Plantago lanceolata L. from Serpentine Soils in Central Bosnia Tolerates High Levels of Heavy Metals in Soil

Abstract

Plants evolved a number of coping mechanisms wherewith they overcome negative environmental influences. Secondary metabolites are essential in plants’ stress management toolbox. One of the crucial environmental problems is contamination of soil with toxic heavy metals by different human activities. Serpentine soils are naturally burdened with heavy metals, thus presenting a great model for studying heavy metal tolerance in plants and their mechanisms of adapting to metalliferous soils. Plantago lanceolata L. is a widespread species adapted to both different environmental factors and different soils. In order to analyze the physiological status of P. lanceolata populations from metalliferous and non-metalliferous soils, we collected specimens from metalliferous soils including serpentine outcrops of central Bosnia and area artificially contaminated with heavy metals as well as from non-metalliferous soil. Heavy metal content (Cd, Cr, Mn, Co, Cu, Ni, Pb, Zn, and Fe) was determined in both herb and soil in order to test metal availability and accumulation potential of the analyzed individuals. Contents of total phenolics, phenolic acids, flavonoids, chlorophylls a and b, and proline were determined using spectrophotometric methods. The highest content of total phenolics was observed in a sample from anthropogenic site while proline showed a higher concentration in plants from serpentine soils. Regardless of high concentrations of Ni, Zn, and Cr in soil, P. lanceolata showed remarkable tolerance to serpentine soils as no significant differences in biochemical and physiological parameters were found in plants from metalliferous and non-metalliferous sites. These results indicate the existence of adaptive mechanisms and potential use of P. lanceolata in the remediation of heavy metal–polluted soils.