The effect of acetylcholine on growth and on growth inhibition by CCC in wheat seedlings.

The inhibition of the growth of wheat seedlings by 2-chloroethyltrimethylammonium chloride (CCC) was strongly reduced by root application of acetylcholine (Ach). Ach was applied after uptake of CCC by the roots or by the leaves. Ach also stimulated growth of non-CCC-treated seedlings up to 30% when applied to the roots. Growth stimulation appeared to be dependent on pH of the medium and most effective at pH 4.5 and 6. At pH 7.5 Ach did not promote growth of wheat seedlings.