Structural characteristics of leaf trichomes and epidermis in species from three sections of the genus Aristolochia.

Abstract

The structure of leaf epidermis in species from three sections (Diplolobus, Gymnolobus, and Siphisia) of the genus Aristolochia has been examined by light and scanning microscopy methods. As the results show, the number of the stomata and the length of stomatal guard cells in plants growing ex situ are not related to habitat conditions but are probably determined genetically. According to the type of leaf epicuticular waxes, the studied taxa can be divided into three groups, of which the Aristolochia-type is the most common. This type is characteristic of all studied species of the section Siphisia. The presence of two types of trichomes in members of this section distinguishes them from the other sections. Representatives of the sections with the Convallaria-type wax lack trichomes. The noted differences allow accurate identification of each of the species in the genus. The features of the epidermis surface, types and arrangement of stomata, and types of trichomes are additional diagnostic characteristics useful for taxonomy.