Agronomic Properties of Mycorrhizal Alfalfa as Affected by Pb and Zn using Rhizobox System and Assessing its Ability for Phytoremediation Purposes

The objective of present papaer is assessing the responses of alfalfa to lead and zinc when it is contributed with mycorrhizal symbiosis in a precise condition, using rhizobox system. Soil with low levels of Zn and Pb and soil with high amounts of Zn and Pb have been considered as media for mycorrhizal alfalfa. Mycorrhizal symbiois resulted in 1.39 fold and 1.32 fold increases in the dry weight of roots and shoots, respectively. Contrary to zinc, in all treatments lead concentration in roots was more than shoots. It seems that it is because of more mobility of zinc in comparison to lead. Pollution and fungi inoculation and their interaction significantly affected Pb concentration in roots. Zn and Pb contamination and fungi inoculation and their interaction had a significant effect on Zn concentration in roots adjacency to rhizospheric soil and increased it to 104.87 ?g g- 1, although Zn concentration in other treatments of these roots were 51.12, 30.87 and 29.37 ?g g-1 in polluted without inoculatation, low amounts of metals, non- inoculated and inoculared, respectively. Results showed that alfalfa can be an eligible plant for accumulating Pb in their roots while their shoots will be edible for animals. In highly contaminated soils, alfalfa cannot be an important accumulator for zinc, in addition zinc can transfer to shoots and in toxic concentrations can enter animals and the human food chain.