Protection of reaction center II from photodamage by low temperature and anaerobiosis in spinach chloroplasts.

ABSTRACT

The rate of the irreversible damage to the reaction center II, caused by exposure of spinach thylakoids to high light was slowed down by anaerobic conditions and by lowering the temperature. The protective mechanisms of these conditions were different. In both cases Fmax decreased more slowly than in control photoinhibition. A reversible intermediate step was only observed under anaerobic conditions. This state was inactive for oxygen evolution and it was characterized by an increase of Fo.