Some biological effects of volatiles emanating from wood

Abstract

Early in vitro observations on the biological activity of volatiles from heat-dried woods indicated two major properties: one of retarding growth of higher plants and another of stimulating growth of a wood-inhabiting Basidiomycete. For the purpose of determining the chemical nature of the active volatiles and their parent sources principally in red pine wood (Pinus resinosa), these two properties were investigated separately with the aid of bioassay techniques. Two test organisms were used: germinated kidney beans (Phaseolus vulgaris) and the fungus Fomes annosus. Various dose levels of volatile sources were suspended over the test organisms for a fixed period of time, after which growth was measured.Experimental evidence indicated that bean growth inhibition and fungus growth stimulation could be attributed to volatile autoxidation products derived from certain unsaturated fatty components of wood. In particular, linoleic acid appeared to be a major phytoactive source. A number of aliphatic aldehydes, reported in the literature as fat autoxidation products, were found to be phytotoxic to beans in appropriate quantities, but none had any growth promoting properties on the fungus. Also, indications were that fungus response to wood volatiles was largely independent of the nutrient status of the substrate, provided a suitable nutrient complement was present. It was proposed that yet unidentified non-aldehydic substances, or specific untested aldehydes, functioned as the growth factors.