The architecture of the dwarf shrub Thymus petraeus (Lamiaceae) in the conditions of Southern Siberia
E. B. Talovskaya1, V. A. Cheryomushkina1, I. N. Barsukova2
1Central Siberian Botanical Garden of SB RAS, Novosibirsk, Russia
2Katanov Khakass State University, Abakan, Russia
Keywords: адаптация, экотоп, архитектурная единица, Thymus petraeus, Южная Сибирь, adaptation, ecotope, architectural unit, Southern Siberia
Abstract
The structure of Thymus petraeus individuals was studied using the architectural approach. It is established that in the South of Siberia the species occurs in similar habitats: in the present, meadow, sandy steppes and their petrophytic variants on the slopes and low rocky peaks of hills. Classification I. G. Serebryakov [1964], T. petraeus - vegetatively-semimobile dwarf shrub with persistent throughout the life system of the main root and with rooting runners. In the structure of individuals T. petraeus identified 3 architectural units that differ in the position of the compound skeletal axis in space (orthotropic-plagiotropic, plagiotropic, orthotropic). Each architectural unit consists of the main compound skeletal axis, the compound skeletal axes of 1st order, formation shoots, branching and enrichment shoots. It is shown that the structure of individuals can be formed by repeating only two architectural units. It is established that in the present steppes and their petrophytic variants the structure of individuals is built at the expense of repetition of orthotropic-plagiotropic and plagiotropic architectural unit; in sandy steppes - at the expense of repetition of plagiotropic and orthotropic architectural unit. The features of T. petraeus development in specific ecological and cenotic conditions are shown. In this regard, characterized by: 1) morphological polyvariance, which is based on changes in the structure of shoots (shortened, elongated) and the composition of architectural units (no compound skeletal axes of the 1st order or enrichment shoots); 2) dimensional polyvariance, manifested in the change in the length and number of compound skeletal axes; 3) dynamic polyvariance, associated with fluctuations in the duration of monopodial growth of shoots formation (from 2 to 5 years) and the architectural unit as a whole (from 6 to 20 years). The revealed modifications of architecture do not lead to a change in the life form of the dwarf shrub, but reflect the mechanisms of its adaptation.
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