Comparison Between the Anatomical Structures of Inhabited and Uninhabited Domatium in Two Species of Genus Rhamnus L. (Rhamnaceae)

Introduction: Domatia are small structures usually located on the underside of leaf, in the axils of the major veins. They are related to a mutualism between plants and small animals (arthropods) such as mites or ants. There is a large ecological background on domatia, but only a few detailed reports on their anatomy, and less information on the histological changes resulting from plant-mite interaction within domatia. There are many species of the genus Rhamnus L. that have leaf domatia, which anatomical structure is known, but the anatomical differences between inhabited and uninhabited domatia have not been studied. In this work, Rhamnus alaternus L. and Rhamnus ludovici-salvatoris Chod. are studied to know the differences between the anatomy of inhabited and uninhabited domatia and to assess the plant response to the presence of domatium inhabitant.Method: Anatomical study focused on examining epidermis and subepidermal collenchyma in the leaf blade, uninhabited domatium and inhabited domatium and a comparison were performed. The anatomical structure of the non-domatia leaf lamina is used to contrast the changes and to better understand the domatia and the effect of inhabitants.Results: The structure of the domatium shows certain differences from the structure of the non-domatia leaf blade. In the domatium, there is a thickening of the outer cell walls of the epidermis, a disordered appearance of the epidermis and subepidermal collenchyma, and larger and more abundant trichomes. The inhabited domatia had more disorder in the epidermis and subepidermal collenchyma.Conclusions: The presence of inhabitants in the domatium is related to a major alteration of the tissue structure. However, the location of the epidermis and collenchyma, as well as the presence, location and type of domatia do not vary.