Crassulacean Acid Metabolism in Roots of a Leafless Orchid, Campylocentrum tyrridion Garay & Dunsterv.

The characteristics of carbon assimilation were studied in roots of a leafless orchid, Campylocentrum tyrridion, from an epiphytic tropical habitat in Venezuela. The body of these orchids consists almost exclusively of autotrophic roots which are characterized by a well developed cortex of voluminous, chloroplast-containing cells. The carbon gain of the roots is mainly via CO2 dark fixation involving Crassulacean acid metabolism (CAM). Although stomata are lacking, the root's net CO2 exchange pattern during 12 hour light/12 hour dark cycles shows all the features known from conventional CAM plants.