Light Induced Uptake of Potassium and Chloride by Chlorella pyrenoidosa

Abstract

RECENT studies of mechanisms of ion transport across the membranes of isolated mitochondria and chloroplasts have been designed to show whether the energy is derived directly from electron transport or from high energy chemical intermediates^1,2. A similar argument concerning the active transport of ions across the protoplasmic membranes of intact animal and plant cells³ has also been considered for many years. Perhaps the most convincing evidence that the active transport of an ionic species is intimately linked with electron transport has come from studies on the giant cells of Nitella translucens⁴ and Hydrodictyon africanum⁵. In these algae, it has been shown that the light stimulated influx of chloride, unlike the uptake of potassium, is independent of photophosphorylation and seems to be associated with the oxygen evolving system 2 of photosynthesis.