Effect of heavy metal pollution on mineral absorption in sunflower (Helianthus annuus L.) hybrids

The present study was conducted in a potted experiment to examine the effects of chromium pollution on absorption of mineral nutrients and some morpho-physiological attributes of two sunflower (Helianthus annuus L.) hybrids (FH-331 and FH-259) in the presence and absence of ethylene diamine tetra acetic acid (EDTA) used as a chelating agent. Four concentrations of chromium (Cr3+) i.e., 0, 20, 30 and 40 mg kg(-1) with and without 0.3 g kg(-1), EDTA as chelating agent were applied to 25-day-old sunflower plants. A gradually decreasing trend in absorption of all minerals and other parameters studied were observed. Different treatments of Cr3+ as well as Cr3+ and EDTA significantly reduced root and shoot fresh weight; however, root, shoot and achene Cr3+ contents of two sunflowers hybrids under higher chromium and EDTA stress varied significantly whereas movement of Cr3+ contents to leaves was non-significant. Absorption of Na+, K+, N-2 and P through roots and shoots significantly reduced with increasing concentration of Cr3+ treatments. In fact addition of EDTA to the medium further enhanced the toxicity of chromium.