Effect of Enterobacter S16-3 as plant growth-promoting rhizobacteria on drought stress reduction in canola (Brassica napus) cultivars

The goals of study were to investigate the inoculation effects of Enterobacter S16-3 on growth characteristics of canola cultivars under drought stress.

This experiment was conducted as factorial-experiment based on randomized complete block design with three replications at hydroponic system of greenhouse, College of Agriculture, University of Tabriz. Inoculated and non-inoculated six canola cultivars were evaluated under two levels of drought stress conditions (0.6 and 1.2 MPa) and control.

Results showed drought stress caused a significant reduction in canola growth parameters such as fresh and dry weights of plant organs, height, root length, leaf relative water content and biological yield. Chlorophyll and proline content were suppressed under stress. Inoculation of canola cultivars with plant growth-promoting rhizobacteria not only improved height and root length, but also increased biological yield by 57.5 %. Bacterial inoculation also increased chlorophyll content and the concentration of proline under different stress conditions. Inoculated canola cultivars have better growth characteristics and biological yield than non-inoculated plants under drought stress conditions. Among canola cultivars inoculated Hyola308 surpassed other cultivars in all parameters under drought stress and the lack of a negative response to increasing drought stress indicated enhanced drought tolerance of Hyola308.

Taken together, these results demonstrated that Enterobacter S16-3bacteria probably has moderated the negative effects of drought stress and reduced the negative response of rapeseed cultivars to increasing drought stress by modifying the plant growth.