Response of spring canola (Brassica napus L.) cultivars inoculated with P. fluorescens FY 32 to drought stress

Plant growth promoting rhizobacteria have been known to reduce harmful effects
of stresses such as water deficit. This study was designed to investigate the inoculation
effects of P. fluorescens FY 32 on the growth of canola spring cultivars under drought
stress. A factorial-split plot design in completely randomized blocks with three replications
was conducted in hydroponic cultivation system. Six canola cultivars, including Hyola
308, Sarigol, RGS 003, Amica, Hyola 420 and Olga were inoculated with P. fluorescens FY
32 or left non-inoculated as control. Three levels of drought stress (control, 70 and 50%
FC) were applied to the hydroponic cultivation system. Drought stress significantly reduced
relative water content (RWC), leaf area, shoot height, root length and soluble sugar but
augmented chl a and total chl content and the total proline. Our results showed that
bacterial inoculation had a positive effect in reducing the deleterious effects of drought
stress in some cases.