On the nature of pseudomonocotyly in flowering plants

摘要

The history of views on the pseudomonocotyly, its main forms and distribution among flowering plants is presented. Based on our own data on cotyledon initiation and on changes of certain morphometric parameters of its development in plants with different types of cotyledon structure (anisocotyly - Trapa, partial syncotyly - Nelumbo), and on the results of molecular-genetical and experimental studies on embryo morphogenesis in other flowering plants, a concept reconciling two main hypotheses about the origin of single cotyledon in monocotyledonous dicotyledons ( by Hegelmaier, 1878 and by Sargant, 1903) is suggested. The latter can be formed by different pathways: via uni- and bimarginal syncotyly, anisocotyly with heterochrony in the cotyledons setting up and others. However this wide spectrum of phenomena seems to be based on congenital cotyledon fusion controlled at genetical level, arising as a result of reduction of auxin polar transport in embryo and causing common characters of its development in monocotyledonous dicotyledons.