Abstract:

A pot experiment using sterile and unsterile arsenic(As)-contaminated soil was carried out to study effects of different inoculation methods of photosynthetic bacteria (PB) on the growth and As uptake of tobacco. Tobacco planted in unsterile soil was infected by pathogenic fungi and then died. Population of PB declined below the starting density in sterile soil. Inoculation with PB had no significant effects on plant biomass, contents of soluble sugars and chlorophyll and net photosynthetic rate. However, increasing trends of net photosynthetic rate and shoot dry weight were found in all inoculated treatments and those inoculated PB into soil, respectively. Leaf NO3--N concentration was lower in treatments inoculated with PB after transplanting than in other treatments. Inoculation with PB resulted in decreased soil pH, while no difference in concentrations of soil water-extractable and tobacco As were observed among all treatments. In conclusion, PB did not play an important role in tobacco safety in high As-contaminated soil since the development of PB population was suppressed. Nonetheless, PB in tobacco safety prospect is considerable.