Phyto-accumulation of heavy metals by sunflower (Helianthus annuus L.) grown on contaminated soil

Abstract

This study was carried out at the Institute of Biotechnology and Genetic Engineering, KPK Agricultural University, Peshawar, Pakistan to investigate the phyto-accumulation capacity of heavy metals [lead (Pb), chromium (Cr) and cadmium (Cd)] by two cultivars of sunflower (Helianthus annuus L.). The experiment was conducted in pots using completely randomized (CR) design with three replications. Three heavy metals, that is, Pb, Cr and Cd were applied to the pots containing soil before sowing. Statistical analysis of the data recorded eight weeks after sowing revealed that heavy metal and interaction between ethylene diamine tetraacetic acid (EDTA) x cultivar and EDTA x cultivar x heavy metal had a significant (p<0.05) effect on plant height, shoot fresh weight, shoot dry weight, root fresh weight and heavy metal accumulation. The lone effect of cultivars and EDTA was non significant (p>0.05) on all the parameters, except heavy metal accumulation. The data revealed that maximum plant height, number of leaves plant^-1, shoot fresh weight and dry weight, root fresh and dry weight was noted in the control pots (0 mg kg^-1 heavy metal). The data shown eight weeks after sowing suggested that maximum shoot fresh weight, shoot dry weight, root fresh weight and root dry weight were noted in pots kept at control with San Sun-33 applied with 5 mM EDTA. Similarly, maximum heavy metal accumulation was recorded in treatment sown with Hisun-33 and applied with 5 mM EDTA and 50 mM chromium.

Key words: Phytoaccumulation, heavy metals, sunflower, ethylene diamine tetraacetic acid (EDTA).