Time course of spectral shifts in the red-absorption band and loss of photochemical oxygen-liberating capacity in isolated aspidistra chloroplasts

Abstract

1. 1. Out of the various chlorophyll types, Cb650 and Ca680 are preferently labile in isolated Aspidistra chloroplasts.

2. 2. The time course of a thermally induced change of Ca680 coincides with that of the decay of the capability to perform the Hill reaction, either without added oxidant, or in the presence of 10−2 M p-benzoquinone.

3. 3. This coincidence suggests that excited Ca680, in addition to Ca670, is involved in the photochemical O2 evolution. Such a conclusion supports the interpretation of earlier obtained indications.

4. 4. No such correlation occurs upon addition of 2,6-dichlorophenolindophenol as a Hill reagent. It is concluded that in case of the presence of this oxidant only Ca670 operates in the oxidative part of the photochemical system.