中文摘要：

为了给氮高效品种油菜的选育及应用提供科学依据，采用土培试验，在施氮和不施氮条件下研究了3个油菜品种（742，湘油15和汇油50）的功能叶叶绿素含量、硝酸还原酶活性、茎叶硝酸盐含量和累积量及有机氮再利用能力等地上部生理特性与氮效率间的关系．结果表明：施氮对地上部生理特性有显著的影响，施氮条件下所有地上部生理特性指标均比不施氮条件下高；在施氮条件下，油菜功能叶叶绿素含量、硝酸还原酶活性、茎叶硝酸盐含量和累积量以及有机氮再利用能力与油菜氮效率密切相关，是油菜氮素高效利用的可能机理；在不施氮条件下，油菜硝酸还原酶活性、茎叶硝酸盐累积量和有机氮再利用能力与油菜氮效率密切相关，是油菜氮素高效利用的可能机理，而油菜功能叶叶绿素含量和茎叶硝酸盐含量对氮效率影响较小．

英文摘要：

To provide a scientific foundation for breeding and application oilseed rape cultivars with high nitrogen efficiency, the relationshie between physiological characteristics such as chlorophyll contents, the activity of nitrate reductase （NRA）, NO3^-contents and its total amounts and re-transferring organic nitrogen in function leaves of 3 oilseed rape （742, Xiangyou 15, Huiyou 50） at different growing periods were studied by means of greenhouse experiments both under nitrogen application conditions and nitrogen-deficiency condition. The result indicated that nitrogen application had apparent effects on shoot physiological characteristics during the growing periods, all of them increased with the increasing ratio of nitrogen. Under nitrogen application conditions, chlorophyll contents, NRA in function leaves, NO3^- contents and amounts, and re-transferring organic nitrogen in growing periods were closely related with oilseed rape cultivars Nitrogen Use Efficiency（NUE）. All of them might be the factors to indicate the high NUE of varieties. Under nitrogen-deficiency condition, NRA in function leaves, NO3^-amounts and re-transferring organic nitrogen were closely related with oilseed rape cultivars NUE, All of them might be the factors to indicate the high NUE of oilseed rape cultivars, while chlorophyll contents and NO3^-contents was not.