The hypothesis that a mobile compound produced in the coleoptile tip controlled

Coleoptile experiment

The hypothesis that a mobile compound produced in the coleoptile tip controlled its bending toward directional light was tested by P. Boysen-Jensen in 1893. His experimental setup is represented below. Both dark and light treatment groups had intact coleoptiles as controls. The experimental groups included:•coleoptiles in which the tips were removed
•coleoptiles that were cut with the tips separated by mica
•coleoptiles that were cut with the tips separated by agar
Boysen-Jensen left one set of coleoptiles in darkness for 24 hours and one set in directional light for 24 hours and observed whether they elongated and/or bended toward the light