Hydrogen sulfide promotes wheat seed germination under osmotic stress

Effects of NaHS, H(2)S 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 S(2-), SO (4) (2-) , SO (3) (2-) , HSO (4) (-) and HSO (3) (-) , were not able to improve seed germination as NaHS did, confirming H(2)S 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 H(2)S donor treatment could retain higher levels of endogenous H(2)S in wheat seeds under osmotic stress. These data indicated that H(2)S played a protective role in wheat seed against osmotic stress.