不同供氮水平下油菜植株硝態氮與銨態氮的分布差異

摘 要：以硝態氮（NO3-）為氮源，采取正常供氮（全氮）和缺氮（三分之一正常供氮）處理，以2個基因型油菜品種（6號和27號）作為研究材料，通過測定地上部和地下部的硝態氮和銨態氮含量，研究了不同氮水平下油菜體內硝態氮、銨態氮的分布及轉化差異。結果表明：6號銨態氮地上部比地下部低12.7%，硝態氮低44.3%;27號對應的銨態氮地上部比地下部高6.0%，硝態氮低36.2%;總的硝態氮比銨態氮含量高273.6%。不同施氮水平下缺氮處理對應的銨態氮、硝態氮地上部比地下部分別低15.7%和42.1%;全氮處理對應的銨態氮地上部比地下部高9.3%，硝態氮低39.2%。在沒有銨態氮作為氮源的前提下，作物本身可以利用吸收到的硝態氮（僅有NO3-）在體內轉化為銨態氮，在由硝態氮轉變為銨態氮的過程中，植株體內可利用的氮素含量決定了硝態氮與銨態氮的分布與含量差異，以及對應的轉化量。

關鍵詞：硝態氮;銨態氮;硝態氮供氮水平;油菜

中圖分類號：S634.3 文獻標識碼：A 文章編號：1006-060X（2019）01-0022-04

Abstract： 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.

Key words： nitrate-N; ammonium-N; nitrate nitrogen-supply level

氮素是作物生長發育最為需求的營養元素[1]，硝態氮和銨態氮是2種主要的氮素來源，其中硝態氮是最為直接和有效的氮源，并且在植株體內可以被大量轉化、代謝與儲存[2-5]，從而為植物的生長發育提供充足的不同氮形態代謝產物。植物體內的銨態氮與硝態氮可以相互轉化補充，銨態氮氧化變為硝態氮（亞硝酸鹽和硝酸鹽），而硝態氮在相關還原酶的作用下也能被還原為銨態氮[6]，其中亞硝酸鹽是轉化過程的中間產物。

相關研究報道發現，植物體內硝態氮與銨態氮的含量分布會因植物的種類和品種存在差異[7-11];并且就同一植株而言，也存在器官與組織上的差異[12-13]。……