RUI: Restoration of lead (Pb) contaminated soils through chemically enhanced phytoextraction by switchgrass (Panicum virgatum)

尽管在限制新的铅（Pb）排放源方面取得了很大进展，但慢性铅危害仍然存在，特别是在城市地区。 在美国城市，土壤中的扩散铅（从含铅汽油燃烧废气等来源分散在土壤中的铅）是铅的持久储存库，有助于长期慢性接触。开发有效的除铅技术的努力包括一些生物和地球化学操作，每一个单独的，产生了显着的增量改进。该项目的一个目标是将影响铅吸收的各个因素联合收割机，以提高普通快速生长的模型植物（柳枝稷）从土壤中去除铅的效率。项目研究人员正在研究一系列土壤改良剂，包括杀真菌剂，金属螯合剂和植物生长调节剂，以改善土壤中的铅去除并将其集中到植物的地上部分。 植物然后可以被删除，并在一个safe marty.efforts开发有效的铅植物修复技术，包括土壤杀菌剂（苯菌灵）治疗下调丛枝菌根真菌（AMF）的金属排斥行动和铅螯合剂，如柠檬酸，在土壤中的应用，以动员铅，并提高其吸收到植物生物量。然而，在这种情况下，铅的植物毒性限制了植物的生命，并限制了吸收能力。项目研究人员正在研究是否可以通过协调应用叶面铁（Fe）、植物生长调节剂和外源一氧化氮供体来进一步提高植物提取铅的能力。这些操作可能有助于提高高生物量生产柳枝稷（柳枝稷）的植物提取效率。研究小组正在使用肯尼索州立大学最先进的实验温室设施，沿着从亚特兰大市区和佐治亚州塞德敦的前超级基金场地取样的污染土壤。 土壤杀菌剂，螯合物，铁，植物生长调节剂和外源性一氧化氮（NO）供体，单独和组合，以优化每一个和测试的协同效应之间的实验条件正在系统地变化。高通量DNA序列的AMF组合在铅污染和非污染的土壤中提取和分析，以表征AMF的物种组成。正在对土壤和植物组织样本中的铅、铁、磷（P）以及全套宏量和微量营养素进行化学分析。该研究项目有可能为植物修复的科学知识做出贡献，同时也培养了高水平研究的本科生研究人员。该项目的结果有可能大大提高植物提取率，并指导开发适合技术转让的土壤恢复技术。

Despite great progress in limiting new lead (Pb) sources of emissions, chronic lead hazards remain particularly in urban areas.  In U.S. cities, diffuse lead in soils (lead that has been dispersed in soils from a source such as leaded gasoline combustion exhaust) is a persistent reservoir of lead, contributing to long term chronic exposure. Efforts to develop efficient lead removal techniques have included a number of biological and geochemical manipulations that each, alone, has produced significant incremental improvements. A goal of this project is to combine the individual factors affecting lead uptake to increase the efficiency of lead removal from soils in a common, fast growing model plant (switchgrass). The project researchers are investigating a series of soil amendments, including a fungicide, metal chelator, and plant growth regulator, for improving lead removal from the soil and concentrating it into the above-ground parts of the plant. The plants could then be removed and disposed of in a safe manner.Efforts to develop efficient lead phytoremediation techniques have included soil fungicide (benomyl) treatments to down-regulate the metal exclusion actions of arbuscular mycorrhizal fungi (AMF) and the application of lead chelating agents, such as citric acid, in soil to mobilize lead and enhance its uptake to plant biomass. In such cases, however, the phytotoxicity of lead limits plant life and creates a limit on uptake capacity. The project researchers are studying whether phytoextraction of lead can be enhanced further by a coordinated application of foliar iron (Fe), plant growth regulator and exogenous nitric oxide donors. These manipulations may serve to increase the phytoextraction efficiency of the high biomass producing switchgrass (Panicum virgatum). The research team is using state-of-the-art experimental greenhouse facilities at Kennesaw State University, along with contaminated soils sampled from urban Atlanta and a former Superfund site in Cedertown, GA. Experimental conditions are being systematically varied among soil fungicide, chelate, and foliar application of iron, plant growth regulator and exogenous nitric oxide (NO) donor, singly and in combination, to optimize each and test for synergistic effects. High throughput DNA sequences of AMF assemblages in lead-contaminated and non-contaminated soils will be extracted and analyzed to characterize AMF species composition. The chemical analysis of lead, iron, phosphorous (P), and the full suite of macro- and micro-nutrients are being determined in soil and plant tissue samples. The research project has the potential for contributing to scientific knowledge on phytoremediation while also training undergraduate student researchers in high level research. Results of this project have the potential to dramatically improve phytoextraction rates and guide the development of a soil restoration technique appropriate for technology transfer.