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目前氮肥的利用效率很低,很多研究重点放在氮肥在土壤过程中的损失,对植物本身的氮素损失较少注意。作者利用15NH4和15NO3双标记,对Indica和Japonica水稻亚种进行水培,在分蘖期、幼穗分化期、开花期施用,将培养液ρ(N)20mg/L+-的NH4NO3换成相同质量浓度的15NH4NO3或NH4NO3;部分水稻在一周后收获,其他分别在分蘖期、幼穗分化期、开花期、15成熟期收获。植株分成根系、地上部和穗部,对各自的全氮、15N进行测定,计算植物的总吸收量。从施用量、植株总吸收量以及三部分总和的植株氮残存量的比较来研究氮素在两种水稻亚种中的行为。研究结果表明,两种植物都近100%吸收了所施用的15NH4NO3或NH4NO3,但15NH4和15NO3在Japonica的残存量要比Indica多,损失的部分可能往大气中散失了,意15+-味着两种水稻亚种有着明显不同的氮素利用率。比较15NH4和15NO3的残存量,结果表明15NH4留在植株体内要比15NO3多,+-+-尤其在抽穗期施用的情况下,植物体在后期对15NO3的转化能力大大减弱,但这部分的氮如何损失掉尚不清楚。比较植株体-内各部分的氮素含量,发现Japonica的穗部比Indica含有更多的氮素,表明氮在前者的体内转化效率和利用效率高。试验结果表明,不同水稻亚种对氮素的利用以及不同氮素形态在其体内的行为不同。
At present, the utilization efficiency of nitrogen fertilizer is very low. Many studies have focused on the loss of nitrogen fertilizer in the soil process and have paid little attention to the nitrogen loss of the plant itself. The authors used 15NH4 and 15NO3 double markers to hydroponically culture Indica and Japonica rice subsp. At the tillering stage, young spike differentiation stage and flowering stage, NH4NO3 was replaced with ρ (N) 20mg / L + - in the same concentration Of 15NH4NO3 or NH4NO3. Some of the rice was harvested one week later, while others were harvested at tillering stage, young panicle differentiation, flowering stage and 15 mature stage respectively. Plants were divided into root, shoot and panicle, respectively, the total nitrogen, 15N were measured to calculate the total plant absorption. The effects of nitrogen on the two rice subspecies were studied from the comparison of application rate, total plant uptake, and three-component plant nitrogen residuals. The results showed that nearly 100% of both plants absorbed 15NH4NO3 or NH4NO3, but 15NH4 and 15NO3 had more residuals in Japonica than Indica, and the loss could be lost to the atmosphere. Both rice subspecies have significantly different nitrogen utilization rates. Comparing the remaining amounts of 15NH4 and 15NO3, the results showed that 15NH4 remained in the plant more than 15NO3, + - + - especially in the application of heading, the ability of plants to convert 15NO3 greatly reduced later, but this part of the nitrogen How to lose is not clear. Comparing the content of nitrogen in all parts of plant body, it was found that Japonica contained more nitrogen than Indica, indicating that nitrogen had high transformation efficiency and utilization efficiency in vivo. The results showed that different rice subspecies had different effects on nitrogen utilization and different nitrogen forms in their body.