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通过水培试验研究了不同形态和比例的氮素对水稻苗期水分利用效率及其生物效应的影响。结果表明 :随着NH+ 4 N/NO-3 N比例的减小 ,根系鲜重、根日生长率、根系含水量、全氮和全磷含量增加 ,但在全硝态氮条件下减少 ;当NH+ 4 N/NO-3 N比例为 5 0 / 5 0时 ,水分利用率最高 ;叶片光合作用对不同形态比例的氮素反应差异明显 ,NH+ 4 N/NO-3 N比例为 2 5 / 75时 ,光合速率最大。由此表明 ,过高的铵态氮和硝态氮比例均会引起水稻有机物合成和生物量积累的减少 ,其中铵态氮的影响尤为严重。当NH+ 4 N/NO-3 N比例为 5 0 / 5 0和 2 5 / 75时 ,水稻表现出最佳的生物效应。
Effects of different forms and proportions of nitrogen on water use efficiency and its biological effects at seedling stage in rice were studied by hydroponic culture. The results showed that the root fresh weight, root growth rate, root water content, total nitrogen and total phosphorus increased with the decrease of NH 4 N / NO 3 -N ratio but decreased with total nitrate nitrogen. The highest water use efficiency was obtained when the proportion of NH 4 N / NO 3 -N was 5 0/50; the photosynthesis of leaves had obvious difference in the response to different forms of nitrogen, the ratio of NH 4 N / NO 3 N was 25/75 When, photosynthetic rate is the largest. The results showed that excessively high ratio of ammonium to nitrate could cause the decrease of organic matter accumulation and biomass accumulation in rice, especially the effect of ammonium nitrogen. Rice showed the best biological effect when the NH + 4 N / NO-3 N ratio was 50/50 and 25/75.