Relationship of the Cobalt and Light Effects on Expansion of Etiolated Bean Leaf Disks

Abstract

Expansion of etiolated bean leaf disks in the dark is increased by exposing them briefly to light and/or by placing them on a basal soln. containing a cobaltous salt. The 2 effects are additive. Both Co and light cause uniform disk expansion, increase cell enlargement, and also increase enlargement of tissues from other organs. Both effects always occurred in the same plant materials. Co and light may affect the same limiting condition.