不同氮素生理效率油菜生育后期氮素再分配特性研究

 【目的】揭示油菜生育后期氮素再分配与氮素生理效率的关系。【方法】在完全营养液的砂培条件下，采用15N示踪方法，研究了不同氮素生理效率油菜品种生育后期营养体氮素再分配的差异。【结果】与低氮素生理效率品种相比，高氮素生理效率品种的氮素再分配量大，氮素再分配速度先慢后快；向籽粒再分配的氮素量及其比例大，向角果皮再分配的氮素量及其比例小；植株体氮素损失量及其比例小，氮素损失速度慢，这是高氮素生理效率品种氮收获指数高的主要原因之一。比较4个生育期吸收的氮素再分配量及比例表明，蕾苔期吸收的氮素再分配量及其比例最大，角果发育吸收的氮素再分配量及比例最小，苗期和开花期吸收的氮素再分配量及比例位于前二者之间。【结论】生育后期油菜营养体氮素的再分配明显影响其氮素生理效率。

Nitrogen Redistribution Characteristics of Oilseed Rape Varieties with Different Nitrogen Physiological Efficiency During Later Growing Period

The differences of organic nitrogen redistribution in vegetative of oilseed rape varieties with different nitrogen physiological efficiency during the later growing period were studied using 15N trace method under the sand culture of complete nutrient solution condition,. Results showed that high nitrogen physiological varieties had larger amount of organic nitrogen redistribution compared with the low nitrogen physiological efficiency varieties. The speed of organic nitrogen redistribution was slow at first and then fast, the redistribution amount of nitrogen toward seeds and its proportion was larger, the redistribution amount of nitrogen toward weed shell and its proportion was smaller. The amounts of nitrogen loss from plant and its proportion were smaller, and the velocity of nitrogen loss is slower. This may be one of the main reasons why the varieties with high nitrogen efficiency have high nitrogen harvest indexes. By comparing the redistribution amount of nitrogen and its proportion during the four growing periods, the results showed that the largest redistribution amount of nitrogen absorbed by plant and its proportion was found in flower bud stage, the smallest redistribution amount and its proportion at siliquing stage, and those were between them at seeding and flowing stages.