Development of The Environmental Sensor Function in A Plant Leaf

Abstract

A plant leaf responded markedly to CO₂ stress by changing its cellular potential. Moreover its response patterns were modified by the coexistence of small amount of odor compounds, which suggested the presence of excellent sensing function of a plant leaf for odor compounds.
In this study, I have analyzed the CO₂ stress response electrochemical ly with multi-microelectrode system. At first, I have clarified that epidermal cells of Tradescantia virginiana L. within a radius of about 2 mm are electrically short-circuited. Electrochemically, however, they have been found isolated from each other. Based on the electron microscopic analysis and the dye diffusion experiment, I constructed a leaf structure model. Intracellular responses corresponded to the vacuolar potential change. Since the potential change could not be elucidated without taking the electrogenic potential into account, I proved the existence of H⁺-ATPase in the vacuolar membrane of T. virginiana which can generate the electrogenic potential. As the result, the mechanism of CO₂ stress response was explained by the diffusion potential of K⁺ and H⁺, and the electrogenic potential of H⁺.