Guangdong and Guangxi are the major production regions of pitaya and the common area for pitaya canker. Understanding the genetic diversity of Neoscytalidium dimidiatum is of great significance for the disease prevention and control. This research focused on four geographical population of N. dimidiatum mainly collected from Guangxi and Guangdong. To obtain the genetic fingerprints of N. dimidiatum, the isolates were amplified using ISSR genetic molecular markers and further analyzed the genetic diversity. The tested N. dimidiatum isolates were amplified with eight ISSR primers, resulting in 203 bands and the percentage of polymorphic sites was 31.7%, with the genetic similarity coefficient for any two germplasm resources ranged from 0.7619-1.0000. When the genetic similarity coefficient was 0.90 on the UPGMA cluster, all isolates could be divided into three groups, but the genetic groups were not closely related to the geographical distribution. The results of principal component analysis indicated considerable overlap between the four geographical groups and there were no relatively independent geographical poputation. This study proved that there existed lower level of genetic polymorphism in the isolates and there was frequent exchange of inoculum source between different places. The study would provide the scientific basis for researching the genetic architecture and pathogen surveillance of pitaya canker pathogen N. dimidiatum.

This study aimed to identify the key factors influencing vegetation changes on Hainan Island under Typhoon Yagi, determine the disaster thresholds, and provide scientific support for typhoon disaster prediction, assessment, and mitigation. Using the GEE platform, Sentinel-2 NDVI data from August 19 to September 18, 2024, covering the period before and after Typhoon Yagi landfall, were analyzed in conjunction with topographic and meteorological variables (such as typhoon path, maximum wind speed, minimum pressure, and precipitation). An XGBoost model was applied to predict post-typhoon NDVI changes, and SHAP analysis was used to explore the nonlinear effects of meteorological factors. The XGBoost model yielded a coefficient of determination (R²) of 0.75 and a root mean square error (RMSE) of 0.12, indicating a high prediction accuracy for post-typhoon NDVI changes. Feature importance analysis within the XGBoost model revealed that pre-typhoon NDVI, typhoon distance, and maximum wind speed were the primary influencing factors, while slope and aspect had a weaker effect. Further SHAP analysis confirmed that typhoon distance and maximum wind speed were the key meteorological factors driving NDVI changes. When the typhoon distance was less than 76.4 km, NDVI showed a significant decline, while NDVI changes intensified when the maximum wind speed exceeded 29.3 m/s, highlighting the crucial role of strong winds in vegetation damage. Regions within 76.4 km (approximately within the 11th wind radius) of the typhoon's path and with maximum wind speeds greater than 29.3 m/s experienced severe vegetation damage. It is recommended that the high-risk areas be prioritized in typhoon warnings and pre-disaster defense measures.

Lignin serves a crucial defensive function in cassava's resistance to harmful organisms. Among the genes involved in lignin biosynthesis, shikimate hydroxycinnamoyl transferase (HCT) and caffeoyl coenzyme A-O-methyltransferase (CCoAOMT) are of particular importance. Yet, their specific roles in cassava's resistance to the insect pest P. marginatus remain to be fully elucidated. To elucidate the anti-insect defense mechanisms of cassava against P. marginatus, we conducted comparative studies using insect-resistant cultivar C1115 and susceptible cultivar KU50. Life table analysis revealed significant cultivar-dependent effects on pest developmental biology. Specifically, C1115-fed females exhibited significantly prolonged developmental duration (38.50 days in C1115 vs. 28.86 days in KU50), significantly reduced fecundity (221 eggs in C1115 female vs. 331 eggs in KU50 female), and significantly shortened adult longevity (4.30 days in C1115 vs. 8.83 days in KU50). Notably, population growth parameters demonstrated significant comprehensive suppression in C1115 cohorts: net reproductive rate (R₀=224.13 in C1115 vs. 330.67 in KU50), intrinsic growth rate (r_m=0.10 d^‒1 in C1115 vs. 0.12 d^‒1 in KU50), and finite growth rate (λ=1.11 d^‒1 in C1115 vs. 1.12 d^‒1 in KU50). Furthermore, extended generation time (T=50.25 in C1115 vs. 49.98 days in KU50) and doubling time (Dt=6.44 in C1115 vs. 5.97 days in KU50) were observed, indicating multilevel inhibition of pest population dynamics by C1115. Molecular characterization showed progressive downregulation of lignin biosynthesis genes HCT and CCoAOMT post-infestation in C1115. Although both cultivars exhibited suppression patterns, C1115 maintained significantly lower expression levels (52.99%, 66.81% of KU50) and enzymatic activities (74.42%, 73.91% of KU50) across timepoints. Using Spearman correlation analysis, it was found that both HCT and CCoAOMT gene expression levels and the activity of their encoded enzymes were negatively correlated with cassava resistance to P. marginatus. This suggests that the downregulation of these two genes may affect lignin accumulation in cassava leaves and the level of insect resistance defense responses. This study has laid a solid preliminary work foundation for in-depth analysis of the molecular mechanisms by which lignin regulates cassava's defense responses against P. marginatus

It is necessary to establish a sensitive, selective, efficient and accurate method for the simultaneous detection of multiple antibiotic residues in soil. In this study, the method of solid phase extraction-high performance liquid chromatography-tandem mass spectrometry (LC-MS/MS) for the determination of 20 antibiotics simultaneously in soil was established by optimizing the extraction conditions (extractant type, extraction method, shading and overnight) and the purification conditions (cartridge type). Under the optimized analysis conditions, the target antibiotics showed good linearity in the linear range of 0.10-100.00 μg/kg, with R² ranging from 0.9951-0.9999. The recovery ratio ranged from 62%-116%, the relative standard deviation was 0.9%-16.8%, the limit of detection was 0.01-0.50 μg/kg, and the limit of quantification was 0.04-2.00 μg/kg. The method was applied for the detection of antibiotic residues in soil samples collected from greenhouse vegetable bases in Wuqing district, Tianjin, China. It showed that 4 classes of antibiotics were detected in the soil, and up to 16 of target antibiotics could be detected simultaneously. The total residual concentration of antibiotics in the soil varied from 2.52-142.00 μg/kg. The highest concentration of individual antibiotic was 105.00 μg/kg (oxytetracycline). The method established in the study is aim to provide reference for the formulation of the standard for the simultaneous detection of multiple antibiotic residues in soil and provide methodological basis for the prevention and control of emerging contaminants.

The study of methane (CH₄) emission flux from paddy fields is an important part and hot topic in the current study of carbon cycle in terrestrial ecosystems. The multi-time scale characteristics of CH₄ emission flux and its influencing factors [gross primary productivity (GPP), latent heat flux (LE), air temperature (TA), soil temperature (TS)] in paddy fields were analyzed based on wavelet analysis and eddy covariance flux observation data. The CH₄ emission flux and its influencing factors of paddy field ecosystems had obvious seasonal variation characteristics. The CH₄ emission flux from paddy fields in the rice growing season showed obvious single-peak diurnal variation characteristics, while the CH₄ emission flux from paddy fields in the non-rice growing season was low, and the diurnal variation characteristics were not obvious. GPP, LE, TA and TS showed obvious single-peak diurnal variation patterns. Based on continuous wavelet transform and wavelet variance curve analysis, CH₄ flux, GPP, LE, TA and TS had an obvious 1-day cycle during the rice growing season (July—November), while GPP, LE, TA and TS also had a half-day cycle, and TA and TS also had a long-term cycle of 4 days. From the cross wavelet transform and wavelet coherence spectrum analysis, the resonance period between CH₄ flux and GPP, LE, TA and TS was about 1 day. There was a significant resonance relationship in this frequency domain, and oscillation cohesion and coherence were the strongest. However, in the high-frequency band area, there was also a secondary resonance period of about 0.5 days between CH₄ flux and GPP, LE, TA and TS. In addition, in other frequency bands, the resonance energy of CH₄ flux and GPP, LE, TA and TS was low, but in the resonance period of 4 days and 7-10 days, CH₄ flux had good coherence with TA and TS from mid-August to mid-October. This study analyzed the multi-time scale characteristics of CH₄ flux and its influencing factors from paddy fields and would provide a scientific reference for studying the quantitative relationship between CH₄ flux and its driving factors at different time scales.

The study prepared slow-release fertilizers with different ratios of zeolite and nano-zeolite and compared them with conventional urea fertilizers to study the effect of zeolite and nano-zeolite as urea carriers on soil nutrient leaching, including nutrient release patterns, leaching characteristics, and impacts on soil nutrient content. A soil column leaching experiment was conducted with seven treatments, conventional urea (CK) and slow-release fertilizers with different ratios of zeolite (ZU₁, ZU₂, ZU₃) and nano-zeolite (nZU₁, nZU₂, nZU₃). The study analyzed the dynamic changes and cumulative leaching amounts of ammonium nitrogen, nitrate nitrogen, total nitrogen, and total phosphorus in the leachate and measured the soil nutrient content after leaching. Zeolite and nano-zeolite-based slow-release fertilizers significantly prolonged fertilizer effectiveness and reduced the concentration of ammonium nitrogen, nitrate nitrogen, total nitrogen, and total phosphorus in the leachate (P<0.05). Treatments with 50% zeolite (ZU₃) and 50% nano-zeolite (nZU₃) were the most effective in reducing nutrient leaching. Specifically, ZU3 reduced ammonium nitrogen, nitrate nitrogen, total nitrogen, and total phosphorus in the leachate by 7.19%, 6.54%, 14.51% and 9.72%, respectively, while nZU₃ reduced them by 7.20%, 6.91%, 12.84% and 6.36%, respectively. The slow-release fertilizers also significantly increased soil nitrogen content, with total nitrogen in ZU₃ and nZU₃-treated soils increasing by 14.88% and 19.83% compared to the control. From the perspective of nutrient release patterns, it was observed that zeolite and nano-zeolite slow-release fertilizers exhibited a lower release rate in the early stages of the experiment. This is attributed to the strong adsorption properties of zeolite and nano-zeolite, which can effectively slow down the release of urea. The release peak of the fertilizers was delayed to 6–8 days, and the release became more steady in the later stages of leaching. This pattern suggests that the application of zeolite and nano-zeolite can effectively reduce the risk of nutrient loss due to leaching, thereby improving the utilization efficiency of fertilizers. Furthermore, the comparison between zeolite-based and nano-zeolite-based slow-release fertilizers revealed that the differences in reducing the leaching of ammonium nitrogen, total nitrogen, and total phosphorus were not obvious, but both of them had significantly better performance than conventional urea in terms of reducing nutrient leaching (P<0.05). In summary, the use of zeolite and nano-zeolite as urea carriers in slow-release fertilizers showed to be an effective strategy for delaying nutrient release, reducing nitrogen and phosphorus leaching, and enhancing soil nutrient content. The optimal results were achieved with a 50% zeolite and 50% nano-zeolite ratio, indicating a promising application potential in agricultural practices. This approach not only contributes to the sustainable management of soil fertility but also offers a potential solution for reducing the environmental impact associated with excessive fertilizer use.

Rubber plantations represent one of the most widespread planted forest ecosystems in tropical regions, playing a significant role in regional carbon cycles. Global climate change has led to increasingly frequent Compound Drought-hot Events (CDHEs), posing severe challenges to rubber plantation ecosystem functions. This study focuses on rubber plantations in Hainan Island, China. Utilizing standardized soil moisture and land surface temperature indices, we constructed a Compound Drought-Hot Index (CDHI) based on Copula functions to analyze the spatiotemporal dynamics of CDHEs from 2001 to 2020, validated against historical typical drought and hot events in Hainan. Using Gross Primary Productivity (GPP) as an evaluation metric, Copula-based conditional probabilities were applied to quantitatively assess GPP loss risks under different drought-hot scenarios and evaluate compound effects. Key findings include: (1) The developed CDHI accurately identified severe CDHEs during 2001—2020, with 2005 and 2020 being the most extreme years. (2) Across all intensity levels (mild, moderate, severe), CDHEs caused significantly higher probabilities of GPP loss in rubber plantations compared to isolated drought or hot events (P<0.001), confirming the synergistic amplification effect of compound events. (3) GPP loss risks exhibited distinct spatial heterogeneity influenced by regional topography-climate interactions, with northwestern rubber plantation areas showing consistently higher vulnerability across all scenarios. (4) CDHE impacts demonstrated marked seasonal differences, being substantially greater during the dry season (particularly April—May) than the rainy season, coinciding with critical phenological stages of rubber trees and forming sensitive windows of environmental stress. This study reveals the spatiotemporal differentiation of CDHE impacts on rubber plantation GPP, providing scientific foundations for regional climate-resilient management strategies and sustainable rubber plantation practices. It also offers methodological references for studying extreme climate responses in other tropical planted forest ecosystems.

In this study, three pitaya varieties, Spineless Yellow Dragon, Fuguihong, and Jindu No. 1, were selected as rootstocks. Through systematic observation and analysis of key indicators such as the growth potential of cuttings, grafting survival rate, fruit traits and quality, the most suitable rootstock variety was determined. Combined with the environmental conditions in Hainan, corresponding cultivation and management suggestions were put forward, aiming to provide solid technical support for the development of the pitahaya industry. Rootstock Fuguihong performed the best in the comprehensive survival rate of cuttings and grafting. The promoting effect of growth potential on pitahaya was significantly better than that of other rootstocks. Therefore, Fuguihong was determined as the optimal rootstock. Meanwhile, different rootstocks had a significant impact on the fruit traits of pitahaya (including 10 traits such as single fruit weight, peel weight, pulp weight, soluble solids, and total sugar). During the cultivation and management process, the suitable cultivation conditions for pitahaya in Hainan were summarized. Before cultivation, the field should be prepared and ridged first. 17 tons/667 m² of decomposed sheep manure and earthworm manure in a ratio of 3∶1 were spread over the whole garden. After rotary tillage and deep plowing, ridges with a width of 1m, a height of 25–30 cm, a row spacing of 2 m, and a ditch depth of 30 cm were built. Appropriate branches were selected as rootstocks. After treatment, they were planted at a density of 7 plants per meter in early September. In the first and second ten days of October, the “two-bud side flat grafting method” was used for grafting, and paper bags were put on. At the same time, a “丰” -shaped scaffold was built. Field management included soil covering or planting white clover and laying ground cloth, adjusting water and fertilizer according to the growth status, bending branches and leaving buds when the main branches exceeded the scaffold by 1 m, and closely monitoring common diseases such as sooty mold to ensure the orderly progress of all work, thus promoting the growth and development of pitahaya. This study would lay an important technical foundation for the vigorous development of the pitahaya industry in Hainan, effectively promote the progress of the domestic pitahaya cultivation industry, and significantly enhance its market competitiveness.

China is currently the largest sweet potato producer globally. The postharvest starch and soluble sugar (glucose, fructose, and sucrose) contents in storage roots not only influence sweet potato utilization and commercial value (including taste, nutritional quality, and food processing properties), but also affect sprouting, weight loss, and decay during storage and transportation. Studies on tubers/roots such as potato and carrot have demonstrated that vacuolar invertase (VIN) serves as the primary sucrose-cleaving enzyme determining postharvest sugar composition and content. However, the key sucrose-cleaving enzyme regulating postharvest sugar metabolism in sweet potato storage roots remains unclear. This study systematically investigated sugar metabolism characteristics in storage roots of ‘Kokei 14’, a major sweet potato cultivar in Hainan Province, under room temperature storage (25 ℃) and low-temperature storage (15 ℃), aiming to identify the principal sucrose-cleaving enzymes affecting postharvest sugar composition and content. Low-temperature storage enhanced preservation quality by reducing dry matter loss and sprouting rate through suppression of hexokinase (HK) activity and respiratory intensity. Compared with room temperature storage, low-temperature treatment induced greater increases in soluble sugar (glucose, fructose, and sucrose) content and more pronounced starch degradation, accompanied by significantly higher β-amylase activity, indicating that low-temperature storage promotes starch hydrolysis into soluble sugars. During room temperature storage, cell wall invertase (CWIN) and sucrose synthase (Sus) activities generally declined, while VIN activity initially increased before returning to baseline levels. Notably, cytoplasmic invertase (CIN) activity exhibited a continuous upward trend, suggesting CIN as the key sucrose-cleaving enzyme responsible for hexose accumulation under ambient conditions. Conversely, low-temperature storage induced continuous declines in all three invertase activities but progressively increased Sus activity, indicating Sus as the predominant enzyme mediating hexose accumulation under cold storage. Transcriptional analysis identified IbCIN4 as the key gene family members regulating CIN activity elevation at room temperature, while IbSus6 was determined as the primary regulator of Sus activity enhancement under low-temperature conditions. This study reveals that different postharvest storage temperature induces shifts in the predominant sucrose-cleaving enzymes governing hexose accumulation in sweetpotato storage roots. Notably, our findings contrast with previous reports on potato tubers under cold storage, demonstrating that Sus rather than VIN serves as the key enzyme regulating hexose content in sweetpotato roots under low-temperature conditions. The results would establish a theoretical foundation for future genetic engineering approaches to improve postharvest quality of sweetpotato storage roots.

Miniature inverted-repeat transposable elements (MITEs), as active mobile elements in eukaryotic genomes, provide novel molecular markers for germplasm genetic diversity analysis through the insertion polymorphisms. This study systematically identified hAT family MITE transposons in pitaya using bioinformatics approaches based on the whole-genome data of the Guanhua Bai cultivar. A total of 2350 candidate elements with complete terminal inverted repeats (TIRs) and target site duplications (TSDs) were screened, with an average of 213 elements per chromosome pair. Through sequence specificity and polymorphism analysis, 110 highly divergent loci (10 per chromosome pair) were selected for primer design, ultimately yielding 41 stable polymorphic hAT-MITE markers after PCR validation. Genome-wide scanning of 48 pitaya germplasms using the 41 primer pairs detected 81 polymorphic loci (polymorphism rate: 97.59%) via agarose gel electrophoresis. UPGMA cluster analysis revealed substantial genetic variation and diversity among the 48 accessions, with genetic similarity coefficients ranging from 0.57 to 0.91. At a genetic similarity threshold of 0.63, the germplasm resources were categorized into four genetically distinct groups. A digital fingerprinting system covering all germplasm resources was constructed using four core primer pairs (HU-MIT-02/06/26/75) based on the primer-band pattern combination method, achieving 100% cultivar identification accuracy. This study established the first hAT-MITE molecular marker system for pitaya, providing an efficient toolkit including a marker library and standardized identification protocols for precise germplasm classification, cultivar identification and varieties property protection of pitaya. The advancements is of significant application value for intellectual property protection in the pitaya seed industry.