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酸雨对植物生长发育具有显著影响。然而,不同生长阶段植物对逆境胁迫的响应存在差异。以模拟酸雨胁迫水稻(Oryza sativa)(孕穗期、灌浆期),利用植物生理生化方法测定了水稻叶肉细胞叶绿体Mg2+-ATPase活性及其基因表达量、光合磷酸化活性、ATP含量、植株相对生长速率(RGR)和叶片净光合速率(Pn),研究酸雨胁迫下孕穗期、灌浆期水稻叶绿体ATP酶的变化及其对植物光合作用影响的机理。结果表明,p H=4.5酸雨使孕穗期水稻RGR、Pn、叶片ATP质量比和光合磷酸化活性均显著提高,灌浆期上述指标变化不明显;p H=3.5和p H=2.5酸雨使上述指标均下降,且随酸雨p H值降低,变幅增加。p H=4.5酸雨使孕穗期、灌浆期水稻ATP合酶基因表达量及Mg2+-ATPase活性升高;p H=3.5和p H=2.5的酸雨使孕穗期、灌浆期水稻ATP酶基因表达量减少,造成Mg2+-ATPase活性降低,且随酸雨p H值降低变幅增加。可以认为,酸雨通过影响ATP酶转录水平,改变Mg2+-ATPase活性、光合磷酸化活性和叶片ATP质量比,进而影响Pn,并最终影响植物生长发育。酸雨胁迫对孕穗期水稻生长发育及光合作用有低促高抑的剂量效应,而低强度酸雨对灌浆期水稻影响不明显。与灌浆期相比,孕穗期对酸雨胁迫较敏感,表明植物不同生长发育阶段对酸雨胁迫响应存在差异,此发现应成为评价酸雨影响植物的一个因素。
Acid rain has a significant impact on plant growth and development. However, the response of plants to stress during different growth stages is different. The physiological and biochemical methods were used to determine the activity of chloroplast Mg2 + -ATPase and its gene expression, photosynthetic phosphorylation activity, ATP content, relative growth rate of plant in rice Oryza sativa (booting stage and filling stage) (RGR) and net photosynthetic rate (Pn) of leaf were studied to study the changes of chloroplast ATPase and its mechanism of plant photosynthesis under booting stage and filling stage under acid rain stress. The results showed that acid rain with p H = 4.5 significantly increased RGR, Pn, leaf ATP mass ratio and photosynthetic phosphorylation activity at the booting stage, with no obvious change at the filling stage; p H = 3.5 and p H = All decreased, and with the acid rain p H value decreases, amplitude increases. p H = 4.5 acid rain increased the expression of ATP synthase gene and Mg2 + -ATPase in rice at booting and filling stages; acid rain at p H = 3.5 and p H = 2.5 decreased the expression of ATPase gene in rice at booting and filling stages , Resulting in the decrease of Mg2 + -ATPase activity, and increasing with the decrease of p H value of acid rain. It can be concluded that acid rain affects the Pn through influencing the transcription level of ATPase, changing the activity of Mg2 + -ATPase, photosynthetic phosphorylation activity and leaf ATP mass, and finally affecting plant growth and development. Acid rain stress had a dose-effect on the growth and photosynthesis of rice at booting stage, but the effect of low-intensity acid rain on rice at filling stage was not obvious. Compared with the filling stage, the booting stage is more sensitive to acid rain stress, indicating that there are differences in the response to acid rain stress in different growth stages of the plants. This finding should be a factor in evaluating the plant affected by acid rain.