干旱胁迫对不同葡萄砧木光合特性和荧光参数的影响

干旱胁迫导致葡萄砧木实生苗叶片光合能力下降.在正常供水和轻度干旱下，砧木的P_n 以3309C最高，其次是1103P，420A较低，各砧木的G_s和T_r差异不显著；中度干旱下，则以1103P的P_n最高，3309C最低；而严重干旱胁迫下，1103P的P_n比3309C高出124%，水分利用效率是3309C的1.95倍.干旱胁迫下，3种砧木的共同趋势是可变荧光 (F_o) 升高，最大荧光 (F_m)、实际光能转化效率 (ФPSⅡ）和可变荧光与最大荧光比 (F_v/F_m) 降低，但品种变幅不同.中度干旱使3309C的F _o升高17.1%，F_v/F_m降低了8.5%，而1103P的F_o升高6.8%，F_v/F_m降低了5.8%；严重干旱则使3309C的F_o升高36.2%，F_v/F_m降低了20.1%，而1103P的F_o升高9.9%，F_v/F_m降低了10.2%.干旱胁迫对不同葡萄砧木光合和荧光参数的影响与其抗旱性密切相关，其中F_v/F_m和P_n的相关系数最大（r=0.9883）.

Photosynthetic characters and fluorescence parameters of different grape stocks under water stress

The study showed that water stress decreased the net photosynthetic rate (Pn), stomatal conductance (Gs), Tr transpiration rate (Tr), maximum fluorescence (Fm), ratio of variable to maximum fluorescence (Fv/Fm), and actual activities of PS II (phiPS II), but increased the minimal fluorescence (Fo). The alterations of test parameters differed with grape stocks. Under adequate water supply and mild water stress, the Pn of 3309C was higher than that of 1103P and 420A, while the chlorophyll fluorescence parameters of these three stocks changed a little. Under moderate water stress,the Pn of 1103P was higher than that of 420A and 3309C,the Fo of 3309C increased by 17.1% while Fv/Fm decreased by 8.5%, and the Fo of 1103P increased by 6.8% while Fv/Fm decreased by 5.8%. Under severe water stress,the Pn of 1103P was the highest (5.6 micromol x m(-2) x s(-1)), which was 24% higher than that of 3309C, and the water use efficiency of 1103P was about 1.95 times as high as that of 3309C. The Fo of 3309C increased by 36.2% while Fv/Fm decreased by 20.1%, and the Fo of 1103P increased by 9. 9% while Fv/Fm decreased by 10.2%. It was implied that there was a close correlation between drought-resistance and the alteration of photosynthetic characters and chlorophyll fluorescence parameters, of which, the correlation index of Fv/Fm and Pn was the highest (r = 0.9883).