Specificity of induction of the lignification response in wounded wheat leaves

Abstract

A range of abiotic treatments reported to induce phytoalexin accumulation in various plants failed to induce lignification in a wounded primary wheat leaf system. The inducers included antimetabolites, metabolic inhibitors, DNA-intercalating compounds, basic polypeptides, oxidising and reducing agents, halogen anions, heavy metal ions and u.v. irradiation. Only mercuric ions elicited a response. A range of fungi, including species normally of saprophytic habit, species pathogenic on plants other than wheat, and wheat pathogens all elicited lignification. Yeasts and bacteria, unlike the mycelial fungi, were poor elicitors of the response. Thus lignification appeared to be induced almost exclusively by fungi, unlike phytoalexin production which can also be elicited by a wide range of abiotic treatments.