Effect of Some Environmental Factors on the Growth of Azospirillum Species Isolated from Saline Soils of Satkhira District, Bangladesh

Abstract

Twelve isolates of Azospirillum, recovered and identified from non-rhizosphere soil, rhizosphere soil of Cynodon dactylon and the roots of the same plant, were collected from five different locations of saline area in the district Satkhira, Bangladesh. The isolates were belonged to Azospirillum lipoferum, A. brasilense, A. halopraeferans and A. amazonense. All isolates, except MR-5, preferred neutral to alkaline condition for their optimal growth. Three isolates (MR-3, MR-4 and MR-8) showed maximum growth at 41°C, while the others grew best at temperature between 35° and 37°C. The optimal NaCl concentration for the growth was found to be 3% for 5 isolates (MR-1, MR-3, MR-4, MR-8 and MR-11) and 5% for the rest 7 isolates (MR-5, MR-6, MR-7, MR-13, MR-14, MR-15 and MR-16). All isolates were true halophilic since they did not show grow in absence of salinity, and all of them were also fungicide (Perfeckthion and Indofil M-45) tolerants to some extent.