Phosphorus amendment competitively prevents chromium uptake and mitigates its toxicity in Spinacea oleracea L

In this study, we assessed the role of phosphorus in preventing chromium uptake by plants. Two-factor complete randomized pot experiment (5x5 pattern) was conducted hydroponically with Spinacea oleracea L. (spinach), for 28 days in green house. Five concentrations of Cr (2.0, 3.5, 5.0, 6.5 and 8.0 mM), each amended with five concentrations of phosphorus (25, 50, 75, 100 and 125 mM) were supplied. With the phosphorus amendment in the growth medium, accumulation of chromium decreased up to 55% in root and 50% in shoot tissues. A 1.8-fold enhancement in total chlorophyll and 2-fold increase in the biomass of root and shoot were observed due to phosphorus amendment. Levels of superoxide dismutase, catalase, peroxidase and malondialdehyde were reduced by 27, 11.7, 38.1 and 45.5% in root tissues; and 27, 17.4, 32.3 and 35.1%, in shoot tissues, respectively. In conclusion, the phosphorus amendment has been shown not only to moderate the Cr-toxicity in S. oleracea but also enrich chlorophyll content as well as the biomass.