Plant physiology and biochemistry : PPB | 2021
Hydrogen sulfide alleviates salinity stress in Cyclocarya paliurus by maintaining chlorophyll fluorescence and regulating nitric oxide level and antioxidant capacity.
Abstract
Cyclocarya paliurus is commonly used to treat diabetes in China. However, the natural habitats of C. paliurus are typically affected by salt stress. Hydrogen sulfide (H2S) is a growth regulator that is widely used to enhance plant stress tolerance, but the possible mechanism underlying H2S-alleviated salt stress in C. paliurus remains unclear. C. paliurus seedlings pretreated with NaHS (an H2S donor) were exposed to salt stress, and then, the leaf and total biomass, chlorophyll fluorescence parameters, nitric oxide (NO) content, oxidative damage, and proline and phenolic content were investigated to test the hypothesis that H2S and NO were involved in the salt tolerance of C. paliurus. The results showed that H2S pretreatment maintained chlorophyll fluorescence and attenuated the loss of plant biomass. We also found that H2S pretreatment further increased the endogenous NO content and nitrate reductase activity compared with salt treatment. Moreover, H2S pretreatment alleviated salt-induced oxidative damage, as indicated by lowered lipid peroxidation, through an enhanced antioxidant system including more proline and phenolic accumulation and increased antioxidant enzyme activities. However, C. paliurus leaves treated with the NO scavenger significantly diminished H2S-mediated NO production and alleviation of membrane lipid peroxidation. Thus, we concluded that H2S-induced NO was involved in C. paliurus salt tolerance.