Permeability and conductance properties of the maize root epidermis

Abstract

Permeability properties of the epidermis have been studied separately for seven elements [1], [2], [3], [4], [5]. Potential difference E_T (Fig. 1A, B) across an epidermis, experimentally measured for single ions according to the percentage of the relevant ion present in litre of solution, shows the sequence:

$$ \begin{array}{*{20}c} {\text{E}_\text{T} \left( {\text{K}^\text{ + } } \right) > \text{E}_\text{T} \left( {\text{Na}^ + } \right) > \text{E}_\text{T} \left( {\text{Mn}^{2 + } } \right) > \text{E}_\text{T} \left( {\text{Ca}^{2 + } } \right) > } \\ { > \text{E}_\text{T} \left( {\text{Mg}^{2 + } } \right) > \text{E}_\text{T} \left( {\text{Fe}^{3 + } } \right) > \text{E}_\text{T} \left( {\text{Zn}^{2 + } } \right).} \\ \end{array} $$

(1)