Ontogeny of beech seedlings in the first vegetation period in stand conditions

Abstract

The ontogenetic properties of moesian beech seedlings were analysed in the first vegetation growth period at identical sites, but in different stand conditions based on the divergent values of unique and complex biological characteristics. The seedlings were formed on the deluvium at the site of montane beech forests (Fagetum moesiacae montanum typicum Jov. 1976) on deep eutric brown soil. The terrain is gently sloped, exposure east-southeast, altitude about 470 m The seedlings from the completely closed part of the stand are the phenotype of the sciomorphic structural form. Their above-ground shoots usually consist of: hypocotyl, cotyledons (or their scars), above-cotyledon internode-epicotyl, a weak (leafless, as a rule), sylleptically formed "above-epicotyl axis", two opposite, primary, leaves and vegetative buds, large terminal and undeveloped in the axyl cotyledons and primary leaves Compared to the conditions in the closed canopy, seedlings on the felling area differ in some biological properties and form a different phenotype In the different environment conditions, the greater significance of differences between identical biological properties is expressed according to the order of their origin. The most expressed differences occur in the development of the "above-epicotyl axis". In the juvenile stage of ontogeny, in the conditions of more illuminated felling area, Moesian beech can form shoots with shortened or incomplete cycle of morphogenesis and thus it is ontogenetically adapted to site and weather conditions More intensive growth of the "above-epicotyl axis" of the seedlings on the felling area conditioned the averagely higher seedlings at the end of the first vegetation growth period, more numerous assimilation apparatus, larger diameter root collar, larger diameter of hypocotyl and epicotyl parts. The range between average effects of growth in closed stands and in felling area points to the development potentials of beech depending on the factors of ecological nature, which can be controlled, to some extent, by silvicultural measures.