Search Results (177)

Salinity is a major factor limiting the increase in crop yield around the world. Wheat starch and straw are important raw materials for producing bioethanol, and their productivity is adversely affected by salinity. Polyacrylic acid-modified Mn₃O₄ nanoparticles (PMO) have been reported to improve crop tolerance to stressors, including salt stress. Therefore, this study aimed to elucidate the mechanism by which seed soaking with PMOs enhances wheat salt tolerance. PMO seed soaking promoted wheat germination (increase of 30.9%) under salt stress, and seedlings treated with PMO seed soaking had a higher fresh weight (increase of 31.4%). PMO seed soaking increased the POD activity (by 31.9%) but decreased superoxide dismutase and catalase activities of wheat seeds and the O₂⁻ and H₂O₂ contents (by 25.0 and 71.4%, respectively). Furthermore, PMO soaking increased the ATP, NADPH, and NADH contents (by 367.6, 212.0, and 283.2%, respectively) by regulating sugar metabolism and enhanced the ascorbic acid–glutathione cycle. Additionally, the PMO soaking treatment optimized energy allocation in wheat under salt stress and increased yield (by 9.7%). PMO modulated sugar metabolism, thereby optimizing energy allocation to plant growth and the antioxidant system, which enhanced wheat germination and yield formation under salt stress. Full article

Niacin contents vary significantly among fresh-cut potato cultivars with different browning sensitivities, whereas its role as a browning inhibitor for fresh-cut produce has not been previously reported. In this study, potato slices were soaked in distilled water (control) or 1% food-grade niacin solution for 5 min, then stored at 4 ± 1 °C for 8 days with sampling every 2 days for physiological and molecular analyses. In particular, the optimal niacin (1%) treatment showed higher brightness and lower color change than the control. The activities of polyphenol oxidase (PPO), peroxidase (POD), and phenylalanine ammonia lyase (PAL), and phenol content were reduced. Higher activities of superoxide dismutase (SOD) and catalase (CAT), and greater glutathione accumulation, were observed following niacin treatment. Meanwhile, lower levels of malondialdehyde and reactive oxygen species (ROS), and lower nicotinamide adenine dinucleotide phosphate oxidase (NOX) activity, indicated lower oxidant damage. The contents of NADP and NAD, and activities of nicotinamide adenine dinucleotide kinase (NADK) and glucose-6-phosphate dehydrogenase (G6PDH) were improved. Furthermore, the gene expression patterns of StRBOH, StPPO, and StG6PDH also supported the hypothesis that niacin regulates pyridine nucleotide and ROS homeostasis. Full article

Nitric oxide (NO) and hydrogen sulfide (H₂S) are key gasotransmitters that regulate multiple aspects of plant growth, development, and stress adaptation. Although their individual signaling pathways have been extensively investigated, the integrated mechanisms underlying NO–H₂S crosstalk and its potential agronomic applications remain unclear. This review summarizes current advances in understanding the biochemical interplay between NO and H₂S in plants, emphasizing their synergistic roles in redox regulation, antioxidant activation, ion homeostasis, and photosynthetic protection under abiotic and biotic stresses. Special attention has been given to recent progress in nanotechnology-based delivery systems that enable the controlled, localized, and sustained release of gasotransmitters, thereby improving bioavailability and minimizing environmental losses. Studies on foliar, seed, and nutrient-solution applications have demonstrated that combined NO/H₂S treatments increase stress tolerance by activating the ascorbate–glutathione (AsA–GSH) cycle, reducing the expression of oxidative markers such as hydrogen peroxide (H₂O₂) and malondialdehyde (MDA), and improving both short-term (Fv/Fm, antioxidant enzyme activity) and long-term (biomass, SPAD index, yield) physiological outcomes. By integrating molecular insights with applied strategies, this review outlines the emerging potential of NO–H₂S signaling as a sustainable tool for crop management in the context of climate change and food security. Full article

Allelopathy means that one plant produces chemical substances to affect the growth of other plants. Crop rotation is considered as a potential strategy to alleviate the allelopathic inhibition. So, it is important to identify rotation crops with wide availability and low inhibitory effects. In this study, the allelopathic potential of soil extracts was investigated on the germination, seedling growth, biomass, and biochemical parameters (malondialdehyde, photosynthetic pigments, and antioxidant enzyme activities) of five crops, by a series of laboratory experiments. Firstly, both soil water extracts (SWE) and soil ethanol extracts (SEE) exhibited allelopathic inhibition on the seed germination and the root length of all seedlings in a dose-dependent relationship. The SWE significantly promoted the shoot length of bok choy and Chinese lettuce, while the SEE had no significant effect in bok choy. The application of SEE resulted in a significant increase in the dry weight of bok choy and rocket. In contrast, SWE had a negligible effect on bok choy and lettuce. Both of them caused decrease in the dry weight of the other seedlings. Then, the allelopathic synthetic effect index of water/ethanol extracts was chemo-inhibitory, and the inhibitory effect increased with increasing extract concentration. The SWE had the strongest inhibition on rocket and the SEE on lettuce. Both of them had the weakest effect on bok choy. The extracts significantly inhibited the photosynthetic capacity in five crops, manifested as decrease in photosynthetic pigments and dose-dependent effects. The malondialdehyde (MDA) content in all crops increased in a dose-dependent manner, confirming that the extracts caused lipid peroxidation. However, the defense strategies of different crops vary significantly. There is crop with active defense, such as bok choy treated with SWE. It delayed oxidative damage by continuously upregulating the activities of superoxide dismutase (SOD) and catalase (CAT). This is the key physiological mechanism for tolerance. There is also the oxidative stress failure type, as follows: CAT activity of rocket and cabbage increased, but the SOD activity did not increase by SEE. This reveals the physiological essence of their sensitivity—the lack of persistent scavenging ability for reactive oxygen species. Based on the inhibition of peroxidase (POD) and ascorbic acid peroxidase (APX), it is speculated that the extracts may inhibit the hydrogen peroxide scavenging pathway, which centered on the ascorbate–glutathione cycle. It is the fundamental reason why the continuous accumulation of MDA though SOD/CAT is up. This study confirmed the allelopathic effects of the water and ethanol extracts on five vegetable crops, and found that bok choy was less affected by them. The soil extracts affected the growth and development of seedlings by regulating their oxidative metabolism and photosynthetic capacity. These results support recommending pak choi as a rotation crop. This provides crops for subsequent field experiments and a new direction for next-step research on continuous cropping obstacles. Full article

Soil salinity as a major abiotic stressor has significantly affected crop production worldwide. However, plants have developed complex signaling networks that enable them to adapt and cope with such environmental shifts. Recent research has demonstrated the involvement of hydrogen sulfide (H₂S) in signaling cascades that link plant development with stress tolerance management. Similarly, glutathione (GSH), a non-enzyme antioxidant, and a vital tripeptide, has been found to protect plants from oxidative damage and regulate metabolic functions under abiotic stress. As a potential scavenger of ROS, GSH maintains cellular redox homeostasis through the ascorbate-GSH cycle and acts as a signaling molecule for the sulfur-status of plants. This review focusses on: (i) revisiting the concept and current status of soil salinity; (ii) highlighting its impact at cellular and whole-plant levels; (iii) elucidating the role of a H₂S and GSH in plant salt stress tolerance; and (iv) exploring the potential interactive roles of H₂S and GSH in mitigating salinity impacts. This review will provide valuable insights into the complex network involving H₂S and GSH, suggesting pathways for developing climate-resilient crops. Full article

Bangia fuscopurpurea is a marine alga with significant commercial value. Although a high-light adapted species, the productivity of its commercial cultivation is frequently limited by environmental light attenuation, resulting in the algae operating under energy-limiting, sub-saturating conditions. This study investigated its physiological responses and antioxidant defense mechanisms across a sub-saturating light gradient (20, 40, and 80 µmol photons m⁻² s⁻¹). We employed exogenous ascorbic acid (AsA) supplementation to evaluate the dynamic response of the ascorbate-glutathione (AsA-GSH) cycle. Without AsA supplementation, the 40 µmol photons m⁻² s⁻¹ condition supported redox homeostasis and the highest soluble protein accumulation. In contrast, the lowest irradiance (20 µmol photons m⁻² s⁻¹) restricted physiological performance. At 80 µmol photons m⁻² s⁻¹, which remained below the light saturation point, the algae experienced oxidative stress, indicated by elevated lipid peroxidation and hydrogen peroxide levels. The efficacy of exogenous AsA depended on these energy states. Under the highest tested irradiance (80 µmol photons m⁻² s⁻¹), AsA reduced malondialdehyde (MDA) and maintained electron transport capacity, but these effects were accompanied by a significant degradation of photosynthetic pigments. These findings imply an altered partitioning of cellular reducing power, where the demand for AsA regeneration might limit the resources available for biosynthetic pathways. The study highlights that antioxidant efficacy is constrained by the cellular energy availability, which limits simultaneous stress mitigation and growth in light-limited aquaculture environments. Full article

Abiotic stresses disrupt redox homeostasis and reduce crop productivity. Antioxidant networks support resilience by limiting excess reactive oxygen species (ROS) and maintaining redox signalling for stress perception, gene expression, and metabolic reprogramming. We summarize advances (2000–2025) in ROS generation, detoxification mechanisms, and signalling across organelles, including chloroplasts, mitochondria, peroxisomes, and the apoplast. This includes compartmentalized enzymes—superoxide dismutase (SOD), catalase (CAT), ascorbate peroxidase (APX), glutathione peroxidase (GPX), and glutathione reductase (GR)—as well as the peroxiredoxin–thioredoxin system and non-enzymatic buffers like ascorbate, glutathione, tocopherols, carotenoids, and flavonoids. We uniquely synthesize these findings in a compartment-resolved “redox rheostat” model, linking ROS concentration–time windows (signaling vs. damage) to antioxidant network design (kinetic tiers, compartmentation, and trade-offs) and identifying intervention points for breeding, genome editing, and field-scale priming. We emphasize constraints, such as NADPH supply and antioxidant recycling capacity, that lead to context-dependent outcomes. We evaluate omics, transgenic strategies, genome editing (CRISPR and Cas systems), exogenous applications, and plant–microbe associations. This synthesis clarifies how antioxidant systems protect photosynthetic and respiratory machinery while supporting signalling, thus outlining routes to climate-resilient, yield-stable crops across varied environments and stresses. Full article

Ascorbate peroxidase (APX) is a heme-containing enzyme involved in hydrogen peroxide (H₂O₂) detoxification within the ascorbate–glutathione (AsA–GSH) cycle. In this study, the full-length genomic DNA and cDNA of an APX1 gene (VsAPX1) were cloned and characterized from Vicia sativa. The genomic sequence of VsAPX1 is 2425 bp in length and comprises 10 exons separated by nine introns, with the first intron located within the 5′ untranslated region (5′UTR). The corresponding cDNA is 1010 bp long and includes a 61 bp 5′UTR, a 753 bp open reading frame, and a 196 bp 3′UTR. VsAPX1 encodes a predicted cytosolic APX protein of 250 amino acids, with a molecular weight of 27.1 kDa and a theoretical isoelectric point (pI) of 5.60. Bioinformatics analysis revealed that the deduced VsAPX1 protein shares high sequence similarity with cytosolic APX1 proteins from other plant species, contains conserved APX domains, and clusters within the cytosolic APX clade in phylogenetic analysis. Quantitative real-time PCR analysis showed that VsAPX1 expression exhibits transient and moderate changes in response to abiotic stress and phytohormone treatments. Transcript levels increased at early time points following heat stress (42 °C), abscisic acid, and salicylic acid treatments, and after 4 h of jasmonic acid exposure, whereas hydrogen peroxide treatment resulted in a gradual down-regulation of expression. Overall, this study provides the first molecular and expression characterization of a cytosolic APX1 gene from Vicia sativa and establishes a foundation for future functional analyses of antioxidant genes in this species. Full article

Pitaya (Hylocereus undatus) is a typical Crassulacean Acid Metabolism (CAM) plant with strong drought tolerance but high sensitivity to low temperatures. In this study, the responses of pitaya cultivated in the karst areas of Guizhou Province in southwest China to drought and low temperature were examined in winter seasons. The stems of ‘Zihonglong’ pitaya were used as materials to investigate the physiological responses to cold temperatures of pitaya stems under different water conditions, so as to understand the effects of drought stress on the response to low temperatures. The results showed that the severity of chilling injury in pitaya stems was influenced by cold degree and duration and temperature variation. Under sustained low-temperature conditions, the lower the temperature and the longer the duration, the more severe the chilling injury, particularly at 4 °C and below. Drastic temperature rise after exposure to low temperature of 5 °C aggravated the damage, especially when the temperature rise exceeded 10 °C. Compared to normally irrigated plants, those subjected to drought pretreatment exhibited milder chilling injury and higher survival rates under a temperature shift from 5 to 20 °C. The drought-treated pitaya stems had significantly lower membrane leakage and malondialdehyde (MDA) and reactive oxygen species (ROS) contents compared with the well-watered control under different temperature increases starting from 5 °C. Drought significantly reduced soluble sugars and soluble proteins but increased proline under a temperature shift from 5 to 20 °C. It significantly enhanced the activities of catalase (CAT) and ascorbate peroxidase (APX) under temperature shifts from 5 to 10 or 20 °C, but had no significant effect on peroxidase (POD) and superoxide dismutase (SOD). Drought also significantly increased ascorbic acid (ASA) content but significantly reduced glutathione (GSH). It is concluded that a drastic post-cold temperature rise causes more severe damage than the cold temperature itself. Drought pretreatment increases the chilling tolerance of pitaya stems. This effect involves an enhanced ASA-GSH cycle, which strengthens ROS scavenging and prevents membrane damage. Full article

Toxic Cd (cadmium) pollution in agricultural soil has been drawing global attention. Using exogenous regulators to detoxify Cd in crops is a promising approach to alleviate Cd stress and prevent Cd accumulation in human bodies through the food chain. Natural compounds show great potential due to their environmentally friendly properties. We have found that thymol (a plant-derived natural compound) protects plants from Cd stress. To extend the application of thymol in agriculture, further studies are needed to understand the detailed mechanism by which thymol induces Cd tolerance and limits Cd accumulation in crops. In this study, hydroponic experiments using the roots of Brassica rapa L. exposed to a nutrient solution containing Cd (3 µM) and thymol (15 µM) were conducted to investigate the mechanism of thymol-induced Cd tolerance. Pot experiments with different vegetables (B. rapa, water spinach, and pepper) growing in Cd-polluted soil (0.5 µM Cd) were carried out to investigate the role of foliar spraying of thymol (15 µM) in decreasing the Cd content in vegetables. In the hydroponic study, thymol enhanced the shoot fresh weight and root fresh weight of B. rapa by 313% and 125%, respectively, upon Cd exposure. Thymol detoxifies Cd-induced ROS accumulation by increasing the activity of superoxide dismutase (SOD), peroxidase (POD), and catalase (CAT) in B. rapa by 8.9–33.6%, 12.9–31.6%, and 57.8–135%, respectively. The thymol-activated AsA-GSH (ascorbic acid-glutathione) cycle also contributed to the decrease in ROS level. Thymol also reduced the Cd content in the shoots and roots of B. rapa by 55.7% and 46.6%, respectively, which was associated with the modulation of the expression of a set of genes accounting for Cd accumulation and transport. In the pot study, foliar spraying of thymol significantly decreased the Cd content in various vegetables, including leafy vegetables (B. rapa and two water spinach varieties, with leaf Cd decreasing by 40.5–45.9%) and solanaceous fruits and vegetables (three pepper varieties, with fruit Cd decreasing by 26.9–35.8%), which was accompanied by a growth-promoting effect. The results from this study elucidate the multifaceted function of thymol in helping vegetables detoxify Cd and decrease Cd bioaccumulation, shedding new light on developing thymol as a potential plant regulator to safeguard agroproduct security in Cd-polluted environments. Full article

Silicon (Si) plays a crucial role in mitigating biotic and abiotic stress in crops, yet its effects on cucumber seed germination under drought stress remain unclear. This study investigated the impact of exogenous Si on the ascorbic acid-glutathione (AsA-GSH) cycle during cucumber seed germination under PEG-6000-induced drought stress. Seeds of the cucumber cultivar ‘Xinchun No. 4’ were used in this study. Na₂SiO₃ served as the silicon source, and drought stress was simulated using PEG-6000. The treatments included distilled water (CK), 10% polyethylene glycol (PEG), and PEG combined with five concentrations of silicon (1, 3, 5, 7, and 9 mM Si). Results showed that 10% PEG significantly inhibited seed germination and reduced antioxidant capacity. In contrast, 5 mM Si (5.0 Si + PEG) alleviated PEG-induced stress, reducing malondialdehyde (MDA) and proline (Pro) by 36.87% and 13.71%, respectively, and decreasing reactive oxygen species (ROS) accumulation. Specifically, H₂O₂ and O₂·⁻ contents declined by 20.00–41.76% and 14.29–27.27%, respectively. The 5.0 Si + PEG treatment also reduced soluble sugar content by 29.08% and 27.84% at 48 h and 72 h, respectively, while increasing soluble protein content by 9.97% and 10.30% at 6 h and 12 h. Additionally, it enhanced activities of dehydroascorbate reductase (DHAR), glutathione reductase (GR), and glutathione Stransferase (GST) by 15.00%, 17.48%, and 18.81%, respectively, and elevated ascorbic acid (AsA) content and the GSH/GSSG ratio. In conclusion, 5 mM Si alleviated drought stress by activating the AsA-GSH cycle and enhancing antioxidant defense, providing valuable insights for Si application in agriculture. Full article

Phytochelatin synthases (PCSs) are pivotal enzymes in heavy metal detoxification, yet also implicated in sulfur homeostasis and redox regulation. In this study, we report the molecular and functional characterization of the PCS gene from the green alga Scenedesmus acutus (SaPCS), comparing wild-type and chromium-tolerant strains of this microalga. RT-qPCR, immunoblotting and mass spectrometry analyses revealed that SaPCS expression and protein abundance are primarily regulated by sulfur availability rather than by chromium stress. Two protein isoforms (~70 kDa full-length and ~34 kDa truncated) were detected, both more abundant in the chromium-tolerant strain than the wild-type and responsive to sulfur availability. Furthermore, three alternatively spliced transcript variants (SaPCSa, SaPCSb, SaPCSc) lacking the C-terminal domain coding region but retaining a functional or partially disrupted N-terminal catalytic domain were identified, contributing to the post-transcriptional diversification of PCSs. Mass spectrometry analyses showed negligible phytochelatin production in response to chromium treatment, indicating that detoxification of this metal in S. acutus relies mainly on glutathione (GSH) conjugation and the ascorbate–GSH antioxidant cycle. Overall, these results suggest that SaPCS may promote chromium tolerance by modulating sulfur and redox metabolism rather than by driving phytochelatin accumulation, highlighting the remarkable functional plasticity of PCSs in algal stress responses. Full article

Slug herbivory is an important but poorly explored driver of plant defence and belowground multitrophic interactions. This study examined how aboveground feeding by Arion vulgaris and Deroceras reticulatum affects oxidative status, photosynthetic pigments, and volatile organic compound (VOC) emissions in cabbage (Brassica oleracea L. var. capitata), and whether these changes influence slug-parasitic nematodes. Slug feeding induced strong oxidative stress in leaves and roots, reflected by depletion of total ascorbate and glutathione contents and increased proportions of their oxidized forms, indicating a systemic redox imbalance. Photosynthetic pigments were also markedly affected, characterized by decreased chlorophylls and carotenoids and activation of the xanthophyll cycle towards more zeaxanthin, particularly in plants attacked by D. reticulatum. Headspace SPME–GC–MS analysis revealed tissue-specific, herbivory-induced shifts in VOC profiles. Based on these changes, three VOCs—3-phenylpropionitrile, allyl isothiocyanate, and 2-hexenal—were selected for chemotaxis assays. Behavioural experiments showed that VOC identity and nematode species markedly influenced motility and chemotactic responses. Phasmarhabditis papillosa exhibited the strongest attraction to 3-phenylpropionitrile, whereas allyl isothiocyanate acted as a weak repellent to P. papillosa, Oscheius myriophilus, and Oscheius onirici. In contrast, 2-hexenal elicited no consistent directional response. These results demonstrate that slug herbivory alters cabbage metabolism and volatile signalling, shaping species-specific nematode behaviour and highlighting its potential for sustainable slug management. Full article

Citrus trees are mainly cultivated in acidic soils. Excessive manganese (Mn) is the second most limiting factor for crop productivity in acidic soils after aluminum toxicity. The roles of reactive oxygen species (ROS) and methylglyoxal (MG) detoxification systems in augmented pH-mediated amelioration of excessive Mn are poorly understood. ‘Sour pummelo’ (Citrus grandis (L.) Osbeck) seedlings were exposed to nutrient solution at a Mn concentration of 500 (Mn500) or 2 (Mn2) μM and a pH of 3 (P3) or 5 (P5). The increase in pH attenuated Mn500-induced increases in ROS production and MG and malondialdehyde accumulation in roots and leaves. Additionally, the increase in pH enhanced the coordinated detoxification capability of both ROS and methylglyoxal scavenging systems in these tissues under Mn500. These findings corroborated the hypothesis that augmenting pH enhances the capability of these tissues to detoxify ROS and methylglyoxal under Mn excess. Therefore, this study provided new evidence on the roles of ROS and MG detoxification systems in the augmented pH-mediated amelioration of oxidative damage in ‘Sour pummelo’ leaves and roots caused by Mn excess, as well as a basis for correcting Mn toxicity by augmenting soil pH. Full article

Micronutrient malnutrition persists as a global health burden, while conventional biofortification approaches suffer from low efficiency and environmental trade-offs. This study aimed to develop and evaluate a foliar-applied selenium–zinc nanocomposite (Nano-ZSe, a mixture of zinc ionic fertilizer and nano selenium) for synergistic Se/Zn co-biofortification in Brassica chinensis L., using a controlled pot experiment that integrated physiological, metabolic, molecular, and rhizosphere analyses. Application of Nano-ZSe at 0.18 mg·kg⁻¹ (Based on soil weight) not only increased shoot biomass by 28.4% but also elevated Se and Zn concentrations in edible tissues by 7.00- and 1.66-fold (within the safe limits established for human consumption), respectively, compared to the control. Mechanistically, Nano-ZSe reprogrammed the ascorbate-glutathione redox system and redirected carbon flux through the tricarboxylic acid cycle, suppressing acetyl-CoA biosynthesis and reducing abscisic acid accumulation. This metabolic rewiring promoted stomatal opening, thereby enhancing foliar nutrient uptake. Simultaneously, Nano-ZSe triggered the coordinated upregulation of BcSultr1;1 (a sulfate/selenium transporter) and BcZIP4 (a Zn²⁺ transporter), enabling synchronized translocation and the tissue-level co-accumulation of Se and Zn. Beyond plant physiology, Nano-ZSe improved soil physicochemical properties, enriched rhizosphere microbial diversity, and increased crop yield and economic returns. Collectively, this work demonstrates that nano-enabled dual-nutrient delivery systems can bridge nutritional and agronomic objectives through integrated physiological, molecular, and rhizosphere-mediated mechanisms, offering a scalable and environmentally sustainable pathway toward functional food production and the mitigation of hidden hunger. Full article