Endangered orchid plant Epipactis atrorubens on serpentine and granite outcrops of Middle Urals, Russia: A comparative morphophysiological study

The morphophysiological features assessment (leaf area, specific leaf mass per unit leaf area, the thickness of the leaf, mesophyll and epidermis, number of chloroplasts and cell layers, the photosynthetic pigment content) was performed on Epipactis atrorubens (Hoffm. ex Bernh.) Bess. (Orchidaceae family) from the serpentine and granite rock sites of Middle Urals (Russia) for the first time. Despite lower photosynthetic pigments, E. atrorubens growing on serpentine dump showed high viability as compared to granite rocks. The reduced content of photosynthetic pigments in E. atrorubens from the serpentine site was compensated by leaf restructuring. Thus, E. atrorubens being an endangered species can be saved by growing them on serpentine habitats. Future perspective includes identifying adaptive physiological mechanisms that contribute to the survival of plants under extreme detrimental conditions of the serpentine dump.