Impact of simulated acid rains on leakage of mineral elements from foliage of conifers and monocotyledons – adaptability matters 

The concept of the research is based on the effects of acid rains on plants foliage. Studies were carried out on 12 coniferous tree (Thuya, fir, larch, juniper, Scots pine, black pine, common spruce, silver spruce, cypress, yew tree, oriental thuya, Douglas fir) and 8 monocotyledonous plants (Maize, wheat, barley, oats, rye, ryegrass, fescue, ditch reed). Needles and leaves samples were collected from 20 species during the growth season from spring to summer at different sites of Poznan agglomeration. The needles and leaves were treated with 6 simulated acid rains (SAR) of pH 3.0, 3.5, 4.0, 4.5, 5.0, and 5.5 and kept for 72 hours at 22 °C. The filtrates were tested for Ca, Mg, K, Na, Zn and Fe. Data showed that the concentrations of leaked elements were closely related to the pH of SAR and depended also on the species. The most deleterious simulated acid rains for all tested plants were within the range pH = 3.0 – 4.0. Mineral leakage of coniferous needles as well as monocotyledonous leaves fitted mostly exponential and linear models, with exception to Na, which was described by the quadratic course. On the basis of the photosynthetic maintenance index [PMI = Mg/(Zn+Fe)], 67% of coniferous tree (CT) represented the very low photosynthetic maintenance as compared to monocotyledons (MP) with 75% for the low photosynthetic maintenance. The high share of MP to this range is a finding, which decidedly points out at the potential flexibility of these species to adaptation to highly anthropogenic ecosystems. Urban green covers should not be in prevalence managed with conifers. Some may develop slight (Grand fir, cypress, oriental thuya, Douglas fir) to high adaptability (Thuya occidentalis, juniper, yew tree). Quite all monocotyledons, particularly ryegrass, fescue, wheat, barley, oats and rye may be growing within anthropogenic zones with strong adaptability features