IMPACT OF SHORT-TERM EXPOSURE TO LEAD AND CADMIUM OF COMMON BUCKWHEAT (FAGOPYRUM ESCULENTUM MOENCH) SEEDLINGS GROWN IN HYDROPONIC CULTURE

In a model hydroponic experiments, the impact of short-term exposure to lead (Pb2+) and cadmium (Cd2+) in a nutrient medium on seedlings of two cultivars of common buckwheat (Fagopyrum esculentum Moench) has been examined. Cadmium and lead were added separately into the nutrient medium (Hoagland solution) in concentrations of 0 (control). 0.01, 0.10 or 1.00 mM. To evaluate the effect of the examined metal ions, the elongation of shoots and primary root of buckwheat seedlings. proline and malonic dialdehyde (MDA) content, as well as the level of photosynthetic pigments were measured. This study concludes that the presence of Pb and Cd in a nutrient medium causes reduction in biochemical activities and distinctly inhibits the growth of buckwheat seedlings. Cadmium and lead ions had a more inhibitory effect on the growth of roots than shoots of buckwheat seedlings. Increasing the concentration of both metals caused an increase in the content of malonic dialdehyde and proline in all examined organs of seedlings. Short-term exposure of seedlings to cadmium and lead ions stimulated the accumulation of a and b chlorophylls. and carotenoids in buckwheat cotyledons. Highly significant correlation between elongation of primary root and proline level, and elongation and MDA content indicate that roots are particularly sensitive to the presence of lead and cadmium in nutrient medium. Common buckwheat is known to be a lead hyper-accumulator, and the results obtained in this study confirm it. Buckwheat seedlings show higher resistance to lead in a nutrient medium than to cadmium.