土壤水分和氮素水平对春小麦水分与氮素利用效率的影响

以抗旱性不同的三个春小麦品种为材料,研究它们在不同水氮水平下水分利用效率(WUE)和氮素利用效率(NUE)的变化,探讨二者间的相关性。结果表明:三个品种中,和尚头和定西35号的WUE相当,而定西35号的NUE最高。三个春小麦品种叶片NUE均随施氮量增加而降低,整株水平的NUE与氮素水平负相关。施氮量对春小麦叶片光合作用的瞬时WUE影响不显著,整株WUE与施氮量显著正相关。水氮耦合作用对春小麦NUE具有重要影响,整株NUE对水分条件的响应表现出明显的氮水平依赖性。春小麦品种氮素利用和水分利用两个生理过程之间存在"负偶联"关系。

The Influence of Soil Moisture and Nitrogen on Water and Nitrogen Use Efficiency of Spring Wheat

Three cultivars differing in drought resistance were employed to study water use efficiency(WUE) and nitrogen use efficiency(NUE) of spring wheat,and the relationship between NUE and WUE under different water and nitrogen levels.The results showed that cultivars of Heshangtou and Dingxi No.35 had higher WUE than Ningchun No.4,and Dingxi No.35 had the highest NUE.Leaf level NUE of the three cultivars decreased as nitrogen supplement increased,whole plant NUE was negatively correlated with nitrogen levels.No significant relation was found between nitrogen supplement and leaf WUE,but whole plant WUE was significantly positively correlated with nitrogen level.Obviously,the integral effect of soil water and nitrogen had an important influence on NUE of spring wheat,the response of whole plant NUE to water conditions significantly depended on nitrogen levels.Clear physiological trade-off was found between nitrogen and water use efficiency in wheat,i.e.cultivars with high water use efficiency will have low nitrogen use efficiency,and vice versa.