不同氮素利用效率小麦品种的氮效率相关生理参数研究

在不同氮处理条件下，研究了不同氮效率小麦品种的子粒产量、植株氮含量和植株氮累积量及氮效率相关的生理参数。结果表明，在低氮处理（LN）下，氮高效品种沧核036较氮低效品种衡6599具有较高的子粒产量、植株氮含量和植株氮累积量，其产量比对照的下降幅度也明显小于衡6599；单位面积穗数的大幅减少是衡6599产量明显下降的主导因素。在LN条件下，沧核036在挑旗期、开花期和灌浆期，植株上部三片展开叶均具有较高的硝酸还原酶（NR）、亚硝酸还原酶（NIR）和谷氨酰胺合成酶（GS）活性，以及较高的光合色素含量和可溶蛋白含量；生育后期该品种的气孔导度和光合速率也高于衡6599。在LN条件下，叶片的可溶性糖含量和脯氨酸含量以衡6599较高；各测定时期的丙二醛含量，沧核036也低于衡6599，但SOD活性在两品种间差异较小。表明LN条件下，氮高效品种沧核036表现的氮高效特征，是其具有较强的氮素吸收和同化能力；较高SOD活性，缓解了细胞的膜脂过氧化程度；光合色素含量增加和光合暗反应活性增强，使光合碳同化能力提高的综合作用结果。

Studies on the physiological parameters related to nitrogen use efficiency in wheat cultivars with different nitrogen utilization

The physiological parameters related to grain yield, nitrogen (N) content and N accumulation in plant, and N use efficiency were studied using wheat cultivars with different N use efficiency capabilities. Under deficient-N (LN) condition, Canghe036, a wheat cultivar with typical high-N use efficiency, had higher yield, plant nitrogen concentration, and N accumulation than Heng6599(H6599), a wheat cultivar with typical low-N use efficiency. The yield decrease more in LN condition for Canghe036(CH036) compared to Heng6599, which was mainly attributed to the significant decrease of spike number per plant area in Heng6599. At the stages of flag leaf expansion, flowering and grain filling, the activities of nitrate reductase (NR), nitrite reductase (NIR), and glutamine synthetase (GS), as well as photosynthetic pigments and soluble protein content in the top three unfolded leaves of Canghe036 were all higher than Heng6599 under deficient-N condition. The stomatal conductance and photosynthetic rate (Pn) were also higher in Canghe036 at late growth stage than in Heng6599, but the soluble sugar content and proline content was lower in Changhe036. There were no significant differences on superoxide dismutase (SOD) activities between these two cultivars, but the MDA contents were significantly lower in Canghe036 than in Heng6599. Therefore, the high-N efficiency in Canghe036 under deficient-N condition was resulted from integrated effects of the stronger capabilities in nitrogen acquisition and assimilation, higher over-oxidation degree of the cytoplasm, and stronger carbon assimilation functions.