The Influence Of Silicon On Cabernet Sauvignon Seedling Under Salt Stress

By means of a system of nutrient solution culture under greenhouse, the effects of different concentration of exogenous silicon (Si) on anti-oxidative system, reactive oxygen species, soluble protein and praline content, root activity and ion content in leaves and roots of Cabernet Sauvignon seedlings were investigated under salt stress condition (50 mM NaCl).The main results of the dissertation were presented as follows:1. Compared with no salt addition treatment, the accumulation of plant biomass decreased, water content, root activity, chlorophyll and content of soluble protein of Cabernet Sauvignon seedlings obviously declined. Under salt stress condition, the accumulation of plant biomass, water content, root activity, chlorophyll and content of soluble protein of Cabernet Sauvignon seedlings obviously increased by exogenous silicon.2. Compared with no salt addition treatment, the activities of sueroxide dismutase (SOD), peroxidase (POD), catalase (CAT), ascorbate peroxidase (APX) and glutathione reducatase (GR) of Cabernet Sauvignon seedlings increased in the early period of stress but decreased in the later period. The content of ascorbic acid (AsA) decreased gradually all through the treatment, but the glutathione (GSH) increased in the former period of stress then gradually decreased later. Under salt stress condition, the SOD, POD, CAT, APX and GR activity got the farther increased, and the content of AsA and GSH were also increased by exogenous silicon.3. Compared with no salt addition treatment, the generation rate of superoxide radical (O2 ) and the content of hydrogen peroxide (H2O2) in leaves of Cabernet Sauvignon seedlings under salt stress increased, leading to the accumulation of ROS, the lipid peroxidation of membrane was more serious, leading to more content of malonaldehyde (MDA), and the relative permeability of membrane was also higher. So the membrane of leaves was damaged. The generation rates of O2 and the content of H2O2 in leaves of Cabernet Sauvignon seedlings were decreased, the lipid peroxidation of membrane alleviated, and then the content of MDA and the relative permeability of membrane decreased. So the damage to the leaves of Cabernet Sauvignon seedlings under salt stress was alleviated by exogenous silicon. 4. Compared with no salt addition treatment, the content of Na+ increased, but the content of K+, Ca2+ and Mg2+ decreased gradually along with the salt stress treatment. The balance of ion got serious destroyed. Under salt stress condition, the content of Na+ in leaves and root of Cabernet Sauvignon seedlings decreased, and the content of K+, Ca2+ and Mg2+ increased by exogenous silicon.5. The effects of different concentration of exogenous silicon to the Cabernet Sauvignon seedlings were different, there were obviously differences among each concentration treatment, there into, the concentration of 2.0 mM treatment was better than other concentration treatment in synthesis. Therefore, we suggest that we could according to this concentration to carry on farther investigation, and then provide reasonable gist for production.