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本文以籼(原丰早)、粳(京引127)稻为材料,研究了它们对 NO_3的吸收和同化 NO_3为氨基酸过程中有关酶的活力。结果指出:1)籼稻幼苗根对外液NO_3的吸收能力高于粳稻;2)籼稻叶片把 NO_3~-同化为 NH_4~+的硝酸还原酶(NR)和亚硝酸还原酶(NiR)活力都高于粳稻;3)在进一步同化 NH_4~+(无机态氮)为氨基酸(有机态氮)的谷氨酸脱氢酶(GDH)和谷氨酰胺合成酶(GS)/谷氨酸合酶(GOGAT)两条途径中,籼稻叶片的 GDH、GS 和 GOG-AT 活力都高于粳稻。这些结果说明了耐肥性弱的籼稻对 NO_3的吸收同化能力高于耐肥性强的粳稻,也就是说籼稻比粳稻对氮肥的反应更敏感。籼、粳稻的这种差异可能也存在于其他不同耐肥性的作物品种间。这就以作物内在的氮素代谢基础说明了作物品种对氮肥反应的差异原因,即作物耐肥性的生理基础。还应指出在作物对 NO_3吸收同化的诸因素中硝酸还原酶起着主要的和关键的作用。
In this paper, the indica (original Feng early morning), japonica (Jingyin 127) rice as materials, to study their absorption of NO 3 and the assimilation of NO 3 as the amino acid activity of the enzyme. The results showed that: 1) The ability of NO3 uptake by the seedling root of indica rice was higher than that of japonica rice; 2) The activity of nitrate reductase (NR) and nitrite reductase (NiR) assimilating NO_3 ~ - into NH_4 ~ Japonica rice; 3) In the process of further assimilating glutamate dehydrogenase (GDH) and glutamine synthetase (GS) / glutamate synthase (GOGAT) with NH_4 ~ + (inorganic nitrogen) In both pathways, GDH, GS and GOG-AT of indica rice leaves were higher than those of japonica rice. These results indicate that indica rice with weaker tolerance has higher absorption and assimilation ability to NO 3 than japonica rice with higher fertility, that is to say, indica rice is more sensitive to nitrogen fertilizer than japonica rice. This difference between indica and japonica rice may also exist between other varieties of crops with different tolerances. This explains the difference of crop response to nitrogen fertilizer based on the inherent nitrogen metabolism of crops, that is, the physiological basis of crop resistance. It should also be noted that nitrate reductase plays a major and central role in the assimilation of NO 3 by crops.