Light Growth Response and Auxin Curvatures of Avena

Abstract

Growth hormone was unilaterally placed on decapitated coleoptiles of oat seedlings. The resulting curvatures were continuously recorded from the moment of auxin application until 216 min. later. If the plants were exposed to light (from all sides) then the rate of curvature dropped during the first 36 min. of exposure. After this period the rate of curvature increased sharply and surpassed the rate of the control plants (in the dark) in many instances. If low auxin concns. were applied this light growth reaction was relatively larger than at the higher concns.