Effects of Phosphorous Fertilizers and Arbuscular Mycorrhiza Fungi Symbiosis with Sunflower on Pb Availability in a Contaminated Soil

Soil contamination by Pb leads to a reduction in the quality and quantity of crop yield, because it is highly toxic in soluble ionic forms. The availability of this element for plant roots can reduce by the formation of compounds with low solubility and their sedimentation by phosphorous amendments.. Root symbiosis with mycorrhizal fungi can also increase plant resistance against heavy metals. This study was carried out as a factorial experiment in a randomized complete block design asa greenhouse experiment on sunflower plant at Shahrood University. Treatments included mycorrhizal fungi with two levels of inoculation, (with and without inoculation), organic and inorganic phosphorous fertilizers such as humic acid, diammonium phosphate, bone meal and bone meal蛩 acid. The results showed that inoculation with mycorrhizal fungi resulted in a significant increase (P&ge0.05) in percentage of mycorrhizal colonization and an increase in soil EC,shootdry weight and phosphous uptake by the plant. Phosphorus fertilizers significantly increased the available phosphorus in soil, dry weight and uptake of phosphorus by the shoots. The interaction effects of mycorrhiza and phosphorus fertilizers on soil exchange able Pbwere significant. The application of diammonium phosphate and mycorrhiza had the greatest impacton the reduction of Pb (by 25.48percent) in the soil exchange. Mycorrhizal plants had a lower rate of lead concentrations in shoots, which was equal to 78/14%, and also the application of phosphorus fertilizers significantly reduced Pb in plant shoots.