International Research Journal of Engineering and Technology (IRJET) e-ISSN: 2395-0056 Volume: 02 Issue: 03 | June-2015 www.irjet.net p-ISSN: 2395-0072 © 2015, IRJET.NET- All Rights Reserved Page 742 ALLEVIATION OF SALINITY STRESS IN GROUNDNUT BY APPLICATION OF PGPR Ghorai, S. 1 , Pal, K. K. 1 , Dey, R. 1 1 Directorate of Groundnut Research, P.O. Box 5, Ivnagar Road, Junagadh 362001, INDIA Abstract-Two high salt tolerant Plant Growth Promoting bacteria(BM6, AMAAS57) were isolated from Gujarat kuttch region. Their PGP characters were characterized at lab by different biochemical test. To study their ability to promote growth of plant under salinity, pot trial was conducted using groundnut. Different physiological parameters (carbohydrate, phenol and free amino acid, SLA, RWC) were studied. Two pseudomonas culture having plant growth promoting tratits like production of IAA, HCN, ammonia, phosphate solubilisation, antifungal activity and tolerant to salinity (10% NaCl). These cultures were identified by 16s rRNA sequencing viz. Pseudomonas aeruginosa AMAAS57 and Pseudomonas aeruginosa BM6. Application of Pseudomonas aeruginosa AMAAS57 increased the production of phenol and free amino acids with soil salinity of 2 ds/m but thereafter decreased gradually with increasing salinity the decrease as compared to control. application of Pseudomonas aeruginosa AMAAS57 lowered the level of RWC% with increase in salinity. Application of Pseudomonas aeruginosa AMAAS57 and Pseudomonas fluorescens BM6 reduced the electrolyte leakage. Key words: Salinity alleviation, RWC%; Ds/m; SLA; RWC%; electrolytic leakage; carbohydrate, phenol and free amino acid content. 1. INTRODUCTION: Salinity is a major environmental constraint to crop productivity throughout the arid and semi-arid regions of the world. In India, around 25000-30000 ha of cultivated land is coming under salinity each year affecting crop productivity and thus, management of salinity is of urgent need to sustain productivity. Soil salinity has been reported to limit productivity of crops by impairing the root growth, nutrient uptake and by affecting the metabolic processes of the plant. Due to impairment of root growth and development, the active rhizosphere zone gets reduced and thereby, uptake of nutrients from the Ǯlimited pool of available nutrientsǯ becomes difficult. Besides, salinity also affects the nodulation and nitrogen fixation processes in leguminous plants [17], [8]. Salinity stress also decreases photosynthetic capacity of plant due to osmotic stress and partial closure of stomata [2]. Salinization/alkalization is known to limit nodulation and nitrogen fixation. High salt tolerance aids in tolerance to high pH and temperature. Several Rhizobium species have been reported from salt stressed soil in India and around the world. The synthesis and activity of nitrogenases in A. brasilense is inhibited by salinity stress [19]. The accumulation of compatible solutes such as glutamate, proline, glycine, betaine and trehalose in response to salinity/osmolarity in Azospirillum sp. associated with rice cultivated along the coastline of Tamil Nadu has been reported. In addition to the use of traditional breeding and plant genetic transformations, the use of plant growth promoting micro organisms may prove useful in developing strategies to facilitate plant growth in saline soils [12]. Plant growth promoting rhizobacteria (PGPR) and fungi can facilitate plant growth indirectly by reducing plant pathogens, or directly via phosphorus solubilization, nitrogen fixation, iron sequesterization by siderophores, phytohormone production (e.g. auxin, cytokinin, or giberellin), and/or enzymatic lowering of plant ethylene levels [1], [7]. Inoculation of salt-stressed plants with PGPR strains could alleviate salinity stress [8]. The uninoculated plants, compared to the inoculated plants, under soil salinity conditions had an increased antioxident activity and concentration of proline, MDA, glutathione reductase (GR) and ascorbate peroxidase. Pseudomonas fluorescens strain TDK1 possessing ACC deaminase activity enhanced the saline resistance in groundnut plants, which in turn resulted in increased yield when compared with the groundnuts treated with Pseudomonas strains not having ACC deaminase activity. Many PGPR strains possess the enzyme ACC deaminase [9],[6],[16] and this enzyme can cleave the plant ethylene precursor ACC, and thereby lower the level of ethylene in a developing seedling or stressed plant [17] [13]. By facilitating the formation of longer roots through the action of ACC deaminase, these growth-promoting bacteria may enhance the survival of plant seedling under various abiotic and biotic stresses [7],[20] including salinity. Production of extracellular polysaccharides by plant growth promoting rhizobacteria as a scavenger of cations including Na+ would be one of the mechanisms employed by PGPR to