Biogeochemical transformation of steppe vegetation in atmospheric pollution conditions

In the steppes the affect of atmospheric pollution on grassy vegetation is not visually observed, as it is in the case of coniferous tree species of the taiga zone. But the seeming prosperity of the steppe is deceptive. The results of the quantitative chemical analysis confirm this fact. In the article we have presented data on 20 chemical elements. Information on the chemical composition of different plant species in the background area is compared with analogous plants in the zone of atmospheric pollution, where F, Na, Al, Ni have been identified as the main pollutants. We consider fluoride ion to be the most abundant element with а high toxicity. Its content is from 0.5 to 6.0 TLV and the extent area - about 250 km2. A map of the domimant pollutant, fluorine, in the aboveground green phytomass of steppe landscapes is presented. Based on the theory of mineral detoxification of pollutants in plant cells and according to the level of mineral salts (ash) content, as well as fluorine content in herbaceous plants, lichens, needles and tree leaves, we have determined the resistance of a number of plants to atmospheric pollution by fluorine.