白桦幼苗NH_4^+/NO_3^-吸收特征的研究  

NH_4^+/NO_3^- absorption characteristics of Betula platyphylla seedlings

作　　者：张韫[1] 崔晓阳[1] 

机构地区：[1]东北林业大学林学院

出　　处：《北京林业大学学报》2011年第3期26-30,共5页Journal of Beijing Forestry University

基　　金：国家自然科学基金项目(30371146;30571476)

摘　　要：采用水培方法,研究白桦幼苗氮吸收特征。结果表明:白桦早期对NO3---N呈偏向选择吸收,供氮强度和光强增加使苗木氮吸收总量、NH4+--N吸收量、NO3---N吸收量增加。根系是白桦早期还原NO3-的主要部位;根系和叶片硝酸还原酶活性均因供NO3-强度和光强的增加而增强。较低供氮水平下,NH4+优势处理苗木的营养液pH值下降,NO3-优势处理苗木的营养液pH值上升;氮吸收量增大导致NH4+优势处理苗木的营养液pH值下降程度深化,而供NO3-营养液pH值却未因此进一步升高;较高光强下,各处理苗木营养液pH值均有不同程度下降。We investigated NH4^＋/NO3^- absorption characteristics of Betula platyphylla seedlings using solution cultivation. The results showed that the seedlings preferred nitrate over ammonium in their nutrient regime. Absorption capacity of NH4^＋ -N, NO3^- -N and total N increased with the increase of nitrogen application or light intensity. Most of nitrate was reduced in roots; nitrate reductase activity in roots and leaves responded to increased nitrate availability or increased light intensity. Medium pH value decreased in the low N-application solution of high NH4^＋/NO3^- ratio, and increased with low NH4^＋/NO3^- ratio; medium pH value decreased more markedly in the high N-application solution of high NH4^＋/NO^- ratio, but did not increase sharply in NO^3- solution; medium pH value of all the seedlings decreased with inereased light intensity.

关 键 词：白桦幼苗 NH4^+ NO3^- 硝酸还原酶 PH值 

分 类 号：S511[农业科学—作物学]