Search Results (11,392)

Effective weed control is essential for sustainable and safe rice production, particularly under the long-term and widespread use of chemical herbicides. Oilseed rape (Brassica napus L.) is one of the most important oil crops worldwide, and the oilseed rape–rice rotation system is widely practiced in China. It has been reported to exhibit strong allelopathy on various plants, but the feasibility of using its straw incorporation for weed control in transplanted rice fields remains unclear. In this study, a natural weed management strategy based on shallow tillage of oilseed rape straw (ORS) was evaluated through laboratory bioassays, greenhouse experiments, and field trials. The results indicated that soil decomposition liquids (SDLs) of ORS exhibited strong dose- and decomposition time-dependent allelopathic effects on seven paddy weed species, while rice showed markedly lower sensitivity. ORS incorporated at 700–1100 g/m² generally exhibited high integrated allelopathic inhibition (in lab) and population control effects (in greenhouse) on paddy weeds, especially Leptochloa chinensis (L.) Nees, Cyperus iria L., and Cyperus difformis L. Among the growth parameters of ORS allelopathic stress, root growth was the most sensitive indicator, followed by shoot growth and seed germination. Greenhouse experiments displayed variety-dependent impact on the transplanted rice seedlings, with Xiushui134 and Yongyou1540 showing relatively high tolerance. Field trials revealed that ORS incorporation at 1100 g/m² for 10 d achieved a satisfactory control of population (77.7–84.9%) and fresh weight (80.7–95.6%) across Gramineae, Cyperaceae and Broadleaf weeds, without adverse impact on the growth of transplanted rice seedlings (Yongyou1540). This treatment also significantly promoted theoretical grain yield by 13.4–19.4%. Overall, shallow tillage of oilseed rape straw provides a feasible and environmentally friendly weed control strategy for transplanted rice systems. Full article

Grasslands are key terrestrial ecosystems in which root dynamics regulate soil carbon and nutrient cycling. Although grazing constitutes the predominant land use practice in grassland ecosystems, its impacts on root dynamics remain inadequately elucidated, particularly across a gradient of grazing intensities. In this two-year field experiment, an improved root window method was applied to investigate the effects of four grazing intensities (no grazing, light grazing, moderate grazing, heavy grazing) on root production, root mortality, root standing crop, root turnover, and root lifespan in the saline–alkaline grassland in northern China. The results showed that root production and root mortality exhibited pronounced seasonal dynamics, with peaks in June and August for root production and in September for root mortality. These seasonal patterns were primarily driven by precipitation and were not significantly altered by grazing intensity. Moderate grazing significantly increased root production by 51.2% through changes in soil bulk density and selective livestock grazing, supporting the intermediate disturbance hypothesis. Root turnover was predominantly shaped by plant community composition and interannual precipitation, as opposed to grazing intensity. Overall, these findings indicate that moderate grazing promotes root growth, providing important insights into the sustainable utilization of saline–alkali grassland resources. In other words, appropriate measures must be taken to effectively manage grazing activities in the fragile saline–alkaline grasslands of northern China. Full article

Achieving sustainable development requires moving beyond pollution metrics to holistic measures, such as the load capacity factor (LCF), which balances ecological demand and supply. While recent studies have provided important insights into the determinants of LCF in OECD countries, further research is needed to incorporate additional determinants and updated estimation approaches. This study addresses this gap by examining the impacts of financial innovation, forestry, urbanization, population, and economic growth on the LCF in Organization for Economic Cooperation and Development (OECD) economies from 1990 to 2023. Using second-generation panel econometric methods, including tests for cross-sectional dependence, slope heterogeneity, second-generation unit roots, and cointegration techniques, this paper confirms a stable long-run relationship among the variables. The core analysis applies the method of moments quantile regression to uncover the heterogeneous effects across the LCF distribution. The results indicate that financial innovation consistently enhances the ratio of biocapacity to ecological footprint. In contrast, economic growth and urbanization exert significant negative pressure on the LCF, whereas population size shows a uniformly detrimental effect. Forestry has a positive but less pronounced influence. Robustness checks using fully modified ordinary least squares, dynamic ordinary least squares, and panel-corrected standard errors confirm these results. The present study concludes that targeted financial innovation and stringent urban demographic policies support OECD nations in improving ecological balance and reducing ecological deficits. Full article

Subsoiling can break the plough pan and improve the root growth environment. The effect of the traditional subsoiler is poor, as it relies only on the chisel tine, but pneumatic subsoiling can improve the soil structure more efficiently through the negative pressure generated by the jet hole. This research used computational fluid dynamics and the discrete element method to optimize the biomimetic structure of the jet hole, model the pneumatic subsoiling process at a depth of 330 mm, and observe the movement of soil particles as airflow passes through. The effect of the jet hole at different positions and sizes on the plough pan soil was analyzed, and fluid domains and measurement areas were set up to observe the upward movement, diffusion, stabilization, and settling of soil particles under the action of airflow. The results of the soil bin experiment validated the accuracy of the simulation model through draft force and vertical force, and the average error between the simulation and experimental data was 2.8%. The study revealed that the increase in the rate of soil porosity reached a maximum of 3.65% when the jet hole was positioned above the chisel tine with a radius of 4 mm. The biomimetic jet hole pneumatic subsoiler designed in this study, along with the established CFD-DEM coupled simulation model capable of predicting pneumatic subsoiling performance, can provide references for the design and application of a pneumatic subsoiler. Furthermore, it also provides a theoretical basis for understanding the mechanism of airflow on soil during pneumatic subsoiling operations. Full article

The global demand for Salvia miltiorrhiza Bunge in the botanical medicine market is steadily increasing. However, its production has long relied on asexual root propagation, making it highly susceptible to germplasm degradation. Transitioning to seed reproduction offers the advantage of genetic renewal, yet it is constrained by unstable seed vigor and slow seedling growth. In the present study, comprehensive physiological and microbiome analyses of S. miltiorrhiza seeds from 14 regions across 7 provinces in China were conducted to elucidate the association between the seed microbiome and vigor, and to identify plant growth-promoting (PGP) strains. The results demonstrated: (1) Seed physical traits and germination characteristics varied significantly across geographic origins. Seed vigor, exhibiting the highest coefficient of variation, served as a key parameter reflecting germination quality. (2) High-vigor seeds harbored distinct microbial communities characterized by higher diversity indices, greater network complexity, and the significant enrichment of potentially beneficial bacteria (e.g., Pseudomonas). (3) Through correlation-directed screening of isolated pure cultures, Pseudomonas mendocina P-6 and Enterobacter ludwigii BM-12 were identified as exhibiting robust, multi-trait PGP capacity. In planta validation showed that these two strains significantly promoted the growth of 1-month-old S. miltiorrhiza seedlings, increasing total fresh weight by 33.9–71.3%. This study reveals the microecological drivers of seed vigor and provides candidate strains for inoculant development, thereby supporting the sustainable, seed-based propagation of S. miltiorrhiza. Full article

To support low-cost, non-destructive crop growth monitoring, this study systematically compared different vegetation indices, voxel sizes, and camera angles using a point cloud voxelization approach combined with a vegetation index weighted canopy volume index (CVM_VI) to assess aboveground biomass (AGB) in winter oilseed rape (Brassica napus L.). Field experiments were conducted from 2021 to 2024 at the Yangma Experimental Base of the Chengdu Academy of Agricultural and Forestry Sciences. Red, green, blue (RGB) imagery of oilseed rape was acquired using an unmanned aerial vehicle (UAV) during the following five key growth stages: seedling, bolting, flowering, podding, and maturity. Collected images were processed to generate point clouds, which were subsequently voxelized at four resolutions (0.03, 0.05, 0.07, and 0.1 m). CVM_VI was constructed by integrating vegetation indices (VIs) derived from the RGB data and the voxelized canopy structural information. Regression models were established between the CVM_VI values and field-measured AGB to estimate biomass. Model performance was evaluated using the coefficient of determination (R²), root mean square error (RMSE), and relative error (RE). There were strong correlations (r > 0.80) between the estimated and measured AGB across all voxelization treatments throughout the growth period. Among the 20 VIs tested, regression methods based on the blue green ratio index (BGI), color intensity index, blue red ratio index, vegetative index, and green red ratio index consistently showed superior estimation performance across three consecutive years, demonstrating their good applicability for estimating AGB in oilseed rape under varying agronomic conditions (different varieties, densities, and sowing dates). The cubic regression model CVM_BGI performed best under a 45° UAV camera angle, with the highest R² and lowest RMSE and RE (2021–2022: R² = 0.864, RMSE = 2414.18 kg/ha, RE = 14.8%; 2022–2023: R² = 0.754, RMSE = 2550.53 kg/ha, RE = 14.9%; 2023–2024: R² = 0.863, RMSE = 1953.61 kg/ha, RE = 22.9%). Since the estimation performance showed negligible differences among voxel sizes, and the 0.1–m voxel offered the smallest data volume and shortest analysis time, the CVM_BGI model with a 0.1–m voxel was selected as the preferred approach, providing a practical balance between estimation performance and processing demand. These findings highlight the application potential of point cloud voxelization technology for crop biomass estimation. This study proposes a novel, non-destructive, and efficient framework for estimating field crop AGB using low-cost UAV RGB imagery, facilitating the wider adoption of UAV technology in practical agricultural production. Full article

The increasing agricultural and industrial use of rare earth elements (REEs) has raised growing concerns about their environmental accumulation and ecotoxicity, yet the molecular and epigenetic basis underlying their dose-dependent effects on crops remains poorly understood. In this study, soybean plants were foliar treated with Cerium (Ce) at 0, 5, 10, and 50 mg·L⁻¹. Growth, elemental uptake, genome wide DNA methylation, and gene expression were analyzed using ICP-MS, WGBS, and qRT-PCR. Low dose Ce (5 mg·L⁻¹) showed a hormetic effect, promoting growth and grain quality, whereas high dose Ce (50 mg·L⁻¹) markedly inhibited growth. Foliar absorbed Ce was poorly translocated to roots and seeds, thus reducing food chain contamination risk. Ce significantly altered methylation levels of CG, CHG, and CHH contexts in soybean leaves. Low Ce increased CG methylation, while high Ce decreased CHH methylation. Differentially methylated genes (Low-dose Ce induced 52 hypermethylated DMGs and 23 hypomethylated DMGs, while high-dose Ce induced 76 hypomethylated DMGs and 17 hypermethylated DMGs) were enriched in oxidation–reduction, DNA repair, and cell cycle pathways. qRT-PCR confirmed that Ce mediated toxic responses and growth by regulating methylation related enzymes, oxidative detoxification, and DNA repair genes. This study provides novel genome-wide bisulfite sequencing evidence linking foliar Ce exposure to context-specific DNA methylation reprogramming in a major legume crop. These results demonstrate that the dose-dependent phytotoxicity of Ce in soybean is associated with context-specific changes in genome-wide DNA methylation, supporting the safety evaluation and rational agricultural application of rare earth elements. Full article

Thismia species are non-photosynthetic plants entirely dependent on fungal partners for carbon and nutrients. While their arbuscular mycorrhizal associations are well-documented, bacterial symbiont roles remain unexplored. Using 16S rRNA gene amplicon sequencing, we investigated endophytic bacterial communities in T. gardneriana, T. javanica, and T. mirabilis from geographically distinct locations in Thailand. Despite geographic separation, Thismia spp. consistently harbored bacterial compositions taxonomically and functionally distinct from surrounding soil microbiomes. Root endospheres were significantly enriched in Pseudomonadota and Bacteroidota, particularly Puia, while showing reduced compositional dynamics of Acidobacteriota and Planctomycetota. Bacterial communities in Thismia roots were markedly distinct from surrounding soil, while root endosphere communities from geographically distinct habitats clustered together regardless of spatial separation. Mantel and partial Mantel tests confirmed that host species identity, not geographical location, was the primary predictor of root bacterial community structure. Functional prediction analyses suggested root-associated communities were enriched for nitrogen cycling pathways, particularly nitrogen fixation and nitrate reduction. The selective enrichment of Bacteroidota, known for nitrogen fixation and phosphate mobilization, suggests these bacteria provide critical nutritional support in nutrient-poor forest floor environments. Isolated root strains belonged exclusively to Bacillota, including Neobacillus with plant growth-promoting traits. Our findings highlight the importance of tripartite plant–fungal–bacterial interactions in Thismia nutritional ecology. Full article

Some actinobacterial species have been reported to improve plant growth due to their roles as biostimulants and biological control agents. In this study, the effect of actinobacterial isolate 27, obtained from the rhizospheric soil of melon plants and identified as Streptomyces calvus, was evaluated on the growth of Arabidopsis thaliana and tomato plants. In Arabidopsis, in vitro assays showed that after seven days of interaction, isolate 27 increased fresh weight by 1.4-, 1.5-, and 2.3-fold and lateral root number by 1.7-, 1.3-, and 2.5-fold under physical contact and split-plate systems (MS and ISP2 media), respectively, compared with non-inoculated plants. An increased β-glucuronidase (GUS, encoded by the uidA gene) signal was observed in primary and lateral roots of the Arabidopsis DR5::uidA reporter line during both interaction types, suggesting the activation of auxin-responsive pathways. In addition, isolate 27 rescued the rhd6 (root hair defective 6) mutant phenotype, restoring root hair formation. Gas chromatography-mass spectrometry (GC-MS) analysis revealed that isolate 27 emitted volatile organic compounds (VOCs), including an alcohol and several sesquiterpenes, and that this profile changed during interaction with Arabidopsis plantlets. In soil-based pot assays, inoculation with isolate 27 significantly enhanced the development of Arabidopsis plants after 23 days, both when applied alone and in co-inoculation with Trichoderma atroviride. Furthermore, isolate 27 stimulated tomato plant growth, leading to significant increases in fresh and dry biomass, as well as shoot and root lengths after 28 days. Overall, these results demonstrate that S. calvus isolate 27 promotes plant growth and development through the production of bioactive compounds that modulate plant growth pathways, including hormonal responses, highlighting its potential as a bioinoculant for sustainable and productive agricultural systems. Full article

The intensive use of agricultural inputs and the increasing incorporation of nano-materials into crop management practices raise concerns about their ecotoxicological interactions in plant systems. This study evaluated phytotoxicity, cytotoxicity, and genotoxicity in Allium cepa L. under experimental nano-agrochemical exposure scenarios combining two conventional nitrogen fertilizers—ammonium sulfate (AS) and urea—with silver nanoparticles (AgNPs). Biological responses were assessed across fertilizer concentrations (0.03–0.5 g/L), applied individually, simultaneously, and sequentially, to identify modulatory effects of AgNPs on plant proliferative activity and genomic stability. Results showed the relative stability of morphophysiological indicators associated with root growth, whereas cytogenetic biomarkers exhibited selective alterations under specific conditions. Significant increases in genetic damage markers were detected at intermediate ammonium sulfate concentrations, suggesting sublethal phytotoxicity windows not reflected by macroscopic growth parameters. In addition, modulation of the mitotic index and absence of generalized genotoxic effects in most combined or sequential treatments indicate that AgNPs primarily acted as modulators of proliferative responses rather than direct cytotoxic agents. Overall, these findings highlight the dynamic and non-linear nature of nano-agrochemical interactions in plant systems and underscore the importance of multibiomarker approaches for the early detection of genomic instability. The results provide experimental evidence relevant to the environmental risk assessment of nano-enabled fertilization strategies under realistic mixed-exposure scenarios. This study contributes to advancing the ecotoxicological understanding of emerging agricultural technologies and supports the need for further mechanistic research and field-based evaluations to guide the safe and sustainable use of nanomaterials in crop production. Full article

Understanding of carrot growth dynamics and ecophysiological functioning in tropical highland environments remains limited, despite the crop’s productive importance in the Colombian Andean region. This study aimed to characterize biomass accumulation and partitioning, as well as the photosynthetic response to radiation, in two carrot (Daucus carota L.) cultivars (Berlicum- and Flakkee-type) grown under high-altitude Andean tropical conditions in Rionegro, Antioquia. To account for field spatial heterogeneity, four beds were used as blocks, and both cultivars were evaluated in parallel under comparable field conditions. Weekly destructive samplings were performed to quantify total dry biomass, shoot biomass, root biomass, leaf number, and leaf area. In addition, the response of net CO₂ assimilation to photosynthetically active radiation was evaluated using a portable gas-exchange system. Total and root biomass were described using logistic models, shoot biomass using a Gaussian model, and the photosynthetic response using an exponential model. Berlicum showed higher biomass accumulation, whereas Flakkee exhibited an earlier response of growth and photosynthetic activity. In both cultivars, the highest functional capacity was concentrated in stage III, coinciding with the strengthening of the storage-root sink. Overall, the results indicate contrasting temporal patterns in biomass partitioning and photosynthetic performance between the two carrot cultivars and provide a useful ecophysiological framework for interpreting crop management and harvest timing under high-altitude Andean tropical conditions. Full article

Jasmonates (JAs) are a diverse group of jasmonic acid (JA)-linked metabolites, including the biosynthetic intermediate 12-oxophytodienoic acid (OPDA). Although changes in JAs have been associated with plant responses to abiotic stress, the involvement and kinetics of specific forms such as JA, JA-Ile and OPDA require further clarification. This study analyzed jasmonate profiles in roots and leaves of two oat genotypes differing in drought tolerance. Jasmonates were quantified using UPLC-MS/MS, expression of key biosynthetic genes was assessed by qRT-PCR, and JA/OPDA treatments were applied to evaluate their effects on physiological and morphological responses to drought. Drought induced contrasting jasmonate dynamics in roots and leaves, with overall JA levels increasing in leaves and decreasing in roots, with genotype- and compound-specific differences. JA and JA-Ile ((+)-7-iso-jasmonoyl-L-isoleucine) showed similar trends, whereas OPDA displayed a distinct pattern. The tolerant genotype exhibited an early and marked reduction in root OPDA, while the susceptible one showed minimal change. Exogenous OPDA increased drought symptoms, reduced leaf relative water content and strongly decreased root length by limiting the formation of new thin roots. In contrast, JA application alleviated drought symptoms, reflected in a lower area under the drought progress curve, without affecting root length. Results suggest that under water deficit, reduced OPDA, likely due to its conversion into JA and JA-Ile, is associated with the development of small-diameter roots essential for maintaining water status in oat. Together, these results highlight tissue-specific differences in jasmonate dynamics during drought and show that OPDA and JA treatments lead to distinct drought-related responses in both leaves and roots. Full article

Eastern deciduous forests are undergoing directional compositional shifts, marked by the progressive replacement of Quercus-dominated canopies with generalists and shade-tolerant taxa. These shifts are increasingly interpreted within a regeneration debt framework, in which canopy composition persists despite recruitment failure and regeneration mismatch in smaller size classes. We evaluated 30 years (1995–2025) of compositional and structural change in adjacent upland and cove forests on the southern Cumberland Plateau, Tennessee, using a permanent nested circular plot design to determine whether previously observed upland resistance reflects durable resilience or delayed demographic transition. Both habitats exhibited continued Quercus decline while remaining compositionally distinct. As documented in prior analyses, reductions in small-diameter stems were more pronounced in the cove forest, but now reveal demographic mismatches between canopy and regeneration layers in both habitats. Upland forests maintained a higher representation of species capable of basal sprouting and clonal growth via root suckering, indicating that vegetative regeneration buffered short-term demographic change. However, recruitment into larger size classes declined in both habitats, demonstrating that buffering facilitated by vegetative regeneration delayed but did not prevent the accumulation of regeneration debt. What appeared as differential resistance through 2014 is more accurately interpreted as temporal offset in regeneration debt accumulation. Full article

The demand for sustainable weed management and the limited discovery of new herbicide molecules have led to high interest in plant-derived bioherbicides, such as the water residues (WRs) from the hydrodistillation of aromatic plants, which contain biologically active secondary metabolites. Here, the bioherbicidal activity of WRs of four aromatic plant species was investigated. Chemical composition of WRs was determined by solid-phase microextraction (SPME) coupled to gas chromatography–mass spectrometry (GC-MS), and their effect was assessed on seed germination and seedling growth characteristics of Avena sterilis, Echinochloa crus-galli, and Zea mays. Five concentrations, i.e., 0, 10, 20, 50, and 100% (v/v), with 100% representing pure WR, were tested. Phenolic monoterpenes dominate WRs in oregano and thyme, and oxygenated monoterpenes in laurel and lavender. Germination and growth responses were dose-dependent and species-specific. Oregano and lavender WRs exhibited the strongest inhibitory effect, reducing weed germination by 82% and 79%, respectively. In contrast, laurel extracts showed weaker germination inhibition. Across all tested species, germination delays were observed, making WRs a promising candidate for weed control. The results also showed that WR reduced root growth by up to 95% and shoot growth by 70–80%. Maize exhibited greater tolerance than the weed species, maintaining higher germination. Overall, WRs represent a promising tool for integrated weed management. Full article

When present in excess in the environment, nickel (Ni) can bioaccumulate along the food chain, and become toxic to plants and animals. Phytoremediation represents a sustainable alternative, using plants for soil decontamination. This study aimed to evaluate the growth and phytoremediation potential of four Crotalaria species, cultivated in Ni-contaminated soil. The study was conducted in a greenhouse, under a randomized block design, and a 4 × 5 factorial scheme, containing four species (C. juncea, C. spectabilis, C. breviflora, and C. ochroleuca) and five Ni treatments (0, 35, 70, 140, and 280 mg kg⁻¹). When Ni concentration reached 70 mg kg⁻¹, shoot dry mass decreased by approximately 52% in C. juncea, 53% in C. ochroleuca, 81% in C. breviflora, and 46% in C. spectabilis, compared to the control. C. juncea, C. ochroleuca, and C. breviflora maintained satisfactory growth at 35 mg kg⁻¹ and, for C. breviflora, this concentration increased root dry mass. All species showed high Ni translocation to the shoot, indicating potential for phytoextraction. The concentrations observed did not reach the threshold commonly used to define hyperaccumulator plants (>1000 mg kg⁻¹ dry mass). However, in C. spectabilis, the highest Ni dose led to an increase in root translocation and reduced shoot translocation. Therefore, Crotalaria species demonstrate potential for Ni phytoremediation, although they differ in strategies regarding growth, accumulation, and Ni mobilization. Full article