improvement is poor; combined application of biochar can significantly increase soil pH, available potassium content, improve soil microbial diversity, promote the enrichment of beneficial microorganisms, thereby increasing leaf chlorophyll content, enhancing leaf photosynthesis, and ultimately promoting a significant increase in P. amaryllifolius yield. Therefore, the synergistic application of biochar and mushroom residue is an efficient and safe soil improvement strategy, providing green and sustainable technical support for efficient cultivation of Pandanus.

Ten melon germplasm accessions were treated under simulated low-temperature and weak-light conditions in this study to establish an efficient identification system for low-temperature and weak-light tolerance of melon (Cucumis melo L.) germplasm at the seedling stage. The relative changes in 8 growth indicators (including plant height, stem diameter, leaf area, etc.) and 10 physiological indicators (including chlorophyll content, root activity, relative electrical conductivity, etc.) were determined, and the damage indexs were calculated to initially evaluate the low-temperature and weak-light tolerance of each germplasm. Based on the membership function method in fuzzy mathematics, 19 identification indicators were standardized. Dimensionality reduction was performed via principal component analysis (PCA), and 5 principal components with strong correlations to the low-temperature and weak-light tolerance index, peroxidase (POD) activity, root length, root activity, and soluble protein content were extracted (cumulative contribution rate: 87.026%). Cluster analysis was conducted on the 10 melon germplasm accessions, which were classified into three groups. Group Ⅰ including Vedrantais and M18, was classified as strong low-temperature and weak-light tolerant. Group Ⅱ includding IranH, Topmark, M4 and Nantais oblong, was classified as moderate low-temperature and weak-light tolerant. Group Ⅲ including PI124111, MR1, M76 and PMR5, was classified as weak low-temperature and weak-light tolerant. Finally, stepwise linear regression was used to establish a prediction model for low-temperature and weak-light tolerance of melon at the seedling stage, D=-0.058+0.008X₁₅+0.442X₉+0.058X₁-0.017X₁₉ (R²=0.998, P<0.001), X₁₅ is proline content; X₉ is root length; X₁ is low temperature and low light tolerance index; X₁₉ is peroxidase activity. To verify the reliability of the above identification results, the expression patterns of CmADF1 and CmCYP195 (key genes responding to low-temperature and weak-light stress) were analyzed in germplasm accessions M4, PI124111 and PMR5 at different time points after low-temperature and weak-light treatment. The results showed that the expression characteristics of CmADF1 and CmCYP195 were consistent with the identified low-temperature and weak-light tolerance types of the germplasm, which further confirmed the reliability of the identification system. The results could serve as identification criteria for evaluating low-temperature and weak-light tolerance of different melon germplasm accessions and provide breeding materials for subsequent improvement of melon varieties with low-temperature and weak-light tolerance.

The regulatory effects of exogenous homogentisic acid (HGA) on plant growth, anthocyanin synthesis, and the antioxidant system at phenotypic, physiological and gene expression levels using one-leaf seedlings of Wushansimiao (R534) were studied to explore the role of HGA in rice salt stress response. The results showed that under 140 mmol/L NaCl stress and treatment with 0.25 mmol/L HGA significantly improved the salt tolerance of rice seedlings. On the 3^rd day after treatment, plant height, root length, fresh weight and dry weight increased by 43.95%, 60.00%, 41.86% and 76.38%, respectively, compared to the control without HGA. After 7 days of treatment and 7 days of rewatering, the survival rate of seedlings increased by 56.69%. RT-qPCR analysis revealed that HGA significantly upregulated the key genes involved in anthocyanin biosynthesis in leaves, including OsPAL3, OsCHS8, OsCHI, OsF3H, OsDFR6, OsANS1 and OsUF3GT. Anthocyanin content increased by 15.18%, 24.58% and 39.56% on the 3^rd, 5^th and 7^th day, respectively. On the 3^rd day, the accumulation of reactive oxygen species (H₂O₂ and ) and malondialdehyde (MDA) content decreased, while the activities of antioxidant enzymes SOD, POD and CAT significantly increased. This study preliminarily clarified that HGA could activate the anthocyanin biosynthesis pathway under salt stress to enhance antioxidant capacity, laying a foundation for further understanding the physiological role of HGA.