عنوان مقاله [English]
Background and Objectives: The use of medicinal plants for remediation of heavy metals contaminated soils is an economical, cheap and effective strategy. The widespread transfer of natural materials and pollutants to different parts of the environment (soil, water and atmosphere) has imposed great pressure on the self-purification ability of the soil. Accumulation of pollutants is a concern regarding both humans and ecosystems. Among pollutants, heavy metals are particularly important because they are not decomposable and also have harmful physiological effects on organisms even at low concentrations. Soil pollution with heavy metals in human societies is one of the major environmental problems and the transfer of these elements via crop production to men affecting human population health. One of the modern and low cost methods for remediation of contaminated soils, is the use of plants. Phytoremediation is an emerging technology which utilizes plants and microorganisms in the rhizosphere to delete, modify or limit the toxic chemicals in soil, sediment, groundwater, surface water and even used the atmosphere. The aim of this study was to evaluate the phytoremediation ability Thymus daenensis Celak. symbiotic with mycorrhizal fungi in polluted soils of Lead and Cadmium was by herb with.
Materials and Methods: This study was conducted as a factorial exam in the greenhouse conditions. The first factor was four levels of heavy metals: lead (100 mg kg), cadmium (15 mg. Kg soil), concurrent use of lead and cadmium + control (zero) and the second factor was fungal treatments (at five levels: G. intraradices, G. Mosseae, G. fasciculatum, the simultaneous use of all three species and control-non inoculated -) in a randomized complete block design in three replications.
Results: Analysis of variance showed a significant effect of mycorrhizal fungi on Pb and Cd concentration in shoots and roots of thyme. The highest cadmium concentration in polluted soil was observed in Shoot(62/1 mg.Kg DW) inoculated with G.mosseae and root (56/1 mg kg dry weight) ) inoculated with G. fassiculatum respectively.
Conclusion: The results showed a high ability of Thymus daenensis Celak. to absorb heavy metals from contaminated soils. Other findings of this study was more accumulation of lead in root than shoot. Based on the results, this plant is able to absorb significant amounts of lead and cadmium of bed and accumulate in roots or transfer to shoots. Mycorrhizal fungi especially G.mosseae and G. fassiculatum can improve the Cd and Pb phytoremediation of contaminated soils.
Keywords: Mycorrhizal fungi, Cadmium, Lead, medicinal plants , Phytoremediation