An Electrophysiological Study of the Stomatal Complex ofTradescantia virginiana

Publisher Website
Google Scholar
Abstract
Measurements of electrical potential difference (PD) and potassium activity were carried out on the intact leaf of Tradescantia virginiana. PD gradients across the stomatal complex were observed with both open and closed stomata. The guard cell PD appeared to be linearly related to stomatal aperture. With the stomata open a gradient of potassium activity across the stomatal complex was observed which became reversed on stomatal closure. Calculation of the driving forces on potassium suggested that it was distributed passively between the vacuoles of the cells of the stomatal complex. The electrophysiological data obtained from this investigation enabled potassium activity in the apoplast to be calculated. The results showed that on stomatal closure there was a massive increase in the potassium activity in the guard cell wall.