不同测定环境条件下转PEPC基因水稻及杂交后代光合特性的比较

Comparison of Photosynthetic Characteristics of PEPC Transgenic Rice and Its Hybrid Rice Lines under Field and Lab Conditions

为了揭示转C4光合基因水稻响应不同环境条件的生理机制，以转PEPC基因水稻（PEPC）、未转基因原种（WT）及杂种F1花培株系H45和H137为研究材料，研究了不同测定环境条件下其功能叶片的光合特性。结果表明：在室外[温度25～30℃，相对湿度67％～79％，光强（1200±50）μmol／（m^2·S），CO2浓度（390．0±10．5）μmol／mol]和室内[温度25℃，相对湿度60％～72％，光强（25．0±5．0）μmol／（m^2·S），CO2浓度（420．0±5．5）μmol／mol]的测定环境下，同一水稻品种的净光合速率没有明显差别，只是测定叶片净光合速率所需的光诱导时间不同。多元逐步线性回归分析结果表明，在不同测定环境条件下，不同环境因子对水稻叶片净光合速率的贡献力不同，在室外蒸腾作用对叶片净光合速率的影响最大，其次是相对湿度，而室内条件下气孔导度对水稻叶片净光合速率的影响最大。结果还表明，转PEPC基因水稻的净光合速率和气孔导度均最高，明显高于未转基因野生型（WT）的，这与转PEPC基因水稻具有较高的气孔导度和较强的胞间CO2利用能力（胞间CO2浓度较低）有关。

To elucidate the physiological mechanism of transgenic rice over expressing C4 photosynthetic genes responding to different environments, the photosynthetic characteristics of the functional leaves from PEPC transgenic rice and its hybrid rice H45 and H137 were studied under field and lab conditions. Although the light inducement time of leaves was different, the net photosynthetic rates of investigated rice were not evidently different under filed condition [ air temperature 25 - 30 ℃, relative humidity 67% -76% ,light intensity （ 1 200 ±50）μmol/（m^2·s） ,CO2 concentration （390. 0±10. 5） μmol/mol] and the lab condition [ air temperature 25 ℃, relative humidity 60% -72%, light intensity （25.0 ± 5.0） μmol/（ m^2 ·s）,C02 concentration （452. 0 ± 5.5 ） μmol/mol]. The linear regression analyses by SPSS statistical software showed that the contribu-tions of different environmental factors to net photosynthetic rate varied under field and lab conditions, the transpiration contributing the most in field condition, followed by relative humidity, and the stomatal conductance dominating the contribution in lab condition. Because of its stronger utilization ability of intercellular CO2 , the net photosynthetic rate and stomatal conductance of PEPC transgen-ic rice were higher than those of WT.