Growth Improvements of Sunflower Seedlings by Cr(VI)-Resistant Bacteria

In the present study, three chromium resistant bacterial strains (CrT-1, CrT-2, CrT-3) which could resist veryhigh concentration of K2CrO4 (up to 40 mg ml-1 on nutrient agar plates and 10 mg ml-1 in acetate-minimalmedium) were used to inoculate the sunflower seeds both as control and under chromium stress. Cr(VI)caused severe reduction in different growth parameters (seedling length, fresh weight, dry weight g-1 freshweight) as compared to control, while bacterial inoculations improved different growth parameters both ascontrol and under chromate stress when compared with non-inoculated respective controls. With respectto biochemical parameters, acid phosphatase and auxin content showed marked increment with bacterialinoculation both in chromium stress and unstressed condition. Uptake of chromium in inoculated plantsdecreased significantly as compared to non-inoculated control. Cr (VI) application also severely damages different plant cells/tissues but bacterial inoculation not only improves the growth and yields parameters butalso prevent cell damages caused by the Cr (VI) salt.