Assessment of phytoremediation potential of range vegetation for Lead (Pb) and Chromium (Cr) contamination in the Cholistan Desert, Pakistan

The study was conducted to evaluate the phytoremediation potential of heavy metals by using xerophytes species; Aristida hystrix L. and Aristida adscensionis L. of Cholistan desert. The Phytoremediation, morphology and physiology of the grasses were studied. The experiment was conducted hydroponically in the experimental area of Forestry, range and Wildlife Management, The Islamia University of Bahawalpur. Results showed that under Cromium (Cr) and lead (Pb) stresses A. hystrix and A. adscensionis, exhibited significant differences in their morpho-physiological traits as compared to control treatments. Under 50 to 400 uM Pb treatments A. adscensionis exhibited reduction in root/shoot fresh weight (0.92 B) and (0.61 C) respectively and similar results were obtained in A. hystrix. Increasing Cr concentrations also significantly reduced the membrane stability index (MSI) of both grass species. Under 50 to 400 uM Pb concentrations A. adscensionis exhibit reduction in MSI from (87 A) t0 (42 C). Cr and Pb concentrations in A. adscensionis were increased with elevated treatments. At higher Cr concentration (80 uM) its values were (41 A) while under 20 uM it was (15 C). Pb levels were also increased with increasing Pb level in A. hystrix at 400 uM its concentration was (198 A) and it was (29 C) at 50 uM. Conclusively, both selected grass species have capability to absorb large amount of heavy metals from the soil at the cost of reduction in growth, however, considered as good options for the phytoremediation of Cr and Pb.