Effect of ATP on the Photosynthetic Physiological Characteristics in the Transgenic Rice (ORYZA SATIVA L.) expressing C4 Enzyme Genes

With untransformed rice and transgenic rice with different C4 photosynthesis genes as the materials, the activity of C4 photosynthesis enzymes, the photosynthetic rate and the indexes of active oxygen metabolism were determined. The activities of C4 photosynthesis enzymes in untransformed rice were very low while those of corresponding enzymes in different transgenic rice were all highly expressed. Compared with the photosynthetic rate of the untransformed rice, the photosynthetic rate of the PPDK transgenic rice was not increased; that of the ME transgenic rice was decreased for 6.1% ; that of the PEPC transgenic rice was increased for 38.5% and that of the transgenic rice with PEPC and PPDK genes (CK) and transgenic rice with PEPC,PPDK and ME genes(CKM) were similar with that of the PEPC transgenic rice under high light intensity. After the ATP treatment the rate of O2 evolution was significantly increased for the CK and CKM transgenic rice which reached about 80% of that of maize and exhibited photosynthetic characteristics of C4–like plants. This indicated that ATP is the key factor for constructing C4-like rice. In addition, after photooxidative treatment CKM transgenic rice was more tolerant to photooxidative stress. These results would provide a new technical approach for rice breeding with high photosynthetic efficiency and high grain yield.