转C4光合酶基因水稻的CO2交换和荧光特性

用转PEPC、PPDK、NADP-ME、PEPC+PPDK酶基因水稻(Oryza sativa L.)及原种为材料 ,研究了光合作用对光照、温度、CO2的响应和光抑制条件下的叶绿素荧光特性,结果如下: 1.转C4光合酶基因水稻的饱和光合速率比原种高,其中转PEPC、PEPC+PPDK双基因水稻的光饱和点比原种高200 μmol*m-2*s-1,饱和光合速率比原种分别高51.6%和 58.5%;转PEPC基因水稻的羧化效率比原种高49.3%,CO2补偿点降低26.2%;在高温(35 ℃)下,转PEPC基因水稻的光合速率比原种高17.5%.2.经光抑制处理8 d后,转PEPC、PEPC +PPDK酶基因水稻的PSⅡ光化学效率(Fv/Fm)和光化学猝灭(qP)下降20%- 30%,非光化学猝灭(qN)增加了约30%;但原种的Fv/Fm和qP下降了5 0%多,qN变化不明显,表明转C4光合基因水稻耐光抑制能力增强.这些结果为用生物技术提高水稻光合效率研究提供了新的依据和途径.

Characteristics of CO2 Exchange and Chlorophyll Fluorescence of Transgenic Rice with C4 Genes

The responses of photosynthesis of phosphoenopyruvate carboxylase (PEPC), pyrurate dikinase (PPDK), NADP malic enzyme (NADP-ME) and PPDK+PEPC transgenicrice (Oryza saltiva L.) plant to light, temperature, CO2 and the characteristics of chlorophyll fluorescence under photoinhibition conditions were studied. The results were as follows: 1. The light saturated photosynthetic rates of transgenic rice plants were higher than that of wild type, in which the light saturated point of PEPC and PPDK+PEPC transgenic rice plants was 200 μmol·m-2·s-1 higher than that of untransformed rice and the light saturated photosynthetic rates were 51.6% and 58.5% respectively. The carboxylation efficiency of PEPC transgenic rice plant increased by 49.3% and the CO2 compensation point decreased by 26.2% than that of untransformed rice. Under high temperature (35 ℃), the photosynthetic rate of PEPC transgenic rice plant was higher over 17.5% than that of untransformed rice. 2. On the 8th day after photoinhibition treatment, the PSⅡ photochemical efficiency (Fv/Fm) and photochemical quenching (qP) of PEPC and PPDK+PEPC transgenic rice plants decreased by about 20%-30% while the non photochemical quenching(qN)increased by approximately 30%. But Fv/Fm and qP of untransformed rice decreased by over 50% while qN increased by less than 10%. The result suggested that transgenic rice plants were more tolerant to photoinhibition.