柑桔开花、幼果期的异常高温胁迫对叶片光合作用的影响

Effect of High Temperature Stress on Leaf Photosynthesis of Citrus During Blossom and Young Fruit Stage

研究了柑桔花期、幼果期的异常高温胁迫对柑桔叶片光合速率的影响。受异常高温的突然袭击后，柑桔叶的光合速率迅速大幅度下降。较高的大气相对湿度能很大程度上抵消短期高温的效应，但对较长时间的高温作用不大。高温对叶光合速率的影响，短期内主要通过气孔限制ＣＯ２供应量来实现，随后较长时间内主要通过抑制叶肉细胞的光合活性来实现、经较长高热环境的影响后，叶片的光合速率会产生适应性的恢复，使光饱和点、光补偿点、最适温度及适宜温度范围等产生明显的变化。

The effect of high temperature stress on leaf photosynthesis of satsuma mandarins was investigated during blossom and young fruit stage. Leaf photosynthetic rate decreased significantly and rapidly as plants were subjected to extremely high temperature.Relatively high air humidity could diminish the effect of short-term stress. At the initial stage,the reduction of photosynthetic rate under high temperature stress was attributed to the limitation of CO2 supply by decreasing stomatal conductance, whereas to the inhibition of mesophyll photosynthetic actvities at the fallowing stage.It was found that an acclimative recovery of leaf photosynthetic rate accompanied by changes in light saturation point, light compensation point, optimum temperature and its range following a long-term stress.