关键词: 河西走廊, 生态类型, 旱生植物, 内源激素, 叶水势

Abstract: The leaves of xerophytes of different ecological types distributed over Hexi Corridor were measured for the free abscisic acid(ABA),cytokinins(CTKs) isopentenyladenosine group(iPAs) and zeatin riboside group(ZRs),water potential using enzyme linked immunosorbent assays and pressure chamber method.The mean value of leaf water potential in the less-succulent xerophytes and the succulent xerophytes was -1.44 and -3.31 MPa respectively.The mean value of leaf ABA content in the less-succulent xerophytes and the succulent xerophytes was 5.58 and 3.47 nmol ·g^-1·dw^-1 respectively;the iPAs levels were significantly lower than the ZRs values in the leaves of xerophytes of two ecological types;the mean value of leaf CTKs(iPAs+ZRs) content in the less-succulent xerophytes and the succulent xerophytes was 20.47 and lh 69 nmol·g^-1 · dw_1 respectively;the ratio of ABA content to CTKs content in the less-succulent xerophytes and the succulent xerophytes was 0.27 and 0.30 respectively.These results indicate that the capacity of resistance/tolerance to drought may be mainly correlated with the balance between ABA and CTKs in the xerophytes of different ecological types growing in Hexi Corridor.

Key words: Ecological type, Xerophyte, Endogenous phytohormone, Leaf potential, Hexi Corridor