Photorespiration in C 3 and C 4 Plant Tissue Cultures

Abstract

Photorespiration rates in tissue cultures of a C4 plant, Portulaca oleracea, were compared to those in tissue cultures of a C3 plant, Streptanthus tortuosus. The C4 plant tissue cultures have one-half to one-third the photorespiration rate of the C3 plant tissue cultures and respond to varying O2 concentrations in a manner typical of C4 plants. The results suggest that the lack of detectable photorespiration in C4 plants is not related to leaf anatomy.