The changes in glutamic dehydrogenase activity following illumination of etiolated barley seedlings

Changes in NADH- and NADPH-linked glutamic dehydrogenase (GDH) activity have been measured following illumination of etiolated barley leaves. Both activities initially increase, then decrease to below the etiolated value. The latter change is dependent upon prior illumination but independent of the presence of roots or added ammonium sulphate. Subsequently a sustained increase of both activities occurs. Possible reasons for these changes and alterations in the ratio of the two GDH activities are discussed.