Growth and stress conditions cause similar changes in xylem amino acids for different legume species
Growth and stress conditions cause similar changes in xylem amino acids for different legume species
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DOI：
10.1016/j.envexpbot.2005.07.002
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发表时间：
2006-12-01
影响因子：
5.7
通讯作者：
Sodek, L.
中科院分区：
文献类型：
--
作者：
do Amarante, L.;Lima, J. D.;Sodek, L.
木质部运输到地上部的含氮化合物的组成可以反映根部氮素代谢的重要变化。损害大豆氮素同化的胁迫条件(共生植物的N-2固定和非共生植物的硝酸盐同化)会导致木质部氨基酸组成的特殊变化。在这项研究中，研究表明，在相同的胁迫条件下，这些变化也发生在其他豆科植物(菜豆、长叶豌豆、豌豆、白色羽扇豆和克罗塔里亚芥菜)中，这些植物都是酰脲和酰胺出口类别的。根瘤植株受涝后，木质部谷氨酰胺水平显著降低，这是由于N-2固定功能受损所致。将球茎植物转移到无氮营养液的曝气水培中，除了降低谷氨酰胺外，还会影响N-2的固定，导致天冬氨酸/天冬酰胺比值升高。生长在硝酸盐上的非共生植物转移到无氮水培营养液中(损害硝酸盐同化)，木质部伤流汁液中天冬氨酸/天冬酰胺的比率也显着增加。三种被研究的非豆科植物(番茄、玉米和向日葵)对氮素缺乏产生了类似的反应。因此，木质部汁液中的氨基酸可以作为根系同化过程对胁迫反应的有用指标，无论是输出酰脲和酰胺的豆科植物，还是非豆科植物。(C)2005 Elsevier B.V.保留所有权利。
The composition of nitrogenous compounds transported in the xylem to the shoot can reflect important changes in root N metabolism. Stress conditions that impair N assimilation in soybean (N-2 fixation in symbiotic plants and nitrate assimilation in non-symbiotic plants) lead to specific changes in the amino acid composition of the xylem. In this study, it is shown that these changes also occur in other legume species (Phaseolus vulgaris, Vigna unguiculata, Pisum sativum, Lupinus albus and Crotalaria juncea) of both the ureide- and amide-exporting categories, when subjected to the same stress conditions. Waterlogging of nodulated plants led to a large and specific reduction in xylem glutamine levels, attributed to impaired N-2 fixation. Transfer of nodulated plants to aerated hydroponics with N-free nutrient solution, which also impairs N-2 fixation, resulted in elevated aspartate/asparagine ratios, besides the reduction in glutamine. Non-symbiotic plants grown on nitrate and transferred to a N-free hydroponic nutrient solution (impaired nitrate assimilation) likewise showed a marked increase in aspartate/asparagine ratios of the xylem bleeding sap. Three non-legume species studied (Lycopersicon esculentum, Zea mays and Helianthus annuus) produced a similar response to N deficiency. It is concluded that xylem bleeding sap amino acids can be useful indicators of the response of assimilatory processes in the root system to stress, for both ureide- and amide-exporting legumes, as well as non-legume plants. (c) 2005 Elsevier B.V. All rights reserved.