REPRODUCTIVE BIOLOGY AS THE BASIS FOR PLANT PHYLOGENY AND EVOLUTION

摘要

The origin of life, the organisation and diversification of life forms-plants and animals-through time and space has been a complex process. The fundamental basis of evolution is perhaps rooted in the reproductive machinery, the changing pattern of which is evident in the successive plant groups in the ascending order, Algae, Bryophytes, Pteridophytes together forming cryptogams, the Gymno-sperms and Angiosperms together formling phanerogams or flowering plants. The evolutionary succession is marked by the gradual reduction of vegetative gameto-phyte, and the proportionate expansion of the sporophytic plant body, the final outcome of which is seen in the angiosperms, characterised by the flower morphosystem. in which the male pollen is mobileand the female egg is stagnant, associated by appropriate mechanisms for pollen transfer and fertilization