Abstract
Gravisensitivity of mosses at different stages of their ontogenesis has an adaptive value and contributes to the functional activity of the gametophyte and its stability under extreme conditions in microhabitats. The aim of our research was to determine the participation of gravimorphoses in the adaptive plasticity of mosses depending on thermal conditions of their habitats and UV radiation effect. The objects of the study were sterile cultures of the following moss protonemata: Weissia tortilis, collected in different thermal conditions of Zaporizhzhya and Lviv regions (Ukraine), Bryum caespiticium from Lviv Region (Ukraine), as well as B. caespiticium and Polytrichum arcticum collected in Antarctica (Galindez Island). In all moss cultures, the gravisensitivity of protonemata, the morphological structure and morphogenesis of stolons were analysed. The protonemata of W. tortilis from two populations in Ukraine and of B. caespiticium from Antarctica and Ukraine, growing under conditions of different UV levels, were compared in terms of their sensitivity to UV radiation. Gravity-dependent morphoses of terrestrial dendrites of W. tortilis under arid conditions, branching of apical cells of gravitropic stolons of Antarctic mosses P. arcticum and B. caespiticium as well as the rapid development of shoots on them demonstrate participation of gravimorphogenesis in adaptation of mosses to stressful environmental conditions. Gravisensitivity and ability to form buds at the apex of a gravitropic stolon are considered an important adaptive morphogenetic process. It has been found that plants of W. tortilis from Zaporizhzhya Region were more resistant to UV irradiation than those from Lviv Region. Antarctic moss after UV irradiation showed significantly higher antioxidants activity and contained larger amount of phenolic compounds and flavonoids.
Highlights
Gravity, as well as light, is an inducer of tropism; it is an important factor in plant morphogenesis
Samples of W. tortilis from Zaporizhzhya and Lviv regions were characterized by distinctive differences that are important for their existence in different climatic zones
It has been established that a long-term protonema stage in W. tortilis, which persists throughout the life cycle, is characterized by specific differentiation of morphologically different chloronema and caulonema cells and the formation of lateral branches of the chloronema type
Summary
As well as light, is an inducer of tropism; it is an important factor in plant morphogenesis. A relatively simple growth model, and gravity-dependent moss morphogenetic processes indicate the important role of gravity in plant ontogenesis. A mode of moss spore germination and differentiation of rhizoid and chloronemal stolons, the formation of vegetative and reproductive organs, and the form of a sporogon are gravimorphoses caused by the polarizing effect of gravity (Chaban et al, 1998; Cove et al, 2006; Khorkavtsiv et al, 2015; Lobachevska et al, 2019а). Gravimorphoses are species-specific, change depending on the stages of moss development and environmental factors, and are a widespread adaptive form of growth in the life strategy of bryophytes (Moulia, Fournier, 2009; Kordyum, 2014; Kyyak, Khorkavtsiv, 2016; Lobachevska et al, 2019а). Apart from mosses, the dorsoventral form of tree shoots, wood gravidependent formation, the allocation of lateral buds in orchids and fruiting bodies in fungi are the well known examples of gravimorphoses (Moore et al, 2008; Wojtaszek, 2011)
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
