不同基因型水稻苗期叶片NRA及其受NH4+的影响

对14个基因型水稻幼苗的叶片原始硝酸还原酶活性(NRA)、经NO3^-诱导后的NRA以及添加NH4^ 后的NRA等进行测定。结果表明：在未经诱导的情况下，早稻叶片NRA高于水稻，水稻呈现杂交稻高于常规稻、籼稻高于粳稻的趋势。经NO3^-诱导后，所有供试基因型水稻叶片NRA均大幅度提高，提高幅度为早稻高于水稻、杂交稻高于常规稻、籼稻高于粳稻。NH4^ 的存在对绝大部分基因型水稻叶片NRA有抑制作用，其中以对粳稻的抑制作用最大，对杂交籼稻和早稻的抑制作用较小。

Leaf NRA of Different Genotypes Rice and The Effects of NH4+ on Leaf NRA at Seedling Stage

Leaf nitrate ruductase actizity (NRA) of different genotypes rice were studied before and after NO3- induction at the seedling stage and the effects of NH4+ on leaf NRA were explored. The results obtained indicated that before NO3-induction upland rice had higher leaf NRA than paddy rice, hybrid rice showed higher leaf NRA than conventional rice, and indica rice presented higher leaf NRA than japonica rice. After NO3- induction, leaf NRA of all tested rice increased significantly. Comparing upland rice with paddy rice, Hybrid rice with conventional rice, and indica rice with japonica rice, leaf NRA of the former increased to a greater extent than that of the latter. With NH4+ present, leaf NRA of most varieties decreased. Leaf NRA of japonica rice was inhibited most obviously by the existence of NH4+ , while that of indica rice and upland rice was affected slightly.