硝酸还原酶是植物体同化硝酸盐的限速酶,它不仅对外界氮肥反应敏感,且在植物对氮肥的吸收利用中起着关键作用。前文已报道在小麦、玉米、水稻幼苗中硝酸还原酶活力与作物耐肥性密切相关。在此基础上,本文观察了在不同施氮水平上,不同耐肥性品种的硝酸还原酶活力的变化,并分析了这一期间叶片中氨基氮及叶绿素含量和光合强度之间的关系。 Nitrate reductase is the rate-limiting enzyme of plant assimilation nitrate, which is not only sensitive to the external nitrogenous fertilizer, but also plays a key role in plant nitrogen absorption and utilization. It has been previously reported that nitrate reductase activity in wheat, maize and rice seedlings is closely related to crop resistance. On this basis, we observed the changes of nitrate reductase (NHR) activity in different fertility-tolerant cultivars at different N rates and analyzed the relationship between the content of amino-nitrogen and chlorophyll and the photosynthetic rate in this period.