Distinctions among Conifer Exudates by Proton Magnetic Resonance Spectroscopy

Proton nuclear magnetic resonance spectra have been recorded of exudates harvested from 12 species from the family Araucariaceae, 40 from the Cupressaceae, and one from the Podocarpaceae. These spectra were compared with the spectra previously recorded of 82 species from the Pinaceae. These four families together represent all major groups of extant, resin-bearing conifers. A common set of 10 COSY two-dimensional cross-peaks generally define samples from the Pinaceae, a different set of six peaks define the Araucariaceae, and yet a third set of 10 peaks define the Cupressaceae, with a few exceptions. It is important that proton spectra can distinguish the Araucariaceae and the Cupressaceae, since carbon-13 spectra do not. The one-dimensional peaks not only confirm these familial distinctions but also often characterize genus and species uniquely.