EFFECTS OF MERCURY RESISTANT BACTERIA ON THE GROWTH OF TRITICUM AESTIVUM L. SEEDLINGS AT DIFFERENT CONCENTRATIONS OF MERCURIC CHLORIDE

Fifteen mercury resistant bacteria (viz., AzHg-1 to AzHg-15) were isolated from sewerage and industrial effluents from Kasur, Pakistan. These isolates could resist 200 µg/ml of HgCl2 in the medium. The ability to promote early growth and their effect on metal uptake by a variety of Triticum aestivum i.e., Pak-81, was screened out at different concentrations (0, 1, 2 and 3 mM) of mercury. Different growth parameters (seed germination, seedling root and shoot length, seedling fresh and dry weight, dry weight per gram fresh weight) and accumulation of mercury by inoculated and non-inoculated seedlings were determined and recorded. Results demonstrated that mercury adversely affected and reduced the seed germination and seedling growth of Triticum aestivum, while Hg content of seedlings increased with increasing concentrations of mercury salt. Almost all bacterial strains had stimulatory effect on the germination and various growth parameters of wheat seedlings under salt stress conditions, when compared to respective non-inoculated treatments, except some isolated cases. Mercury content of seedlings was also decreased in inoculated seedlings.