Metal-induced cell rupture in elongating roots is associated with metal ion binding strengths
Metal-induced cell rupture in elongating roots is associated with metal ion binding strengths
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DOI：
10.1007/s11104-009-9917-0
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发表时间：
2009-09-01
期刊：
影响因子：
4.9
通讯作者：
Menzies, N. W.
中科院分区：
文献类型：
--
作者：
Kopittke, P. M.;McKenna, B. A.;Menzies, N. W.
低浓度的Al、Cu和La会迅速降低根的伸长，并导致根皮和外皮层的横向断裂，但其他微量金属是否有类似的影响尚不清楚。6种微量金属Ga、Gd、Hg、In、Ru和Sc降低豇豆根的生长，并造成与Al、Cu和La类似的断裂。计算的金属形态表明，只有Gd几乎完全以三价离子（Gd3+）的形式存在，而其他测试溶液主要是Ga(OH)(2) (+), HgCl2 (0), In3+, In(OH)(2+), In(OH)(2) (+), In(OH)(3)(0)或InCl2+，以及Sc3+或ScOH2+ （Ru没有热力学常数）。这项研究和其他研究的结果表明，这些微量金属（加上Al、Cu和La）导致破裂的能力与微量金属与细胞壁结合的强度有关。因此，有人提出微量金属的毒性作用来自(1)结合强度（离子或共价），以及(2)金属的其他毒性作用不依赖于细胞壁相互作用。
Low concentrations of Al, Cu and La rapidly decrease root elongation and cause transverse ruptures to the rhizodermis and outer cortex, but it is not known if other trace metals have similar effects. Six trace metals, Ga, Gd, Hg, In, Ru, and Sc, decreased cowpea root growth and caused ruptures similar to those caused by Al, Cu and La. Calculated speciation of the metals showed that only Gd was almost exclusively present as the trivalent ion (Gd3+), but the other test solutions were dominated by Ga(OH)(2) (+), HgCl2 (0), either In3+, In(OH)(2+), In(OH)(2) (+), In(OH)(3) (0), or InCl2+, and Sc3+ or ScOH2+ (no thermodynamic constants were available for Ru). The results from this and other studies suggest that the ability of these trace metals (plus Al, Cu, and La) to cause ruptures is related to the strength to which the trace metals bind to the cell wall. Therefore, it is proposed that the toxic effects of trace metals results from (1) the strength of binding (either ionically or covalently), and (2) other toxic effects of the metals not dependent on cell wall interactions.