Geotropism: Its Orienting Force.

Seeds of Pisum sativum L. and other species were germinated and grown for five or more days on a continuously rotating vertical-axis turntable that developed a maximum centrifugal force of 1.79(g). Shoot (epicotyl) orientation in darkness was parallel to the resultant gravitational field. This is presented as confirmation of the hypothesis that the orienting force of geotropism of the higher plants is the inertial force of gravity.