转C4基因水稻的生理表现

以C3水稻原种(WT)和C4玉米为材料,研究了转PEPC+PPDK+ME基因水稻(PKM)的C4光合酶活性、不同光温条件下光合参数和水分利用效率、活性氧代谢等指标。结果表明,PKM水稻饱和光合速率介于WT和C4玉米之间,稍偏向玉米,而水分利用效率与WT接近。由于玉米C4基因的导入,PKM水稻高表达了相关的C4光合酶。在高光和高温条件下,PKM水稻光合速率比原种提高55%以上。另外,虽然PKM水稻光合速率增加,但蒸腾速率亦升高,因此PKM水稻的水分利用效率略有增加,偏向原种。在光氧化条件下,PKM水稻耐光氧化能力进一步增强。

Physiological Performance of Transgenic Rice Expressing C4 Genes

In this study,the activities of C4 photosynthetic enzymes(including PEPC,PPDK,ME and MDH),the gas exchange parameters and water use efficiency(WUE) under different light intensities and temperatures,and the metabolic index of active oxygen were determined in transge-nic rice carrying PEPC,PPDK and ME genes(PKM),taking the C3-type untransformed rice(WT) and maize(a C4 plant) as controls.The result showed that the light-saturated photosynthetic rate of PKM was intermediate between WT and maize,with a slight bias towards maize,while the WUE of PKM was similar to WT.The C4 photosynthetic enzymes were highly expressed in the PKM.Under the conditions of high photon flux density and high temperature,the photosynthetic rate of PKM increased by 55%,as compare to WT.Though Pn of PKM increase,its transpiration rate was also increased.Thus the WUE of CK was only slightly increased,and was similar to WT.In addition,the resistance of CK to photo-oxidation was enhanced under the photo-oxidative conditions.Based on the above results,CK possesses enhanced photosynthetic productivity,providing a new technical approach and physiological basis for constructing C4-like rice with enhanced photosynthetic efficiency and high yields.