|Authors: ||V. Zheljazkov, S. Nikolov|
|Keywords: ||Sylibum marianum, Lady's thistle, Ecological agriculture, Medicinal plants, Heavy metals, Contamination, Metal toxicity, micronutrients, trace elements, Cd, Pb, Cu, Mn, Zn|
In 1989 – 1993 field and pot experiments were conducted to study the effect of heavy metals on the productivity and quality of cv Silmar from Sylibum marianum L. Field experiments were performed in the vicinities of NFMC near Plovdiv in the presence of severe soil and air pollution.
Plants were grown on three spots situated at 0.8, 3 and 10 km (control) from the smelter.
Pot experiments were performed by using soils from the three spots, plus soil taken at 6 km from the smelter.
Plants from field experiment experienced the effect of heavy metal pollution in both soil and air, while those from pot experiment experienced the effect only of heavy metals in soil.
The content of Cd, Pb, Cu, Mn and Zn in soils, plant parts (roots, stems, leaves and seeds), in fat oil and sylimarin were determined on Inductively Coupled Plasma (ICP) apparatus.
It was found that: In field experiments the rate of heavy metal concentration in spot 1 at 0.8 km from the smelter (with content of Cd, Pb, Cu and Zn above or within critical levels for these elements in soils) decreased the yield of seeds by 16 % compared to the control, while yields from spot 2 (at distance of 3 km from the smelter) were 11% lower then in the control, in both cases without visible toxicity symptoms.
In pot experiment, seed yield from soil 1 (taken at 0.8 km from the smelter) was 13 % lower then from the control (soil taken at 10 km from the smelter), while yields from the other soils (taken at 3 and 6 km from the smelter) were not significantly affected by heavy metal pollution.
Content of sylimarin and fat oil in the seed was not affected by heavy metal pollution, besides these products were not contaminated.
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