Exogenous putrescine modulates variety-specific cadmium tolerance in wheat seedlings: synergistic roles of antioxidant defense and physiological homeostasis.

Introduction: Cadmium (Cd) contamination in farmland is a significant environmental issues affecting crop yields. Putrescine (Put), a polyamine compound, functions as a signaling molecule that actively mediates plant responses to environmental adversities. Wheat exhibits a distinctive propensity for translocating the heavy metal Cd into its seeds compared to other crops, which poses a critical environmental adaptation challenge that needs to be addressed in agricultural systems. Methods: This study employed Changmai 4013 (Cd-tolerant) and Chang 6475 (Cd-sensitive) varieties as test materials to investigate the regulatory effect of exogenous Put treatment on the Cd tolerance of both varieties under Cd stress. Wheat seeds were soaked in 0.05, 0.1, 0.2, 0.4, 0.8, and 1.6 mM Put solution, and then cultured in a 80 mg·L Results: The results indicated that Cd stress significantly inhibited wheat germination and seedling vigor. However, exogenous Put treatment effectively alleviated the stress-induced damage. It reduced malondialdehyde (MDA) and hydrogen peroxide (H Discussion: Multivariate analysis revealed distinct mitigation mechanisms between the two cultivars. Changmai 4013 primarily relied on maintaining physiological homeostasis, whereas Chang 6475 depended on enhancing the antioxidant system. Furthermore, the latter exhibited a stronger demand for and utilization capacity of exogenous Put. These findings provide an important theoretical basis for wheat cultivar selection in Cd-contaminated areas and the precision field application of Put.