Induktion phototropischer Reaktionen durch ein künstliches Perzeptionsorgan

Summary

Galston's finding that visible light inactivates indoleacetic acid in the presence of riboflavin, suggested the possibility that under certain conditions the blade of foliage leaves could act as a perception organ for the phototropic stimulus. In the experiments reported above a model system is described which reconstructs the necessary conditions withHelianthus seedlings by substituting two glass capillaries filled with photo-sensitized IAA-solution for the cotyledons. Illumination of one of the tubes produces a marked positive curvature in the darkened hypocotyl. An even more drastic reaction was obtained when the content of one of the tubes was illuminatedbefore the capillaries were fixed to the plant in the dark.