Chromate resistantBacillus cereus augments sunflower growth by reducing toxicity of Cr (VI)

摘要

Impact of four chromium resistant bacterial strains (S3, S4, S6, and S7) was studied on the different growth parameters of sunflower (Helianthus annuus var SF-187) in chromium free or under chromium stress. Strains used exhibited very high-level resistance to chromate (up to 50 mg ml-1 on nutrient agar and 1-2 mg ml-1 in minimal medium). Application of Cr(VI) salt adversely affected the seed germination, root and shoot length, and fresh weight of seedlings. Bacterial inoculations improved the growth parameters. The effects of Cr(VI) on the different biochemical parameters were also very severe but seedlings inoculated with bacteria showed much improvements as compared to non-inoculated controls. Uptake of Cr(VI) was higher than Cr(III) by the seedlings. Inoculated seedlings contained less chromium than non-inoculated seedlings. Much improvement in the internal region of root and shoot was observed in inoculated plants especially in guard cells.