Search Results (2,380)

Negative air ions (NAI) represent an important ecological value indicator for green tree species. Flow of sap is a crucial indicator for water utilization and physiological state of trees. Although there have been some advancements in studies on the correlation between the release of NAI by plants and sap flow in recent years, it is still unclear how the release of NAI by plants changes during drought stress and recovery processes, as well as the coupling effect between the release of NAI by plants and sap flow under drought stress. In this context, four typical green tree species, Robinia pseudoacacia, Quercus variabilis, Pinus tabulaeformis, and Platycladus orientalis, were selected as experimental materials. A drought stress and recovery control experiment was conducted based on OTC. The dynamic data of negative air ion concentration (NAIC) and sap flow rate during the process of drought stress and recovery were monitored to clarify the characteristics and correlations of NAI and sap flow changes in the experimental tree species under drought stress and recovery. The main research results are as follows: (1) At the end of the drought period, the NAI and sap flow in the drought treatment group significantly decreased (p < 0.01), compared with the control group (CK), and the reduction rate of sap flow (77.73 ± 4.96%) for each tree species was higher than that of NAI (47.78% ± 4.96%). (2) At 1 day after rehydration, the recovery amplitudes of NAI and sap flow for all tree species were the greatest; at 7 days after rehydration, the NAI and sap flow of the drought treatment group recovered to the levels of the control group (p > 0.05). (3) During different stages of drought rehydration, the response degree of NAI to sap flow varied. The study found that in the drought-rehydration stage, the correlation between the NAI released by each tree species and sap flow was the lowest at the drought endpoint. In conclusion, this research clarifies the changing patterns of plant NAI release and sap flow during drought-rehydration, as well as the response changes of NAI to sap flow. It provides a theoretical basis for selecting drought-tolerant tree species in arid regions. Full article

Saline–alkaline water resources are globally widespread, and their rational development offers significant potential to alleviate freshwater scarcity. Saline–alkaline water aquaculture farming not only affects fish growth and survival but also impairs reproductive and developmental functions. Largemouth bass (Micropterus salmoides), an economically important fish, has demonstrated excellent high tolerance to such environments, in order to investigate the effects of alkaline water aquaculture environments on its growth performance, sex hormone levels, gonadal development, and molecular adaptation mechanisms. In this study, largemouth bass were chronically exposed to freshwater (0.55 mmol/L), low alkalinity (10 mmol/L), or high alkalinity (25 mmol/L) and cultured for 80 days. Alkalinity exposure more severely impacted the growth rate of females. High alkalinity significantly increased the hepatosomatic index and decreased the gonadosomatic index in both sexes; moreover, it induced oxidative stress in both sexes, evidenced by reduced superoxide dismutase (SOD), catalase (CAT), and total antioxidant capacity (TAOC) levels and elevated malondialdehyde (MDA) content. Furthermore, the levels of sex hormones Serum estradiol (E2), 11-ketotestosterone (11-KT), and testosterone were significantly reduced, accompanied by either an elevated ratio of primary oocytes and follicular atresia, or by reduced spermatogenesis. Apoptotic signals appeared in gonadal interstitial cells, with upregulated expression of genes P53, Bax, Casp3, and Casp8. Ultrastructural damage included fewer mitochondria and cristae blurring, further indicating tissue damage causing dysfunction. Transcriptome results showed that oxidative stress damage and energy metabolism imbalance caused by carbonate alkalinity were key to the delayed gonadal development, which was mainly manifested in enrichment of the ECM–receptor interaction and PI3K-Akt signaling pathways in females exposed to low alkalinity, and the GnRH secretion and chemokine signaling pathways in males. Glycosphingolipid biosynthesis and Ferroptosis pathway were enriched in females exposed to high alkalinity, and the Cortisol synthesis and secretion pathway were enriched in males. Overall, high-alkalinity exposure significantly delayed gonadal development in both sexes of largemouth bass, leading to reproductive impairment. Full article

Drought stress poses a significant threat to tree growth, making the development of drought-resistant species essential for ecological restoration. WRKY transcription factors are critical regulators of plant drought responses; however, the role of WRKY22 in the woody species Populus ussuriensis K. remains unclear. In this study, the PuWRKY22 gene was cloned from P. ussuriensis via homologous cloning and was found to be highly expressed in leaves and responsive to abscisic acid (ABA) signaling. Subcellular localization confirmed that PuWRKY22 is a nuclear protein. Using fluorescein enzyme complementation assays, PuWRKY22 was shown to bind specifically to W-box cis-elements, indicating its function as a transcriptional regulator. Under ABA and osmotic (sorbitol) stress, the seed germination rate, root growth, and biomass of tobacco and Populus davidiana × Populus bolleana strains overexpressing PuWRKY22 were significantly increased. Additionally, these overexpressed strains exhibited a reduction in reactive oxygen species (ROS) accumulation and a decrease in membrane lipid peroxidation. Transcriptomic analyses revealed that PuWRKY22 activates expression of the ABA receptor gene Ptr.PYL4 (Potri.006G104100.v4.1), which regulates stomatal closure to minimize water loss. Consistent with this, stomatal observations and photosynthetic measurements demonstrated that PuWRKY22 enhances drought tolerance by protecting photosystem II and preserving chlorophyll content. Collectively, this study elucidates the molecular mechanism by which PuWRKY22 enhances drought resistance in woody plants through ABA signaling, providing a foundation for breeding drought-tolerant forest species. Full article

Lichens, complex symbiotic associations between fungi and photosynthetic partners, are widespread in terrestrial ecosystems but remain poorly studied in tropical dry forests (TDFs). This review synthesizes current knowledge on the diversity, ecological roles, adaptive traits, and ethnobotanical uses of lichens in TDFs, with a focus on the Neotropics. As most lichens discussed here are crustose species that inhabit tree bark, this paper also provides a thoughtful review of the origin, distribution, and highly heterogeneous floristic composition of TDFs, which directly shape lichen habitats. It discusses how lichens have evolved to cope with seasonal water stress, emphasizing desiccation tolerance as a key feature of the symbiosis. This review also explores lichen community composition, interactions with host trees, microclimatic conditions, herbivory, and soil crust formation. Despite evidence of high species richness, functional diversity, and ecological importance, lichens in TDFs are largely overlooked in conservation strategies. Moreover, several regions remain vastly understudied, and many species likely remain undescribed. Ethnolichenological practices, though scarce, underscore the cultural and medicinal value of these organisms. Given the high rates of habitat loss and endemism in TDFs, there is a pressing need to expand research on lichen diversity and to investigate the evolutionary origins of their survival strategies. The conservation of these lichens is inseparable from the conservation of TDFs themselves. Understanding how lichens adapt to the harsh and variable conditions of TDFs is essential for integrating them into biodiversity conservation and ecosystem restoration frameworks. Full article

Tomato fruit (Solanum lycopersicum) is a valuable agricultural crop worldwide due to its nutritional value and culinary applications, making it one of the most widely consumed vegetables in the human diet. However, excessive solar UV-B radiation represents a significant factor in decreasing productivity, marketable yields, and fruit quality in tomato crops by causing damage to both DNA and the photosynthetic system, as well as chlorophyll degradation. The application of silicon nanoparticles has been shown to increase tolerance to abiotic stressors, including enhanced UV-B radiation. Therefore, this study aims to evaluate the protective effects of foliar silicon nanoparticle (SiNP) application on photosynthetic parameters, photosynthetic pigments, and secondary metabolites under enhanced UV-B stress in tomato plants. Photosynthetic parameters (stomatal conductance to water vapor, net CO₂ assimilation rate, transpiration rate, and intercellular CO₂ molar fraction), biogenic volatile organic compounds (BVOCs), chlorophylls, and carotenoids were evaluated. The application of SiNPs showed beneficial effects on plants grown under ambient UV-B conditions, increasing photosynthetic parameters while also enhancing chlorophyll and carotenoid levels. In plants exposed to enhanced UV-B radiation, SiNP treatment helped to maintain and even improve photosynthetic parameters and stomatal function in leaves while also promoting the accumulation of photosynthetic pigments. Additionally, the application of SiNPs also resulted in a slightly higher content of lycopene and total carotenoids in tomato fruits. Full article

The growing demand for sustainable and antibiotic-free animal production has intensified interest in probiotics as functional feed additives. In this study, novel strains of Weizmannia coagulans (WC412 and WC413) were isolated from pickle water—a previously unexplored source for probiotic screening. These isolates, along with three reference strains (W. coagulans S8, S15, and S17), were evaluated for their tolerance to heat, acid, and bile salts. Strain WC412 exhibited superior environmental resilience, as validated by principal component analysis (PCA) for comprehensive stress-tolerance assessment, and was selected for further investigations. A murine model was employed to assess the physiological and microbiological impacts of WC412 supplementation at varying doses. Medium-dose (1 × 10⁷ CFU·mL⁻¹) administration significantly improved body weight gain by 13% (p < 0.05), modulated serum lipid profiles, and increased antioxidant enzyme activity and IgG/IL-2 levels (p < 0.05). Notably, WC412 uniquely enriched beneficial genera (e.g., Fructilactobacillus and Limosilactobacillus) and promoted metabolic pathways linked to short-chain fatty acid production, as revealed by 16S rDNA sequencing and Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis. These findings highlight WC412 as a robust probiotic candidate for enhancing animal growth performance and gut health through novel microbiota-mediated mechanisms. Full article

Climate change causes major agricultural losses, driven both by the rise of plant diseases and by extreme weather events such as droughts and floods. Increased precipitation can lead to waterlogging of important crops. The roots of plants submerged in water have limited access to oxygen, which leads to hypoxia, which, in turn, reduces plant resistance to other factors, e.g., plant pathogens. On the other hand, beneficial microorganisms can help plants oppose abiotic stress, e.g., by producing plant hormones or osmoprotectants such as trehalose, to increase plant tolerance to drought. It turns out that plant-beneficial microorganisms can also increase plant resistance to waterlogging. This can be achieved by various mechanisms that involve the production of 1-aminocyclopropane-1-carboxylate (ACC) deaminase, which reduces the amount of ethylene accumulated in the submerged roots. This can stimulate the production of reactive oxygen species scavengers that protect plants from the oxidative stress caused by less efficient anaerobic metabolism, produce plant hormones that help plants to better adapt to low-oxygen conditions, and shape the plant microbiome, supporting plant growth in waterlogging conditions. This review outlines plant responses to waterlogging and discusses examples of microorganisms that improve plant tolerance, focusing on their underlying mechanisms. Full article

Water scarcity poses a substantial challenge for turfgrass irrigation in the drought- and heat-stressed Desert Southwest region of the United States. Bermudagrass (Cynodon spp.), renowned for its exceptional drought resistance, is the predominant warm-season turfgrass in the region. Selecting and using drought-resistant bermudagrass cultivars remains a primary strategy for sustaining the turfgrass industry in the region. This study evaluated 48 hybrid bermudagrasses (Cynodon dactylon × C. transvaalensis Burtt-Davy), including two commercial cultivars (‘TifTuf’ and ‘Tifway’, as controls), under 80% × ETo (0.8ET), 60% × ETo (0.6ET) and 40% × ETo (0.4ET) reference evapotranspiration (ETo) replacement irrigation systems at Maricopa, AZ. The experiment was laid out in a split-plot design with two replications, where the 3 irrigation treatments were assigned to main plots and 48 genotypes were in sub-plots. Analysis of data from two years (2022 and 2023) revealed significant differences among bermudagrass hybrids, irrigation treatments, and their interaction effects. The hybrids exhibited substantial variation for spring green-up, density, turf color, and quality. With the largest deficit irrigation treatment 40% × ETo (0.4ET), OSU2104, OSU2106, and OSU2105 showed greater mean greenness and aesthetic quality scores than recorded for ‘TifTuf’ (6.5), a popular drought-tolerant cultivar. The results highlight the prevalence of genetic variation in germplasm with potential for development of improved varieties for drought tolerance. Full article

The use of hydrogel and biostimulants holds great potential for plants’ adaptation to stressful urban conditions, increasing their tolerance to drought stress. In this study, we investigated the plant performance and anatomical response of Petunia × hybrida hort. ex E. Wilm., cultivated under different substrate volumes and compositions, hydrogel amendments, and biostimulant treatments, as well as their interactions under drought stress. Namely, the plants were planted in pots with a substrate depth of 7 cm and 10 cm and cultivated under different combinations of organic (peat) and inorganic (perlite) substrates. Moreover, half of the plants were subjected to hydrogel and biostimulant treatments. Different watering intervals (24–96 h) were applied in combination with exposing the plants to direct sunlight for 8–10 h. The results showed that a larger substrate depth, along with hydrogel and biostimulant amendments in a mixture of perlite and peat, helps plants adapt to dry conditions when grown in shallow substrates, providing optimal water availability and thus contributing to the physiological adaptation of plants to water deficit. The study clearly demonstrates that substrate selection and irrigation frequency must be jointly optimized to ensure resilient urban greening. Hydrogels stand out as essential amendments, enabling significant water savings by extending irrigation intervals without compromising vascular growth or drought resilience. These water-efficient substrate strategies are vital for sustainable urban vegetation management, especially as cities face increasing environmental pressures and the imperative of climate adaptation, thereby supporting multiple Sustainable Development Goals. Full article

Mesocotyl elongation is the key determinant of deep-sowing tolerance in maize. Sowing at an appropriate depth allows the seedling to exploit water and nutrients stored in deeper soil layers, thereby enhancing its ability to withstand drought and other abiotic stresses. Mesocotyl elongation is regulated by the phytohormones brassinosteroid (BR), auxin (IAA), gibberellin (GA), and reactive oxygen species (ROS). However, whether and how BR coordinates IAA, GA, and ROS to control mesocotyl elongation in maize remains unclear. Here, we demonstrated that BRs orchestrate ROS, IAA, and GA signaling to remodel cell-wall metabolism in mesocotyl cells, promote cell elongation, and, consequently, strengthen deep-sowing tolerance. BR promoted mesocotyl elongation through multiple routes: (1) decreasing the contents of cell-wall components (hemicellulose, cellulose, and pectin); (2) activating cell-wall-loosening enzymes (cellulase, pectinase, and acidic xylanase); and (3) disturbing ROS homeostasis by elevating superoxide dismutase (SOD) activity. Combined treatments of BR with either IAA or GA further enhanced mesocotyl elongation in a concentration-dependent manner. In deep-sowing trials (15 cm), application of BR alone or in combination with IAA or GA markedly increased mesocotyl length and emergence rate, thereby improving deep-sowing tolerance. Our work indicated that BR integrated ROS, IAA, and GA signals to restructure the cell wall and derived mesocotyl cell elongation, providing both theoretical insights and practical strategies for breeding maize varieties with enhanced deep-sowing tolerance. Full article

As a key economic tree in southern China, Camellia oleifera faces severe yield losses under drought. Grafting onto drought-tolerant rootstocks offers a potential mitigation strategy. To elucidate the impact of rootstocks on the drought resistance of the superior Camellia oleifera Abel. cultivar “Xianglin 210”, grafted seedlings with five scion–rootstock combinations, were subjected to gradient drought stress. Key physiological and biochemical indices related to photosynthesis, antioxidant enzymes, and osmotic adjustment were measured. Drought resistance was comprehensively evaluated using membership function analysis, and the expression of stress-responsive genes was quantified via quantitative real-time PCR (qRT-PCR). The results demonstrated that under drought stress, (1) stomatal conductance (Gs) decreased by 31.2–48.7%, while instantaneous water use efficiency (WUE) increased by 18.5–35.4%; (2) proline (Pro) and soluble sugars (SS) accumulated significantly, with increases of 2.3–4.1-fold and 1.8–3.2-fold, respectively; (3) activities of antioxidant enzymes were enhanced by 56–127%, mitigating oxidative damage; (4) membership function analysis ranked drought resistance as follows: Xianglin 27 (0.812) > Guangxi Superior Germplasm (0.698) > C. yuhsienensis (0.654) > Hunan Superior Germplasm (0.591) > Xianglin 1 (0.523); (5) qRT-PCR revealed significant upregulation of ABA signaling pathway genes (CoPYL6, CoPP2C75/51/24/26, CoSnRK2.8, and CoABI5) and transcription factors (CoLHY and CoWRKY70), indicating activation of drought-responsive regulatory networks. These findings provide a theoretical foundation for selecting drought-tolerant rootstocks and optimizing cultivation practices in Camellia oleifera, and provide practical criteria for selecting drought-tolerant rootstocks, facilitating sustainable Camellia oleifera cultivation in water-limited regions. Full article

Karrikins, a class of butenolide compounds derived from plant-derived smoke, positively regulate plant development and stress tolerance. However, their effects on postharvest fruit have scarcely been reported. In this study, karrikin solution was prepared by absorbing maize straw smoke into water, and kiwifruits (Actinidia deliciosa) were immersed in different concentrations of this solution to determine the optimal concentration based on respiratory rate, relative conductivity, firmness, soluble solids content, and appearance of the kiwifruits. Subsequently, the regulation of reactive oxygen species (ROS) and soluble sugars metabolism by karrikins were studied. The results showed that the optimal dose of karrikins for kiwifruit was 1.20 μmol L⁻¹. Karrikins enhanced the activities of superoxide dismutase, catalase, enzymes in the ascorbate–glutathione pathway, and soluble sugars metabolism, increased the concentrations of reducing ascorbate, glutathione, sucrose, and fructose-6-phosphate, suppressed ROS concentrations, and maintained the quality of kiwifruit during storage. These results suggest that karrikins could be a potential tool to modulate fruit ripening, with their effects depending on the dosage used. Full article

Ascorbic acid is a non-enzymatic antioxidant compound essential for plant defense under salt stress conditions. It can induce salt stress tolerance and enable the use of saline water in hydroponic cultivation with substrates. This study evaluated the effect of foliar application of ascorbic acid on the yield and postharvest quality of ‘Laranja’ cherry tomatoes grown in saline nutrient solutions under a substrate-based hydroponic system. The experiment was conducted in a greenhouse in Campina Grande, Paraíba, Brazil, in a randomized block design in a 5 × 5 factorial arrangement, corresponding to five levels of electrical conductivity of the saline nutrient solution—SNS (2.1—Control, 2.8, 3.5, 4.2, and 4.9 dS m⁻¹) and five concentrations of ascorbic acid—AA (0, 150, 300, 450, and 600 mg L⁻¹), with four replications. Salinity above 2.1 dS m⁻¹ reduced yield components and phenolic compound content. However, the saline nutrient solution of 4.9 dS m⁻¹ combined with 600 mg L⁻¹ foliar application of AA increased fruit firmness, soluble solids, and titratable acidity. Additionally, SNS of 4.9 dS m⁻¹ enhanced the levels of vitamin C, flavonoids, and anthocyanins. While AA improved postharvest quality of cherry tomatoes, it did not increase production under salt stress. Foliar application is thus a promising approach for enhancing fruit quality of cherry tomatoes grown in hydroponic systems using saline water, supporting sustainable production in semiarid regions. Full article

Climate change, with its altered precipitation and extreme temperatures, significantly threatens global viticulture by affecting grapevine growth, yield, and fruit quality. Understanding the molecular underpinnings of grapevine resilience is crucial for developing adaptive strategies. Our aim is to explore the application of multi-omics approaches (integrating genomics, transcriptomics, proteomics, metabolomics, and epigenetics) to investigate grapevine stress responses. Advances in these omics technologies have been pivotal in identifying key stress-response genes, metabolic pathways, and regulatory networks, particularly those contributing to grapevine tolerance to water deficiency, (such as drought and decreased precipitation), extreme temperatures, UV radiation, and salinity. Furthermore, the rich genetic reservoir within grapevines serves as a vital resource for enhancing stress tolerance. While adaptive strategies such as rootstock selection and precision irrigation are important, future research must prioritize integrated multi-omics studies, including those on regional climate adaptation and long-term breeding programs. Such efforts are essential to exploit genetic diversity and ensure the sustainability of viticulture in the evolving climate. In summary, this review demonstrates how utilizing the inherent genetic variability of grapevines and employing multi-omics approaches are critical for understanding and enhancing their resilience to the challenges posed by climate change. Full article

Cool-season creeping bentgrass (Agrostis stolonifera L., As) is extensively used on golf courses worldwide and is negatively affected by several fungal diseases and abiotic stresses including drought and salinity. CRISPR/Cas9 (clustered regularly interspaced short palindromic repeats/CRISPR-associated) gene editing technology was employed in this project to knock out the AsDREBL (dehydration responsive element binding-like factor) gene, a potential negative regulator in stress tolerance. With our established single guide RNA (sgRNA)-based CRISPR-editing vector and optimized creeping bentgrass tissue culture system using mature seed-derived embryogenic calli of cv. Crenshaw as explant, more than 20 transgenic plants were produced by gene gun bombardment. Fifteen confirmed AsDREBL mutant plants were tested for drought and salinity tolerance by withholding water and applying salt spray in greenhouse settings. Some of the mutants were shown to be more tolerant of drought and salinity stress compared to the non-edited, wild type Crenshaw plants. Our results demonstrate that CRISPR-gene editing technology can be successfully applied to improve the agronomical traits of turfgrass. Full article