Phytochrome regulation of peroxidase activity in maize IV. Photosynthetic independence of peroxidase enhancement

Abstract

The continuous far-red light mediation of the enhancement of peroxidase activity was repressed only partially by inhibitors of cyclic and non-cyclic photophosphorylation. Under far-red light the chlorophyll development was minimal and plastids were differentiated only partially. Isolated plastids from seedlings grown under far-red light developed photosystem I and II activity after a lag of 4 hr, cyclic photophosphorylation after 8 hr, and non-cyclic photophosphorylation at 24 hr. These seedlings, however, failed to show CO2-dependent oxygen evolution upto 24 hr of irradiation. The magnitudes of the various photochemical activities developed under far-red light were considerably lower than those developed under white light. Photosynthetic participation in the far-red mediated 'high irradiance reaction' was excluded as it had a longer lag than the onset of the enhancement of peroxidase activity, and its magnitude was minimal. © 1979 Oxford University Press.