摘要：To explore the effects of calcium fertilizer on photosynthesis of two rice cultivars, maize pepc over ex-pressed transgenic rice ( PC) and Kitaake ( wild type, WT) with different endogenous calcium contents were studied under drought stress. In hydroponics experiments, the net photosynthetic rates of WT and PC rice could be enhanced by appropri-ate concentration of calcium. After one-day treatment, 0. 5 mmol/L calcium presented the best improvement of photosynthe-sis, and two days later, the improvement was not detectable. Through spraying, calcium had promoting effect only on WT rice, not on PC rice. These indicated that hydroponics was favorable for photosynthesis. Under 15% PEG drough stress, the net photosynthetic rate of WT rice was increased by 5. 0 mmol/L CaCl2 treatment for one day, and that of PC was in-creased by both 5. 0 mmol/L and 10. 0 mmol/L CaCl2 treatments, compared to the control. It was concluded that appropriate amount of exogenous calcium supplement could alleviate the damage caused by drought stress, and the a-mount depended on endogenous calcium content of rice cultivar.%以2种不同内源钙含量的水稻品种( WT和PC)为材料,通过不同方式施入钙肥(叶面喷施和水培),以及用15%聚乙二醇(PEG-6000)模拟干旱胁迫研究钙对供试水稻光合作用的影响。结果表明,水培方式中,加入适宜浓度的钙可以增强 WT 和 PC的净光合速率,处理后1 d,0.5 mmol/L的钙对水稻光合作用促进最明显,3 d后促进效应消失,而通过叶面喷施仅对WT的净光合速率有促进效果,对PC没有促进作用,表明通过水培方式施用钙肥更加有利于增强光合作用；在15% PEG-6000模拟干旱胁迫下,5.0 mmol/L的钙处理1 d增强了WT的净光合速率,5.0 mmol/L和10.0 mmol/L的钙处理促进了PC的净光合速率。可见,施用适宜浓度外源钙可以缓解干旱逆境对供试水稻光合作用的影响。
