Rhizobacteria were isolated from rhizosphere of different varieties of rapeseed (Canola, Raya, Toria, Gobi Sarsoon and Sarsoon) selected from different sites of Punjab. These rhizobacteria were tested for auxin production in terms of indoleacetic acid equivalents by colorimeter method both in the presence and absence of an auxin precursor L-tryptophan (L-TRP). This study suggested that auxin production ability varied with variety and site ranging from 0.13 to 11.4 μg mL-1 without L-TRP and from 2.41 to 24.6 μg mL -1 with L-TRP. L-Tryptophan application increased the auxin production upto 184 fold compared with that produced without L-TRP. The significance of auxin production by rhizobacteria is discussed in relation to their effects on plant growth.
Hafiz Naeem Asghar , Zahir Ahmad Zahir , Abdul Khaliq and Muhammad Arshad , 2000. Isolation of Rhizobacteria from Different Rapeseed Varieties and
Their Potential for Auxin Production . Pakistan Journal of Biological Sciences, 3: 1556-1559.