Sunflower Extraction's Potential to Reduce Lead-Induced Toxicity in Lead-Contaminated Soil

Abstract The presence of Lead (Pb) in the environment has become widespread, mainly due to human activities and it’s becoming a major concern globally. This study aimed to determine the responses of Sunflower (Helianthus annuus L.) to varying concentrations of lead and to evaluate its bioaccumulation potentials. Sunflower seedlings (4-weeks old) were spiked once with different concentrations (0, 100, 200 and 500 mM) of lead oxide solutions and observed weekly for 2 weeks. The growth, biomass and lead (Pb) content of sunflower in different treatments was measured. The results revealed that lead significantly (p<0.05) reduced plant height, number of leaves, biomass of shoot and roots. The control had the highest plant height of 35cm while 500 mM treatment had the shortest length of 25cm. For shoot and root biomass, the control had the highest biomass of 13.2g and 3.5g respectively while 100 mM treatment had the lowest biomass of 10.8g and 1.1g respectively for shoot and root. The lead (Pb) concentrations in shoot of Sunflower significantly (p<0.005) increased with increasing concentrations with the highest content (0.478 mg/kg) in 500 mM treatment while the control (0 mM) had the lowest (0.006 mg/Kg) lead concentrations. Lead uptake in the roots showed that 500 mM treatment had the highest (0.515mg/Kg) lead content while the control (0 mM) had the lowest (0.006mg/Kg) lead content. Overall, Sunflower showed differential response and uptake of lead to varying concentrations of lead. Sunflower can serve as a sentinel and good candidate in cleaning lead polluted soils. Keywords: Helianthus annus, Phytoremediation, Lead, Bioaccumulation, Lead Oxide