吉林省不同年代水稻品种叶片硝酸还原酶的活性变化研究

【目的】了解不同年代育成水稻品种叶片硝酸还原酶活性(Nitrate reductase activity，NRA)的变化及其与净光合速率（Pn）和产量的关系，为吉林省水稻高产育种和栽培提供理论依据。【方法】以吉林省1958至2005年育成并在生产上推广的18个水稻品种为材料，研究水稻植株剑叶NRA变化及其与净光合速率和产量的关系。【结果】水稻叶片NRA在孕穗期较低，抽穗期最大,此后呈下降变化；NRA随品种的育成年代推进而降低。不同生育期水稻剑叶Pn在抽穗期达到最大，此后不断下降；随着育成年代的推进，Pn逐渐上升。NRA与净光合速率呈负相关，但不显著，与水稻产量呈显著负相关。【结论】水稻品种遗传改良提高了叶片的光合作用和产量，但NRA却随品种的育成年代推进而降低，这可能也是水稻氮肥利用效率降低的原因。

Changes in nitrate reductase activity of rice cultivars with different released years in Jilin province

【Objective】 The study was conducted to understand the changes in nitrate reductase activity(NRA) and its relationship between yield and photosynthesis of rice varieties bred in different times,and to provide a theoretical basis for high-yield rice breeding and cultivation of Jilin province.【Method】 In this study,the samples of 18 rice varieties bred and extended for production in Jilin province from 1958 to 2005 were used to detect the levels of rice flag leaf NRA and its relationship with flag leaf net photosynthetic rate(Pn) and yield relation.【Result】 Rice leaf NRA was lower in booting stage,and highest in heading stage,then showed a decrease trend;NRA decreased in the course of the breeding years.The net Pn of different rice varieties was highest in heading stage,and then decreased;the net Pn increased in the course of the breeding year.NRA was negatively correlated with the net Pn(P>0.05) and the rice yield(P<0.05).【Conclusion】 Genetic improvement of rice varieties improved the photosynthesis and yield of the leaves,but NRA decreased in the course of the breeding year,which may lead to the decrease of rice nitrogen use efficiency.