STUDIES ON CELL-DIFFERENTIATION: THE ROLE OF AUXIN IN ALGAE, WITH PARTICULAR REFERENCE TO RHIZOID-FORMATION IN BRYOPSIS

¹ Biology Department, Princeton University, Princeton, New Jersey

1. Application of indole-acetic acid, a naturally occurring auxin, to young Bryopsis plants results in the differentiation of rhizoids at the proximal end of most of the exposed "branches." Control plants formed no basal rhizoids.

2. Similar results were obtained with respect to rhizoid formation on secondary "branches" when the primary branches were excised from the original main stem and exposed to auxin. The response was not as strong under these circumstances.

3. Considered with the, fact that auxin is present in large amounts in Bryopsis, with most of the auxin being in the lower (i.e., rhizoid-forming) half of the plant, these experiments verify the hypothesis that the formation and distribution of auxin control rhizoid-formation in Bryopsis in a closely analogous way to auxin's effect on root-initiation in seed-plants.