Halophilic bacteria mediated phytoremediation of salt-affected soils cultivated with rice

Abstract

Salinity is a most important ecological constraint for cereal crop including rice nowadays. Phytoremediation has been used to remediate salt affected soil but the use of halophilic bacteria is limited. In this study, the salt resistant Thalassobacillus denorans (NCCP-58) and Oceanobacillus kapialis (NCCP (National Culture Collection of Pakistan) -76), halophilic bacteria isolated from salt mines near Karak, Pakistan were used to evaluate its effect on rice variety (Basmati-385)in soil contaminated with different concentrations (control, 50, 100 and 150mM) of NaCl. It has been observed that significant increase in germination percentage and germination rate occurred in seeds primed with bacterial strains as compared to non-primed seeds. Root and shoot lengths were more in plants raised from primed seeds than non-treated seeds. Plants raised from inoculated seeds showed a significant increase in fresh and dry weight of seedling after 15days. Significant increase in photosynthetic pigment; chlorophyll a (Chl a), chlorophyll b (Chl b) and carotenoid contents occurred in 28days old plants inoculated with bacterial strains under different saline conditions. Similarly significant increase occurred in total nitrogen and protein contents in inoculated plants. Ca+2 and K+ ion concentration significantly increased while Na+ ion concentration decreased in plants inoculated with bacterial strains as compared to non-inoculated plants under different saline conditions. Bacterial strains O. Kapialis (NCCP-76) was more responsive in term of physiological and biochemical parameters than T. denorans sp. (NCCP-58). The corresponding strains have a positive effect in alleviating the salt stress in plants growing in saline condition.