Photosynthetic response of Solidago gigantea Aition and Calamagrostis epigejos L. (Roth) to complex environmental stress on heavy metal contaminated sites.

Studies of in situ plant response and adaptation to complex environmental stresses, are crucial for understanding the mechanisms of formation and functioning of ecosystems of anthropogenically transformed habitats. We study short- and long-term responses of photosynthetic apparatus (PSA) and anti-oxidant capacity to complex abiotic stresses of common plants Calamagrostis epigejos and Solidago gigantea in semi-natural (C) and heavy metal contaminated habitats (LZ). We found significant differences in leaf pigment content between both plant species growing on LZ plots and their respective C populations. The average values of leaf chlorophyll indexes were 27% lower in the LZ populations of both species and significantly lower in Sg plants in comparison to Ce ones. The average values of the anthocyanin index in CeLZ and SgLZ populations were significantly higher (by 18%) than in their respective controls. In both Ce and Sg plants occurring on LZ plots, the average leaf flavonol indexes were higher than on their controls by 31% and 15% and this index was significantly higher in SgLZ population than CeLZ and CeC plants (by 34% and 54%, respectively). Both Ce and Sg populations growing on LZ plots showed significantly lower photosynthetic rate (A), transpiration rate (E) and stomatal conductance (g