中文摘要：

采用掺沙土培法,以10个氮效率存在显著差异的水稻基因型为材料,分析了6个氮水平下水稻拔节期、孕穗期、抽穗期和成熟期的氮吸收效率（NAE）、氮利用效率（NUE）和氮收获指数（NHI）的基因型差异,建立了氮高效水稻基因型鉴定与筛选的方法。结果表明,水稻NAE随氮水平增加先升后降,以中氮（0.177g/kg,以纯N计）为最高;水稻NUE和NHI随氮水平增加而下降。水稻NAE随生育期推进而上升,水稻NUE的大小则为拔节期〉抽穗期〉成熟期〉孕穗期。基因型和氮水平对水稻NAE、NUE和NHI的影响达极显著水平,以氮水平影响最大,基因型次之。基因型×氮水平互作对NAE和NUE的影响达极显著水平,而对NHI无显著影响。NAE和NUE的基因型差异均以拔节期最大,这一时期为水稻高NAE和NUE基因型鉴定与筛选的最佳时期。土培盆栽下,水稻高NAE、NUE和NHI鉴定与筛选的最适土壤有效氮含量分别为0.157g/kg（拔节期）、低氮（拔节期）和0.277g/kg（成熟期）。

英文摘要：

Genotypic differences in nitrogen absorption efficiency （NAE）,nitrogen utilization efficiency （NUE） and nitrogen harvest index （NHI） were investigated in ten rice genotypes with different nitrogen efficiencies at the elongation,booting,heading and maturity stages under six nitrogen levels in a pot experiment with sand-soil mixtures at various ratios.The results showed that NAE firstly increased and then decreased with increasing nitrogen rates,and the peak NAE was found under medium nitrogen rate （0.177 g/kg）;but NUE and NHI of different rice genotypes decreased with increasing nitrogen rates.NAE of different rice genotypes increased with growing process and NUE followed a trend as follows：elongation stage heading stage maturity stage booting stage.The effects of genotype or nitrogen level on NAE,NUE and NHI were significant at 0.01 level,which showed an order of nitrogen levelsgenotypes genotype×nitrogen level.The effects of genotype×nitrogen level interaction on NAE and NUE were significant at 0.01 level,but the effect of that on NHI was not significant.The elongation stage was the most suitable stage for identifying and evaluating NAE and NUE of rice because the differences of those traits among genotypes at the elongation stage were maximum.The optimum available soil nitrogen and stage for NAE,NUE and NHI identification and screening of rice in the experiment were 0.157 g/kg at the elongation stage,low nitrogen at the elongation stage and 0.277 g/kg at the maturity stage,respectively.