氮、磷、钾配施对水稻植株氮损失的影响

Effects of Combining Application of Nitrogen, Phosphorus and Potassium on Nitrogen Loss from Rice Plant Tissue

在溶液培养条件下,以水稻为材料,采用15N示踪法研究了氮、磷、钾配施对水稻植株氮损失的影响。结果表明,对前期正常供应养分的水稻幼苗进行为期2周的不同氮、磷、钾配合处理,水稻植株生物量增加,不同氮、磷、钾配合处理对地上部和根部氮含量具有显著影响,含氮处理氮含量明显高于无氮处理,但其15N丰度却低于无氮处理,说明含氮处理增加了水稻植株含氮量并稀释了前期吸收的15N,同时含氮处理铵态氮含量高于无氮处理,说明含氮处理增加了水稻植株中铵态氮含量。不同氮、磷、钾配合处理下水稻氮损失率在15.18%～34.35%之间,氮、磷、钾任意两者配施均降低植株氮损失率,并提高植株体内谷草转氨酶活性,降低质膜透性,但以氮、磷、钾配合处理植株氮损失率最低,谷草转氨酶活性最高,质膜透性最低。

15N differential method was adopted to study the influences of combining application of nitrogen, phosphorus and potassium on N loss from Oryza sativa plant tissue for two weeks under solution culture. The results showed that there were not significant changes in biomass for the two weeks with combining application of N, P, K, but N contents of leaves and roots were obviously different among the different NPK combinations treatments. N contents in leaves and roots with N treatments were markedly higher than the no N treatments, while 15N abundance was on the contrary. It meant that the N absorption was increased and the absorbed 15N at early stage was diluted at the same time with N treatments. Meanwhile, NH4＋-N contents of leaves with N treatments were higher than that of no N treatments, which showed that the N level was related with NH4＋-N contents. N loss rates of rice plant were between 15.18% and 34.35% under the combining application of N, P and K. Combining application of the arbitrary two of N, P and K could reduce the N loss rates of rice plants, increase the activity of GOT, and decrease the membrane permeability of leaves. The N loss rate and the membrane permeability was the lowest, and the activity of GOT was the highest in the normal nutrition treatment （NPK）.