Genetic Diversity in Local Taraxacum officinale L. Populations from Habitats Varied in Toxic Load

Abstract

The level of lipid peroxidation (a stress indicator) and the quantitative traits of leaf tissue (the number and size of mesophyll cells and chloroplasts) were determined in Taraxacum officinale L. plants from five habitats near the city of Nizhniy Tagil that differ in terms of the heavy metal content in the soil. It is shown that in polluted habitats, the content of heavy metals (Cu 2+ and Zn 2+ ) in leaves is significantly higher compared to plants from background areas, with leaf thickness, mesophyll cell volume and chloroplast number per cell increasing. Both Inter Simple Sequence Repeat (ISSR) analysis and cluster analysis of dandelion genetic diversity based on eight primers have revealed that four groups of plants are closely related genetically. Of the observed differences between five local populations, 78% are caused by intrapopulation variability and 22% by interpopulation variability. It is supposed that Taraxacum officinale's tolerance to heavy metal contamination in the studied localities is not genetically fixed adaptation, but acclimation within genetically selected ranges of tolerance.