中文摘要：

以玉米自交系178（保绿型）和K12（非保绿型）为材料,采用大田试验,设置2个氮处理,研究2个不同保绿型自交系花粒期叶片光合特性、保护酶活性与氮同化的差异性。结果表明,2个自交系在吐丝期后14d前后光合性能达到最大,而从吐丝21d后又呈现迅速下降趋势;抗氧化酶（SOD、POD和CAT）活性在吐丝14d左右达到峰值后开始下降,丙二醛（MDA）含量一直升高。保绿型玉米活性氧清除系统活性显著高于非保绿型玉米自交系,且表现出更高的光合势和更强的耐低氮能力,最终在产量方面保绿型表现更突出,因此,认为保绿性可作为筛选氮高效玉米自交系的一个重要农艺性状。

英文摘要：

Field experiments were conducted with two nitrogen treatments and two maize inbred lines（178,stay-green;K12non-stay-green）to study the difference of leaf photosynthetic characteristics, protective enzyme activity,and nitrogen assimilation regulation of two different stay-green inbred lines at flowering and grain filling stage.The results showed that the photosynthetic performance of two inbred lines reached the maximum value at 14days after the silking stage,and then rapidly decreased from 21days after silking.The activities of antioxidant enzymes（SOD,POD and CAT）reached the peak at 14days after silking and then decreased.The content of malondialdehyde（MDA）was keeping increase.But the active oxygen scavenging system activity of stay-green maize was significantly higher than that of the non-stay-green maize inbred line.The stay-green maize line also showed higher photosynthetic potential and stronger resistance to low nitrogen,and displayed a remarkable yield performance at last.So stay-green could be an important trait for screening high yield and high nitrogen efficient inbred line.