The distribution and degradation of chlormequat in wheat plants

Abstract

The distribution and degradation of chlormequat chloride (2-chloro 1,2- 14C ethyltrimethylammonium chloride) was determined after uptake by the roots of summer wheat seedlings. This plant regulator was readily translocated from the roots to the above ground parts and converted into choline. Choline was further metabolized to betaine which upon demethylation yielded finally glycine and serine. Both amino acids were incorporated into a protein fraction. The occurrence of radioactively labeled glycine and serine in the amino acid pool and the evolution of 14CO 2 from chlormequat treated plants indicated that serine was formed from glycine under the release of 14CO 2 during photorespiration. One week after the uptake period 82% of 14C chlormequat taken up by the roots was recovered as the parent compound or as breakdown products in wheat plants. In addition 5% of the amount taken up by the roots was released as 14CO 2 by the leaves. Fifty per cent of the total amount of chlormequat originally present in roots and leaves was already metabolized after 7.5 days. No evidence has been obtained for the presence of unchanged chlormequat or an unknown metabolite in the nucleic acid or protein fraction.