Biological Faculty, Saratov University, Astrahanskaya ul. 83, Saratov 410071, Russia

Abstract

It is proved neither experimentally nor theoretically that sex process brings qualitative peculiarities to the acceleration of evolution on above species level. Being the mechanism of species structure maintenance it constrains variability by meiotic recombinogenesis and sexual compatibility. Traditional view is also hardly compatible with recent results of genetic studies of polymorphism. Using angiosperms as an example it is shown that qualitative peculiarities on above species level are brought not by sexual process but agamospermy. It remarkably accelerates the process of species formation because its ability 1) to realise or support any saltation development of new forms when they are self-sterile and not compatible with initial parent forms; 2). to create the immediate isolation of reproduction; 3). to change radically the structure of a species or population excluding recombination as the basis of species integrity. However the potential of agamospermy can be realized only at dynamic equilibrium between apo- and amphimict systems of reproduction. It results the formation of agamic complexes that are the systems with very intensive processes of species development. These new forms can be stabilized as the real biological species only by returning to obligate amphimixis. Seed reproduction systems of angiosperms are characterised by cycle transformation. Temporary destabilisation of sexual reproduction system is changed into equilibrium apo - amphimict one and then back to the obligate amphimict system. Apomixis seems to play an essential role in saltation. It can be partially shown by 1). The distribution of apomict forms that corresponds to the species formation on the basis of parent forms area; 2). Close correlation between agamospermy and polytypical genera; 3). Close correlation between agamospermy, polyploidy and hybridogenesis; 4). The structure of agamic complexes that testifies the saltate origin of species and genera.