不同供氮水平下油菜植株硝态氮与铵态氮的分布差异

Distribution of Nitrate-N and Ammonium-N in Rape plants Under Different Nitrogen Supply Levels

以硝态氮(NO_3^-)为氮源,采取正常供氮(全氮)和缺氮(三分之一正常供氮)处理,以2个基因型油菜品种(6号和27号)作为研究材料,通过测定地上部和地下部的硝态氮和铵态氮含量,研究了不同氮水平下油菜体内硝态氮、铵态氮的分布及转化差异。结果表明:6号铵态氮地上部比地下部低12.7%,硝态氮低44.3%;27号对应的铵态氮地上部比地下部高6.0%,硝态氮低36.2%;总的硝态氮比铵态氮含量高273.6%。不同施氮水平下缺氮处理对应的铵态氮、硝态氮地上部比地下部分别低15.7%和42.1%;全氮处理对应的铵态氮地上部比地下部高9.3%,硝态氮低39.2%。在没有铵态氮作为氮源的前提下,作物本身可以利用吸收到的硝态氮(仅有NO_3^-)在体内转化为铵态氮,在由硝态氮转变为铵态氮的过程中,植株体内可利用的氮素含量决定了硝态氮与铵态氮的分布与含量差异,以及对应的转化量。

To investigate the distribution and transformation difference of nitrate-N and ammonium-N in rape plants under different nitrate-supply levels,the experiment with two treatments(normal nitrogen supply and deficient nitrogen supply-one third of normal level)was conducted by measuring the contents of nitrogen in the two forms from above-ground and underground parts of rape plants.Nitrate was used as nitrogen source,and two rape varieties(No.6 and No.27)as study materials.The results show that for No.6,the contents of ammonium-N and nitrate-N in above part are 12.7%and 44.3%lower than that in underground part,respectively;for No.27,the figure of ammonium-N in above part is 6.0%higher than that in underground part and nitrate-N 36.2%lower.The total amount of nitrate-N in rape plant is 273.6%higher compared with ammonium-N.In deficient nitrogen supply treatment,the contents of ammonium-N and nitrate-N in above-ground part are 15.7%and 42.1%lower than that in underground part,respectively;while in normal nitrogen supply treatment the figures are 9.3%higher and 39.2%lower,respectively.Rape plant can transform assimilated nitrate-N into ammonium-N in the absence of ammonium nitrogen as N-source.In this transforming process,the content of available nitrogen in the plant determines the distribution of nitrate-N and ammonium-N and the corresponding transformed amount.