Fixation of CO2 and Export of Photosynthate by the Carpel in Pisum sativum

Abstract

AbstractPods of Pisum sativum cv. Meteor were supplied with 14CO2 and the fixation and distribution of the radiocarbon studied. A high fixation rate was found in all of the treated pods. In intact control plants about 60 per cent of the total radiocarbon fixed was exported from the carpet into the seeds of the treated pod in the 24 hour period following fixation. Almost all of the remainder was relained in the carpel itself. It was found that the seeds in the treated pod were the major sink for these fixation products and that the weight of the seed determined the level of import of radiocarbon from the carpel in both attached and detached pods. Removal of the seeds from the treated pod prior to 14CO2 treatment reduced export from the fed carpel from 60 to 15 per cent, this being distributed mainly in the other pods and stem fractions. It appears that carpet photosynthate is likely to be of great importance in the growth and development of seeds enclosed by the carpel. control of fixation and export of radiocarbon seemed to be a function of the carpel and the seeds enclosed by the carpel and to be relatively independent of the rest of the plant. This could explain the absence of effect of GA on these processes.