Effects of some heavy metals on content of chlorophyll, proline and some antioxidant chemicals in bean (Phaseolus vulgaris L.) seedlings

Abstract

The effects of lead, copper, cadmium and mercury on the content of chlorophyll, proline, retinol, alpha-tocopherol and ascorbic acid were investigated in 17-day-old bean seedlings (Phaseolus vulgaris L.) grown in Hoagland solution spiked with various concentrations of Pb, Cu, Cd and Hg. Control and heavy metal-treated plants were grown for 10 days in Hoagland solution. Content of total chlorophyll (a and b), proline, retinol, alpha-tocopherol and ascorbic acid was measured in ten-day-old primary leaves by High Performance Liquid Chromatography (HPLC). Total chlorophyll content declined progressively with increasing concentrations of heavy metals. A significant increase of proline, retinol, alpha-tocopherol and ascorbic acid content was detected in primary leaves after ten-day exposure to heavy metals. The strongest effect on total chlorophyll, proline, retinol, alpha-tocopherol and ascorbic acid content was found in plants exposed to mercury, followed by the sequence Cd++ > Cu++ > Pb++.