Abstract
Background: Applying large amounts of potash fertilizer in apple orchards for high apple quality and yield aggravates KCl stress. As a phytoalexin, resveratrol (Res) participates in plant resistance to biotic stress. However, its role in relation to KCl stress have never been reported. Results: Malus hupenensis is a widely used apple rootstock in China and is sensitive to KCl stress. In this study, 100 µmol Res was exogenously applied to alleviate KCl stress in M. hupenensis seedlings. The seedlings treated with Res had higher chlorophyll content and photosynthetic index than those without Res treatment. Moreover, the molecular and physiological mechanisms of Res in ion toxicity, osmotic stress, and oxidative damage induced by KCl stress were also investigated. First, exogenous Res affects K+/Na+ homeostasis in cytoplasm by enhancing K+ efflux outside the cells, inhibiting Na+ efflux and K+ absorption, and compartmentalizing K+ into vacuoles. Second, this compound could respond to osmotic stress by regulating the accumulation of proline. Lastly, this polyphenol functions as an antioxidant that strengthens the activities of POD and CAT thus eliminates the reactive oxygen species production induced by KCl stress.Conclusions: Taken together, these results reveal that resveratrol alleviates the KCl salinity stress of M. hupenensis seedlings by regulating K+/Na+ homeostasis, osmotic adjustment, and reactive oxygen species scavenging.
Osmotic Stress Activates Two Reactive Oxygen Species Pathways with Distinct Effects on Protein Nanodomains and Diffusion