Abiotic Stress Responses and Antioxidant Mechanisms in Plants

Plants are continually exposed to a multitude of abiotic stressors, including drought, salinity, extreme temperatures and heavy metals. These adverse conditions perturb cellular homeostasis, impair photosynthetic efficiency and induce the overproduction of reactive oxygen species (ROS). To mitigate oxidative damage, plants have evolved a finely tuned antioxidant defence system comprising enzymatic components—such as superoxide dismutase (SOD), catalase (CAT) and ascorbate peroxidase (APX)—and non-enzymatic metabolites, including ascorbic acid, glutathione and flavonoids. Stress perception triggers signal transduction pathways, notably those mediated by the phytohormone abscisic acid (ABA), which orchestrate stomatal closure, osmolyte accumulation and the activation of antioxidant genes. Osmolytes such as proline and glycine betaine stabilise proteins and membranes, while maintenance of ion homeostasis through transporters and antiporters safeguards cellular function under salinity and alkalinity. Lipid peroxidation, a hallmark of oxidative injury, is attenuated by coordinated antioxidant action. Integrative studies now reveal cross-talk between hormonal signalling, redox regulation and metabolic adjustment, underscoring a systemic response that balances defence deployment with growth maintenance. Advances in genetic, biochemical and exogenous-application approaches are informing strategies to enhance crop resilience in the face of escalating environmental challenges.

Research from Nature Portfolio

Recent studies have highlighted the central role of ABA in modulating antioxidant defence under salinity stress. Experimental foliar application of ABA in rice seedlings maintained photosynthetic pigment content, reduced lipid peroxidation and restored ionic balance by limiting sodium accumulation while enhancing potassium uptake. Enhanced activities of CAT, APX and peroxidase enzymes in both leaves and roots under ABA treatment underscore its capacity to recalibrate the redox state and mitigate oxidative damage. In wheat, a synthetic ABA analogue was shown to activate key drought-responsive genes, improve leaf water status and reduce ROS toxicity. This analogue mimicked native ABA signalling, driving osmotic adjustment, stomatal regulation and upregulation of antioxidant enzymes, thereby strengthening drought tolerance without compromising growth.

Abiotic Stress Responses and Antioxidant Mechanisms in Plants publication trend

The graph below shows the total number of articles in abiotic stress responses and antioxidant mechanisms in plants across all publications each year (not limited to Nature Index journals).

Technical terms

Reactive oxygen species (ROS): Highly reactive molecules (e.g. superoxide, hydrogen peroxide) generated under stress that can damage proteins, lipids and nucleic acids.

Antioxidant enzymes: Proteins such as superoxide dismutase, catalase and ascorbate peroxidase that detoxify ROS and protect cellular components from oxidative damage.

Abscisic acid (ABA): A phytohormone that mediates stomatal closure, osmotic adjustment and activation of stress-responsive genes under drought and salinity.

Osmolytes: Small organic compounds (e.g. proline, glycine betaine) that stabilise proteins and membranes and contribute to osmotic balance under dehydration or salt stress.

Lipid peroxidation: Oxidative degradation of membrane lipids by ROS, leading to compromised membrane integrity and cellular dysfunction.

Non-enzymatic antioxidants: Low-molecular-weight compounds such as ascorbate, glutathione and flavonoids that scavenge ROS and support enzymatic antioxidant systems.

References

1. Physiological mechanisms of ABA-induced salinity tolerance in leaves and roots of rice. Scientific Reports (2022).
2. A novel ABA functional analogue B2 enhances drought tolerance in wheat. Scientific Reports (2019).
3. Roles of Exogenous α-Lipoic Acid and Cysteine in Mitigation of Drought Stress and Restoration of Grain Quality in Wheat. Plants (2021).
4. Exogenous aspartic acid alleviates salt stress-induced decline in growth by enhancing antioxidants and compatible solutes while reducing reactive oxygen species in wheat. Frontiers in Plant Science (2022).
5. Foliar Spray of Stigmasterol Regulates Physiological Processes and Antioxidant Mechanisms to Improve Yield and Quality of Sunflower Under Drought Stress. Journal of Soil Science and Plant Nutrition (2023).