The effects of lead on growth and stress markers in two types of Vicia faba L.

Lead (Pb) is one of the most dangerous pollutants in the environment. In this research, the effects of Pb on growth, Pb accumulation in root and shoot and the levels of physiological/biochemical stress markers in leaves were investigated in two types of faba bean (Vicia faba L.). Plants were grown in sand, watered with half-strength Hoagland's nutrient solution with 0, 5, 25, 100 or 125 mu M of lead nitrate. Pb did not significantly affect the root and shoot dry weights. After two weeks of Pb treatment, the plants were harvested and stored for analyses. In leaves Pb significantly decreased the relative water content and the total chlorophyll concentration and significantly increased the proline concentration, but did not significantly affect the peroxidase activity and soluble sugar concentration. Overall, the large-seeded and the small-seeded type responded similarly to Pb, although there were barely significant type *Pb interactions for total chlorophyll and proline. The large-seeded type had significantly higher root and shoot dry weights and a higher foliar soluble sugar concentration, compared to the small-seeded one. Pb accumulation in roots was not significantly different between the types. However, the small-seeded type accumulated much more Pb in the shoot, resulting in a significantly higher root to shoot translocation factor.