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Hydrogen sulfide, as a signal and redox molecular with bioactivity, was proved to have the similar physiological function with nitric oxide and carbon monoxide in animals. It is just the beginning about the physical function and the related signal mechanism in plant. However, few studies have shown that H2S acts as a alleviant in plants under oxidative damage induced by salinity stress or aluminum stress. In this paper, we investigate that NaHS, as H2S donor, pretreated wheat seeds with different concentration affects seed germination and potential physiology and biochemistry mechanism under salinity stress or aluminum stress.Salnity (sadium chloride, NaCl) stress has badly inhibition on seed germination, radicle and coleoptile and becomes more seriously with the enhancement of concentration. We found that at the NaCl concentration of 0.16 mol/L germination percentage decreases about half of the control, which was regarded as semi-inhibitory concentration for subsequent experiments. Aluminum (Al) can significantly inhibit seed germination especially on radicle growth. With the enhancement of Al3+ concentration, germination percentage, length of radicle and coleoptile decreased gradually. At 30 mmol/L, germination percentage dropped by 50% compared with that of the control, when radicle growth nearly completely stopped.NaHS, H2S donor alleviated the inhibitory effect of NaCl and aluminum stress and promoted seed germination in a dose-dependent manner. The pretreatment with NaHS at 1.2 mmol/L could pronounced alleviate NaCl stress and increase the growth of radicle, coleptile and radicle numbers, when it was 0.6 mmol/L on aluminum stress. Besides, pretreated with NaHS could notably promote activities of hydrolase and content of reducing suger and amino acid. Further researches showed that H2S could induce the expression of antioxidase such as CAT, POD, APX and SOD, and sustain lower levels of LOX, ROS (H2O2, O2) and malondialdehyde which will result in oxidative stress. Furthermore, the pretreatment with NaHS, extraneous H2S donor enhanced levels of endogenous H2S. These data indicated that H2S was involved the mechanism of germination seeds as a anti-oxidant signal molecule under salinity stress and aluminum stress.
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