Effects of Chelate-Assisted Chromium (Cr+6) on Growth, and Chromium Bioaccumulation in Paragrass (Brachiaria mutica Forssk.Stapf)

The growth pattern, toxicology and chromium bioavailability in 45 days grown Paragrass (Brachiaria mutica Forssk.Stapf) in response to applications of ionic Chromium (Cr+6) and chelate-assisted Cr+6 were undertaken. Root and shoot length of Paragrass significantly decreased with increasing concentration of Cr+6. Paragrass plants grown both in Cr+6 (300 ppm) and chelate(EDTA/CA)-assisted Cr+6 (300 ppm) showed noticeable decrease in root and shoot length, fresh and dry matters whereas ionic Cr+6 or chelate assisted Cr+6- EDTA/ Cr+6-CA stimulated growth at low concentration (10 ppm). Root phytotoxicity was highest (56%) in Cr+6-EDTA (300 ppm) treatment whereas shoot phytotoxicity was 36% in Cr+6 (300 ppm) treatment. High Cr accumulation was found in root (46.65 mg kg- 1) when supplemented with Cr+6-EDTA (300 ppm) as compared to other treatments. Transportation index (Ti) values are high depicting the plants with high translocation for the seedlings grown in ionic and chelate assisted Cr using 10 and 100 ppm concentrations of Cr+6.Bioconcentration Factor (BCF) of Cr increases in chelate assisted chromium treatment than chromium treatment only. Total Accumulation Rate (TAR) in different treated plants (both ionic and chelate assisted) showed increasing trend with increase in chromium treatments which indicates that the plant is tolerant in nature could survive under diverse chemospheric conditions.