Salt tolerant culturable microbes accessible in the soil of the Sundarban Mangrove forest, India

Abstract

Sundarban Mangrove forest is highly productive marine ecosystem where halophilic microbes actively participate in bio-mineralization and biotransformation of minerals. The population of aerobic halophilic microbes was studied to determine their distribution with the availability of different physicochemical parameters with increasing depth of this forest sediment. The present study revealed that microbes present in the top soil region were less tolerant to fluctuation in salinity than the middle and bottom segment. Microbes isolated from bottom segment showed higher growth rate in anaerobic condition. A decreasing trend of total microbial population and organic carbon content of soil were found with increase in depth. In contrary a reverse profile was found for salinity. A significant stratification was found to exist among microbial population and the salty nature of the soil of Sundarban Mangrove forest.

Application of Halotolerant Bacteria to Restore Plant Growth Under Salt Stress

“…The experiment revealed signifi cant improvement of shoot height, root length and biomass of groundnut seedling after 7 days under salinity stress. The application of halotolerant PGPB is not only restricted to legumes and cereals, but is also performed on trees such as banana and mangrove forest growing under hard environmental conditions caused by salinity (Maziah et al 2009 ;Das et al 2011 ). Furthermore, Shukla et al ( 2012 ) demonstrated an increase of NaCl-stress inhibited growth of peanut ( Arachis hypogaea ) after inoculation with the diazotrophic rhizosphere bacterium Brachybacterium saurastrense (Gontia et al 2011 ) and other halotolerant isolates from the halophyte Salicornia .…”

Osmotolerant Microbial Resources of Saline Ecologies of India: Dynamics and Potential

“…The plant growth-promoting bacteria (PGPB), besides improving crop yield, solve environmental problems viz., soil erosion, restoration of mangrove ecosystems, phytoremediation etc. (Holguin et al 2001;Das et al 2005Das et al , 2011Das et al , 2012de-Bashan et al 2012). The microbes in the mangrove ecosystems also transform nutrients from dead mangrove vegetation into N, P and other mineral nutrients that are used by the plants and use the root exudates for their growth (Holguin et al 2001;Sahoo and Dhal 2009;Mishra et al 2011Mishra et al , 2012a.…”

“…Various groups of bacteria like nitrogen fixers, phosphate solubilizers, cellulose decomposers, nitrifiers and denitrifiers, sulphur and iron oxidizers, iron reducers, methanogens, magnetic behavioral, human pathogens, antibiotics and enzyme producer etc. are usually present in the ecosystem (Holguin et al 2001;Das et al 2005Das et al , 2011Das et al , 2012.…”

“…The Archaea are extremely halophilic (about 30 % NaCl tolerance) primary decomposer microbes (Zahran 1997) which utilize low concentration of dissolved organic compounds, assimilate inorganic substances like nitrate and phosphate, decompose nutrient-poor plant tissues and have efficient anaerobic metabolism i.e., adapted to both aerobic and anaerobic status (Holguin et al 2001;Das et al 2005Das et al , 2011Das et al , 2012. Various groups of bacteria like nitrogen fixers, phosphate solubilizers, cellulose decomposers, nitrifiers and denitrifiers, sulphur and iron oxidizers, iron reducers, methanogens, magnetic behavioral, human pathogens, antibiotics and enzyme producer etc.…”

“…km which, however, is decreasing over the years. The Island has clayey or sandy loam and acid sulphate soil with pH 4.5-6.82, salinity 6.81 mS/ cm, available P 30.00 kg/ha, available K 338.00 kg/ha, total C 0.49 % and total N 0.04 % (Das 1999;Gopal and Chauhan 2006;Das et al 2011Das et al , 2012.…”