Effects of exogenous nitric oxide on seed germination, seedling growth and antioxidant enzyme activities of several plant species

Nitric oxide (NO) plays an important role in growth and development of plants. In this study, Sodium nitroprusside (SNP) is used as NO donor to examine the effects of NO on seed germination, seedling growth and activities of antioxidant enzymes of maize, wheat, peanut, pakchoi, radish and cucumber. The results show that the low concentrations (0.01 and 0.1 mmol/L) of SNP could promote the germination viability and germination percentage of seeds, while the high concentration (1.0 mmol/L) of SNP inhibits seed germination, and the effects on radish are the most obvious. The low concentrations of SNP promotes the growth of shoot significantly, and the effects on wheat and cucumber are the most obvious. The low concentrations also promotes the growth of root, and the effects on radish are the most obvious. The effects of SNP on seedling growth maybe related to the plant species. SNP could promote the root activities of most plants, the effects on radish are the most obvious. Suitable SNP concentration also enhances the activities of CAT, POD and SOD and the content of soluble protein, but declines the content of MDA. The optimal SNP concentration differs with different plants. In addition, the proper concentration for most plants is 0.1 mmol/L under the experimental conditions.