Abstract: One year old Elaeagnus angustifolia L. seedlings were used to study the effect of exogenous abscisic acid and silicon on the leaf relative water content, leaf water potential, membrane relative permeability, MDA content, protective enzyme(SOD, CAT, APX) activities under 30 days drought stress（T2:SRWC=35%~40%）. Results showed that: When the seedlings were under T2 drought stress, the leaf relative water content and water potential decreased ascompared to control seedling(ck), and the membrane relative permeability increased, and the E.angustifolia L.seedlings were injured to a certain extent. After using exogenous abscisic acid on the same treatment, the leaf relative water content and catalase(CAT) activity of E.angustifolia L.seedlings increased, and its membrane relative permeability and MDA content decreased significantly, and the leaf water potential decreased too, therefore, using of exogenous abscisic could alleviate the injury of E.angustifolia L.seedlings under drought stress. Meanwhile, after using exogenous silicon on the same treated seedlings, the superoxide dismutase activity was enhanced, and leaf relative water content increased, its leaf water potential reduced to a certain extent, thereby, exogenous silicon could diminish the harm of E.angustifolia L.seedlings, by T2 drought stress.

Key words: drought stress, exogenous abscisic acid, exogenous silicon