摘要:以原种和转PPDK光合酶基因水稻为材料,测定了C4光合酶活性、光合速率以及活性氧代谢有关指标,结果如下:原种中具有全套的C4光合酶,但活性很低,而转PPDK光合酶基因水稻高表达了相应的C4酶活性。在高光条件下,与原种相比较,转PPDK基因水稻的光合速率未增加。NaHSO3激活剂NaHSO3处理后,可显著提高转PPDK基因水稻的光合放氧速率,显现出类似C4的光合特点,表明ATP是构建类似C4水稻的重要限制因素。光氧化条件下,转PPDK基因水稻的耐光氧化能力得到进一步的增强。这些结果为构建C4水稻提供了技术途径。
关键词:转PPDK基因水稻;亚硫酸氢钠;光合磷酸化;光合作用
Abstracts: With untransformed rice and transgenic rices with different C4 photosynthesis genes as the materials, the activity of C4 photosynthesis enzymes, the net photosynthetic rate (Pn) 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 rices were all highly expressed. The Pn of the PPDK transgenic rice was not increased. After treatment with ATP and its activator NaHSO3,the photosynthetic rate of O2 evolution were significantly increased in the PPDK transgenic rice and the transgenic rice which reached 80.7% of that in maize and exhibited photosynthetic character of C4–like plants.This indicated that ATP is the key limited factor for constructing C4–like rice. In addition, after MV( artificial photooxidative activator) treatment,the PPDK transgenic rice was more tolerant to photooxidative stress. These results would provide a new technical approach to constructing C4-like rice.
Key Words:transgenic rice; photosynthetic characteristics; C4 photosynthetic cycle;Adenosine triphosphate(ATP)