The Effect And Mechanism Of ROS On Germination Of Hedysarum Scoparium Seeds

The ecological restoration of sandy area has been a hot issue in recent years, and the paints growing in desert take important place in sand fixation, vegetation recovery. This study takes the psammophyte Hedysarum Scoparium as experimental materials, explored the role of reactive oxygen speciese (ROS) in seed germination.(1)We found the germination and vigor index were increased after the seeds were treated by cold stratification. Further studies found the ROS content, enzyme activity of antioxidant system changing after the cold stratification.(2) After treated the seeds with exogenous ROS donor hydrogen peroxide (H2O2), methyl viologen (MV), we found that the donor could also increase the germination rate as the cold stratification treatment, while the antioxidant N-acetyl-L-cysteine (NAC) can reduce the germination. This indicated that the cold stratification is related to ROS accumulation in seed. Though staning the seed hypocotyls of imbibed seed, we found the ROS content showed a rising trend during imbibition, and mainly in the hypocotyle epidermal cells within the axis. Protein carbonyl detected showed that in the fast germinated seeds, there emerged the modification of the protein carbonyl, and this direct modification of protein may be involved in seed germination.(3) By studying the relationship between ROS and plant hormones as in the seed germination, it was discovered that abscisic acid (ABA) can reduce the germination rate and down regulate the ROS content. And ROS treatment also reduced the ABA content, in the same time, up regulated the gibberellin (GA) activity. Therefore, it was inferred that ABA and ROS keeps an antagonistic relations during seed germination. And it was the mutual regulation of the hormones, that affecting seed germination.Based on the results, we made a conclusion that ROS content was increased during the process of cold stratification which released the seed dormancy. The protein carbonyl modification induced by ROS and the interaction with plant hormones playing an active role in the germination.