Authors:
Dr Shafaqat Ali | Government College University Faisalabad | Pakistan
Saima Aslam Bharwana | Government College University Faisalabad | Pakistan
Muhammad Rizwan | Government College University Faisalabad | Pakistan
sehar afshan | Government College University Faisalabad | Pakistan
Mujahid Farid | Government College University Faisalabad | Pakistan
PhD Nabeel Khan Niazi | Southern Cross University/University of Agriculture Faisalabad | Pakistan
Dr Irshad Bibi | Southern Cross University/University of Agriculture Faisalabad | Pakistan
Chromium (Cr) toxicity is wide spread in crops grown on Cr-contaminated soils and has become a serious environmental issue which requires affordable strategies for the remediation of such soils. This study was performed to assess the performance of citric acid (CA) through growing brassica napus in the phytoextraction of Cr from contaminated soil. B. napus plants were grown in soil in greenhouse and four-week-old seedlings were treated with different Cr (0, 100 and 500 µM) and citric acid (0, 2.5 and 5.0 mM) treatments alone and in all combinations. Plants were harvested after ten weeks of sowing and the data were recorded regarding growth characteristics, biomass, photosynthetic pigments, malondialdehyde (MDA), electrolytic leakage (EL), antioxidant enzymes and Cr uptake and accumulation. The results showed that the plant growth, biomass, chlorophyll contents and carotenoid as well as soluble protein concentrations significantly decreased under Cr stress alone while these adverse effects were alleviated by application of CA. Cr concentration in roots, stem and leaves of CA-supplied plant was significantly reduced while total uptake of Cr increased in all plant parts with CA application. Furthermore, in comparison with Cr treatments alone, CA supply reduced the MDA and EL values in both shoots and roots. Moreover, the activity of superoxide dismutase (SOD), peroxidase (POD), catalase (CAT) and ascorbate peroxidase (APX) in shoots and roots markedly increased by 100 µM Cr exposure, while decreased at 500 µM Cr stress. CA application enhanced the activities of antioxidant enzymes compared to the same Cr treatment alone. Thus, the data indicate that exogenous CA application can increase Cr uptake and can minimize Cr stress in plants and may be beneficial in accelerating the phytoextraction of Cr through hyper-accumulating plants such as B. napus.