Growth-promoting Effect of Ethanol on Oat Seedlings

Abstract

THE effects of carbon dioxide on the growth of etiolated oat seedlings¹—promotion of the mesocotyl and depression of the coleoptile—have been under investigation for some time^2,3 and the observed behaviour has been attributed to a prolongation of the activity of the nodal meristem². Attempts have recently been made to correlate these growth phenomena with auxin metabolism by supplying indoleacetic acid (10 p.p.m.) to intact oat seedlings via their roots. In these experiments promotion of the mesocotyl was observed when ethanol was used as the solvent for indoleacetic acid but not when the potassium or ammonium salts were used dissolved in water. The effects on growth of 0.2 and 0.3 per cent ethanol were investigated, and they occasioned growth responses which exactly parallelled those induced by carbon dioxide.