外源H2O2对孕穗期转C4PEPC水稻及原种光合特性的影响

Effect of Exogenous H_2O_2 on Photosynthetic Characteristics in PEPC Transgenic Rice

为阐释转C4PEPC光合基因水稻过氧化物胁迫条件下的光合生理特性,以转PEPC基因水稻(PC)、未转基因原种(Kitaake)为材料,运用Li-6400便携式光合仪观测其在不同浓度外源H2O2处理下的净光合速率(Pn)、气孔导度(Gs)、胞间CO2浓度(Ci)、蒸腾速率(Tr)以及水分利用率等光合参数的变化。结果发现,与未用H2O2处理的PC相比,PC在0.5～5mmol/LH2O2浓度处理下,其Pn在不同光强下均表现下降,与其Gs的下降一致,这个抑制过程随光强的增加而减弱,而50mmol/LH2O2处理下PC,虽Gs增加,但是其Pn并没有增加,表现不同H2O2的浓度效应;而未转基因水稻则没有上述表现,推测PC可能通过低浓度的H2O2参与气孔运动的调节,从而影响其光合特性。

To elucidate the physiological mechanism of transgenic rice over expressing C4 photosynthetic genes responds to peroxide stress,the photosynthetic characteristics of the functional leaves net photosynthetic rate Pn,stomatal conductance Gs,intercellular CO2 concentration Ci,transpiration rate Tr and water utilization rate from PEPC transgenic rice and its wild type Kitaake were studied with Li-6400 portable photosynthesis system under different density exogenous H2O2. Net photosynthetic rate of transgenic rice treated with 0. 5-5 mmol/L H2O2 descend as same as changing of stomatal conductance compared to control,and the inhibition are weaken as light intensity increasing. Stomatal conductance of transgenic rice under 50 mmol/L H2O2 treatment is raise but net photosynthetic rate is unchange. Photosynthesis physiological nature of Kitaake under H2O2 concentration gradient are not characteristic like transgenic rice. So 0. 5 mmol/L is effective density to regulate stomatal conductance of transgenic rice,to affect photosynthesis physiological characteristic.