Nano-FeO: Enhancing the tolerance of Elymus nutans to Cd stress through regulating programmed cell death.

Cadmium (Cd) poses a significant threat to plant growth and the environment. Nano-FeO is effective in alleviating Cd stress in plants. Elymus nutans Griseb. is an important fodder crop on the Qinghai-Tibetan Plateau (QTP). However, the potential mechanism by which nano-FeO alleviates Cd stress in E. nutans is not well understood. E. nutans were subjected to single Cd, single nano-FeO, and co-treatment with nano-FeO and Cd, and the effects on morphology, Cd uptake, antioxidant enzyme activity, reactive oxygen species (ROS) levels and programmed cell death (PCD) were studied to clarify the regulatory mechanism of nano-FeO. The results showed that Cd stress significantly decreased the germination percentage and biomass of E. nutans. The photosynthetic pigment content decreased significantly under Cd stress. Cd stress also caused oxidative stress and lipid peroxidation, accumulation of excessive ROS, resulting in PCD, but the effect of nano-FeO was different. Seed germination, seedling growth, and physiological processes were analyzed to elucidate the regulatory role of nano-FeO nanoparticles in promoting photosynthesis, reducing Cd accumulation, scavenging ROS, and regulating PCD, to promote seed germination and seedling growth in E. nutans. This report provides a scientific basis for improving the tolerance of Elymus to Cd stress by using nano-FeO.