Coniferyl alcohol metabolism in conifers -- II. Coniferyl alcohol and dihydroconiferyl alcohol biosynthesis.

Coniferaldehyde and NADPH when incubated with microsomes isolated from developing xylem of Pinus strobus yielded coniferyl alcohol and dihydroconiferyl alcohol in vitro. D-(+)-Pinitol was also found to be a microsomal constituent. Endogenous E-coniferyl alcohol content, quantified in dormant buds, cambium, bark and needles of Pinus resinosa and P. strobus by isotope-dilution combined gas chromatography mass spectrometry (GC/MS) using ring-(13)C(6)-coniferyl alcohol, was at a level similar to that of endogenous indol 3-ylacetic acid (IAA). Wounding (branch girdling) induced more than a 10-fold increase in content of endogenous E-coniferyl alcohol in dormant non-lignifying cambium, a clear indication that monolignol biosynthesis is not coupled to lignification.