Ultrastructure of Mesophyll Glands Secreting the Aromatic Substances in Patchouli Leaves

抄録

The mesophyll gland in patchouli (Pogostemon patchouli) was composed of secretory materials covered with a cuticle, a secretory head cell, a stalk cell and a basal cell. A large number of polysomes, mitochondria and smooth-appearing endoplasmic reticula showing a contracted figure were observed in the secretory head cells. Some endoplasmic reticula were sometimes observed in ramiform profiles. The aromatic cyclic sesquiterpenes were assumed to secrete into a subcuticular space through the thick cell wall from the peripheral area of the secretory head cell. Some cytoplasmic inclusions were localized in the secretory head cells and were considered to have been caused by a viral infection. On the basis of the ultrastructural details of the mesophyll glands, we discuss the secretory machinery by which the cyclic sesquiterpenes are produced and the possibility of the disturbance by viruses of the production of aromatic substances.