TURNER, GLENN W.* AND RODNEY B. CROTEAU. Institute of Biological Chemistry, Washington State University, Pullman, WA 99164-6340. - Development of peltate glandular trichomes of peppermint.
We describe the ultrastructure of the essential oil producing peltate
glandular trichomes of Mentha x piperita L. During oil secretion, the
cuticle covering the glandular cells separates from the cells to form
an oil storage cavity. Filling of the cavity is correlated with the
enlargement of gland cell plastids, and the development of an
extensive smooth endoplasmic reticulum. Immunocytochemical
localizations, and the occurrence of plastidial targeting sequences
indicate that the enzymes responsible for the early steps of menthol
biosynthesis (to limonene) occur in gland cell leucoplasts, while
subsequent hydroxylation and reductions occur elsewhere.
Key words: glandular trichome, Mentha x piperita, monoterpene, peppermint