不同小麦品种氮效率与氮吸收对氮素供应的响应及生理机制

以具有典型特征的不同氮效率小麦品种为材料，研究了低氮和高氮条件下小麦的生物学性状、生理参数和氮同化代谢酶活性.结果表明:低氮条件下，不同氮效率小麦品种根系干质量、茎叶干质量、植株氮累积量基本上为氮高效品种>中效品种>低效品种.低氮条件下，氮吸收高效品种（冀97-6360）的根系活跃吸附面积、TTC还原力、叶片硝酸还原酶活性和叶片NO₃^-含量最大；生理高效品种(石新5418)具有较高的叶片亚硝酸还原酶活性和谷氨酰胺合成酶活性，较低的植株全氮含量、叶片NO₃^-含量和硝酸还原酶活性.低氮条件下植株氮利用效率与氮吸收系数显著相关.不同小麦品种在高氮条件下的生物学性状、生理参数和氮同化代谢酶活性与低氮条件下不尽一致.

Responses and corresponding physiological mechanisms of different wheat varieties in their nitrogen efficiency and nitrogen uptake to nitrogen supply.

In this paper, the biological traits, physiological parameters, and enzyme activities related to N assimilation and metabolism of wheat varieties with different nitrogen (N) efficiency were studied under low and high N supply. The results showed that under low N supply, the dry mass of root, leaf, and stem as well as the accumulated N amount in plant were in the order of high N efficiency variety>mid N efficiency variety>low N efficiency variety. The variety with high N uptake efficiency (Ji 97-6360) under low N supply had the highest root active absorption area and TTC-reductive activity and the highest leaf nitrate reductase activity and NO3-content, while the variety with high N physiological efficiency (Shixin 5418) had higher nitrite reductase and glutamine synthetase activities but lower NO3-content and NR activity in its leaf. There was a significant positive correlation between nitrogen use efficiency (NUE) and nitrogen uptake index (NUI) under low N supply. The biological traits, physiological parameters, and enzyme activities related to nitrogen assimilation and metabolism of test wheat varieties were not always the same under high and low N supply.