土壤干旱对小麦旗叶和穗器官C_4光合酶活性的影响

 研究了土壤干旱胁迫下小麦旗叶和穗器官C4途径主要酶及RuBP羧化酶活性变化的差异及其与光合性能的关系。结果表明 ,穗光合活性对水分胁迫的敏感性低于旗叶叶片的 ,在水分胁迫下穗光合速率下降幅度远小于叶片 ,这种差异与各器官C4途径酶活性的相对强弱及其对水分胁迫的响应程度不同有关。穗器官具有比叶片较高的C4酶活性 ,在轻度水分胁迫下 ,旗叶和穗器官的C4途径酶活性被诱导增强 ,其增强幅度以穗器官的高于叶片的。重度胁迫下外稃仍保持较高的C4酶活性 ,而叶片酶活性却下降。穗器官相对较高的C4酶活性及其在水分胁迫下诱导增加的特性可能是逆境下穗光合保持相对稳定的重要原因。

Effect of Soil Drought on C4 Photosynthesis Enzyme Activities of Flag Leaf and Ear in Wheat

The activities of RuBPC and C 4 photosynthetic enzymes in ear and flag leaf blade were examined in wheat. The results showed that photosynthesis of ear was less sensitive to soil drought than that of flag leaf, and decrease of CO 2 assimilation in flag leaf blade with water stress was more than that in ear. Compared with flag leaf, ear organs(awn,glume and lemma) had higher C 4 enzyme activities and lower RuBPC activity. Under mild water stress, C 4 enzyme activities were induced , and the increase was higher in ear than that in flag leaf. Under severe water stress, relatively higher C 4 enzyme activities were still maintained in ear, rather than that in flag leaf. It suggests that high activities of C 4 enzyme in ear may contribute to its high tolerance of photosynthesis to water stress.