Studies on plant growth‐regulating substances: XXI. The release of pectic substances from wheat coleoptile tissue incubated with solutions of ethylenediamin etetraacetic acid

Abstract

SUMMARYThe effect on excised wheat coleoptiles of solutions of ethylenediaminetetraacetic acid, at concentrations which produce a significant growth response in segments of this tissue, was investigated.The removal not only of calcium ions, but also of pectin, from coleoptiles by these solutions of the chelator was demonstrated and the implications of these findings are discussed. An increase in the plasticity of the cell walls is considered to arise from the removal of both of these constituents, and the small extension of the coleoptile segments to be a direct consequence of these changes.The concentration of EDTA required to give either the growth‐regulating response or to cause the loss of pectin and calcium was shown to approach that which also caused visible signs of toxicity, and this was taken as further support for the ‘subacute toxicity’ theory put forward earlier by Fawcett, Wain & Wightman.