Comparative embryology of three Gentianaceae species from the Central Caucasus and the European Alps

A comparative investigation was carried out on the ovule and seed development of three mountain species of Gentianaceae, the perennial species Gentiana pyrenaica, and the two short-lived monocarpic species Gentianella caucasea and G. germanica. In all three species most embryological characters conform to those generally found in the family of the Gentianaceae. In some features, however, G. pyrenaica and the two Gentianella species differ from each other. In G. pyrenaica the ovule is anatropous, the integument 8-10 layered and the three reduced antipodals degenerate soon after fertilization. In contrast, G. caucasea and G. germanica form a hemitropous ovule, a 4-5 layered integument and up to 16 antipodal cells by secondary multiplication. All three species exhibit differences in synchronization between embryogenesis and endosperm development. Functional relations between the antipodal structure and the dynamics of seed development of the investigated species are postulated.