Isolation, characterization and salt tolerance activity of Rhizobium sp. from root nodules of some legumes

Nitrogen is one of the most essential nutrients required for growth and development of plants. The nitrogen can be provided for plants in the form of chemical fertilizers and biological fixation. Among these two, biological nitrogen fixation is the less costly and ecofriendly. According to Franche et al., (2009) leguminous plants fix atmospheric nitrogen into soil with the help of nitrogen fixing micro-organisms. Rhizobium acts as primary symbiotic fixer of nitrogen by infecting root of leguminous plants. Kiers et al., (2003) state that, Rhizobium bacteria stimulates the growth of leguminous plants by fixing atmospheric nitrogen into soil by symbiotically interaction. Several environmental stresses may affect the nitrogen fixation in plants. It includes salinity, water stress, soil pH, temperature and heavy metals (Kucuk and Kivanc 2008). Waraporn Payakapong (2006) reported that, nearly 40% of total world land is affect due to salinity. Most of the leguminous plants are more sensitive to salinity and they require slightly acidic ISSN: 2319-7706 Volume 3 Number 5 (2014) pp. 1005-1008 http://www.ijcmas.com