Search Results (2,791)

Nutrient additions including nitrogen (N) and phosphorus (P) are widely considered as an important strategy for enhancing grassland productivity. However, the effects of these nutrients additions on soil nitrous oxide (N₂O) emissions and the underlying mechanisms remain debated. We conducted a two-year field experiment in an alpine grassland on Kunlun Mountain in northwestern China to assess the effects of N and P additions on N₂O emissions, in relation with nitrifying enzyme activity (NEA), denitrifying enzyme activity (DEA), and key functional genes abundance responsible for nitrification (amoA and Nitrobacter-like nxrA) and denitrification (narG, nirS, nirK and nosZ). Compared to the Control without nutrient addition (CK), N addition alone substantially increased cumulative N₂O emission (ƩN₂O) by 2.0 times. In contrast, P addition or combined N and P (N+P) addition did not significantly affect ƩN₂O, though both treatments significantly increased plant aboveground biomass. Such results indicate that P addition may mitigate N-induced N₂O emission, likely by reducing soil N availability through enhanced plant and microbial N uptake. Compared to CK, N or N+P addition significantly elevated NEA but did not affect DEA. Structural equation modeling (SEM) indicated that NEA was directly influenced by the gene abundances of ammonia-oxidizing bacteria (AOB) and Nitrobacter-like nxrA but not by ammonia-oxidizing archaea (AOA). However, SEM also revealed that soil environmental variables including soil temperature, pH, and water-filled pore space (WFPS) had a stronger direct influence on N₂O emissions than the abundances of nitrifiers. These results demonstrate that soil environmental conditions play a more significant role than functional gene abundances in regulating N₂O emissions following N and P additions in semi-arid alpine grasslands. This study highlights that the N+P application can potentially decrease N₂O emissions than N addition alone, while increasing productivity in the alpine grassland ecosystems. Full article

Water scarcity continues to challenge arid regions such as Egypt, where growing population demands, climate change impacts, and increasing agricultural pressures intensify the need for sustainable water management. Treated wastewater has emerged as a viable alternative resource, provided that the effluent meets stringent quality standards for safe reuse. The purpose of this study was to develop a comprehensive model of the Khorshed Wastewater Treatment Plant (KWWTP) to depict the processes used for biological nutrient removal. Operational data was gathered and examined over a period of 18 months to describe the quality of wastewater discharged by the Advanced Sequencing Batch Reactor (ASBR) of the plant, using specific physicochemical parameters like TSS, COD, BOD₅, and N-NO₃⁻. A process flow diagram integrating the Activated Sludge Model No. 1 (ASM1) for biological nutrient removal was created using the GPS-X. The study determined the parameters influencing the nutrient removal efficiency by analyzing the responsiveness of kinetic and stoichiometric parameters. Variables related to denitrification, autotrophic growth, and yield for heterotrophic biomass were the main focus of the calibration modifications. The results showed that the Root Mean Square Error (RMSE) for the dynamic-state was COD (0.02), BOD₅ (0.07), N-NO₃⁻ (0.75), and TSS (0.82), and for the steady state was COD (0.04), BOD₅ (0.11), N-NO₃⁻ (0.67), and TSS (0.10). Since the model’s accuracy was deemed acceptable, it provides a validated foundation for future scenario analysis and operational decision support that produces a trustworthy model for predicting effluent data for the concentrations of TSS, COD, BOD₅, and N-NO₃⁻ in steady state conditions. Dynamic validation further confirmed model reliability, despite modest discrepancies in TSS and nitrate predictions; addressing this issue necessitates further research. Full article

Phenotypic plasticity is a key mechanism by which crops adjust to fluctuating environmental conditions, yet its genetic basis under drought remains poorly characterized in barley (Hordeum vulgare). We hypothesized that phenotypic plasticity under drought is controlled by a distinct, trait-specific genetic architecture that can be detected using complementary plasticity metrics and genome-wide association studies (GWAS). Here, we examined data from 1277 spring barley genotypes grown under well-watered and water-limited conditions to quantify plastic responses across two developmental traits (i.e., heading time, and maturity) and seven productivity-related traits (i.e., total dry matter, plant grain yield, grain number, grain weight, harvest index, vegetative dry weight, and grain-filling period). The experimental design, based on contrasting water regimes across a large diversity panel, allowed robust assessment of genotype-by-environment interactions. We combined five complementary plasticity estimators with four independent GWAS approaches to resolve the genomic architecture underlying trait-specific plasticity. Environmental effects dominated variation in yield-related traits, whereas developmental traits remained more genetically determined. The different plasticity metrics captured distinct but partially overlapping response dimensions, and their integration greatly increased the robustness of association signals. A total of 239 high-confidence SNPs obtained for top traits, those associated across metrics and methods, were enriched in coding regions and mapped to genes involved in osmoregulation, carbohydrate metabolism, hormonal pathways, and ion transport. A total of 27 high-confidence SNPs were located in coding regions, showing genotype-specific differences in the magnitude and even direction of phenotypic plasticity. These loci exhibited opposite allelic effects across water regimes, consistent with context-dependent antagonistic pleiotropy. The fact that candidate alleles for the plastic response modulate environmental sensitivity differently highlights that drought resilience arises from environment-contingent genetic architectures. Overall, these results provide a comprehensive framework for dissecting plasticity and identify concrete genomic targets for indirect selection targeting crop resilience with improved performance under increasingly variable water availability. Full article

It is generally believed that plant polyploids exhibit greater tolerance to abiotic stress conditions than their diploid counterparts. The aim of the present research was to investigate the mechanisms underlying enhanced drought tolerance in the autotetraploid apple ‘Redchief’ as compared to its diploid counterpart. The study was conducted on potted plants over two growing seasons, and simulated drought conditions were induced by limiting or withholding irrigation. Under drought stress, the responses of the clone ‘Redchief’ 4x-25 and its diploid counterpart were compared at physiological, biochemical, and molecular levels. In addition, changes in leaf anatomical structure, stomatal characteristics, and parameters related to growth dynamics were examined in drought-challenged plants. The results indicate that apple tetraploids have a greater ability to adapt to water-deficit conditions than diploids. Under drought stress, apple tetraploids exhibited better physiological and biochemical parameters and maintained a greater capacity for continued growth than diploids. We propose that the primary mechanism underlying the increased drought tolerance in apple tetraploids is a faster and more efficient activation of antioxidant defenses and proline accumulation compared to diploids. The high plasticity of anatomical traits in apple tetraploids in response to adverse environmental conditions was also demonstrated. Full article

Vegetable cultivation is currently facing complex challenges related to climate change, with negative repercussions on plant performance. In this scenario, the employment of eco-friendly agronomic tools capable of boosting plant tolerance to abiotic stresses is fundamental. Among them, the use of non-microbial biostimulants, such as seaweed extracts (SwEs), and microelements, like selenium (Se), is considered an efficient approach to overcome abiotic stresses. In this experiment, the performance of chicory plants cultivated under three different irrigation levels (100%, 75% or 50% of substrate water holding capacity) and treated with SwE, Se or their combination (SwE + Se) was evaluated. The results revealed that drought stress significantly decreased growth, productivity and relative water content but increased soluble solid content, dry matter percentage, and proline and malondialdehyde concentrations. The application of Swe, Se or Swe + Se enhanced growth, productive features and soluble solid content and reduced dry matter percentage, proline and malondialdehyde compared to the control. Based on our results, Se and SwE combined application could be a valuable approach to face moderate drought stress on curly endive plants and improve productive and quality traits. Full article

Stylosanthes scabra, a legume native to the Brazilian semiarid region, exhibits remarkable drought tolerance and represents a valuable model for studying molecular adaptation in legumes. Transcription factors of the AP2/ERF superfamily play central roles in plant development and stress response. This study aimed to identify and characterize AP2/ERF genes in Stylosanthes scabra and to analyze their transcriptional response to root dehydration. Candidate genes were identified through a Hidden Markov Model (HMM) search using the AP2 domain profile (PF00847), followed by validation of conserved domains, physicochemical characterization, prediction of subcellular localization, phylogenetic and structural analyses, and functional annotation. A total of 295 AP2/ERF proteins were identified and designated as SscAP2/ERF, most of which were predicted to be localized in the nucleus. These proteins exhibited a wide range of molecular weights and isoelectric points, reflecting structural diversity, and were classified into four subfamilies: AP2, ERF, DREB, and RAV. Functional annotation revealed predominant roles in DNA binding and transcriptional regulation, while promoter analysis identified numerous stress-related cis-elements. A total of 32 transcripts were differentially expressed under 24 h of water deficit, and four selected genes had their expression patterns validated by qPCR. These findings provide new insights into the AP2/ERF gene subfamily in Stylosanthes scabra and lay the groundwork for future biotechnological approaches to enhance stress tolerance in legumes. Full article

Drought severely limits plant growth, threatening global food security and biodiversity. This review provides a comprehensive overview of the recent advances in plant responses to drought, ranging from initial sensing to physiological adaptation, as well as guidelines for experimental design. We focus on key regulatory components, specifically the ABA signaling core (PYR/PYL/RCARs, PP2C phosphatases, and SnRK2 kinases) and ROS signaling. We provide a detailed description of transcriptional networks, highlighting the pivotal roles of DREB, NAC, and MYB transcription factors in coordinating gene expression. Furthermore, we explore downstream tolerance strategies, including osmoprotectant (e.g., proline) accumulation, cell wall remodeling involving expansins and pectin methylesterases, as well as stomatal regulation. We also discuss how combining genetics with multi-omics and high-throughput phenotyping bridges the gap between molecular mechanisms and whole-plant physiological performance. Ultimately, these insights provide a foundation for refining research approaches and accelerating the development of drought-resilient crops to sustain agricultural productivity and ecosystem stability in increasingly arid environments. Full article

As a monophyletic group, bryophytes—mosses, liverworts, and hornworts—represent some of the earliest land plants, evolving under harsh terrestrial conditions that prompted major morphological, physiological, and molecular changes. Limited water availability, extreme temperatures, and osmotic stresses often caused cellular desiccation in these pioneering plants. Because bryophytes occupy a key position in land-plant evolution and are closely related to streptophyte algae, their desiccation-tolerance strategies hold significant evolutionary importance. Early adaptations included changes in growth patterns and the formation of specialized vegetative structures. Bryophytes also survive extreme habitats by regulating physiological and biochemical traits such as photosynthetic pigment maintenance, osmotic adjustment, membrane stability, redox balance, and the accumulation of compatible solutes and stress-responsive proteins. Advances in molecular biology and whole-genome sequencing of model mosses and liverworts have further revealed that they possess diverse stress-responsive signaling components, including phytohormones, receptor proteins, protein kinases, and key transcription factors that control stress-related gene expression. However, a comprehensive synthesis of these molecular mechanisms is still lacking. This review aims to provide an updated overview of how mosses and liverworts use plant growth regulators, stress-responsive proteins, compatible solutes, antioxidants, and integrated signaling networks to survive in dry terrestrial environments. Full article

Water deficit is a major constraint limiting the growth and yield of faba bean (Vicia faba L.). A pot experiment was conducted under controlled conditions to evaluate the effect of inoculation with Rhizobium leguminosarum bv. viciae BIHB 1148 (strain F14) and Pseudomonas alkylphenolica PF9 (strain L13) on faba bean drought resilience. Two irrigation regimes were applied: well-watered (80% of field capacity) versus water-stressed (40% of field capacity). Strain F14 was used to ensure effective biological nitrogen fixation, while strain L13 was applied in co-inoculation to evaluate its biostimulatory effects. The control plants received nitrogen in its chemical form. Results indicated that water deficit significantly (p < 0.001) reduced plant growth, nodulation, and photosynthesis-related parameters, and increased hydrogen peroxide (H₂O₂) and malondialdehyde (MDA) levels, which are key markers of oxidative stress. However, co-inoculation with strains F14 and L13 significantly enhanced shoot and root biomass, as well as most agro-morphological traits. It also stimulated (p < 0.05) the antioxidant activities of superoxide dismutase (3-fold), guaiacol peroxidase (12%), and catalase (104%), and increased proline content (119%), which led to lower levels of MDA (54% decrease) and H₂O₂ (55% decrease), improved membrane stability, water status, and enhanced photosynthesis. Overall, co-inoculation of faba bean with Rhizobium leguminosarum bv. viciae BIHB 1148 and Pseudomonas alkylphenolica PF9 offers a promising and sustainable approach to improve plant resilience under water deficit. Full article

Nitrogen (N) is the most critical element influencing plant growth and development. Different plant species exhibit varying preferences for different N forms. In order to identify an appropriate nutrient solution N formula for optimizing blueberry substrate cultivation, we investigated the effects of seven different NH₄⁺-N/NO₃⁻-N ratios on the growth characteristics, photosynthetic physiology, mineral element content, enzymes related to N metabolism, and fruit quality, with ‘F32’ used as the experimental material and water served as controls. The results demonstrated that both the aboveground and belowground parts of blueberry plants exhibited enhanced growth when NH₄⁺-N was used as the primary N source in the nutrient solution, compared to single NH₄⁺-N or a high NO₃⁻-N ratio. The most significant growth promotion occurred when the NH₄⁺-N to NO₃⁻-N ratio was 7:3. When NH₄⁺-N and NO₃⁻-N are concurrently supplied in the nutrient solution, the processes of NO₃⁻ reduction, the GS-GOGAT cycle, and NH₄⁺ assimilation are significantly enhanced during nitrogen metabolism. Thereby, providing a theoretical foundation for optimizing nutrient solution management in substrate-cultivated blueberry. Full article

This study estimates the levels of chemical contamination and the responses of biochemical and cytogenetic biomarkers in Unio pictorum from the Nemunas River after a large-scale fire at a tire storage and processing warehouse (in October 2019), as well as after the subsequent discharge of partially cleaned water used for firefighting. The impact of firefighting water (FW) on the River Nemunas ecosystem was assessed. Elevated levels of trace metals (Pb, Cu, Co, Cr, Al, Zn) in U. pictorum mussels collected downstream from the wastewater treatment plant (WTP) discharger were measured in the first year after the accident. Genotoxic aberrations in gill cells were significantly more frequent in mussels collected downstream of the WTP discharger, along with higher frequencies of cytotoxic damage and changes in acetylcholinesterase activity. PAH metabolite concentrations, including naphthalene (Nap) and benzo(a)pyrene (B(α)P), were also elevated in haemolymph in U. pictorum gathered downstream from the discharger, but differences were not statistically significant. The total sum of 16 PAH concentrations in mussels collected in 2021 and 2022 was over 5 times higher than those in 2020, and the profile of accumulated metals shifted, with Ni, Cd, Cr, and Pb concentrations decreasing while Zn increased significantly. Mussel haemolymph in 2021 contained the highest levels of B(α)P-type PAH metabolites, indicating increased oxidative stress and neurotoxic impact. The results of chemical analysis and the values of genotoxic aberrations determined in gill cells of U. pictorum collected in 2021 and 2022 indicate an increase in PAH contamination and geno-cytotoxic impact compared to the results of 2020; these changes might be related to the gradual cancellation of COVID-19 restrictions and restoration of routine activities. The study provided an opportunity to demonstrate the unique response of a less anthropogenically stressed ecosystem to the extreme impact of contamination related to the fire on the tire recycling plant. Full article

Clinacanthus nutans (Burm.f.) Lindau is a medicinal plant known for its antioxidant, anti–inflammatory, and antiviral properties. Drought is a major abiotic stress affecting plant physiology and secondary metabolite biosynthesis. This study investigated the physiological and biochemical responses of C. nutans under drought stress. Relative water content declined with prolonged drought, while hydrogen peroxide and proline levels increased, indicating oxidative and osmotic stress. Antioxidant activities (DPPH and ABTS) peaked at days 4–8 and showed positive correlations with phenolic and flavonoid contents and triterpenoids, particularly schaftoside and lupeol. Molecular docking supported the bioactivity of drought–induced metabolites, with schaftoside and lupeol showing favorable interactions with inflammation–related targets. Multivariate analysis revealed that short–term drought enhanced stress tolerance and secondary metabolite accumulation, whereas prolonged stress reduced biosynthetic capacity and survival. These findings suggest that controlled drought exposure can enhance bioactive compound levels in C. nutans, supporting its potential for drought–adaptive cultivation for medicinal use. Full article

Aims: The plant and soil microbiome serve as a reservoir of beneficial endophytic bacteria, including plant-growth-promoting (PGP) Bacillus subtilis, which enhances nutrient acquisition and protects plants against environmental stresses. We isolated novel bacteria from cultivated peanut plants selected from agricultural fields that survived a season of water scarcity and high temperatures. Experiments were conducted to determine whether plant survival was partially attributable to the presence of beneficial microbes that could be harnessed for future biotechnology applications. Methods and Results: Seven bacterial isolates of Bacillus spp. were identified through 16S rRNA sequencing, revealing close affiliations to B. subtilis, B. safensis, and B. velezensis. Growth curve analysis and colony morphology characterization revealed distinct growth patterns across different media types, while phytohormone production assays demonstrated variable indole-3-acetic acid (IAA) synthesis among isolates. When applied as seed biopriming agents to two hybrid peanut varieties, bacterial inoculation significantly enhanced root surface area and root tip development, with B. subtilis-TAM84A showing the most pronounced effects on ‘Schubert’ roots. In addition, vegetative growth assessments indicated increased branch numbers and plant height, particularly with treatments with B. velezensis strains TAM6B and TAM61A, and a consortium of all isolates. Under drought conditions, inoculated plants exhibited delayed wilting and improved recovery after rehydration, indicating enhanced drought resilience. Conclusions: Several local Bacillus strains recovered from drought-tolerant peanut plants showed improved growth and drought tolerance in greenhouse-grown peanut plants. Ongoing field studies aim to evaluate the potential of regionally adapted microbial populations as soil amendments during planting. Impact Statement: This study demonstrates that local strains of Bacillus isolated from drought-resistant peanut plants possess significant potential as bioinoculants to improve growth and drought tolerance in potted peanut plants. This work provides a foundation for utilizing regionally adapted microbial populations to address agricultural challenges related to water scarcity. Full article

Around 85% of all land plants have symbiotic relationships with arbuscular mycorrhizal (AM) fungi, microscopic soil fungi that build extensive filamentous network in and around the roots. These links strongly influence plant development, water uptake, mineral nutrition, and defense against abiotic stresses. In this context, the use of AMF as a biological instrument to enhance plant drought resistance and phenotypic plasticity, through the formation of mutualistic associations, seems like a novel strategy for sustainable agriculture. This review synthesizes current understanding on the mechanisms through which AMF alleviates drought stress in agriculture. We focus on how AMF help maintain nutrient and water homeostasis by modulating phytohormones and signaling molecules, and by orchestrating associated biochemical and physiological responses. Particular emphasis is placed on aquaporins (AQPs) as key water-and stress-related channels whose expression and activity are modulated by AMF to maintain ion, nutrient, and water balance. AMF-mediated host AQP responses exhibit three unique patterns under stressful conditions: either no changes, downregulation to limit water loss, or upregulation to promote water and nutrient uptake. Nevertheless, little is known about cellular and molecular underpinnings of AMF effect on host AQPs. We also summarize evidence that AMF enhance antioxidant defenses, osmotic adjustment, soil structure, and water retention, thereby jointly improving plant drought tolerance. This review concludes by outlining the potential of AMF to support sustainable agriculture, offering critical research gaps, such as mechanistic studies on fungal AQPs, hormonal crosstalk, and field-scale performance, which propose future directions for deploying AMF in drought-prone agroecosystems. Full article

Polydeoxyribonucleotide (PDRN), a DNA fragment mixture, exerts biological effects via adenosine A2A receptor and salvage pathway activation. Here, Paeonia lactiflora-derived PDRN (Peony PDRN) is proposed as a plant-based alternative to salmon-derived PDRN. While P. lactiflora is known for its medicinal properties, the biological functions of Peony PDRN have not been characterized. To validate and optimize its efficacy, we systematically compared the biological activities of three molecular weight groups of Peony PDRN (high, medium, and low) using in vitro assays and clinical studies. The low-molecular-weight fraction (Low-Peony PDRN) markedly enhanced skin cell proliferation and migration, upregulated extracellular matrix-related genes (COL1A1, COL5A1, ELN, and FBN1), and promoted keratinocyte differentiation and epidermal barrier formation by increasing COL7A1, IVL, FLG, and OCLN expression. It also reduced reactive oxygen species levels and suppressed key inflammatory mediators. Clinically, topical application of Low-Peony PDRN for 2 weeks markedly reduced transepidermal water loss in a sodium lauryl sulfate-induced skin damage model, enhancing barrier recovery (n = 10). Periorbital skin elasticity improved after 4 weeks of treatment (Approval No. Intertek IRB-202505-HR(1)-0001, 20 June 2025). These results indicate that Low-Peony PDRN is a promising plant-derived biomaterial of pharmacological and cosmetic significance, with potential to address skin aging. Full article