Features of grass and subshrub reproduction in forest phytocoenoses

Abstract

The north-east region of Ukraine stands out from the other regions including the Carpa thians for high forest cover. Grass and subshrub layer significantly affects the formation of tree layer (the early stages of forest demutation). The study is conducted in forest phytocoenoses of the National Nature Park "Desniansko-Starogutsky" and the adjacent territories. The study objects are model plant species of grass and subshrub, each presented by 3-5 coenopopulations. Two main types of reproduction are found in forest grasses and subshrubs: seed (or by spores in spore-bearing plants) and vegetative. In case of generative reproduction, an important biological characteristic is the so-called reproductive effort, which characterizes the contribution of organic matters and energy to the reproductive process. An important common feature of reproduction of the vast majority of forest grasses is the ability for vegetative reproduction and clone formation. It is established that the main indicators of generative reproduction of clone forming plants of grass and subshrub layer depend on plantspecies,andareinfluencedbytheecologicalandcoenoticfactors.Ithasbeen found that the smallest contribution (2 %) to the reproduction organs is characteristic of C. vulgaris, and the highest contribution (almost 50 %) is found in the coenopopulations of M. сaerulea. Overall, generativity of the studied plants of grass and subshrub layer is determined by the ecological and coenotic factors, and, therefore, is consistently varied from association to association.