AUTHOR=Hart Genna , Gilly Austin , Koether Marina , McElroy Thomas , Greipsson Sigurdur 

TITLE=Phytoextraction of lead (Pb) contaminated soil by switchgrass (Panicum virgatum L): Impact of BAP and NTA applications

JOURNAL=Frontiers in Energy Research

VOLUME=Volume 10 - 2022

YEAR=2022

URL=https://www.frontiersin.org/journals/energy-research/articles/10.3389/fenrg.2022.1032404

DOI=10.3389/fenrg.2022.1032404

ISSN=2296-598X

ABSTRACT=The accumulation of Pb deposits in soil is a growing global concern. Soil remediation options include phytoextraction that involves the use of plants and associated soil microorganism. Switchgrass (Panicum virgatum L.), a second-generation bioenergy crop was used in this study due to its ability to produce high biomass and grow in metal polluted soils.  Plants were grown in Pb-contaminated soil (5,802.5 mg kg-1) in an environmentally controlled greenhouse. Plants were treated with exogenous application of the plant growth regulator (PGR) benzyl aminopurine (BAP) or foliar nutrient solution (Triple-12®) twice a week until harvested.  Plants also received the soil fungicide propiconazole (Infuse™) that was followed by the soil chelate nitrilotriacetic acid (NTA).  Two concentrations of NTA were compared (5 mM and 10 mM) and combined application of NTA (10 mM) + APG (alkyl polyglucoside). Soil fungicide (propiconazole) was used to arrest arbuscular mycorrhizal fungi (AMF) activities in the roots.   Lead (Pb) was measured in dry plant materials using an ICP-OES. Phytoextraction by switchgrass was significantly improved by enhanced by soil application of 10mM NTA, APG and foliar application of BAP, foliar nutrients, and soil fungicide. Switchgrass treated with 5mM NTA showed an average Pb concentration of 858 mg kg-1, but this was improved with applications of 10mM NTA, with an average concentration of 3196.5 mg kg-1. Ddual soil applications of 10mM NTA, APG and foliar applications of BAP which resulted in the greatest highest average Pb concentration of 5,.942 mg kg-1 and one plant showed the highest Pb concentration of 10,820 mg kg-1. The average dry mass of plants and the average value for total phytoextracted Pb (mg) per pot wereas significantly greatest for plants treated with 10mM NTA, APG and BAP. Also, plants treated with NTA and BAP showed average bioconcentration factor of 1.02. The results suggested that chemically enhanced phytoextraction significantly improved significantly biomass production of switchgrass and at the same time increased phytoextracted Pb which is important for phytoremediation and bioenergy industry. soil applications of 10 mM NTA, APG, soil fungicide and foliar applications of BAP could be a beneficial technique for phytoremediation by switchgrass of Pb-contaminated soils.