The Biosynthesis of Geraniol and Citronellol in Pelargonium roseum Bourbon

Abstract

Geraniol and citronellol were biosynthesized from [2-14C]mevalonic acid by the leaves of Pelargonium roseum Bourbon, The degradation of the radioactive specimens revealed that the major radioactivity (70–80%) was located at C-4 in the skeleton derived presumably from isopentenyl pyrophosphate and the rest of the activity at C-8 (and/or C-10) in the moiety from 3,3-dimethylallyl pyrophosphate. The unbalance of labeling was distinct from the result observed for the monoterpenes biosynthesized from the same labeled precursor by the flowers of the rose. A discussion is given on factors causing such a discrepancy in the labeling pattern owing to the difference of the plant and/or the organ. Time-course experiments with the use of [2-14C]mevalonic acid indicated the formation of geraniol prior to citronellol both in the intact plant and in the cell-free extract.