Abstract:

Effects of relative soil water content on the changes of chlorophyll content , photosynthesis and the parameters of chlorophyll fluorescence in pistachio ( Pistacia vera L. ) leaves were investigated. The results were as follows : the content of Chl1a and Chl1b and the net photosynthetic rate in pistachio leaves were decreased while the content of carotenoid were enhanced by drought stress. The activity of PS Ⅱand the parameter of chlorophyll fluorescence in pistachio leaves such as conversion efficiency of primary light energy ( Fv/ Fm) of PS Ⅱ, the photochemical quenching coefficient (qP) , the Non2photochemical quenching coefficient (qN) and the quantum yield of PS Ⅱelectron transport (ΦPS Ⅱ) were decreased respectively when the relative soil water content is 20 %. The reasons of Pn decreased were stomatal and nonstomatal limitation respectively in light and severe drought stress condition. Under drought stress , It is a primary reason of net photosynthetic rate decreasing in pistachio leaves that the the quantum yield of PS Ⅱelectron transport (ΦPS Ⅱ) were reduced by soil drought and high irradiance.

Key words: Pistachio, Relative soil water content, Chlorophyll fluorescence, Photosynthesis