Die Anfangsphasen des durch Steringlucoside und Indol-3-essigsäure stimulierten Wachstums bei Avenakoleoptilen / Initial Phases of Growth Induced by Sterylglucosides and Indole-3-acetic Acid in Avena Coleoptiles

Abstract

Abstract The initial phases of growth induced by sterylglucosides were investigated by means of a high resolution recording technique. Avena coleoptile segments were preincubated with 10-6 M IAA in buffered solution, then the β-vglucosides of sitosterol, stigmasterol, campesterol, and cholesterol respectively were added in the concentration range from 10-7 –10-6 m . It could be demonstrated that the first response to the applied sterylglucosides is a reduction of the growth rate lasting about 15 min, followed by a sharp increase of the growth rate. As the growth response of the coleoptiles after treatment with sterylglucosides is very similar to that observed after application o f IAA alone, it is concluded from the results that sterylglucosides or sterols may also exhibit their primary action at the membrane level, perhaps by influencing microviscosity of the membrane and/or H +-secretion.