Physiological effects of exogenous nitric oxide on Brassica campestris ssp. Chinensis L. seedlings under salt stress

In the last decade, the role of NO in plants has received much attention. Due to its multifunctional activities in plants, NO is now being considered as a new candidate plant hormone. However, it is not very clear that the physiological mechanism of exogenous NO alleviates salt effects in vegetable plants. Therefore, an experiment was conducted to study the effects of exogenous NO on physiological and biochemical characteristics in Brassica campestris ssp. Chinensis L. seedling leaves under salt stress. In the paper, different concentrations of sodium nitroprussiate (SNP) were served as the NO donor, and first used to irrigate the root of Brassica campestris ssp. Chinensis L. seedlings, then, to pour the seedling leaves. After these inducements of SNP, all treatments were dealt with 150 mM NaCl solution. On the 7th day after salt stress, morphologic characters, physiological and biochemical indexes were mensurated. The results indicated that exogenous NO could significantly improved stem height and diameter, number of leaves, fresh and dry mass and healthy index of seedlings. Moreover, exogenous NO could markedly increase chlorophyll and soluble protein content, free proline content, (SOD), peroxidase (POD), catalase (CAT) and ascorbate peroxidase (APX) activies, while significantly restrain the production of MDA. These results suggested that NO could regulate the antioxidative enzymes activity, mass-eliminate ROS, which improved salt-tolerance ability of Brassica campestris ssp. Chinensis L. seedlings.