SHOOT FORMATION OF EPILOBIUM HIRSUTUM L. IN CONNECTION WITH THE ADAPTATION OF HERBS OF THE SEASONAL CLIMATE TO THE CONDITIONS OF VARIABLE HUMIDIFICATION / WATERING

Abstract

One of the fundamental problems of modern biology is the identification of adaptations of organisms to existence in different environments of the biosphere, the mechanisms and methods of the formation of their adaptations. A comparative analysis of shoot formation and ontogenesis of individuals makes it possible to reveal these features in plant biomorphs, including during the development of reservoirs by herbs by mesophytes. The article describes the shoot formation of the hygromesophyte Epilobium hirsutum L. The development and structural-functional zoning of shoots were assessed from the standpoint of modular organization and compared with the peculiarities of shoots formation in mesophytic and hydrophyte grasses. Shown: their similarity with monocarpic shoots of mesophytic herbs at the initial stages; further prolongation in the form of basipetal development through heterochronies and heterotopies with the development of lateral sylleptic shoots as in hydrophytes; increasing the area of the assimilating surface of an individual and ensuring the autonomy of individual shoot systems due to this with early morphological disintegration of the individual. It is proposed to distinguish the following stages in the development of the terrestrial part of the shoot system: vegetative uniaxial shoot - monocarpic shoot - disjunctive system of monopodial shoot - synflorescence system (double heterothetical frondose-frondular brush) at the shoot apex and replacement shoots in the transitional phase of its development in the zone of renewal , broken by the middle zone of inhibition, is more multicomponent and branched in comparison with those in mesohygrophytes like Veronica longifolia L., but less complexity than in hydrophytes - the aquatic form of V. anagallis-aquatica L. It is noted that the early transformation of the universal module (monocarpic shoot) into the main module (the shoot system formed on its basis) is provided by polyvariance in the development of leaf rudiments and axillary structures of elementary modules (elementary metameres) in connection with the conditions of the location of the apex and demonstrates possible mechanisms of adaptation of flowering plants with a sympodial long-shoot model of shoot formation to life in water bodies: abbreviation of ontogeny of an individual and monocarpity of ramet with polycarpicity of an organism (prolongation of ontogeny of an individual).