NITROGEN ASSIMILATION AND THE CONTROL OF AMMONIUM AND NITRATE ABSORPTION BY MAIZE ROOTS
NITROGEN ASSIMILATION AND THE CONTROL OF AMMONIUM AND NITRATE ABSORPTION BY MAIZE ROOTS
复制标题
DOI：
10.1093/jxb/43.11.1385
复制
发表时间：
1992-11-01
影响因子：
6.9
通讯作者：
SAKER, LR
中科院分区：
文献类型：
--
作者：
LEE, RB;PURVES, JV;SAKER, LR
对以氨氮或硝酸盐为氮源的完整玉米植株进行了影响氮素同化途径的试验处理。这些处理包括：外部氨基酸喂养；GS、GOGAT和氨基转移酶的特异性抑制剂；以及N饥饿。它们在体内的作用通过N-14-或N-15-核磁共振波谱或组织提取物的高效液相分析得到证实。根中谷氨酰胺和天冬酰胺的水平之间有很强的相关性。然后测量了植物在短时间(5min)和长时间(1.5h)内对铵和硝酸盐的吸收速率。结果分为两类。在提高细胞内谷氨酰胺和/或天冬酰胺浓度的处理后，氮素的净吸收受到抑制，而降低根部谷氨酰胺和/或天冬酰胺的处理则促进了氮素的净吸收。
Experimental treatments designed to affect the pathway of nitrogen assimilation were applied to the roots of intact maize plants growing with ammonium or nitrate as N-sources. The treatments comprised: external amino acid feeding; specific inhibitors of GS, GOGAT, and aminotransferases; and N-starvation. Their actions in vivo were confirmed by N-14- or N-15-NMR spectroscopy, or by HPLC analysis of tissue extracts. A strong correlation was noted between the levels of glutamine and asparagine in the roots.Rates of ammonium and nitrate absorption by the plants were then measured, over both short (5 min) and longer (1.5 h) periods. The results fell into two classes. After treatments which raised the intracellular concentrations of glutamine and/or asparagine, net uptake of N was suppressed, while conditions which decreased root glutamine and/or asparagine, stimulated net uptake of N. These findings are discussed in relation to the control of N-absorption during growth with differing levels of nitrogen supply.