This study assesses whether the distinct altitudinal cline in leaf morphology (decreased leaf width and length with increased altitude) in Tasmanian mountain pepper (Tasmannia lanceolata) is associated with changes in the leaf chemistry of wild populations from different ecological landscapes and altitudes. The presence of distinct pungent drimane sesquiterpenoid chemotypes was identified: subalpine woodland and wet sclerophyll forest chemotypes. Isolation studies and analysis of extracts revealed that wet sclerophyll forest T. lanceolata populations featured polygodial as the principal terpenoid, with profiles similar to the commercial cultivars sampled. In contrast, the subalpine woodland populations contained the drimane sesquiterpenoids 1β-acetoxy-9-deoxyisomuzigadial and 3β-acetoxydrimenin and the conspicuous absence of the pungent principle polygodial.
Keywords: Tasmanian mountain pepper; altitudinal cline; drimane chemotypes; pungent leaf phytochemicals.