春玉米叶片光合速率变化规律的研究

试验研究了不同营养条件下，春玉米“掖单4号”单叶片一生光合速率的动态变化，植株不同叶位叶片的光合速率和不同生育时期叶片平均光合速率的变化。结果表明：施氛可明显提高叶片光合速率，特别是对老龄叶片、植株的中下位叶片及植株生育后期叶片；氮磷配施可进一步提高叶片光合速率，尤其对展开1周左右的叶片、植株的中位叶及大喇叭口期至灌浆期的植株叶片光合速率的影响更明显；在氮磷配施的基础上增施钾肥，对叶片光合速率影响不明显，但在散粉期前后的高温低湿条件下，对中上位叶片维持较高的光合速率有一定作用。

STUDIES ON THE CHANGING PATTERN OF LEAF PHOTOSYNTHESIS OF SPRING MAIZE

The experiment studied the dynamic changes of the photosynthetic rates of individual leaves, at different sites and various in growth stages of Spring Maize " Yedan No. 4" under different nutritional situaions. The results indicated that Napplication can positively improve photosynthetic rates, especially on old leaves , middle and lower leaves, leaves of latter growing stages; N and P application can further raise photosynthetic rates, especially at about one week after leaf expansion, middle leaves and leaves of male tetrad stage to tasseling stage; Kapplication based on N. P have not obvious effect, but upper leaves can maintain high photosynthetic rates under condition of high temperature and low humidity during andthesis stage.