低浓度NO对高表达转玉米C4型pepc水稻光合的促进

Promotion of Photosynthesis of Transgenic Rice Plant with Overexpressing C_4 pepc from Maize under Low Concentration NO

为了揭示C3植物中C4pepc高表达带来的生理差异与其高光合效率的关系。本文以高表达的转玉米C4pepc光合基因水稻(PC)及原种Kitaake(WT)为材料,通过水培在孕穗期通过根吸入的方法,进行不同浓度的NO供体、NO合成抑制剂以及相关影响信号分子的试剂单独和联合过夜处理12 h,选取倒二叶研究NO对供试材料净光合速率(Pn),气孔导度(Gs)和胞间CO2浓度(Ci)的影响。结果表明:WT和PC在200μmol·L-1SNP(Sodium ni-troprusside)和1 mmol·L-1 L-Arg(L-Arginine)处理下,Pn分别增加20.8%、10.7%,差异显著(p<0.05);随SNP和L-Arg浓度的增加,其表现不同程度的抑制,与PC相比,WT的Pn抑制更显著(p<0.05),而Gs和Ci的变化则相反(p<0.05);进一步结合200μmol·L-1SNP和1 mmol·L-1L-Arg与SA处理,结果与高浓度的NO供体处理类似;在联合6 mmol·L-1Ca2+螯合剂EGTA处理下,与PC相比,WT的Pn抑制达到极显著水平(p<0.01),Ci的变化则相反(p<0.05)。相关分析结果表明:PC的Pn的高低与Gs的相关性小于WT,PC与WT决定系数分别为0.654 9、0.773 5;而与Ci的相关性则更大些,PC与WT决定系数分别为0.466 5、0.419 6,显示PC可能有不同的调节方式,尤其在低浓度的NO,PC可在Ca2+参与下调节气孔的开放,在气孔关闭的条件下,仍能维持一定的Pn。

In order to reveal the relationship between physiological difference and high photosynthetic efficiency in C3 plant with high expression C4 pepc, the transgenic rice with high expression of maize C4 pepc（PC） and the untransformed rice plant Kitaake （WT） were used as the material plants. The up-second leaves of the rice plants were used to treat by root system during the booting stage. After the treatments of the different concentrations of NO donor, NO synthesis inhibitors and related signal related reagents as well as in the dark for 12 h, the effects of NO on the net photosynthetic rate （Pn）, stomatal conductance （Gs） and intercellular CO2 concentration （Ci ） of the test material leaves were measured. The results showed that： Pn of WT and PC increased by 20. 8% and 10.7%, respectively under the treatments of 200 μmol· L-1 SNP（ Sodium nitroprusside） and 1 mmol · L-1 L- Arg （L-Arginine）, which was significantly different（p 〈 0.05 ） ; However, with increasing the concentrations of SNP and L-Arg, the Pn, Gs and Ci of two rice plants were gradually suppressed. Compared with PC, the Pn of WT was significantly inhibited （p 〈 0.05 ）, but the changes of Gs and Ci were opposite ; When treated by 200 μmol· L-1 SNP and 1 mmol· L-1 L-Arg as well as SA （salicylic acid） for the test materials, the changes of P., Gs and Ci were similar with those under high concentrations of NO donors treatment ; Under united 6 mmol · L- 1 EGTA of Ca2 · chelator treatment, compared with the PC, the Pn of WT was significantly inhibited at the level （p 〈 0.01 ）, that Ci was opposite （p 〈 0.05 ）. Correlation analysis showed that： The correlationship between the Pn and the Gs in PC was less than that of WT, the determination coefficients were 0. 654 9 and 0.773 5 ; However, The correlationship between the Pn and the Ci in PC was larger than that of WT, the determination coefficients were 0. 466 5 and 0. 419 6, which implied that there might be different way of the regulation of photosynthesis between PC and WT, especially at lower concentrations of NO in PC, NO might participate in the process of the stomatal movement with high concentration of free Ca2＋. It can still maintain the stability of P, in PC under the conditions in stomatal closure.