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以原种粳稻Kitaake为对照,研究了转玉米PEPC基因水稻的PEPC的高表达和碳同化特性的关系.结果显示:与原种相比,转PEPC基因水稻气孔导度和光合速率显著增加,经统计分析,气孔导度的增加与光合速率的增加并无相关性.而在高光强下,与CO2浓缩有关的PEPC,CA酶蛋白的表达显著增加.因此在大气CO2浓度下可显著增加光合能力(50％);无CO2条件下,可减少叶内CO2释放量,从而降低了CO2补偿点.用专一的抑制剂DCDP处理,证明转PEPC基因水稻叶内PEPC的高表达与碳同化能力的提高和Fv/Fm的稳定性有关.用14C示踪20 s,转PEPC基因水稻14C较多的分配在C4光合原初产物天冬氨酸中,意味着叶内存在着一定的C4光合代谢途径.上述结果说明,用代谢工程可以在叶内构建初级的CO2浓缩机制,为转基因的高光效育种技术提供了生理依据.
Compared with the original japonica Kitaake, the relationship between the PEPC expression and carbon assimilation in PEPC transgenic rice was studied.The results showed that the stomatal conductance and photosynthetic rate of PEPC transgenic rice increased significantly There was no correlation between the increase of stomatal conductance and the increase of photosynthetic rate, but the expression of PEPC and CA related to CO2 concentration was significantly increased under high light intensity, so photosynthetic capacity was significantly increased under atmospheric CO2 concentration 50%). Under CO2-free conditions, CO2 release in leaves could be reduced and CO2 compensation point decreased. Using a specific inhibitor of DCDP, the high expression of PEPC and enhanced carbon assimilation in PEPC transgenic rice leaves And the stability of Fv / Fm.The 14C tracing for 20 s, PEPC transgenic rice 14C was more distributed in the aspartate of C4 photosynthetic primary, which means that there is some C4 photosynthetic metabolic pathway in leaves. The results showed that the primary CO2 enrichment mechanism could be constructed in leaves by metabolic engineering, which provided the physiological basis for the high light efficiency breeding of transgenic plants.