Date of Award


Degree Name

Master of Arts


Biological Sciences

First Advisor

Dr. Dona J. Fowler

Second Advisor

Dr. Leo VanderBeek

Third Advisor

Dr. Imy Holt

Access Setting

Masters Thesis-Open Access


Bean plants were used to study effects of IAA and related chemicals on plant growth patterns. Plant apical growth tips were removed, eliminating apical donimance. Decapitated plants were treated in experimental groups with IAA, tryptophan, 5-hydroxy indoleacetic acid, serotonin, and melatonin. Two other groups served as controls, one cut, and one uncut.

Growth measurements were taken to determine if the treatments could effectively restore apical dominance. Cut control plants showed a loss of apical dominance, with decreased apical growth, and release of inhibition of axillary growth, when compared to the uncut group.

Tryptophan and meltonin treatments restored little or no apical dominance. IAA, 5-HIAA, and seratonin treatments promoted apical dominance, with enhanced apical, and inhibited axillary growth.

This study indicated an ability of bean plants to utilize animal hormones chemically related to IAA to produce a variety of plant growth patterns.

Included in

Botany Commons