玉米根细胞外钾电势依赖的数学分析。
Mathematical analysis of the dependence of cell potential on external potassium in corn roots.
机构信息
Department of Botany, University of Illinois, Urbana, Illinois 61801.
出版信息
Plant Physiol. 1979 Jan;63(1):1-4. doi: 10.1104/pp.63.1.1.
The K(+) dependence of normal (psi) and diffusion (psi(D)) potentials in corn roots [Zea mays L., hybrid (A619 x Oh43) x A632] was determined experimentally and analyzed with respect to the parameter xi [defined as exp (F psi/RT)]. In the presence of 10 micromolar carbonyl cyanide p-trifluoromethoxyphenylhydrazone (FCCP), psi behaved as expected of a diffusion potential. Based upon the assumptions (a) that FCCP did not change any term of the Goldman-Hodgkin-Katz equation, and (b) that total potential was functionally the algebraic sum of psi(D) and psi(P) (the deviation from psi(D) due to an electrogenic system), psi(P) was found to be a complex function of external potassium and to have a minimum value of 0.69 millimolar K ion activity outside the cell. Analysis of psi allowed us to develop an equation which predicts a complicated K(+) dependence of psi such as that found by Mertz and Higinbotham (Membrane Transport in Plants and Plant Organelles. Springer-Verlag 1974).
用实验方法测定了玉米根（Zea mays L.，杂种（A619 x Oh43）×A632）正常（ψ）和扩散（ψ（D））电位的 K（+）依赖性，并根据参数 ξ [定义为 exp（F ψ/RT）]进行了分析。在存在 10 微摩尔羰基氰化物 p-三氟甲氧基苯腙（FCCP）的情况下，ψ 的行为符合扩散电位的预期。基于以下假设：（a）FCCP 不会改变 Goldman-Hodgkin-Katz 方程的任何一项；（b）总电位是 ψ（D）和 ψ（P）（由于电致系统偏离 ψ（D））的代数和，发现 ψ（P）是外部钾的复杂函数，并且在细胞外的钾离子活度为 0.69 毫摩尔时达到最小值。对 ψ 的分析使我们能够得出一个方程，该方程预测了 ψ 的复杂 K（+）依赖性，就像 Mertz 和 Higinbotham（植物和植物细胞器的膜运输。施普林格出版社 1974 年）所发现的那样。
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