Drought Stress and the Modulation of Physiochemical Parameters and Antioxidant Enzymes in Grapevine Rootstocks: Insights into the Protective Role of Methyl Jasmonate

The present study scrutinized the influence of foliar application of methyl jasmonate on the physiochemical characteristics and antioxidant enzymes of two grapevine rootstocks, ‘SO4’ (high drought tolerance) and ‘101-14’ (low drought tolerance), under drought conditions. The grapevine seedlings were sprayed with methyl jasmonate at 100 µM at 3-day intervals throughout the 28-day drought stress period. The results showed that treating both rootstocks with methyl jasmonate greatly minimized the adverse effects of reactive oxygen species caused by drought. Specifically, methyl jasmonate substantially reduced levels of malondialdehyde, hydrogen peroxide, and ion leakage while increasing photosynthetic pigment levels, soluble carbohydrates, proline, protein, and total phenols content. Additionally, applying methyl jasmonate improved the action of antioxidant enzymes like superoxide dismutase, ascorbate peroxidase, and catalase. This made the membranes of leaves more solid during drought conditions. Methyl jasmonate treatment reduced oxidative damage and improved mineral element (P, K, Mg, Ca, Fe, and Zn) accumulation in the green leaves of treated plants as opposed to the drought-untreated plants. These results were more noticeable in ‘SO4’ compared to ‘101-14’ rootstocks. Based on these results, applying methyl jasmonate at 100 µM to the leaves of grapevines may be considered a novel strategy for mitigating water scarcity in the grapevine production system.