Towards angiosperms genome evolution in time

Abstract

In this communication, direction of evolutionary variability of parameters of genome size and structurally functional activity of plants in angiosperm taxa among life forms, are analysed. It is shown that, in the Cretaceous-Cenozoic era, the nuclear genome of the plants tended to increase. Functional genome efficiency (intensity of functions per picogram of DNA) decreased as much as possible from highest, at trees and lianas of rain and monsoonal forests of the Paleogene, to minimum, at shrubs, perennial and annual grasses of meadow-steppe vegetation appeared in the Neogene. Environmental changes in temperature, humidity and carbon dioxide concentration in adverse direction, critical for vegetation, are discussed as the cause of growth of evolutionary genome size and loss in its functional efficiency. The growth of the genome in the Cenozoic did not lead to the intensification of functions, but rather led to the expansion of the adaptive capacity of species. Growth of nuclear deoxyribonucleic acid content can be considered as one of the effective tools of an adaptogenesis.