Contamination of soil with chromium (Cr) is a rising problem in terms of agricultural sustainability and food safety. Here, the effects of methyl jasmonate (MJ; 0, 5, and 10 µM) on alleviating Cr stress (0, 100, and 200 µM) were surveyed in pot marigold (Calendula officinalis L.). The results showed that Cr stress significantly reduced photosynthetic pigments and leaf accumulation of total soluble sugars, total starch, and mineral nutrients and, consequently, lowered the height and biomass of pot marigold plants. Chromium toxicity also increased the leaf levels of oxidative stress markers and induced oxidative stress, which was associated with damage to bio-membranes and increased levels of malondialdehyde. However, MJ supplementation reduced the leaf accumulation of Cr, increased the content of photosynthetic pigments, and improved the performance of the photosynthetic machinery in Cr-stressed plants. MJ supplementation boosted the antioxidant defense system by upregulating antioxidant enzymes, glyoxalase enzymes, and the ascorbate-glutathione (AsA-GSH) pool redox, which significantly diminished Cr-induced oxidative stress. Hence, MJ supplementation might be a practicable approach for reducing Cr absorption and its negative impacts on pot marigold plants growing under Cr-contaminated conditions.

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