Hydrogen sulfide promotes wheat seed germination under osmotic stress

Abstract

Effects of NaHS, H2S donor, on germination and antioxidant metabolism in wheat (Triticum aestivum L.) seeds under osmotic stress were investigated. With the enhancement of osmotic stress, which was mimicked by PEG-6000, the seed germination dropped gradually. NaHS treatment could promote wheat seed germination against osmotic stress in a dose-dependent manner; while Na+ and other sulfur-containing components, such as S2−, SO42−, SO32−, HSO4− and HSO3−, were not able to improve seed germination as NaHS did, confirming H2S or HS− derived from NaHS contribute to the protective roles. Further experiments showed that NaHS treatment combined with PEG enhanced the activities of amylase and esterase in comparison to PEG treatment alone. Alternatively, NaHS treatment significantly reduced malondialdehyde and hydrogen peroxide accumulation in seeds. Significant enhancement of catalase and ascorbate peroxidase activities and decrease in lipoxygenase activity were observed in NaHS treated seeds, while peroxidase and superoxide dismutase activities were not affected as compared with the control. Furthermore, the H2S donor treatment could retain higher levels of endogenous H2S in wheat seeds under osmotic stress. These data indicated that H2S played a protective role in wheat seed against osmotic stress.