Production and Distribution of Assimilate in Chickpea (Cicer arietinum L.)

Abstract

Chickpea plants were supplied with ¹⁴CO₂ to various organs and the assimilation and distribution of ¹⁴C was measured in order to investigate the sources of assimilate for pod development and the distribution of assimilate within the plant.

Leaves were the main photosynthetic organ and pod wall photosynthesis was not a significant source of assimilate for seed development. However, the pod wall contributed a significant amount of photosynthate to its own growth.

Individual branches on the plant acted as independent units in terms of photosynthate production and utilization. Attempts to create a gradient by selective defoliation or pod removal did not result in movement of assimilate from one branch to others.

Within the individual branch, photosynthate was utilized close to its site of production. The export of ¹⁴C-labelled photosynthate was not dependent on the age of a leaf but was regulated by the presence or absence of an axillary pod. The amount of assimilate drawn by a pod from the subtending leaf was dependent on the size of the pod.