Microscopic investigation of trichomes of wild-growing Satureja montana L

Abstract

Considering the importance of S. montana L. as a medicinal plant, due to the essential oils produced in its glandular trichomes, and the lack of data about the leaf ultrastructure and micromorphology, we have carried out a comprehensive study of trichomes distributed in the vegetative and reproductive organs. Micromorphological and ultrastructural investigations of the glandular trichomes of Satureja montana L. and autofluorescence analyses of their secreted products were carried out using scanning electron microscopy (SEM), transmission electron microscopy (TEM), confocal laser scanning electron microscopy (CLSM) and light fluorescence microscope. The leaves, stem and calyx bear numerous nonglandular, unbranched trichomes and two types of glandular trichomes - peltate and capitate. Ultrastructural analyses showed the presence of mitochondria, plastids and proliferations of the granular endoplasmatic reticulum in secretory phases of the heads of glandular trichomes. Strong red autofluorescence of the lipophilic and hydrophilic secreted material was observed with CLSM. Green-yellow autofluorescence of secreted material were noticed in peltate and capitate trichomes observed with a fluorescence microscope.