甘蔗光合速率的日变化及其对光温的响应

在田间和盆栽正常生长条件下，Ｃ４植物甘蔗的光合速率日变化明显地不同于Ｃ３植物甘薯．甘薯为典型的双峰曲线，中午Ｐｎ的明显降低主要是由非气孔因素限制引起；而甘蔗为单峰曲线，其峰值出现在上午１０００左右．甘蔗Ｐｎ变化受到光温条件的强烈影响，强光有利于Ｐｎ提高，弱光下其Ｐｎ略低于甘薯，温度过高（＞４０℃）或过低（＜１５℃）明显地抑制甘蔗光合作用．还分析了引起Ｐｎ变化的气孔和非气孔限制．

Diurnal variation of photosynthetic rate in sugarcane and its responses to light and temperature

The diurnal variation of photosynthetic rate in sugarcane greatly differed from that in the sweet potato under the normal growing condition of field or pot culture. Two peaks of the net photosynthetic rate (Pn) were found in the sweet potato, and the midday depression of Pn was caused by the non stomatal limitation. However, only one peak of Pn was observed at 10∶00 a.m. in sugarcane.The Pn in sugarcane increased in the strong light, but lower than that in sweet potato in the weak light. It was also greatly inhibited by high temperature (>40 ℃) or low temperature (<15 ℃).The stomatal and non stomatal limitations affecting Pn were discussed .