Accumulation of cadmium in maize roots inoculated with root organ culture of Rhizophagus irregularis improving cadmium tolerance through activation of antioxidative defense enzymes

Monoxenic culture of arbuscular mycorrhiza, Rhizophagus irregularis in root organ cultures, was formulated in a dextrin-based carrier. R. irregularis was coated in maize seeds (African tall composite) at the rate of 50 g kg -1 . R. irregularis was evaluated for heavy metal tolerance at 25, 50, and 75 ppm cadmium (Cd) in a pot culture experiment. The mean root colonization potential at 25 ppm Cd inoculated with R. irregularis was 48%, which had the highest probability to reach its maximum during 30 DAS. In the present study, Cd was accumulated to a tune of 22.2–38.3% in mycorrhizal roots, which was more than non-mycorrhizal roots. Cd addition at 25 and 50 ppm levels decreases its translocation to shoots to 28% in R. irregularis inoculated plants when compared to uninoculated treatments. The highest tolerance indices were observed in T 6 and T 7 with 100.59 and 98.34, respectively, showing its increased ability of cadmium to bear heavy metal up to a level of 50 ppm. R. irregularis inoculated maize adapted well at 25 ppm Cd and confirmed its significant role in reducing Cd accumulation toward the shoot system.