INFLORESCENCE ODOR OF SENECIO-ARTICULATUS - TEMPORAL VARIATION IN ISOVALERIC ACID LEVELS

Isovaleric acid (3-methylbutanoic acid) was found to be a major consti tuent of the inflorescence odour of Senecio articulatus and contribute s to its fetid smell. Other important constituents were linalool and i ts oxides. Production of isovaleric acid from a single capitulum was f ound to be greater during the day, when new florets opened, than durin g the night, whereas the terpenoids showed less temporal variation. Th e odour is distinct from that of sapromyophilous plants whose odours m imic dung and carrion but, in producing isovaleric acid, shows similar ities to other potentially fly pollinated flowers with unpleasant odou rs. (C) 1997 Elsevier Science Ltd. All rights reserved.