Photorespiration in the protonemata of Funaria hygrometrica Hedw.

The protonemata of Funaria hygrometrica Hedw. were shown to photorespire, first by demonstrating that immediately after a period of illumination oxygen was consumed at a rate greater than that characteristic of long-term dark respiration, and secondly by observing a greater release of14CD2 from 1 – 14C glycolate in light than in darkness. The glycolate-oxidizing enzyme had the ability to decompose L (-) lactate but not D (-) lactate, and must therefore be considered to be a glycolate oxidase and not a glycolate dehydrogenase such as operative in some algae. Some implications of these findings are discussed.