اثر سويه و غلظت باكتري آزوسپيريلوم برازيلنس روي رشد و نمو ريشه ارقام گندم

The Effect of Strain and Concentration of Azospirillum brasilense Bacterium on Growth and Development of Root in Wheat Cultivars

Azospirillum brasilense is one of the diazotroph microorganisms which has been isolated from the rhizosphere of grasses in both tropical and temperate regions. In the last few years there have been several reports, indicating different results as regards significant increases in cereal growth when applying of this bacterium. This research was conducted in the research laboratory of Biology. Dept. in Isfahan University in 2000 to find out the suitable strain and optimum concentration of inoculum for cultivars of wheat as well as the effects on wheat root growth. In the study, wheat seeds (T aestivum) of three cultivars Ghods, Roshan and Omid were inoculated with two Azospirillum strains (Sp7 and Dolatabad strains) with concentrations of 101 up to 10^9 cfu/ml, then the root length, dry weight and number of root branches, being measured and evaluated. Inoculation with 10^6-10^7 cfu/ml in all cases resulted in the largest root development. However, concentrations of 10^8 to 10^9 cfulml of strains, caused inhibition in root development. Inoculations with Dolatabad strain exhibited more positive effect on root in Ghods cultivar but Sp7 strains caused the most root development in Roshan cultivar. Either strain had a low effect on Omid cultivar.