Search Results (257)

Fresh fruit are highly perishable commodities, facing significant postharvest losses primarily due to physiological deterioration and microbial spoilage. Conventional preservation methods often face limitations regarding safety, residue, and environmental impact. Because of its rapid decomposition and low-residue-impact characteristics, ozone has proven superior as an efficient and eco-friendly solution for preserving fruit quality after harvest. The maturation and aging processes of kiwifruit are closely linked to the involvement of reactive oxygen species (ROS) metabolism. This study aimed to investigate the effects of intermittent ozone treatment (21.4 mg/m³, applied for 0, 1, 3, or 5 h weekly) on ROS metabolism, the antioxidant defense system, and storage quality of kiwifruit during cold storage (0.0 ± 0.5 °C). The results showed ozone treatment slowed the decline in titratable acid (TA) content and fruit firmness, inhibited increases in total soluble solids (TSSs) and weight loss, and maintained the storage quality. Additionally, ozone treatment enhanced the activities of antioxidant-related enzymes. This includes superoxide dismutase (SOD), catalase (CAT), peroxidase (POD), and ascorbate peroxidase (APX). Furthermore, it delayed the reduction in ascorbate (ASA), glutathione (GSH), total phenolic compounds, and flavonoid content, while also preventing the accumulation of ROS and the rise in malondialdehyde (MDA) levels. In summary, the results indicate that ozone treatment enhances the antioxidant capacity of kiwifruit by increasing the structural integrity of cell membranes, preserving the structural integrity of cell membranes, and effectively maintaining the storage quality of the fruit. Full article

Aluminum (Al) stress is an important factor that inhibits crop growth in acidic soils and poses a threat to pumpkin (Cucurbita moschata) production. In this study, we investigated the effect of endophyte (endophyte) strain J01 of blueberry (Vaccinium uliginosum) on the growth, development, and transcriptional regulatory mechanisms of pumpkin under aluminum stress. The results showed that the blueberry endophyte strain J01 significantly increased the root length of pumpkin under aluminum stress, promoted the growth of lateral roots, and increased root vigor; strain J01 reduced the content of MDA and the relative conductivity in the root system; strain J01 enhanced the activities of superoxide dismutase and catalase in the root system but inhibited ascorbate peroxidase activity. Transcriptome analysis further revealed that strain J01 significantly regulated the expression of key genes associated with aluminum tolerance, including the upregulation of transporter protein genes (aluminum-activated malate transporter and aquaporin), affecting the gene expression levels of genes encoding antioxidant enzymes (ascorbate peroxidase and glutathione S-transferase) and cell wall modification genes (xyloglucan endotransglucosylase/hydrolase and pectin methylesterase). This study provides a theoretical basis and practical guidance for using microbial resources to improve aluminum tolerance in cucurbit crops. Full article

Air pollution acts as a pervasive oxidative stressor, disrupting global crop production and ecosystem health through the overproduction of reactive oxygen species (ROS). Hazardous pollutants impair critical physiological processes—photosynthesis, respiration, and nutrient uptake—triggering oxidative damage and yield losses. This review synthesizes current knowledge on plant defense mechanisms, emphasizing the integration of enzymatic (SOD, POD, CAT, APX, GPX, GR) and non-enzymatic (polyphenols, glutathione, ascorbate, phytochelatins) antioxidant systems to scavenge ROS and maintain redox homeostasis. We highlight the pivotal roles of transcription factors (MYB, WRKY, NAC) in orchestrating stress-responsive gene networks, alongside MAPK and phytohormone signaling (salicylic acid, jasmonic acid, ethylene), in mitigating oxidative stress. Secondary metabolites (flavonoids, lignin, terpenoids) are examined as biochemical shields against ROS and pollutant toxicity, with evidence from transcriptomic and metabolomic studies revealing their biosynthetic regulation. Furthermore, we explore biotechnological strategies to enhance antioxidant capacity, including overexpression of ROS-scavenging genes (e.g., TaCAT3) and engineering of phenolic pathways. By addressing gaps in understanding combined stress responses, this review provides a roadmap for developing resilient crops through antioxidant-focused interventions, ensuring sustainability in polluted environments. Full article

Alkaline stress (AS) is one of the major threats that severely affects rice growth and grain yield. However, the differences in the damage caused by the main components of soda saline-alkali land, sodium carbonate (Na₂CO₃), and sodium bicarbonate (NaHCO₃) to rice seedlings are still unclear. This study explored the effects of different carbonate stresses (Na₂CO₃ and NaHCO₃) on rice seedling growth, root damage, physiological responses, and molecular changes. By administering equivalent concentrations of sodium ions through these different carbonate treatments, we observed that both stresses significantly inhibited rice growth. However, the inhibitory effect was more pronounced under the Na₂CO₃ treatment. Compared with the NaHCO₃ treatment, Na₂CO₃ stress caused more severe damage to root cell membranes and led to a substantial decline in root vigor. Moreover, the contents of reactive oxygen species (ROS) and malondialdehyde (MDA) were markedly increased, indicating that Na₂CO₃ induces more severe oxidative damage. Transcriptomic and metabolomic analyses revealed a greater number of differentially expressed genes (DEGs) and differentially expressed metabolites (DEMs) in the Na₂CO₃ treatment group. The integrative analysis and validation demonstrated that pathways related to auxin, ascorbate, flavonoids, and glutathione metabolism were particularly enriched under Na₂CO₃ stress. These findings suggest that Na₂CO₃ stress may interfere with auxin signaling pathways and exerts a more profound impact on endogenous antioxidant systems, affecting rice growth at multiple levels. In summary, this research highlights the differential impacts of Na₂CO₃ and Na₂CO₃ stresses on rice seedling growth, physiology, and molecular processes, particularly oxidative damage and antioxidant responses. The insights gained provide a valuable theoretical foundation for enhancing rice alkali tolerance and developing strategies for the rational cultivation of rice in saline-alkaline soils. Full article

Drought deficit inhibits oat growth and yield. Fulvic acid (FA) can enhance plant stress tolerance, but its effects on regulating the ascorbate–glutathione cycle, chlorophyll synthesis, and carbon–assimilation ability remain unclear. Therefore, this study aimed to elucidate the physiological mechanisms of the FA regulation of drought tolerance in oats and its relationship with growth and yield using the drought-resistant variety Yanke 2 and the drought-sensitive variety Bayou 9. The effects of FA on growth and yield, the antioxidant system, chlorophyll synthesis, and carbon–assimilation capacity of oats under drought stress were investigated by systematically assessing changes in morphogenesis, ascorbate–glutathione cycle, chlorophyll and its intermediates, carbon–assimilation enzyme activities, and carbohydrate metabolism. The results showed that under drought stress, FA treatment significantly promoted oat growth (leaf area, dry matter) and yield, elevated glutathione peroxidase, ascorbate peroxidase, glutathione reductase, and dehydroascorbate reductase activities, reduced ascorbic acid, and reduced glutathione content. In addition, FA increased chlorophyll, as well as magnesium protoporphyrin IX, protoporphyrin IX, and protochlorophyllin acid ester content, enhanced 1,5-bisphosphate ribulose carboxylase, 1,5-bisphosphate ribulose carboxylase enzyme, 1,7-bisphosphate sestamibiose heptulose esterase, 1,6-bisphosphate fructose aldolase, sucrose synthase, sucrose phosphate synthase, acid invertase, and neutral invertase activities, and increased sucrose, glucose, and fructose content. Overall, fulvic acid (FA) alleviates drought-induced damage in oats by enhancing the ascorbate–glutathione cycle, promoting chlorophyll biosynthesis, and improving carbon assimilation and carbohydrate metabolism. The drought-sensitive variety (Yanke 2) was more effective in application compared to the drought-resistant variety (Bayou 9). This research provides valuable insight into its potential as a biostimulant under abiotic stress. Full article

Plants face various abiotic stresses in their natural environments that trigger the production of reactive oxygen species (ROS), leading to oxidative stress and potential cellular damage. This comprehensive review examines the interplay between plant antioxidant defense systems and ROS under abiotic stress conditions. We discuss the major enzymatic antioxidants, including superoxide dismutase, catalase, reductases, and peroxidases, as well as non-enzymatic antioxidants, such as ascorbic acid, glutathione, polyphenols, and flavonoids, which play crucial roles in ROS detoxification. This review elaborates on different types of ROS, their production sites within plant cells, and their dual role as both damaging oxidants and key signaling molecules. We discuss how various abiotic stresses—including heat, cold, drought, flooding, salinity, and heavy metal toxicity—induce oxidative stress and trigger specific antioxidant responses in plants. Additionally, the mechanisms of ROS generation under these abiotic stress conditions and the corresponding activation of enzymatic and non-enzymatic scavenging systems are discussed in detail. This review also discusses recent advances in understanding ROS signaling networks and their integration with other stress-response pathways. This knowledge provides valuable insights into plant stress-tolerance mechanisms and suggests potential strategies for developing stress-resistant crops by enhancing antioxidant defense systems. Moreover, the strategic ROS modulation through priming, exogenous antioxidants, nanoparticles, or genetic tools can enhance plant resilience. Integrating these methods with agronomic practices (e.g., irrigation management) offers a sustainable path to climate-smart agriculture. Our review reveals that ROS accumulation can be detrimental; however, the coordinated action of various antioxidant systems helps plants maintain redox homeostasis and adapt to environmental stress. Full article

Developing crop varieties with combined salinity and waterlogging tolerance is essential for sustainable agriculture and food security in regions affected by these stresses. This process requires an efficient method to rapidly and accurately assess the tolerance of multiple genotypes to these stresses. Our study examined the use of a pot trial in combination with the assessment of multiple traits to assess the tolerance of 100 wheat (Triticum aestivum L.) genotypes sourced from around the world to these combined stresses. The stresses were imposed on the plants using 100 mM NaCl and by submerging the root systems of the plants in their bathing solutions. The data gathered were subjected to principal component analysis (PCA), and an integrated score (IS) for each genotype was calculated based on multiple morpho-physiological traits; the score was used to rank the genotypes with respect to tolerance or susceptibility. There were significant differences among the 100 wheat genotypes in terms of the relative reductions in their growth parameters and chlorophyll contents, suggesting a rich, genetic diversity. To assess the accuracy of this methodology and to gain insight into the causes of tolerance or susceptibility, the five most tolerant (Misr4 (W85), Corack (W41), Kzyl-Sark (W94), Hofed (W57), BAW-1157 (W14)), and two least tolerant (Livingstong (W60) and Sunvale (W73)) genotypes were selected based on their IS and PCA analysis. These genotypes were then grown hydroponically with and without salinity stress. The data from this second trial were again subjected to PCA, and their IS were calculated; there was reasonable agreement in the ranking of the genotypes between the two trials. The most tolerant genotype (W85; Misr4 from Egypt) and most susceptible genotype (W73; Sunvale from Australia) were then examined in further detail in a third trial. Plants of Misr4 (W85) had lower Na⁺/K⁺ ratios, higher superoxide dismutase, peroxidase, catalase, and ascorbate peroxidase activities, and higher glutathione concentrations. As a result, plants of Misr4 (W85) had lower concentrations of reactive oxygen species (H₂O₂ and O₂^•−) and malondialdehyde than those of Sunvale (W73). This study offers an efficient methodology for the assessment of multiple sources of germplasm for stress tolerance. It has also identified germplasm that can be used for future breeding work and for further research on the mechanisms of tolerance and susceptibility to combined salinity and waterlogging stresses. Full article

In Northeast China, waterlogging has emerged as a significant challenge due to climate change, particularly during the June–August period when spring maize (Zea mays L.), at the post-tasseling phase, impedes a comprehensive understanding of responses and the development of resistance technologies. 2-(3,4-dichlorophenoxy) triethylamine (DCPTA) is suitable for the entire lifecycle of various economic and food crops, improving crop quality and enhancing stress resistance. The study investigated the ear leaf photosynthesis in relation to the root antioxidant systems’ differential responses of spring maize to waterlogging among the tasseling (VT), vesicle (R2) and dough (R4) stages, and the exogenous DCPTA regulating effect. Results revealed that waterlogging inhibited root physiological activity due to oxidative damage. Consequently, the stomatal restriction and non-stomatal restriction on photosynthesis appeared successively, and R4 was the most sensitive stage. Pretreatment with DCPTA reduced stomatal restriction by maintaining water transfer to the leaf through maintaining root physiological activity via enhanced ascorbate–glutathione cycle. Delayed non-stomatal restriction appeared due to relatively stable chlorophyll content and photosynthetic activities, and VT stage exhibited the highest susceptibility to DCPTA. The study provides a necessary theoretical foundation for comprehending the physiological mechanisms underlying yield formation of spring maize under waterlogging stress in Northeast China, and offers valuable insights for the development of chemical regulation technology. Full article

Prunella vulgaris, an essential component of traditional Chinese medicine, is suitable for growing in soil with a pH value ranging from 6.5 to 7.5. However, it is primarily cultivated in acidic soil regions of China, where its growth is frequently compromised by acidic stress. Selenium (Se) has been recognized for its potential to enhance stress tolerance in plants. However, its role in acid-stress-induced oxidative stress is not clear. In this study, the effects of varying Se concentrations on the growth and quality of P. vulgaris under acidic stress were investigated. The results showed that acid stress enhanced antioxidant enzyme activities, non-enzymatic antioxidant substances, and osmolyte content, accompanied by an increase in oxidant production and membrane damage. Furthermore, it decreased the photosynthetic capacity, inhibited root and shoot growth, and diminished the yield of P. vulgaris. In contrast, exogenous application of Se, particularly at 5 mg L⁻¹, markedly ameliorated these adverse effects. Compared to acid-stressed plants, 5 mg L⁻¹ Se treatment enhanced superoxide dismutase, peroxidase, ascorbate peroxidase, and glutathione peroxidase activities by 150.19%, 54.94%, 43.43%, and 45.55%, respectively. Additionally, soluble protein, soluble sugar, and proline contents increased by 11.75%, 23.32%, and 40.39%, respectively. Se application also improved root architecture and alleviated membrane damage by reducing hydrogen peroxide, superoxide anion, malondialdehyde, and electrolyte leakage levels. Furthermore, it significantly enhanced the photosynthetic capacity by elevating pigment levels, the performance of PSI and PSII, electron transfer, and the coordination of PSI and PSII. Consequently, plant growth and spica weight were significantly promoted, with a 12.50% increase in yield. Moreover, Se application upregulated key genes involved in flavonoid and phenolic acid metabolic pathways, leading to elevated levels of total flavonoids, caffeic acid, ferulic acid, rosmarinic acid, and hyperoside by 31.03%, 22.37%, 40.78%, 15.11%, and 20.84%, respectively, compared to acid-stressed plants. In conclusion, exogenous Se effectively alleviated the adverse effects of acid stress by improving the antioxidant system, growth, and photosynthetic capacity under acid stress, thus enhancing the yield and quality of P. vulgaris. Full article

Low-temperature storage is an effective method to extend the shelf life of harvested winter jujube fruit; however, the quality of winter jujube fruit decreases after refrigeration. To enhance the quality of winter jujube with minimum qualitative deterioration during cold storage, this study investigated the effects of different melatonin concentration (100, 150, and 200 µmol/L) treatments on the storage quality of winter jujube (during the white ripening stage) at 0 ± 1 °C (RH, 90 ± 5%) for 90 days. The relative indexes of the fruit quality and the antioxidant system were measured every 15 days. The results showed that different concentrations of melatonin treatments could maintain the fruit’s firmness, retard the fruit’s redness, and inhibit the decrease in weight, total soluble solid (TSS), titratable acidity (TA), and the contents of total phenols, flavonoids, glutathione, and ascorbic acid; they also inhibited the increase in relative conductivity, malondialdehyde (MDA), and hydrogen peroxide (H₂O₂) content of jujube fruits and enhanced antioxidant enzyme activities (superoxide dismutase (SOD), catalase (CAT), ascorbate peroxidase (APX), glutathione reductase (GR), and peroxidase (POD)). As a whole, the 200 µmol/L melatonin treatment had the best effect. Therefore, melatonin treatment can maintain the cold-stored quality of postharvest winter jujube by improving its antioxidant capacity. Full article

Cadmium (Cd), as one of the most toxic nonessential elements, severely prohibits plant growth and development. Hydrogen sulfide (H₂S) and methyl jasmonate (MeJA) play essential roles in plant response to abiotic stress. However, the potential mechanism of H₂S and MeJA in alleviating Cd stress in plants remains unclear. In the current study, the importance and crosstalk of H₂S and MeJA in the Cd tolerance of cucumber seedlings have been investigated. Our results revealed that Cd stress obviously prohibited the growth of cucumber seedlings. Optimal concentrations of H₂S donor sodium hydrosulfide (NaHS) or MeJA treatment, respectively, or in combination, significantly enhanced seedling growth under Cd stress. However, the positive effects of H₂S during seedling growth were obviously reversed by the application of MeJA biosynthesis inhibitors, which implied that MeJA might be involved in the H₂S-improved growth of cucumber seedlings under Cd stress. Moreover, Cd stress resulted in the increase in hydrogen peroxide (H₂O₂), superoxide radical (O₂^·−) accumulation, and impaired the functioning of the ascorbate–glutathione cycle. Both H₂S and MeJA decreased the reactive oxygen species (ROS) level and ameliorated the negative effects of Cd stress through significantly increasing the ratio of ascorbate (AsA)/dehydroascorbic acid (DHA) and reduced glutathione (GSH)/oxidized glutathione (GSSG). Besides that, the expression level of ROS scavenge genes was significantly upregulated by the application of exogenous H₂S or MeJA treatment. Moreover, H₂S and MeJA significantly enhanced the chlorophyll concentration and inhibited chlorophyll degradation through decreasing the expression levels of chlorophyll catabolic enzymes. Additionally, exogenous H₂S and MeJA obviously enhanced the chlorophyll fluorescence. However, MeJA biosynthesis inhibitors significantly suppressed the positive role of H₂S. The above results suggested MeJA is involved in H₂S-induced Cd stress alleviation in cucumber seedlings through enhancing ROS-scavenge capacity and improving the photosynthesis system. Full article

A previous exposure to drought priming (DP) or salt priming (SP) could significantly improve future tolerance to both the same and different abiotic stresses, which is an effective mitigation strategy for plants to adapt to changing environmental conditions. If the type of stress priming is different from subsequent abiotic stress, this indicates that plants are trained to acquire cross tolerance. The objective of this study was to explore DP-regulated cross tolerance to salt stress and SP-induced cross tolerance to drought associated with changes in growth, antioxidant defense, proline metabolism, and the expression of the dehydration-responsive gene Dehydrin b involved in the stabilization of membrane systems, cryoprotection of intracellular proteins, and enhancement in water retention capacity in white clover (Trifolium repens). Plants were pretreated by initial DP or SP and then subjected to subsequent salt stress or drought stress for 10 days, respectively. The results demonstrated that DP significantly increased number of roots during subsequent salt stress, whereas SP significantly improved stem length, root length, and number of roots under drought stress, which indicated that the SP exhibited more pronounced and positive effects on mitigating subsequent drought-induced growth retardant. Both salt stress and drought resulted in significant increases in electrolyte leakage and contents of superoxide anion, hydrogen peroxide, and malonaldehyde due to reduced superoxide dismutase, peroxide, and catalase, as well as key enzyme activities in the ascorbate–glutathione cycle. SP or DP could significantly enhance these enzyme activities to alleviate subsequent drought- or salt-induced oxidative damage. SP or DP also significantly improved the accumulation of proline contributing to better water homeostasis by promoting biosynthetic enzyme activities (Δ¹-pyrroline-5-carboxylate synthetase and aminotransferase) and restricting proline dehydrogenase activity for proline degradation under drought or salt stress, respectively. In addition, SP significantly up-regulated the expression of dehydrin b under drought stress, but DP failed to induce the expression of dehydrin b in response to subsequent salt stress. The current findings proved that the pre-exposure of white clover plants to DP or SP could effectively mitigate the negative effects of subsequent salt stress or drought related to some common and different pathways. Plants pretreated by initial DP or SP exhibited better adaption to subsequent different stress by regulating growth, physiological, metabolic, and transcriptional changes. Full article

Light is a vital regulator of photosynthesis, energy production, plant growth, and morphogenesis. Although these key physiological processes are well understood, the effects of light quality on the pigment content, oxidative stress, reactive oxygen species (ROS) production, antioxidant defense systems, and biomass yield of plants remain largely unexplored. In this study, we applied different light-emitting diode (LED) treatments, including white light, red light, blue light, and a red+blue (1:1) light combination, to evaluate the traits mentioned above in alfalfa (Medicago sativa L.). Fluorescence staining showed that red light significantly triggered the oxidative stress indicators compared to blue and white light, while the combined red and blue light treatment significantly reduced the ROS (O₂^•−, H₂O₂) intensity in alfalfa seedlings. Interestingly, the combined light treatment significantly boosted the seed germination rate (%), maximum photochemical quantum yield of PSII (Fv/Fm), leaf greenness (SPAD score), photosynthetic pigment levels (chlorophyll a, chlorophyll b, and carotenoids), and plant biomass yield in alfalfa seedlings. The red and/or combined (red+blue) light treatments significantly regulated antioxidant enzymes (SOD, CAT, APX, and GR) and the expression of genes related to the ascorbate–glutathione (AsA-GSH) pathway, including monodehydroascorbate reductase (MsMDHAR), dehydroascorbate reductase (MsDHAR), ascorbate peroxidase (MsAPX), and glutathione reductase (MsGR). These results indicate that light quality is crucial for regulating the morphological, physiological, and molecular traits linked to alfalfa improvement. These findings suggest a new approach to enhancing the adaptation, as well as the morphological and agronomic yield, of alfalfa and forage legumes through light-quality-mediated improvement. Full article

Most commercial citrus fruits are grown in acidic soils with high copper (Cu) and low organic matter levels in China. Sweet orange (Citrus sinensis (L.) Osbeck cv. Xuegan) seedlings were treated with 0 (HA0), 0.1 (HA0.1), or 0.5 (HA0.5) mM humic acid (HA) and 0.5 (Cu0.5) or 400 (Cu400 or Cu excess) μM CuCl₂ for 24 weeks. The purpose was to validate the hypothesis that HA reduces the oxidative injury caused by Cu400 in roots and leaves via the coordination of strengthened antioxidant defense and glyoxalase systems. Copper excess increased the superoxide anion production rate by 27.0% and 14.2% in leaves and by 47.9% and 33.9% in roots, the malonaldehyde concentration by 199.6% and 27.8% in leaves and by 369.4% and 77.4% in roots, and the methylglyoxal concentration by 18.2% and 6.6% in leaves and by 381.8% and 153.3% in roots, as well as the H₂O₂ production rate (HPR) by 70.5% and 16.5% in roots, respectively, at HA0 and HA0.5. Also, Cu400 increased the leaf HPR at HA0, but not at HA0.5. The addition of HA reduced the Cu400-induced production and accumulation of reactive oxygen species and methylglyoxal and alleviated the impairment of Cu400 to the antioxidant defense system (ascorbate-glutathione cycle, antioxidant enzymes, sulfur-containing compounds, and sulfur-metabolizing enzymes) and glyoxalase system in roots and leaves. The HA-mediated amelioration of Cu toxicity involved reduced oxidative injury due to the coordination of strengthened antioxidant defense and glyoxalase systems. These findings highlight the promise of HA for sustainable citrus cultivation in heavy metal (Cu)-polluted soils. Full article

Rosa roxburghii fruit has a short postharvest shelf life, with rapid declines in quality and antioxidant capacity. This research assessed how phytic acid affects the antioxidant capacity and quality of R. roxburghii fruit while in the postharvest storage period and reveals its potential mechanism of action. The findings suggested that phytic acid treatment inhibits the production of malondialdehyde (MDA) and enhances the activities and expressions of glutathione peroxidase (GPX), peroxidase (POD), catalase (CAT), and superoxide dismutase (SOD) while decreasing the generation of superoxide anions (O₂^•−) and hydrogen peroxide (H₂O₂). Phytic acid treatment activates the ascorbate–glutathione (AsA-GSH) cycle and enhances the activity and expression of key enzymes in the cycle: ascorbate peroxidase (APX), glutathione reductase (GR), dehydroascorbate reductase (DHAR), and monodehydroascorbate reductase (MDHAR). It also increases the levels of non-enzymatic antioxidants, such as ascorbic acid (AsA) and glutathione (GSH), while reducing the production of dehydroascorbic acid (DHA) and oxidized glutathione (GSSG). Moreover, phytic acid treatment enhances the ratios of AsA/DHA and GSH/GSSG, maintaining the reduced state of the fruit. In summary, phytic acid improves antioxidant defense system and activates the AsA-GSH cycle, alleviating oxidative damage and ensuring R. roxburghii fruit quality after harvest. Full article