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 very high concentration of K2CrO4 (up to 40 mg ml 1 on nutrient agar plates and 10 mg ml 1 in acetate-minimal medium) 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 fresh weight) as compared to control, while bacterial inoculations improved different growth parameters both as control and under chromate stress when compared with non-inoculated respective controls. With respect to biochemical parameters, acid phosphatase and auxin content showed marked increment with bacterial inoculation both in chromium stress and unstressed condition. Uptake of chromium in inoculated plants decreased 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 but also prevent cell damages caused by the Cr (VI) salt.