Mitigating Chromium Toxicity in Hibiscus sabdariffa: Role of Foliar-Applied Putrescine in Regulating Oxidative Damage and Biomass Production

Chromium (Cr) toxicity is a major abiotic stressor that adversely affects plant growth by inducing oxidative damage and disrupting cellular homeostasis. This study aimed to evaluate the potential mitigating effects of exogenous putrescine on Hibiscus sabdariffa L. under Cr stress. A factorial experiment was conducted under greenhouse conditions using five Cr levels (۰, ۱۰, ۲۰, ۴۰, and ۸۰ mg kg¹ soil) and four foliar-applied putrescine concentrations (۰, ۰.۵, ۱, and ۲ mM). Chromium stress significantly increased malondialdehyde (MDA) content and electrolyte leakage (EL), while it reduced total phenolics and flavonoids, antioxidant enzyme activities (CAT, POD, and APX), and shoot dry weight. However, putrescine application, particularly at ۲ mM, markedly alleviated oxidative damage by reducing MDA and EL, while enhancing the accumulation of phenolic and flavonoid compounds, boosting antioxidant defense responses, and improving shoot biomass production. Notably, the application of ۲ mM putrescine was most effective in enhancing biochemical and physiological traits. These findings suggest that exogenous putrescine enhances Cr stress tolerance in Hibiscus sabdariffa by modulating oxidative stress markers and promoting antioxidative capacity, thereby contributing to improved plant performance under heavy metal stress. Overall, this study provides valuable evidence for the role of polyamine-based regulation as a promising avenue for enhancing plant tolerance to environmental contaminants like heavy metals.

کلیدواژه ها:

Antioxidant defense ، Food security ، Heavy metal stress ، Hibiscus sabdariffa ، Putrescine