Phytoremediation of Lead-Contaminated Soil by using Ornamental Plants

Phytoremediation is an eco-friendly technology to mitigate soil heavy metals pollution. Using of food crops for phytoremediation causes contamination of food chain. Therefore, application of ornamental plants could be explored to reduce soil heavy metal pollution. In this study, snapdragon, stock and gladiolus plants were explored to mitigate soil lead (Pb) pollution. Different levels of Pb (0, 25, 50, 75, 100 mg/kg) were applied through irrigation to the plants arranged according to the CRD (Complete Randomized Design) two-factorial design arrangement. PB at 25 mg kg-1 significantly increased the shoot dry weight (14.89, 17.5 and 16.79%), root dry weight (35.81, 28.44 and 21.09%) and chlorophyll contents (3.39, 9.09 and 21.69%) in snapdragon, stock and gladiolus respectively. At 25 mg kg-1 significantly improved net photosynthetic rate (0.96, 1.14, and 3.38%) and transpiration rate (1.44, 1.45 and 3.70%) respectively. At 25 mg kg-1 the enzymatic antioxidant activities of CAT (3.45, 2.78 and 13.48%), POX (11.12, 27.3 and 25.53%) and SOD (3.22, 5.74 and 13.04 %) increased and low level of H2O2 (21.82, 9.52 and 12.8%) and MDA (18.18, 31.81 and 33.3%) indicate that plants are resistant against oxidative injury. Lead at 100 mg kg-1 significantly reduced the shoot dry weight (89.83, 46.96 and 50.35%), root dry weight (85.63, 92.35 and 51.81%), chlorophyll contents (18.14, 19.93 and 45.72%) in snapdragon, stock and gladiolus respectively. At 100 mg kg-1 significantly improved net photosynthetic rate (14.26, 16.63 and 14.69%) and transpiration rate (2.71, 4 and 8.98%) respectively. At 100 mg kg-1 the enzymatic antioxidant activities of CAT (18.37, 4.34 and 6.99%), POX (50, 52.69 and 66.92%) and SOD (40.62, 69.1 and 72.84%) noticed to reduce and high level of H2O2 at 100 mg kg-1 (79.91, 74.32 and 43.18%) and MDA (73.13, 70 and 56.19%) indicate cellular damage. The research findings indicate that ornamental plants possess significant phytoremediation capabilities for lead with notable reductions in soil contaminant levels observed over the experimental period.