小麦叶片电阻抗图谱参数对重金属胁迫的响应

 为了研究小麦在重金属胁迫下电阻抗图谱参数的规律，测定了小麦叶片在重金属离子Zn²⁺、Pb²⁺、Cr（Ⅲ）、Cu²⁺、Ni²⁺、Cr（Ⅵ）6种离子胁迫下的胞外电阻、胞内电阻、弛豫时间和弛豫时间分布系数，并通过回归分析建立上述电阻抗图谱参数与重金属离子浓度之间的关系。研究表明，随着重金属离子浓度的增加，小麦叶片的胞外电阻和弛豫时间表现为减小，胞内电阻和弛豫时间分布系数增加，与其他4种离子相比，Cu²⁺和Cr(Ⅵ)离子更能显著减小胞外电阻和弛豫时间的数值，可以用弛豫时间来预测小麦叶片受重金属毒害的程度。研究表明，弛豫时间的变化基本满足logistic模型。

Response of Electrical Impedance Spectroscopy Parameters of Wheat(Triticum aestivum L.)Leaves to the Stress of Heavy Meatals

To study the rules of electrical impedance spectroscopy parameters of wheat (Triticum aestivum L.) under the stress of heavy metals, the extracellular resistance, intracellular resistance, relaxation time and distribution coefficient of relaxation time in the leaves of wheat were measured. The heavy metals Zn²⁺、Pb²⁺、Cr（Ⅲ）、Cu²⁺、Ni²⁺and Cr (VI) with different concentration were used. The relationship between electrical impedance spectroscopy parameters and the concentration of above ions was established by means of regression analysis. The results suggested that when heavy metal ions increased within concentration of 0~200 mmol·L^-1, the extracellular resistance and relaxation time in leaves of wheat decreased, whereas the intracellular resistance and distribution coefficient of relaxation time enhanced. Compared with the other four ions, Cu²⁺ and Cr (VI) could remarkably reduce extracellular resistance and relaxation time. Relaxation time was accord with logistic model and could predict the wheat toxicity extent stressed by heavy metals.