Effects of preillumination on dark nitrogen fixation and respiration by anabaena cylindrica

Abstract

In whole filaments of Anabaena cylindrica dark nitrogen-fixing activity (measured as acetylene reduction) and respiration increased with the light intensity of a fixed period of preillumination, saturating at ca. 10,000 lux. With saturating light during preillumination, the amount and duration of dark nitrogen-fixing activity increased with length of preillumination, but respiration declined rapidly in the dark.At dark respiration rates below 250 nmol O2 uptake mg protein-1·h-1 (State 1) no significant nitrogen-fixing activity is observed. From 250 to 550 nmol O2 uptake·mg protein-1·h-1 (State 2), nitrogen-fixing activity depends on O2 uptake while above 550 nmol O2 uptake·mg protein-1·h-1 (State 3), nitrogen-fixing activity no longer increases with further increase in O2 uptake rate. Copyright © 1984. The Japanese Society of Plant Physiologists.