Biodiversity of Endorhizospheric Plant Growth Promoting Bacteria

Abstract

Endorhizospheric bacteria also known as endophytic bacteria that resides within living plant tissues without substantially harming plants have found a large number of applications in today's agriculture such as nutrient cycling, tolerance to biotic and abiotic stress as well as promotion of plant growth. In present study an attempt has been made to test biodiversity of endophytic plant growth promoting bacteria from different plant species. As nitrogen fixation is one of the prime mechanism of plant growth promoting activity exerted by microorganisms, endophytic nitrogen fixing bacteria were isolated from from surface sterilized plant parts viz. root, stem and leaves of species Cynodon dactylon (Durva), Pothos scandens (Money plant), Ipomea batata (Sweet potato), Saccharum officinarum (Sugarcane) cv. CO.LK-8001 and CO.-84135, Musa paradica (Banana) and Zea mays (maize) cv. GM-6 by using nitrogen free media selective for growth of nitrogen fixing bacteria. In all total 10 isolates were obtained form different plant species and parts and showed variation in their biochemical and physiological characteristics. All the isolates were found to fix nitrogen and nitrogen fixation rates of all the isolates ranged from 4.0 to 36.3 mg N fixed / gm of sugar consumed. Moreover, they also showed solubilizing tri calcium phosphate in Pikovskaya's broth.