【摘要】 在温室条件下控制不同土壤水势梯度,从叶绿素含量、叶绿素 a 荧光、光合速率和蒸腾系数等方面,探讨水分胁迫下木麻黄苗木的光合作用和水分利用效率的变化。结果显示,供试木麻黄树种的光合作用呈现明显的日变化规律。在干旱胁迫情况下,随着叶水势的降低叶绿素总含量、叶绿素 a 荧光强度和水分利用效率先是增加而后降低,叶绿素 a/b 值和净光合速率则逐渐下降。更多还原

【Abstract】 Based on the condition controlling soil water potential in the green house,the experiments were carried out within-photosythesis and water use efficiency of Casuarina species under the circumstance of wa- ter stress,by testing the indicators of chlorophyl content,chlorophyl A fluorescence,net photosynthesis rate and transpiration coefficient.The results showed that Casuarina species examined have clearly daily variation in photosynthesis.Under the condition of drought stress,total chlorophyl content,intensity of chlorophyl A fluorescence and water use efficiency increase first,then fall as water potential decrcase,but chlorophyl a/b and net photosynthesis rate drop gradually.更多还原