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为研究水稻不同时期吸收的氮素在其体内的行为,作者利用15NH4+和15NO3-双标记,对Indica水稻亚种(品种Hinohikari)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NH415NO3;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、成熟期收获。植株分成根系、地上部的底部、地上部的顶部、旗叶和穗部,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,各个时期的15NH4NO3或NH415NO3处理下水稻的N吸收总量上没有差别,但1周后收获的15NH4-N处理的水稻中15N的含量比15NO3-N要高得多,直到成熟期收获的水稻都有同样的结果,这意味着各个时期吸收的NH4-N和NO3-N有着不同的损失量,吸收的NO3-N比NH4-N要损失得多。水稻叶片的氮素损失可能以N2O和NH3的形式。不同氮肥形态的处理下转移到穗部的氮素的量和来源也不相同,在NH415NO3的处理中穗部的15N主要来自地上部的底部,而在15NH4NO3的处理中穗部的15N主要来自分蘖期吸收的15N,少量来自成熟期并且15N主要来自植株的各个部分。
In order to study the nitrogen absorption in different periods of rice in vivo, the authors used 15NH4 + and 15NO3-double markers to hydroponically culture Indica rice subspecies (Hinohikari) and applied them at tillering stage, young panicle differentiation and flowering stage, The culture medium ρ (N) 20mg / L of NH4NO3 replaced by the same mass concentration of 15NH4NO3 or NH415NO3; part of the rice harvested after a week, the other were tillering, panicle differentiation, flowering, maturity harvest. Plants were divided into root system, the bottom of the shoot, the top of the shoot, the flag leaf and the ear. The total N, 15N was 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 15NH4NO3 or NH415NO3 treatments had no significant effect on the total nitrogen uptake of rice in all periods, but the content of 15N in 15NH4-N-treated rice after 1 week was much higher than that of 15NO3-N until maturity The same results were obtained for the harvested rice, which means that NH4-N and NO3-N absorbed at different times had different losses and absorbed much less NO3-N than NH4-N. Nitrogen losses in rice leaves may be in the form of N2O and NH3. The amount and source of nitrogen transferred to ear were different under different forms of nitrogen fertilizer. In NH415NO3 treatment, 15N of ear mainly came from the bottom of shoot, while in 15NH4NO3 treatment, 15N of ear mainly came from tiller 15N uptake, a small amount from maturity and 15N mainly from various parts of the plant.