The Impact of Short-Term Exposure to Pb and Cd on Flavonoid Composition and Seedling Growth of Common Buckwheat Cultivars

The aim of this study was to compare the tolerance of seedlings of three Polish buckwheat cultivars (Hruszowska, Kora, and Luba) for short-term exposure to Pb and Cd. Seedlings were grown under controlled conditions in Hoagland nutrient solution, with the addition of low/high Pb or Cd ions (0.01 and 1.00 mM, respectively). After 3 days of treated seedling growth, the levels of total anthocyanins and content of particular flavonoids were measured. The presence of low concentrations of both Pb and Cd resulted in a small stimulation of the growth of seedlings of all studied cultivars, while higher doses inhibit root growth and, to a much lesser extent, that of shoots. Cadmium (Cd) ions were more harmful for growth of buckwheat seedlings than Pb ions. More resistant to stress caused by the presence of high concentrations of Pb and Cd in the growth medium were seedlings of Hruszowska and Luba cultivars, compared to Kora seedlings. Cotyledons of more resistant cultivars (Hruszowska and Luba) contained much more flavonoids than cotyledons of Kora.