【作者】 仇明；

【导师】 杨建昌； 朱庆森；

【作者基本信息】 扬州大学 ， 作物栽培学与耕作学， 2004， 硕士

【摘要】 以已导入玉米C₄光合关键酶PC（磷酸烯醇式丙酮酸羧化酶，PEPC）、PK（丙酮酸磷酸二激酶，PPDK）、NADP-ME（NADP-苹果酸酶）和CK（PEPC+PPDK）的转基因水稻为材料，以其受体品种Kitaake（WT）为对照。观察了结实期土壤水分胁迫对C₄转基因水稻的产量、叶片光合速率和水分利用效率等的影响。主要试验结果如下： 1．随土壤水分胁迫的加重，各品系的产量随之下降，但C₄转基因品系的产量下降少，未转基因的对照品种WT下降显著。在田间种植条件下，PC、CK、ME和PK 4个转基因品系的产量均显著高于WT。与WT相比，土壤水势为0kPa时，4个转基因品系的产量高出5.1％—25.9％；土壤水势为-25kPa时，产量高出为9.16％—30.9％；土壤水势为-50kPa时，产量高出12.94％—29.12％。土培池种植和盆钵种植的产量结果与田间种植的结果趋势一致。表明C₄转基因水稻的产量较高，在水分胁迫条件下尤为突出。 2．在光强为1100—1400μmol m^-2s^-1时，C4转基因品系剑叶光合速率，在正常灌溉条件下是对照品种WT的1.2—1.6倍，在水分胁迫下是WT的1.5—2.1倍，中午12：00—13：30时是WT的2—3倍。表明C₄转基因水稻的叶片光合速率高、午休现象轻、对水分胁迫的忍受能力强。 3．随土壤水分胁迫的加重，各品系的收获指数提高。表明水分胁迫促进了光合同化物向籽粒的运转。在相同土壤水分条件下，C₄转基因品系的收获指数与对照品种无显著差异，说明C₄转基因产量的增加主要是物质生产能力增加所致。 4．随土壤水分胁迫的加重，各品系叶片的蒸腾速率下降，水分利用效率（或蒸腾效率）提高。但对照品种WT的光合速率严重降低，而C₄转基因品系的光合速率下降较少或下降不显著。表明C₄转基因水稻在一定的水分胁迫下，可以不牺牲物质生产而增加水分利用效率。 5．与对照品种WT相比，在相同的土壤水分尤其是在水分胁迫条件下，C₄转基因水稻叶片的丙二醛含量低，超氧化物歧化酶活性及叶绿素含量高，根系伤流量多，根系活力强。扬州人学硕十学位论文 6.稻米奎白粒率和至白度，以轻度土壤水分胁迫卜25kPa)的处理最低，其次为浅水层灌溉（0 kPa），严重土壤水分胁迫卜SOkPa)处理的最高。在相同的土壤水分条件下，转基因品系PC、CK和PK的至白米率和至白度明显低于对照品种WT。随土壤水分胁迫加重，直链淀粉含量显著增加，胶稠度随土壤水分胁迫加重而变小，糙米中铜（Cu）含量增加。在严重水分胁迫下，C;转基因品系糙米中Cu含量较对照品种WT高。土壤水分胁迫对稻米粗蛋白质含量影响不显著。 对光合速率与产量的关系、光合速率与水分利用效率的关系以及C;转基因水稻对水分胁迫反应的特点及其机理等进行了讨论。更多还原

【Abstract】 With four transgenic rice lines over-expressing maize phosphoenolpyruvate carboxylase (PC), pyruvate. othophosphate dikinase (PK). PC + PK (CK), and rice nicotinamide adenine dinucleotide phosphate-malic enzyme (ME) as materials, and an untransformed wild type Kitaake (WT) as the control, the effects of water stress imposed during grain filling on the grain yield, photosynthetic rate of leaves, and water use efficiency of the transgenic rice were investigated. The main results are as follows:1. With the decrease of soil water potentials, the grain yield decreased, with the transgenic lines decreased less and untransformed WT decreased more. Under the field-grown condition, the grain field of four transgenic rice lines of PC, CK, ME, PK was significantly higher than that of WT. In contrast with WT, the grain yield of the four transgenic lines was increased by 5.1% to 25.9%. 9.16% to 30.9%, and 12.94% to 29.1%, respectively, when the soil water potential was at 0 kPa, -25 kPa, and -50 kPa. Similar results were obtained in both cement tank and pot experiments, indicating that C4 transgenic rice lines have higher grain field than WT, especially under water stress conditions.2. When photosynthetically active radiation at the top of the canopy was between 1100 -1400 umol m’V, the photosynthetic rate of the flag leaves for C4 transgenic lines was 1.2 to 1.6 fold and 1.5 to 2.1 fold as high as that for WT, respectively, under the normal irrigation and water stress conditions. Photosynthetic rate of the transgenic lines was 2 to 3 fold as high as that of WT at 12:00-13:30 h of the day, implying that C4 transgenic rice has higher photosynthetic rate, less performance of "noon break", and stronger ability to endure water stress.3. The harvest index of all the test lines increased with the decrease of soil water potentials, indicating that water stress enhances translocation of assimilates to grains. There was no significant difference in harvest index between the transgenic lines and WT when soil water potential was the same, suggesting that increase in the grain yield for the transgenic rice was mainly attributed to an enhanced capacity of dry matter production.4. The transpiration rate decreased and water use efficiency or transpiration efficiency increased with the decrease of soil water potentials. Photosynthetic rate of WT was seriouslyreduced, but that of the transgenic lines was less or not significantly reduced, at water stress, suggesting that C4 transgenic rice increases water use efficiency without sacrifice dry matter production at a certain level of water stress.5 In contrast with WT, C4 transgenic rice showed lower malondialdehyde (MDA) concentration and higher superoxide dimutase (SOD) activity and chlorophyll content in leaves, more root exudates and stronger root activity at the same soil water potential, especially at waterstress.6 The percentage of chalky grains and chalkiness were the lowest at the moderate water stress (soil water potential at -25 kPa), the highest at the severe water stress (soil water potential at -50 kPa). and was the between at the normal irrigation (soil water potential at OkPa). At the same soil water potential, the percentage of chalky grains and chalkiness of the transgenic lines were significantly lower or less than those of WT. Amylose and copper (Cu) contents in grains increased and gel consistency decreased with the decease of soil water potentials. At the severe water stress, the content of Cu in the grains of C4 transgenic rice was higher than that of WT. The effect of water stress on protein content in grains was insignificant.The relationships of photosynthetic rate with grain yield and water use efficiency and the response of C4 transgenic rice to water stress and its mechanism were discussed in the paper.更多还原