Identification, Chelated Strengthening And Application Of Pb Hyperaccumulating Flowers

Phytoremediation is a cost effective and environmentally friendly alternative, and applying flowers to phytoremediation is promising. Lead (Pb) contamination in different ecosystems has run to serious degree due to industrial processes,therefore, it is an urgent and challenging task to remediate Pb-contaminated sites with appropriate remediation methods. However, the bioavailability of Pb in soils is low and the plant capacity to absorb this contaminant is weak. Chelator-enhanced phytoremediation is considered as a suitable method for the extraction of Pb by plants.In order to promote the effective and economic remediation of soils contaminated with Pb, a field-screening hyperaccumulators study from 30 varieties of flower was carried out to determine characteristics of flowers enduring and accumulating Pb by field pot-culture experiments. Chelate-induced phytoextraction with high Pb-accumulative flower species provide theory and practice for the clean-up of heavy metal from polluted soils.The results showed that 9 varieties had strong Pb-endurance and high Pb-accumulative ability, 12 varieties possessed strong Pb-endurance and weak Pb-accumulative ability, and others were weak Pb-tolerance plants with weak Pb-accumulative ability.According to the concentration gradient experiment, Gypsophlia elegans and Celosia cristata pyramidalis generally prossessed basic characteristics of hyperaccumulators. The translocation factor and concentration of Pb in Gypsophlia elegans's shoot were satisfied the characteristics of hyperaccumulators, however, it had weak endurance to severe Pb pollution and the enrichment coefficient was less than 1. Celosia cristata pyramidalis possessed strong tolerant ability and concentration of Pb in its shoot was higher than 1000 mg kg-1, while the translocation factor and enrichment coefficient were less than 1.The chelate-induced phytoextraction experiment suggested the application of two different chelating agents, i.e. EDTA and NTA, is effective. Among the tested application ratios of 1:1, 1:2 and 2:1 (EDTA: NTA), 2:1 of EDTA: NTA was the most efficient ratio for remediation, and NTA was applied one week after EDTA. The combined application of EDTA and NTA before harvest was effective, economical, safe and public acceptable.