干旱处理对澳洲坚果光合特性的影响

为探究澳洲坚果‘桂热1号’苗期对干旱的生理响应机制,研究该品种在持续干旱处理7 d的叶片含水量、光合色素含量、荧光参数、渗透调节物质和保护酶活性的变化规律。结果表明:随着干旱程度的增加,‘桂热1号’土壤含水量和叶片含水量均呈逐渐下降趋势,在断水7 d最为明显。干旱导致‘桂热1号’叶绿素含量显著下降,但胡萝卜素含量先升后降。光合速率在断水5和7 d下降明显,伴随着活性氧清除酶活性下降。表明,‘桂热1号’对干旱的自身调控能维持5 d。

Effects of Drought on the Photosynthesis of Macadamia integrifolia

The plants of macadamia variety ‘ Guire 1’ (Macadamia integrafolia) were treated with drought for 7 days,and their leaf water content,chlorophyll contents,fluorescence parameters,osmoregulation substance and protective enzyme activities were determined to elucidate the mechanisms of their physiological response to drought.The results showed that soil water content and leaf water content of macadamia ‘ Guire 1’ tended to decrease gradually with an increase in drought stress,most obviously at the 7th day of drought stress.Under drought stress the leaf chlorophyll content decreased significantly while the leaf β-carotene content first increased and then decreased.Both photosynthetic rate and ROS scavenging enzyme activities decreased at the days 5 and 7 under drought stress.This indicated that the macadamia Guire 1 could regulate drought stress by itself for 5 days.