Adaptive Morphophysiological Features of Neottia ovata (Orchidaceae) Contributing to Its Natural Colonization on Fly Ash Deposits

In previous decades, some species of the Orchidaceae family have been found growing in man-made habitats. Neottia ovata is one of the most widespread orchids in Europe, however it is quite rare in Russia and is included in several regional Red Data Books. The purpose of this study was to compare the chemical composition and morphophysiological parameters of N. ovata from two forest communities of the Middle Urals, Russia: natural and transformed (fly ash dump of Verkhnetagil’skaya Thermal Power Station) for determining orchid adaptive features. The content of most of the studied metals in the underground parts (rhizome + roots) of N. ovata was considerably higher than in the leaves, which diminished the harmful effect of toxic metals on the aboveground organs. The adaptive changes in the leaf mesostructure of N. ovata such as an increase in epidermis thickness, the number of chloroplasts in the cell, and the internal assimilating surface were found for the first time. The orchids from the fly ash deposits were characterized by a higher content of chlorophyll b and carotenoids than plants from the natural forest community that evidenced the compensatory response on the decrease in chlorophyll a. The ability of N. ovata from the transformed habitat to maintain a relatively favorable water balance and stable assimilation indexes further contribute to its high viability. The study of orchid adaptive responses to unfavorable factors is necessary for their successful naturalization and introduction into a new environment.

The effect of the substrate on the anatomical and morphophysiological parameters of Pimpinella saxifraga L. on the ash dump

The structural and functional features of the species Pimpinella saxifraga L., which grows in the ash dumpof the Verkhnetagil State District Power Station, were investigated, compared with the natural habitat. We studied suchindicators as biomass distribution, parameters of the leaf mesostructure (the area and thickness of the leaf blade, thethickness of the mesophyll and epidermis, the size of cells and chloroplasts and their number per unit area of the leaf, thenumber of chloroplasts in cell, etc.). Pimpinella saxifraga, growing on the ash dump, showed a change in morphologicalparameters, compared with the control: a decrease in the weight of the roots, an increase in the weight of the aerialorgans, a decrease in the area of the leaf blade and the thickness of the leaf. The structural adaptation of mesophyll toenvironmental conditions consisted in changing the number and size of cells without changing the parameters of theplastid apparatus (number and size of chloroplasts). The properties of the substrate did not significantly influence on theinternal leaf area. Such adaptive changes allows this species to grow on technogenic substrates.