XVI International Botanical Congess

The data on embryo development (regularities of cell growth and divisions at laying down and formation of cotyledons, changes of some morphometrical parameters, their influence on further embryo and seedling morphogenesis) in the model subjects, including embryomutants, on the types of cotyledonary apparatus (di-, mono-, syn-, poly-, schizo- and heterocotyly) are represented. The main hypotheses on monocot embryo origin (undevelopment, syncotyly, heterocotyly, Abort-hypothesis etc.) are considered. The conclusion about syncotyly as a most real way of its arising is maintained. Basing on the data on dependence of the syncotyly processes on the balance of auxines during the cotyledon initiation the connection between evolutionary establishment of monocotyly and seed dormancy is supposed.