Bioaugmentation of Soil with Pseudomonas monteilii Strain Eliminates Inhibition of Okra (Abelmoschus esculentus) Seed Germination by m-Cresol.

Cresols are ubiquitous in nature due to their bulk production and end uses in various industrial processes as well as due to their natural presence. They are highly toxic to both fauna and flora and are included in the list of priority pollutants. In the present study, the effect of m-cresol on germination of ten different crop seeds was tested and the seeds of okra and eggplant were found to be very sensitive, okra being the most vulnerable. Okra seeds lost its viability in the presence of m-cresol, which was proportionate to its concentration as indicated by the standard 2,3,5-tetrazoliumtrichloride (TTC) test. Marked decrease in protease and amylase activities was observed in germinating seeds exposed to the compound. The inhibitory effect of m-cresol on germination was eliminated effectively by bioaugmentation of the soil with the cresol-degrading Pseudomonas monteilii S-CSR-0014. Normal germination and seedling vigor were obtained when the seeds were sown four and eight days after the soil inoculation with the bacterial cells, whereas the seeds sown immediately did not show proper germination. The inoculated bacterium degraded m-cresol efficiently from the spiked soil and exhibited concomitant growth. It can be concluded that m-cresol-contaminated soils could be effectively bioremediated to render the soil suitable for normal seed germination and healthy seedling growth of sensitive crops.