INTERACTION BETWEEN CADMIUM AND IRON - ACCUMULATION AND DISTRIBUTION OF METALS AND CHANGES IN GROWTH-PARAMETERS OF PHASEOLUS-VULGARIS L SEEDLINGS

The interaction between cadmium, one of the most toxic heavy metals, a nd iron, an essential plant nutritional element, was investigated in P haseolus vulgaris L. (cv. Slowianka) seedlings. The interaction was ex ternally induced by changing the content of both metals in the nutrien t medium. Under iron deficiency conditions (0 and 0.5 of normal dose o f this element), the toxic effects of cadmium on plant growth paramete rs, like fresh and dry weight accumulation, primary leaves area, etc., were generally much more pronounced than under normal iron supply. At normal and excess iron supply (1, 2 and 4 doses) cadmium diminished i ron accumulation in roots and primary leaves, but on the other hand ex cess iron decreased cadmium level, preventing plants from extreme toxi city of very high cadmium concentrations in the growth environment. It is to be noted that iron is classified also as a heavy metal, and its excess may become toxic, e.g. decreasing root dry weight or diminishi ng leaf area, especially at the highest dose. The detoxication role of iron against cadmium, and possibly other toxic metals is, however, li mited to concentrations of this element in the nutrient solution which themselves are not toxic for the organism.