Exogenous application of Methyl jasmonate alleviates chromium-induced toxicity in Avena sativa L. by enhancing the antioxidant defense system and regulating lipid peroxidation

High levels of hazardous metals such as chromium (Cr) have been produced over decades of growing industrial activity, which reduces crop productivity. The impact of Cr on the physio-biochemical characteristics of A. sativa L. was assessed in this study. It was further shown that exogenous application of MeJA mitigated Cr-induced toxicity. The performance of oats was first assessed by measuring growth parameters (Plant Shoot length, root length, and biomass) and physio-biochemical parameters (Enzymatic and Non-enzymatic antioxidants). This study examined how methyl jasmonate (MeJA 50 and 100 µM) reduced Cr stress at concentrations of 50, 100, and 150 µM. The findings demonstrated that Cr stress drastically decreased photosynthetic pigments, protein content, and total carbohydrate content accumulation in the leaves, which in turn decreased the biomass and height of plants. In addition to inducing oxidative stress and raising leaf levels of oxidative stress markers, chromium toxicity was linked to elevated malondialdehyde levels by 44.70% compared to the control. However, in plants under Cr stress, MeJA supplementation enhanced the amounts of photosynthetic pigments, decreased the Cr accumulation in plants, and enhanced the efficiency of the photosynthetic machinery. By upregulating antioxidant enzymes, MeJA supplementation improved the antioxidant defense system, including POD (+ 127%) at 150 mM Cr + 100 µM MeJA, CAT at 150 µM Cr + 100 µM MeJA (+ 93% vs. control), and SOD (+ 82.9%) at 150 µM Cr + 50 µM MeJA. By lowering the MDA content by 44.70% and 25.37%, respectively, MeJA application also reduced lipid peroxidation (E1 and E2). MeJA at a concentration of 100 µM was found to be more effective in reducing Cr toxicity. Consequently, MeJA supplementation might be a practical way to reduce Cr absorption and its negative effects on plants of the A. sativa L. grown in environments contaminated with Cr.