模拟干旱胁迫对转C_4双基因水稻幼苗光合功能及部分抗氧化酶活性的影响

Impact of simulated drought stress on photosynthesis and activities of some antioxidant enzymes of transgenic rice seedlings harboring maize PEPC and PPDK genes

为了探究转玉米C4双基因水稻抗旱性,以野生型恢复系水稻R299及其转PEPC&PPDK基因水稻恢复系纯合品种R2P为材料,木村B营养液培养至3叶1心。对两种水稻在20%浓度(质量体积比)PEG6000(聚乙二醇)模拟干旱条件下光合及相关生理生化指标的变化进行了比较。结果表明:在正常木村B营养液水培条件下,转基因株系R2P的叶绿体超微结构、光合及其相关生理指标与R299相比,未见明显差异;但在20%PEG6000模拟干旱条件下,两种水稻之间显示出了明显的变化,表现为R2P的光合速率、C4光合酶活性、SOD(超氧化物歧化酶)活性、Pro(游离脯氨酸)含量均显著高于R299,叶绿体超微结构较R299稳定,而MDA(丙二醛)含量、O2·-(超氧阴离子)产生速率显著低于R299。说明转C4双基因水稻抗旱性增强,光合及抗氧化系统在PEG6000模拟干旱条件下能保持相对较高的稳定性。

The drought tolerance of transgenic rice with maize PEPC ＆ PPDK genes were studied using wild-type rice restorer line R299 and its PEPC ＆ PPDK transgenic rice homozygous restorer line R2 P as materi-als, cultured in Kimura B nutrient solution to three-leaf period. The photosynthesis, related physiological and biochemical indexes of R2P and R299 subjected to PEG6000 simulated drought stress were compared. The＆amp;nbsp;chloroplast ultramicrostructure, photosynthesis and the related antioxidant physiological indexes had no significant difference between R2P and R299 cultured in Kimura B nutrient solution. However, under drought stress, R2P showed faster photosynthesis rate, higher activities of C4 photosynthetic enzyme and SOD （ superoxide dismutase） , higher content of proline, and greater stability of chloroplast ultrastructure than R299, and lower the content of MDA and generation rate of superoxide anion （ O2·-） . The results indicated that the PEPE and PPDK transgenic rice R2 P was more tolerant to the drought.