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Organic acids promote the uptake of lanthanum by barley roots
Author(s) -
Han Fang,
Shan XiaoQuan,
Zhang Jing,
Xie YaNing,
Pei ZhiGuo,
Zhang ShuZhen,
Zhu YongGuan,
Wen Bei
Publication year - 2005
Publication title -
new phytologist
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.742
H-Index - 244
eISSN - 1469-8137
pISSN - 0028-646X
DOI - 10.1111/j.1469-8137.2004.01256.x
Subject(s) - lanthanum , chemistry , malic acid , hordeum vulgare , kinetics , shoot , citric acid , organic acid , absorption (acoustics) , inorganic chemistry , botany , biochemistry , poaceae , biology , physics , quantum mechanics , acoustics
Summary• Organic acids play an important role in metal uptake by, and accumulation in, plants. However, the relevant mechanisms remain obscure. • Acetic, malic and citric acids increased the uptake of lanthanum (La) by barley ( Hordeum vulgare ) roots and enhanced La content in shoots under hydroponic conditions. • Concentration‐dependent net La influx in the absence and presence of organic acids yielded nonsaturating kinetic curves that could be resolved into linear and saturable components. The saturable component followed Michaelis–Menten kinetics. The K m values were similar; however, the V max values in the presence of acetic, malic and citric acids were 4.3, 2.8, 1.5‐times that of the control, respectively. • Enhanced uptake of La by organic acids was mediated mainly, but not solely, by Ca 2+ channels. X‐ray absorption spectroscopic techniques provided evidence of La–oxygen environment and established that La(III) was coordinated to 11 oxygen atoms that are likely to be involved in the binding of La(III) to barley roots via carboxylate groups and hydration of La(III).