The Influence of Light Intensity on the Activation and Operation of the Hydroxyl Efflux System ofChara corallina

Abstract

The interrelationships between light intensity and the activation of OH⁻ bands was investigated. The lag period prior to OH⁻ efflux activation was longer than the photosynthetic induction period. It was found that this lag period depended upon the light regime employed as well as the photosynthetic capacity of the cell. The response of the cell to low light intensities revealed that all OH⁻ bands were not of equal status. Below a critical light intensity the cell did not develop any bands even after prolonged illumination. An hypothesis is presented to account for these results, interms of total cell OH⁻ band activation and the regulation of the HCO₃⁻ and OH⁻ transport systems. It is proposed that the electrical properties of the Chara corallina plasmalemma, observed at high pH values, can be explained on the basis of the hypothesis presented in this paper