Exogenous Application of Chitosan Mitigates the Inhibitory Effects of Zinc on the Growth of Wheat Seedlings by Modulating Zn Transport and ROS Scavenging
摘要
Zinc (Zn) stress adversely affects the growth of wheat seedlings. Chitosan (CTS), a growth regulator, can mitigate stress-induced damage in plants. This study aims to investigate the alleviating effects of chitosan on zinc stress in wheat seedlings. A hydroponic experiment was conducted to examine the impact of various concentrations of exogenous chitosan (0, 25, 50, 100, 200, and 400 mg·L−1) on the physiological and biochemical characteristics of wheat seedlings under Zn stress (500 µmol·L−1). Chitosan enhanced biomass accumulation, root morphology, chlorophyll content, photosynthetic parameters, the ascorbate-glutathione (AsA-GSH) cycle, antioxidant enzyme activity, and soluble protein content in wheat seedlings, while reducing malondialdehyde (MDA) levels and Zn translocation to the above-ground parts. Additionally, partial least squares (PLS) analysis identified zinc accumulation as a key factor in wheat seedlings’ response to Zn stress. Specifically, 100 mg·L−1 CTS increased the tolerance index of shoots and roots by 30.59% and 47.90%, respectively, and significantly reduced oxidative damage caused by Zn stress. The study recommends using 100 mg·L−1 CTS as an effective exogenous treatment to enhance zinc stress tolerance in wheat seedlings.