Page 2 Plant-Bacteria Interactions Edited by Iqbal Ahmad, John ...

24j 2 Physicochemical Approaches to Studying Plant Growth Promoting Rhizobacteria
Figure 2.2 Infrared spectra of dried biomass of A. brasilense
(facultatively endophytic strain Sp245) grown (a) in a standard
phosphate–malate medium (control) and in the same medium in
the presence of 0.2 mM Co 2þ (b), Cu 2þ (c) or Zn 2þ (d) [10].
of strain Sp7 to outcompete other co-inoculated strains [27], as well as to a lower
sensitivity of strain Sp7, as compared to strain Sp245, to copper ions, including a less
pronounced copper-induced decrease in auxin production [12,30].
As noted above, the amount of cobalt accumulated by strain Sp7 (up to about
0.01% wt/wt dry biomass) induces a significant metabolic response in the bacterium,
comparable to that of about fourfold higher amount of copper or about 36-fold