Sexual and asexual processes in reproductive systems of flowering plants

摘要

In understanding ontogenesis it is important to elaborate some aspects of the theory of flowering plant reproduction. As a result of critical analysis of the literature and original data, the unification of some concepts and terms is proposed. The terms "sexual" and "asexual" in reference to flowering plants should be used to characterize only the mode of formation of new individuals (with or without the participation of meiosis and gamete fusion). The concept of "multiplication" is defined; it should denote an increase of the number of descendants, whereas the formation of a new individual, regardless of mode, is the meaning of the term "reproduction." The various modes of formation of the individual (sexual, asexual), morphogenetic pathways (embryogenesis, embryoidogenesis, gemmorhizogenesis), types of multiplication (seed, vegetative) and the correlations between them are described. Special attention is paid to the attributes of stem cells and their role in plant reproduction. Theoretical questions concerning such phenomena as polyembryony and genetic heterogeneity of seeds in plants are examined.