Effects Of PEG And SA Pretreatment On Proline Content And The Proline Metabolic Enzymes Of Rice Seedlings Under Water Stress

Rice (Oryza sativa L.)is an important crop in China. It costs a lot of water. Drought is the most important abiotic stress limiting rice productivity in China which affects rice yield. Proline as an osmolyte play a crucil role in plants during adaption to various types of environmental stresses.The paper mainly studied the effects of PEQSA pretreatment on proline accumulation, activities of the metabolic enzymes, physiological and biochemical changes in rice seedings under water stress(15% PEG treatment). Pretreatment with salicylic acid (0.1 mmol/L) was used to alleviate water stress in rice seedings, effect of PEG pretreatment is not obvious. Results were showed as follows:1.Effects of PEQSA pretreatment on plant height of rice seedlings under water stress were no difference, but root length increase rate were greater than those of CK1 and CK2 group during water stress.2.At the end of water stress processing, effects of PEG,SA pretreatment on relative water content in leaves of rice seedlings under water stress were higher than that of CK2 and SA was higher than PEG.3.PEG,SA pretreatment on soluble protein content in leaves of rice seedlings were higher than that of CK2, the roots had the same trend, but later period roots soluble protein content of PEG pretreatment reduced quickly, lower than that of CK1; PEG,SA pretreatment on soluble sugar content in leaves of rice seedlings were higher than that of the CK2, and PEG was lower than that of SA; the level of SA pretreatment on Soluble sugar content in roots was increased significantly to the highest in 48 hours; and SA pretreatment was signifieantly higher than those of other three groups.4.After the treatment to 15% PEG, the level of PEQSA pretreatment and the proline of CK2 in leaves and roots were increased significantly, the level of SA pretreatment on proline in leaves was significantly higher than that of other three group in latter water stress, SA pretreatment can significantly enhanced the level of proline in leaves. compared the level of root proline content in 72 hours, CK2 is significantly higher than other groups.5.The level of PEQSA pretreatment on P5CS activities in leaves were increased significantly to the highest in 48 hours, but CK2 appeared in 24 hours. The level of PEQSA pretreatment and theδ-OAT of CK2 activities in leaves and roots were increased significantly, and the level of SA pretreatment onδ-OAT activity in roots was higher than PEG pretreatment and CK2 groups; After water stress, proline accumulation was closely related with ProDH activity reduced; When the content of proline beginning to reduce, ProDH activity increased.