The structure of dandelion cenopopulations and specific features of heavy metal accumulation

The accumulation of Pb, Cd, Cu, and Zn by two dandelion species Taraxacum dahlstedtii Lindb. hi. and I: pectinatiforme Lindb. fil. was studied. The first, more abundant species was shown to accumulate smaller amounts of toxicants from slightly polluted soils than the second species. The inverse effect was observed on heavily polluted soils. The threshold concentrations of heavy metals in the soil, at which they penetrate the root barrier, were determined. The coefficients of Ph and Cd transfer to the aboveground organs were greater in I: pectinatiforme in the heavily polluted zone; in the background zone, they were greater in T. dahlstedtii. The plants of the latter species in the impact zone strongly fixed toxicants in the roots, ensuring the protection of vegetative and generative organs. Coefficients of copper and zinc transfer to the aboveground biomass were similar in both species.