中文摘要：

采用土培盆栽试验，以3个氮素利用效率（NUE）有显著差异的水稻基因型秀恢2号（低NUE）、R83—12（中NUE）和五优244（高NUE）为材料，研究了拔节期叶片碳氮代谢的基因型差异及其与氮素高效利用的关系。结果表明，拔节期不同基因型水稻的叶片蔗糖和可溶性糖含量、淀粉／可溶性糖含量比和淀粉／蔗糖含量比存在极显著差异，前两者为五优244〉R83—12〉秀恢2号，后两者则相反；而淀粉和蔗糖／可溶性糖含量比各基因型差异不显著。不同基因型水稻的叶片伞氮含量（TNC）、蛋白氮含量（PNC）、PNC／TNC、Rubisco含量（RC）／PNC和RC／TNC存在极显著或显著差异，前两者为五优244〈R83—12〈秀恢2号，后三者则相反；RC无基因型差异。五优244叶片的叶绿素a含量、类胡萝h素含量、PSⅡ潜在活性、羧化效率、碳酸酐酶、酸性转化酶和蔗糖磷酸合成酶活性极显著或显著高于其他基因型；其叶片的硝酸还原酶、谷氨酰胺合成酶、谷氨酸合成酶和谷氨酸脱氧酶活性也极显著高于其他基因型。统计分析表明，高NUE水稻叶片具有较高的可溶性糖和蔗糖含量及较大的RC／TNC和RC／PNC，其生理摹础是其叶片的高符氨酰胺合成酶活性和PSⅡ潜在活性。

英文摘要：

The leaf carbon and nitrogen metabolism characteristics and their relationships with nitrogen utilization efficiency（NUE） at jointing stage were investigated with Xiuhui 2 （low NUE）, R83-12 （medium NUE） and Wuyou 244 （high NUE） as materials under the lower nitrogen level （58 mg/kg）. The results showed that the contents of sucrose and soluble sugar in the leaves of different rice genotypes were Wuyou 244 〉 R83-12 〉 Xiuhui 2, the ratio of starch content to soluble sugar content and the ratio of starch content to sucrose content were Xiuhui 2〉R83-12〉Wuyou 244, significantily differed among genotypes. The starch content and the ratio of sucrose content to soluble sugar content were not genotypically specific. The total nitrogen content （TNC）, protein nitrogen content （PNC）, PNC/TNC, RC（Rubisco content）/PNC and RC/TNC in the leaves of different rice genotypes exhibited significant differences, showing an increasing trend of Wuyou 244 〈 R83-12 〈 Xiuhui 2 for the former two indices and a trend of Xiuhui 2〉R83-12〉Wuyou 244 for the latter three; RC was not genotypically-specific. The contents of chlorophyll and carotenoid, activity of PS 11, carboxylation efficiency, activities of carbonic anhydrase, acid invertase and sucrose phosphate synthase in the leaves of Wuyou 244 with high NUE were significantly higher than those of the other genotypes. The activities of nitrate reductase, glutamine synthetase and glutamate synthase and glutamate dehydrogenase in the leaves of Wuyou 244 with high NUE were also significantly higher than those of the other genotypes. Statistical analyses indicated that the leaves of rice genotype with high NUE bad the distinguished characteristics of higher soluble sugar content, sucrose content, RC/TNC and RC/PNC, their physiological base were higher glutamine synthetase activity and primary PS II activity.