Green plants: electrochemical interfaces

The most rapid methods of long distance communication between plant tissues and organs are bioelectrochemical signals. The action potential propagates rapidly throughout the plant along electrified interfaces. A potential pat hway for transmission of this electrical signal might be the phloem sieve-t ube system since it represents a continuum of plasma membranes. A phloem is an electrical conductor of bioelectrochemical impulses over long distances . At the cellular level in plants, electrical potentials exist across membr anes, and thus between cellular compartments, as well as within specific co mpartments. Electrochemical phenomena are primary, and then deep cytophysio logical reactions occur. Possible effects of the electric double layer of t he Earth on the electrical activity of plants are discussed. Effects of unc ouplers and acid rains on green plants are studied. Uncoupler carbonyl cyan ide-p-trifluoromethoxyphenyl hydrazone (FCCP) induces ultra fast action pot entials and decreases the resting potential in a soybean. The speed of the propagation of action potentials in a soybean induced by FCCP reaches up to 40 m s(-1). The duration of single action potentials after treatment by FC CP was 0.0003 s. Adding FCCP to soil decreases the resting potential to zer o level. The automatic measurements of the electrical potential difference can be effectively used in bioelectrochemistry, environmental plant electro physiology, for the study of molecular mechanisms of transport processes an d the influence of external stimuli on plants. (C) 2000 Elsevier Science S. A. All rights reserved.