Lead uptake by Matricaria chamomilla L.

Abstract

Investigations were carried out under laboratory conditions in a nutrient solution according to Knop to observe the influence of increasing concentrations of Pb (5, 25, 50, 75 μmol/l) on its uptake and accumulation in chamomile (Matricaria chamomilla L.), diploid cv. Novbona. The essential part of Pb taken up by chamomile plants accumulated in roots; only minor portion of the metal was translocated to the above-ground part of the plant. Addition of Pb to the growth medium reduced significantly the root biomass (-46.3% at the highest supply of Pb); reduction in the above-ground dry matter (-18.3%) was insignificant. Pb treatment also reduced chlorophyll content in leaves (P < 0.01). The highest level of Pb resulted in a decrease of Chl a by 52% and of Chl b by 48%. Lead in the nutrient medium induced accumulation of free proline (Pro) in leaf rosette tissues (P < 0.01). Distribution of Pb in chamomile plants (cv. Novbona) and accumulation of Pb with focus on accumulation in inflorescences (drug Flos chamomillae) was investigated in a pot experiment with soil (Orthic Luvisol) supplemented with 50 mg Pb/kg dry soil. At this treatment, the content of Pb in chamomile inflorescences was 3-fold higher in comparison with the control (P < 0.05) but the level of accumulated Pb (2.08 mg Pb/kg dm flowers) was far below the limit (10 mg/kg) set by the WHO as the highest acceptable level of Pb in the chamomile drug.