Pisum sativum and associated plant growth promoting Rhizobacteria: Effect of normal and sewage irrigation

Abstract

The rhizosphere or the zone of influence around roots harbour a multitude of microorganisms that are affected by both abiotic and biotic stresses. This study investigates the impact of sewage irrigation on culturable rhizobacterial communities of Pisum sativum L. The representative PGPR strains of Bacillus, Pseudomonas, Rhizobium and Azotobacter were tested for plant growth promoting activities and heavy metal tolerance pattern. Rhizobacterial strains isolated from sewage-irrigated soil were more tolerant to heavy metals. The test rhizobacterium Pseudomonas putida was both metal tolerant and efficient in producing PGP compounds like indole acetic acid, ammonia, siderophore and catalase, was subjected to seed germination test. Results confirmed that this bacterium had significant impact on stimulation of root and shoot growth. Our findings suggest that P. putida is a strong candidate for development as soil/seed inoculants to enhance crop yields where untreated sewage water is used in irrigation. © 2012 Academic Journals Inc.