Energy conversion and changes in physical parameters in chloroplasts and subchloroplast particles I. Ion transport, ionic environment and the light-induced 475–515 nm absorbance change

摘要

The light-induced absorbance change at 515 nm and the light-induced hydrogen ion uptake in chloroplasts are sensitive to physical treatment and to changes in ionic environment. High concentrations of salts (chlorides) were inhibitory to the 515-nm absorbance change. This inhibition was stronger in chloroplasts than in subchloroplast particles. In subchloroplast particles, NH4Cl was slightly stimulatory for the 515-nm change at low concentrations (˜0.5 mM), as was the case with photophosphorylation.Tetraphenylboron (TPB), as a permeant anion, inhibited the 515-nm change and the rate of hydrogen ion uptake. Tetraphenylarsonium (TPA) and tetraphenylphosphonium (TPP), both permeant cations, diminished the 515-nm change but did not affect the hydrogen ion uptake. These results are analyzed in connection with a discussion of the significance of the membrane potential and hydrogen ion gradient in the energy conversion of chloroplasts and subchloroplast particles