SEASONAL FEATURES OF METABOLISM OF WOODY GREENERY OF THE SHRUB LAYER BOREAL FORESTS

Abstract

A common juniper (Juniperus Communis L.) is a representative of shrub layer of boreal forests. In this work seasonal dynamics of quantitative content of main group of juniper woody greenery extractive substances is considered. Sampling was carried out during the spring-summer-autumn period in the Arkhangelsk region outside the zone of anthropogenic impact. Forest type – blueberry, mixed spruce-pine forest stand, class of Bonita-IV. In study samples content of mineral, water-soluble, alcohol-soluble and removing by steam distillation compounds and lipids content have been determined. According to these data, content of alcohol-soluble components is from 27.1 to 33.3%. It has maximum in April which is the last month of subarctic plants resting phase. The start of growth season in May is followed by sharp decrease of alcohol-soluble components content till it is the least value. Part of the components of alcohol extracts is precipitated when cooled in the form of wax (esters of fatty acids and alcohols or sterols with an admixture of fatty acids, hydrocarbons, pigments). The maximum content (4.3%) of wax substances falls on April, the minimum (1.4%) was detected in May. Lipids content ranges from 8.6 to 12.2%. This is somewhat below in comparison with pine tree, fir and other coniferous species. The three minimums of lipids content (in May, August and December), which were extracted with petroleum ether, in juniper woody greenery are observed in annual dynamic, and one maximum (July). The content of essential oil varies slightly by season and the number (2.4–2.8%) is second only to the DZ of fir. In the group of water-soluble substances there are two highs (June and November) and a low of August. The first maximum is associated with the flow of aqueous solutions from the soil, the second corresponds to the period of phenol accumulation. The minimum is explained by the slowing down of the aspiration current through the water supply channels at the end of the summer.
 It has been established that seasonal dynamics of main group of extractive substances content of juniper woody greenery as a whole is correspond to phenological cycle.