The stochastic generalized Burgers-Huxley equation (SgBHE) introduces a power law parameter in its nonlinear terms, offering a robust framework for modeling reaction-convection-diffusion processes under uncertainty. While existing research has mainly focused on theoretical aspects, this work represents the first attempt to study the strong convergence of an explicit full-discrete scheme for the SgBHE driven by an additive fractional Gaussian noise. To approximate the continuous problem, we propose a temporal nonlinear-tamed exponential integrator combined with the spatial spectral Galerkin method. We derive strong error estimates and examine convergence rates for the fully discrete scheme, depending on the regularity of both time and spatial variables. In contrast to the stochastic Burgers-Huxley equation (SBHE), we develop a progressive technique to overcome the challenges posed by the generalized nonlinear terms, ensuring the boundedness of moments for the numerical solution. A numerical experiment is conducted to validate the theoretical results.
Soil gas diffusion plays a critical role in maintaining soil ecosystem functions. However, in non-rigid shrinkage and swelling soils, soil wetting not only leads to water blockages in gas transport pathways, but also induced soil particles expansion, resulting in compressed macropores and soil aeration deterioration. This study aimed to (1) separately quantify the dynamic characteristics of water-filled and air-filled pores during soil swelling using KI labeling and CT scanning, and (2) identify the critical air-filled pore characteristics for better predicting gas diffusivity. Undisturbed soil cores collected from the subsoil layer in a Vertisol under tillage and fertilization treatments were used to investigate changes in pore characteristics and the relative gas diffusivity coefficient (Ds/D0) during soil swelling. Our results showed that wetting cores with a 10% KI solution enabled accurate segmentation of water- and air-filled pores from CT images. Although soil swelling enlarged pores Ø < 30 μm micro-pores, it squeezed the Ø > 30 μm macropores, resulting in more dead pore ends and thereby increased macropore tortuosity but decreased pore connectivity. Under the coupled effect of water blockage and mineral swelling, air-filled pores showed a more rapid decline in porosity and connectivity than the macropores. It was only the percolating pores that connected the top and bottom surfaces of the cores maintained good aeration over the swelling process. Among pore characteristics, the critical air-filled porosity (AFP), defined as the porosity of percolating air-filled pores in limiting layer (the voxel layer with the minimum porosity), exhibited the closest relation with Ds/D0. A new model that incorporated the critical AFP, percolation air-filled pore tortuosity and the total porosity was established. Compared to the previous models, the new model provided better Ds/D0 prediction, exhibiting the highest R2 (0.792) and lowest RMSE (0.0077). Our results demonstrated that incorporating three-dimensional parameters of air-filled pores allows for better prediction of gas diffusion during soil swelling. Utilizing proper agricultural practices to form percolating air-filled pores represents as a potential strategy for improving soil aeration in the non-rigid Vertisol.
The combined treatment of 1-MCP and sucrose has been shown to delay postharvest senescence in leafy vegetables, but the underlying mechanisms remain unclear. In this study, pakchoi was treated with 1‑MCP, sucrose, or their combination and stored at 20 °C for 7 days. The combined treatment (MST) exhibited the strongest effect in comprehensively delaying leaf yellowing, reducing ROS accumulation, and suppressing the expression of chlorophyll degradation genes. MST also inhibited protease activity and downregulated the autophagy‑related gene BrATG7, while all treatments preserved RuBisCO activity relative to the control, with ST showing the strongest protective effect. Furthermore, MST effectively protected chloroplast ultrastructure. Correlation analysis revealed that BrATG7 expression was significantly associated with quality parameters and chlorophyll degradation. Overexpression of BrATG7 in pakchoi significantly reduced RuBisCO activity. Furthermore, the transcription factor BrNAC29 was shown to bind the BrATG7 promoter. These results suggest that the combined treatment delays senescence by simultaneously alleviating carbon starvation, suppressing ROS accumulation, and inhibiting the transcription factor BrNAC29. This, in turn, downregulates BrATG7, thereby limiting BrATG7-mediated autophagic degradation of chloroplast proteins. This study provides a novel mechanism for postharvest preservation and identifies BrATG7 as a potential molecular target.
Peach fruit is highly susceptible to postharvest soft rot caused by Rhizopus stolonifer, resulting in substantial economic losses. This study investigated the efficacy and mechanism of trans-2-hexenal (E2H) in controlling postharvest soft rot in peach fruit. Exogenous E2H treatment significantly inhibited R. stolonifer infection in peach fruit, reducing both disease incidence and lesion diameter. RNA-Seq revealed that E2H-induced differentially expressed genes were mainly enriched in pathways associated with disease resistance and pathogenesis-related (PR) proteins. In E2H-treated peach fruit, the expression levels of PpWRKY75, PpGLU1, and PpPR10 were significantly upregulated. Subcellular localization and transactivation assays demonstrated that PpWRKY75 was localized in the nucleus and possessed transcriptional activation activity. Dual luciferase reporter (DLR) assay and electrophoretic mobility shift assay (EMSA) further confirmed that PpWRKY75 can activate transcription of PpGLU1 and PpPR10 by binding to their promoters. Consistently, transient overexpression of PpWRKY75 in peach fruit significantly inhibited lesion expansion, reduced disease incidence, and markedly increased the expression levels of the defense-related genes PpGLU1 and PpPR10, thereby enhancing fruit disease resistance. Conversely, silencing PpWRKY75 in peach fruit weakened disease resistance. In addition, the transient expression analysis of PpGLU1 and PpPR10 indicated that they had the function of enhancing disease resistance. In summary, this study demonstrated that exogenous E2H activated PpWRKY75 expression, which in turn regulated the expression of PpGLU1 and PpPR10, thereby enhancing peach fruit resistance against R. stolonifer. These findings provide novel insights into the regulatory mechanism underlying postharvest soft rot resistance in peach fruit.
Under the dual pressures of rapid urbanization and climate change, cropland systems in China are facing escalating degradation risks, posing a critical threat to national food security. However, the compound driving mechanisms and nonlinear threshold effects underlying cropland degradation remain insufficiently understood, particularly across the contrasting contexts of southern and northern China. Therefore, this study constructed a multidimensional cropland degradation index and integrated interpretable machine learning (XGBoost–SHAP) with Generalized Additive Model (GAM) to identify dominant drivers and nonlinear thresholds from 2000 to 2020. Results indicated that, although cropland degradation in China generally followed a fluctuating mitigation trend, degradation levels remained consistently higher in the south (0.435) than in the north (0.398). Socioeconomic pressures dominated cropland degradation in southern China, whereas climatic stressors were more influential in northern China. Slope, temperature, and population density emerged as the primary drivers of cropland degradation at the nationwide, northern, and southern levels, respectively. At the county level, dominant drivers displayed marked spatial heterogeneity characterized by both longitudinal zonation and terrain dependence. GAM results further revealed complex nonlinear responses of cropland degradation to major drivers, with clear sensitivity intervals and time-varying thresholds. These thresholds differed substantially between southern and northern China. At the national scale, the cropland degradation index reached its peak at a population density of 75 persons/km², a temperature of 20°C, and a slope of 8°. Meanwhile, degradation risk shifted progressively from steep to moderate slopes and from sparsely populated to more densely populated areas. These findings provide a scientific basis for threshold-based early warning and regionally differentiated cropland protection policies, thereby supporting land degradation neutrality and sustainable development.
