供氮形态和水分胁迫耦合作用对磷在苗期——分蘖期水稻植株不同部位含量与分配的影响

为探讨不同形态氮素营养对干旱条件下水稻P吸收与分配的影响， 采用室内营养液培养及聚乙二醇（PEG6000）模拟水分胁迫处理的方法，在分蘖期设置3种供氮形态（NH4+ N、NO3- N以及NO3- N和NH4+ N相同浓度下等体积混合）和两种水分条件（非水分胁迫及水分胁迫）的耦合处理进行研究。结果表明： 1）在水分胁迫条件下，水稻植株及各部位含P量均是全NH4+ N营养明显高于全NO3- N营养；同时，在分蘖期，全NO3- N营养水稻植株含P量明显低于非水分胁迫条件下的相应处理，但水分胁迫对全NH4+ N以及NO3- N和NH4+ N混合营养水稻含P量影响不大；2）在两种水分条件下，全NH4+ N以及NO3- N和NH4+ N混合营养均相对降低了水稻对吸收进入体内的P向叶片和根系的运输比例；而全NO3- N营养则只相对降低了水稻体内的P向叶片的运输比例。此外，由分蘖初期到中期，在水分胁迫条件下，全NH4+ N营养水稻积累的P素增加比例最高。

Effects of Coupling Between Nitrogen Forms and Water Stress on Content and Distribution of Phosphorus in Different Parts of Rice Plants at the Seedling and Tillering Stages

By using the method of nutrient solution culture and simulated water stress with PEG6000, the effects of different nitrogen forms (NO_3--N, NH_4+-N and the mixture of NO_3--N and NH_4+-N) and water statuses (non-water stress and water stress conditions) on P distribution in the different parts of rice plants at the seedling-tillering stage were studied. Under water stress, P content in the different parts of NH_4+-N supplied rice plants was higher than that of the other two nitrogen forms supplied ones, meanwhile, P content in NO_3--N supplied rice plants under non-water stress was higher than that under water stress, whereas water stress had no significant effect on P content in the rice plants supplied with NH_4+-N and the mixture of NO_3--N and NH_4+-N. Regardless of water conditions, from the early tillering stage to the middle tillering stage, the ratio of P distributed to leaves and roots supplied with NH_4+-N singly and the mixture of NO_3--N and NH_4+-N was reduced, while NO_3--N nutrition only reduced the rate of P distributed to leaves at this stage. Furthermore, the increased rate of P accumulated in rice plants was higher under NH_4+-N supplied plus water stress than other treatments in this period.