The application of exogenous trace elements can help improve the yield and quality of certain economic crops. However, the effects of exogenous zinc on the photosynthetic physiological characteristics and volatile compounds in Pandanus amaryllifolius Roxb. (Pandan) remain unclear. Therefore, this study established a field control experiment on Pandan leaves with different zinc spray treatments, 0 kg/hm² (CK), 3.2 kg/hm² (Zn₁), 4.0 kg/hm² (Zn₂), and 4.8 kg/hm² (Zn₃). The aim was to monitor the temporal and spatial dynamics of the photosynthetic rate and volatile compounds content following zinc fertilization. The results indicated that Zn₂ treatment significantly increased the chlorophyll content, promoted the leaf growth and development, and resulted in the highest leaf count at all stages post-treatment. However, prolonged high-concentration zinc fertilization could inhibit leaf expansion and plant height. The photosynthetic physiology, photosynthetic rate, stomatal conductance, and transpiration rate increased with zinc concentration. Around 30 days post-treatment, Zn₃ treatment performed the best, followed by Zn₂ treatment. Zinc fertilization increased the content of volatile compounds. Zn₂ and Zn₃ treatments were notably effective in promoting the synthesis of several volatile compounds, such as 2-acetyl-1-pyrroline, 2-hexadecanol, and ethyl palmitate. Under Zn₂ treatment, the content of 2-acetyl-1-pyrroline and 2-hexadecanol increased by 203% and 80.89%, respectively, compared with CK. Zn1 treatment significantly increased 2-acetyl-1-pyrroline content at 20 days post-application, while Zn₃ treatment significantly promoted the synthesis of squalene, neophytadiene, and phytol. Correlation analysis showed that the main volatile compounds in Pandan interacted with agronomic traits and photosynthetic physiological indicators. The increase in photosynthetic rate and leaf count promoted the synthesis of squalene and neophytadiene, whereas elevated intercellular CO₂ concentration might inhibit the accumulation of 2-acetyl-1-pyrroline and squalene. This study demonstrates that appropriate zinc fertilization can effectively enhance photosynthesis, increase chlorophyll content, promote leaf growth, and boost the content of volatile compounds and characteristic volatile compounds in Pandan. The findings would provide a theoretical basis for optimizing high-efficiency cultivation techniques for Pandan and promoting the sustainable development of Pandan-related industries.

Xinglong coffee, a pillar of the local characteristic agriculture in Wanning, faces severe threats to its sustainable production from anthracnose. This disease can cause leaf scorching, branch ulcers, and berry brown rot, making it one of the major diseases in the industry. In this study, samples of coffee anthracnose were collected from the main coffee-growing areas in Wanning and the pathogenic fungi were isolated. The pathogenic fungi were identified through the combined analysis of multiple genes, including ITS, TUB2, CHS-1, ACT and GAPDH. Furthermore, a rapid detection system based on the loop-mediated isothermal amplification (LAMP) technique was established. 50 typical disease samples were collected, and through tissue separation and purification, a total of 24 Colletotrichum isolates were obtained. The pathogen population structure in the five planting areas of Wanning was clarified to comprise four species of Colletotrichum spp.: C. tropicale, C. karstii, C. fructicola, and the dominant species was C. siamense (accounting for 45.8%). Based on the specific region of TUB2, a specific LAMP primer set (Tub-L1) was designed and screened. The optimized reaction parameters were established as follows: isothermal amplification at 63 ℃ for 50 minutes, outer-inner primer concentration ratio of 8∶1, Mg²⁺ 8 mmol/L, dNTPs 0.8 mmol/L, and without the need for betaine. Validation experiments demonstrated that the detection sensitivity of this system reached 100 pg/μL (10 times higher than conventional PCR). Furthermore, the system showed no positive reactions to seven closely related species within Colletotrichum spp. (including C. tropicale, C. fructicola, C. karstii) or seven non-target plant pathogens [including Hemileia vastatrix (coffee leaf rust), Diaporthe phaseolorum, and others]. Using the optimized LAMP detection system, the diseased leaf samples collected from the field were analyzed. C. siamense was successfully detected in all samples, and the results were completely consistent with those obtained by conventional PCR methods. In summary, the LAMP-based rapid detection system for Colletotrichum sp. established and optimized in this study demonstrates significant advantages, including simplified operation, high reaction efficiency, strong specificity, enhanced sensitivity, and visualizable results, making it highly suitable for field-based rapid detection of C. siamense. This system would provide reliable technical support for the precise identification and efficient detection of coffee anthracnose fungus, and have important practical significance and application value for the early warning, disease monitoring, and integrated control of coffee anthracnose.

Odontoglossum ringspot virus (ORSV), one of the major pathogens affecting orchids, seriously degrade the ornamental and economic value of orchids by causing leaf chlorosis, mottling, and floral deformities. To enable early-stage diagnosis, this study developed a rapid reverse transcription-recombinase polymerase amplification (RT-RPA) assay targeting ORSV. Primers and a fluorescent probe were designed based on conserved regions of the ORSV coat protein (CP) gene. Specificity, sensitivity and field applicability of the assay were systematically validated in this study. Results identified F1/R1 as the optimal primer pair, enabling amplification within 20 minutes at 41 ℃. The method exhibited high specificity, distinguishing ORSV from Cymbidium mosaic virus and Cucumber mosaic virus, and achieved a detection limit of 2.8×10^–5 ng/μL total RNA. Practical verification result of 20 Phalaenopsis field samples showed 100% concordance with TaqMan qPCR results. The RT-RPA assay would provide a rapid, sensitive, and field-deployable tool for ORSV surveillance, supporting timely disease management and sustainable orchid cultivation. Its simplicity and reliability make it particularly valuable for large-scale screening in industrial orchid production systems.

The three-year-old Phyllostachys prominens in the coastal sandy land of Dongshan was used to determine the contents of chlorophyll (Chl), soluble protein (SP), soluble sugar (SS), proline (Pro), and malondialdehyde (MDA) in the leaves in different seasons, and to explore the difference of physiological indexes of bamboo leaves under different seasonal environmental conditions, and analyze its adaptation in different seasonal environments in coastal sandy land, provide theoretical basis for constructing a more complete, abundant and economically valuable coastal shelter forest ecosystem. The chlorophyll a (Chla) and chlorophyll b (Chlb) had the same seasonal variation trend, and reached the highest content in summer. The total chlorophyll content in summer was 24.54%, 11.39% and 21.2% higher than that in autumn, winter and spring, respectively. The content of SP was the highest in winter and the lowest in summer. The content of SP in winter was 50.65%, 131.42% and 18.52% higher than that in spring, summer and autumn, respectively. The content of SS in summer was significantly higher than that in other seasons, which was 269.83%, 112.65% and 99.93% higher than that in spring, autumn and winter, respectively. The content of MDA decreased gradually from autumn to summer, and the difference between seasons was significant. The content of Pro was the highest in summer, which was 18.37%, 44.06% and 23.13% higher than that in spring, autumn and winter, respectively. Temperature and precipitation had significant effects on soluble sugar, soluble protein and malondialdehyde content. In the coastal area of Dongshan, during the same period of temperature and precipitation, compared with the highest and lowest periods of temperature (precipitation), the content of soluble sugar increased by 99.93%, the content of soluble protein decreased by 56.79%, and the content of malondialdehyde decreased by 52.72%. In summary, P. prominens ensures the smooth progress of photosynthesis by regulating chlorophyll content, and adapts to seasonal changes by regulating the content of osmotic substances. Photosynthesis and osmotic adjustment system are the key mechanisms for P. prominens to adapt to adversity environment.

Rubber tree is one of the “Three Trees” of Hainan, and it is cultivated in several cities and counties across the island. Rubber tree powdery mildew is a typical airborne fungal disease that occurs annually, severely affecting rubber yield and tree health. This study analyzed the potential airborne dispersal pathways of rubber tree powdery mildew spores from February 1, 2021, to March 31, 2023, with a focus on Baoting as the starting point for spore diffusion. Using the Lagrangian Hybrid Single-Particle Trajectory (HYSPLIT) model, airflow trajectories at various altitudes were simulated, and trajectory clustering analysis was performed with TrajStat software and the MeteoInfoMap platform to identify representative air mass transport paths. Results indicated that Baoting was the earliest outbreak area of rubber tree powdery mildew in Hainan, where airflows predominantly spreaded southwestward and northwestward, covering neighboring regions such as Sanya, Ledong and Wuzhishan. This suggests that spore dispersal via airflow may accelerate disease progression in the areas. Additionally, the study found that the spatiotemporal dynamics of spore spread primarily occurred from January to April each year, coinciding with the spring temperature and humidity conditions in Hainan and the phenological stages of rubber trees. The average budburst and disease onset times in Baoting preceded those in other regions, further the importance of Baoting as an early monitoring and warning site for powdery mildew in rubber trees. In conclusion, this study reveals the regional spatiotemporal transmission patterns of powdery mildew spores in Hainan island through the simulation and analysis of airborne spore dispersal from Baoting. The findings would provide scientific evidence and technical support for the formulation of targeted regional control measures, contributing to the effective management of powdery mildew and the stable development of Hainan’s rubber industry.

Bok choy (Brassica campestris ssp. chinensis) is an important vegetable crop native to China and is also one of the leafy vegetables favored by people in Hainan. The high temperature and intense sunlight in Hainan’s summer greatly affect the normal growth and development of bok choy, reducing its yield and quality. At present, research on the growth of bok choy under abiotic stress is mostly focused on heat tolerance, while study on the response of bok choy to strong light stress is relatively scarce. To investigate the molecular regulatory mechanisms of bok choy in response to strong light, this study used the variety ‘Aijiao Huang’ as the research object. We compared and analyzed the physiological indicators, photosynthetic characteristics, and expression levels of response genes in the leaves of bok choy under normal light [300 μmol/(m²·s)] and strong light [1500 μmol/(m²·s)]. Under strong light, dry weight of bok choy significantly increased, and the R/S ratio gradually increased from day 0 to day 10, followed by a significant decrease on day 15. The chlorophyll content significantly decreased in the later stages. Pn, Tr, and Gs significantly increased on day 5 under strong light, and then gradually decreased, while Ci remained relatively stable. Using RNA-seq technology for transcriptome sequencing, a total of 2324 differentially expressed genes (DEGs) were identified. GO and KEGG enrichment analyses revealed 14 DEGs related to photosynthesis and photoprotection mechanisms, and 6 DEGs associated with antioxidant enzyme activity. 8 DEGs were selected for qRT-PCR validation, which were consistent with the transcriptome sequencing results, confirming the reliability of the transcriptome analysis. Strong light had a certain impact on the antioxidant enzyme activity of bok choy. During days 0-5, the activity of SOD, POD, and CAT was induced to increase, while from days 5-15, the activity of SOD and POD gradually decreased, and CAT showed an upward trend. In summary, bok choy may rapidly respond to photosynthesis-related mechanisms and regulate antioxidant enzyme activity under strong light conditions, thereby alleviating the inhibitory effects of strong light on growth and enhancing the seedlings adaptability to strong light.

The response of nitrogen, phosphorus and potassium nutrient accumulation, yield and output value of flue-cured tobacco in multi-planting area of tobacco-rice to the nitrogen application and basal-topdressing ratio was studied to provide a theoretical basis for the development of fertilizer application strategies for paddy-tobacco. Cultivar Yunyan 87 was used and three nitrogen application treatments (150 kg/hm², 165 kg/hm² and 180 kg/hm²) and two basal-topdressing ratio of nitrogen treatments (3∶7 and 5∶5) were set up. The effects of nitrogen application and basal-topdressing ratio on the accumulation and distribution of nitrogen, phosphorus and potassium nutrients, also on yield, output value and fertilizer utilization of paddy-tobacco, and the contribution rate of nitrogen application and basal-topdressing ratio and the interaction to the accumulation of nitrogen, phosphorus and potassium were analysed using the effect value (). The results showed that nitrogen, phosphorus and potassium nutrients accumulated by flue-cured tobacco were mainly allocated to tobacco leaves, and the proportion allocated to tobacco leaves decreased with the growth of flue-cured tobacco. With the increase of nitrogen application, nitrogen accumulation and tobacco yield and output value of flue-cured tobacco increased, meanwhile reducing the proportion of base fertilizer nitrogen could significantly increase the nitrogen accumulation of the tobacco plant and yield and output value of tobacco leaf, also significantly increase the utilization rate of nitrogen fertilizer and the partial productivity and the partial production benefit of nitrogen, phosphorus and potassium fertilizers. On average, nitrogen application and basal-topdressing ratio and the interactions contributed 42.89%, 29.63% and 27.47% to nitrogen accumulation of flue-cured tobacco, and 38.62%, 24.12% and 37.25% to phosphorus accumulation, and 41.22%, 21.24% and 37.54% to potassium accumulation, and 62.13%, 6.34% and 31.53% to yield, and 47.30%, 14.74% and 37.95% to output. Throughout the reproductive period, nitrogen accumulation was relatively high in the nitrogen treatments of 180 kg/hm² and the 3∶7 basal-topdressing N ratio. In the rosette stage and dome stage, the accumulation of phosphorus and potassium was relatively high in the nitrogen treatments of 180 kg/hm² and 3∶7 basal-topdressing N ratio. The highest yield and output value were achieved in the nitrogen treatments of 180 kg/hm² and 3∶7 basal-topdressing N ratio. Therefore, in the multi-planting area of tobacco-rice, the nitrogen application has the greatest influence on the accumulation of nitrogen, phosphorus and potassium nutrients in flue-cured tobacco, and the reduction of the proportion of base fertilizer nitrogen from 50% to 30% can increase the accumulation of nitrogen of tobacco leaf, which is conducive to the improvement of the yield and output value of tobacco leaf and the utilization rate of nitrogen fertilizer.

The study investigated the effects of different exogenous hormones on somatic embryo maturation to improve the maturation efficiency of somatic embryos and increase the yield of normal mature embryos and embryo-derived plantlets in the rubber tree variety Yunyan 73-477. Primary somatic embryos from anthers at different developmental stages were cultured on media supplemented with various types and concentrations of exogenous hormones. The maturation rates, normal mature embryo rates, and plantlet conversion rates were comprehensively analyzed to compare maturation efficiencies and optimize hormone combinations for different developmental stages. The maturation efficiency increased with embryo developmental progression, with cotyledon embryos showing optimal results. The maturation rates exceeded 50% [range: 50.74%-74.83%, mean: (66.25±6.98)%]. Most mature embryos displayed bipolar structure and could normally germinate into complete plantlets, with normal mature embryo rates ranging from 35.0%-59.96% [mean: (47.80±6.89)%] and plantlet conversion rates ranging from 15.62%-49.17% [mean: (26.67±8.99)%]. Torpedo-shaped embryos showed intermediate performance, while heart-shaped embryos performed the poorest, both with maturation rates below 31% [means: (30.05±12.68)% and (29.33±10.93)%, respectively]. Most mature embryos from the stages were malformed (leaf-like or callus-like) and failed to develop into complete plantlets. The normal mature embryo rates were only (15.64±7.01)% and (5.46±4.28)%, respectively, 32.16% and 42.34% lower than cotyledon embryos. Plantlet conversion rates were (7.22±3.41)% and (0.83±0.80)%, merely 0.27-fold and 0.03-fold of cotyledon embryos. Optimal exogenous hormones varied with developmental stages: heart-shaped embryos required 6-BA 0.5 mg/L+NAA 0.15 mg/L+KT 0.25 mg/L, torpedo-shaped embryos needed ABA 0.4 mg/L+GA₃ 0.5 mg/L+6-BA 2.0 mg/L+NAA 0.15 mg/L, and cotyledon embryos performed best with ABA 0.1 mg/L+GA₃ 1.0 mg/L+6-BA 1.5 mg/L+NAA 0.2 mg/L.

Sugarcane is a crucial crop for both sugar and bioenergy production, with sugar accumulation and cell wall formation being critical biological processes during its growth and development. This study employed transcriptome sequencing on the ROC22 sugarcane variety, collecting samples from leaves at the 1^st, 3^rd, and 5^th nodes, bark tissues at the 3^rd, 5^th, 7^th, 11^th, and 17^th internodes, and pith tissues at the 1^st, 3^rd, 5^th, 7^th, 11^th, and 17^th internodes. A comprehensive analysis of 42 transcriptome datasets using Weighted Gene Co-expression Network Analysis (WGCNA) revealed 34 distinct co-expression modules. Notably, the midnight blue, purple, and magenta modules demonstrated significant and specific correlations with the 1^st node leaf, 7^th internode pith, and 5^th internode bark, respectively. KEGG and GO enrichment analyses indicated that the modules participated in tissue-specific biological processes. The blue, yellow, turquoise, and black modules were primarily expressed in leaves, young pith, immature internodes, and bark, respectively. Within the blue module, key enzymes implicated in photosynthesis were identified, such as LFNR1, PSAK, PETE, PSAN, and NADP-ME4, which are essential for the initial production and accumulation of sugar in sugarcane. The yellow module featured a sucrose metabolism network centered on SUS4, including SWEET2 and an array of sugar transport-related enzymes and proteins, suggesting that the pith serves as the primary site for sugar transport and storage in sugarcane. The turquoise module contained glycoproteins and enzymes potentially involved in the synthesis and modification of the primary cell wall. Meanwhile, transcription factor NST1, which regulates secondary cell wall biosynthesis, along with other cell wall-modifying enzymes in the black module, may contribute to cell wall deposition in the cortex, providing mechanical strength and a barrier against external stresses for sugarcane. The findings would provide important references for studying the regulatory networks of sugar accumulation and cell wall formation in sugarcane.

Plant fructokinase (FRK) specifically catalyzes fructose phosphorylation into glycolysis pathway, which is a key enzyme for fructose metabolism and soluble sugar accumulation. This study elucidated the expression pattern and enzyme characteristics of red pitaya HpFRK2 gene, which would provide a theoretical basis for understanding the molecular mechanism of fruit soluble sugar accumulation and improving fruit quality. HpFRK2 was cloned from red pitaya ‘Zihonglong’, and its expression pattern was analyzed by real-time fluorescence quantitative PCR. Subcellular localization was performed by transiently expressing in tobacco mesophyll cells, and the recombinant protein was obtained by prokaryotic expression and its enzyme activity was detected. The open reading frame (ORF) was 1026 bp, encoding 341 amino acids. The relative molecular weight of HpFRK2 was 36.95 kDa, and the theoretical isoelectric point was 5.94. Phylogenetic analysis showed that HpFRK2 was closely related to cassava MeFRK2, tomato SlFRK1, apple MdFRK1 and Arabidopsis AtFRK1. HpFRK2 contained a conserved domain of the phosphofructokinase type B (pfkB) family. The expression level of HpFRK2 was the highest at 20 days of fruit development, gradually decreased with fruit development, and the expression level was the lowest at 30 days. In addition, the expression of HpFRK2 in stems was significantly lower than that in fruits. Subcellular localization results showed that HpFRK2 was mainly located in the cytoplasm. A prokaryotic expression vector was constructed and expressed in Escherichia coli, and recombinant protein was successfully induced. The results of enzyme activity characteristics showed that HpFRK2 specifically catalyzed fructose phosphorylation, fructose did not have the substrate inhibition on its enzyme activity, and the Km value for fructose phosphorylation was 1.84 mmol/L. The results showed that HpFRK2 was located in the cytoplasm, specifically catalyzed fructose phosphorylation, was mainly expressed during the veraison period (20-23 d after flowering) of red pitaya fruit, and may negatively regulate fructose accumulation in fruit.