Study on effect of manure on phytoremediation of blanket flower ‎‎(Gaillardia grandiflora) and soil lead uptake

In order to investigate the effect of farmyard manure application on phytoremediation of blanket flower a split factorial experiment based on a randomized complete blocks design with four replications was carried out. The factor year was in main plots and lead factors at four levels (0, 40, 80 and 120 mg/kg soil) and farmyard manure application at three levels (0, 25 and 50 g/kg soil) was in sub plots. Oxidative stress caused by increasing the concentration of lead in the soil reduced the chlorophyll content, which ultimately led to reduction of plant growth as well as plant biomass. With increasing of Pb concentration in soil, activities of catalase and peroxidase in leaves, first increased and then declined, while superoxide dismutase enzyme activity ascending up to highest level of Pb concentration. The application of farmyard manure by increasing the activity of antioxidant enzymes reduced the peroxidation of membrane lipids and hydrogen peroxide in the plant and thus reduced the intensity of stress in blanket flower. Application of farmyard manure increased the lead concentration in the roots and shoots of blanket flower, so that the the highest lead content of shoots and roots was founded in 50 g/kg of farmyard manure under 120 mg/kg of lead in rate of 0.72 and 1.96 mg/kg, respectively, and the highest leaf proline content was obtained in this treatment. So, it can be concluded that manure fertilizer play a promising role in increasing the Pb uptake and reducing its phytotoxicity on blanket flower.