The Effect of Metabolic Inhibitors, Sugars and Fusicoccin on the Electrical Potential Difference Arising Across an Intact Chenopodium Rubrum L. Plant

An analysis of the effect of metabolic inhibitors, sugars, and fusicoccin on the trans-plant electrical potential difference arising across one-week-old green or herbicide-treated Chenopodium rubrum L. plants was performed. The substances were applied either to the solution bathing the root or in the form of drops to the stem. The respiratory inhibitors (KCN and salicylhydroxamic acid), sulfhydryl agents (N-ethylmaleimide and p-chloromercuribenzene sulfonic acid) and proton ionophore (carbonyl cyanide m-chlorophenylhydrazone) affected the electrical potential, the kinetics of the induced changes varying with different inhibitors and site of application. None of the applied sugars (sucrose, glucose or sorbitol), ATPase stimulator fusicoccin or inhibitor vanadate exerted any appreciable effect on the electrical potential. An effect of sucrose could be observed in the case of its application immediately following de-rooting, especially in the case of herbicide-treated plants. These results we explain by non-participation of the sucrose transporter or the proton ATPase in the generation of the electrical potential difference across intact plants (apoplast-apoplast configuration).