Abstract:
Many dicotyledonous plants produce structures called leaf domatia. Approximately 28%
of 290 families have species with leaf domatia. These structures are abundant within the Rubiaceae
and Vitaceae. 26% and 16% out of 206 representative species cited in literature from 48 plant families
belong to the Rubiaceae and Vitaceae respectively. Leaf domatia are usually associated with mites and
often mediate mutualistic relationships with predacious mites. These structures are pockets found in
the underside of the leaf, where the secondary vein axils meet the major vein. In the present study,
we examine the anatomical structures of leaf domatia from three plant species (Gardenia thunbergia
Thunb., Rothmannia capensis Thunb., Rothmannia globosa (Hochst.) Keay) from the Rubiaceae family in
order to find out if their internal tissues differ. These plants were sectioned and viewed under a Light
Microscope in order to document their internal anatomy. A Transmission Electron Microscope was
used to search for the presence of cuticular folds in their epidermis, which are thought to assist plant
to communicate with mites. Results from this study suggested that the main features of domatial
anatomy are the presence of an extra layer of tissue in the lower epidermis, a cuticle, cuticular folds,
trichomes and the presence of an invagination. Cuticular folds were present inside the domatia but
were not restricted to the domatial lamina. Thus, we conclude that these structures do not assist
plant in plant-mite communication. This study provides a better understating of the anatomy of leaf
domatia of the Rubiaceae.
