The anatomical structure and the distribution of arabinogalactan proteins were investigated in the ovule of an energetic plant Sida hermaphrodita (L.) Rusby after pollination. Material was collected from an experimental field of the University of Life Sciences in Lublin (Felin). After embedding for immunoflurescence, semi-thin sections were stained with toluidine blue or incubated with JIM 13 or MAC 207 monoclonal antibodies for immunolabeling of arabinogalactan proteins. The structure of the ovule showed some differences in comparison to other representatives of the Malvaceae family. Conversely, the distribution of arabinogalactan proteins did not differ significantly from their distribution in the ovules of other angiosperms at the investigated stage of development.
Arabinogalactan proteins (AGPs) are a diverse class of highly glycosylated plant cell surface proteoglycans. They are discussed as signal molecules participating in cell-cell interaction or cellular signalling during morphogenetic processes. AGPs are abundant in the stigma and transmitting tissue of different flowering plants, and are supposed to play an important role in pollen tube adhesion and guidance. In the present work we localized two epitopes of AGPs using the monoclonal antibody JIM 8 and JIM 13 in ovules of anatomically different types. Although some differences in the localization of these epitopes in different plant species were observed, in all the studied ovules they were present on the pathway of pollen tube growth. In particular plant species they appeared at the time of the ovule’s highest receptivity.