Studies On The Effects Of Water Stress On Lipid Peroxidation,Protective Enzyme Activities And Related Physiological Indexes Of Hot Pepper

Xiangyan NO.1, Xiangyan NO.5 and Xiangyan NO.10 were used as the materials to study changes of some physiological indexes under water stress. The physiological indexes included relative water content, relative permeability of plasmalemma, MDA content, protective enzyme (SOD, POD and CAT) activities, endogenous antioxidant(endogenous ascorbic acid) content, chlorophyll content and free proline content. The results indicated that under drought stress, the relative water content, AsA content and chlorophyll content always decreased; The free proline content always increased; The protective enzyme (SOD, POD and CAT) activities increased at first and then decreased; The relative permeability of plasmalemma and MDA content at the seedling stage increased after decreasing a little, and the two physiological indexes at the flowering stage and the fruit setting early stage always increased. On the whole, under drought stress, Xiangyan NO.5 kept great relative water content, chlorophyll content, free proline content. AsA content and protective enzyme activities (or increase of activities), and kept little relative permeability of plasmalemma and MDA content. However, Xiangyan NO.1 was opposite. Xiangyan NO.10 lay between Xiangyan NO.1 and Xiangyan NO.5; The seedling stage kept great relative water content, chlorophyll content, AsA content, free proline content and protective enzyme activities and kept little relative permeability of plasmalemma and MDA content. However, the flowering stage was opposite. The fruit setting early stage lay between the seedling stage and the flowering stage. This indicated that among the three cultivars, Xiangyan NO.5 had the greatest ability to resist drought stress while Xiangyan NO.1 had the least ability to do it. it also indicated that among the three different growth-development stages, hot pepper had the greatest ability to resist drought stress at the seedling stage and had the least ability to do it at the fruit setting early stage. Under water-soaked stress, the relative permeability of plasmalemma and MDA content always increased while the protective enzyme (SOD, POD and CAT) activities increased at first and then decreased. Moreover, Xiangyan NO.5 kept little relative permeability of plasmalemma and MDA content and kept great protective enzyme activities. Xiangyan NO. IC had the opposite results. Xiangyan NO.1 lay between Xiangyan NO.5 and Xiangyan NO.10. This indicated that among the three cultivars, XiangyanNO. 5 had the greatest ability to resis1 water-soaked stress, and Xiangyan NO.10 had the least ability to resist water-soaked stress. Tlx variant analysis and principal component analysis indicated the changes of the physiologica indexes of the different cultivars and the different growth-development stages under water stress 2 ? 7 were both complete and independent. These physiological indexes and their changes could be used as basis to identify the water stress resistance of the different cultivars and the different growth-development stages. Song Zbirong (Vegetable culture physiology) Directed by Liu Mlngyue (Professor)...