Effect of Plant Growth Promoting Rhizobacteria on Growth, Nutrient Uptake and Physiological Parameters in Sugar Beet under Different Watering Regimes

Abstract

Two experiments were conducted in order to investigate the of nine ACC deaminase-containing, IAA-producing, N2-fixing and/or P-solubilizing bacteria, on the growth, yield, chlorophyll, macro- and micro-nutrient content, and selected morpho-physiological parameters of sugar beet, under five watering regimes. The experiment was set up in two sets; and the first set was harvested after 65 days and the second set was done after 130 days. Inoculation with multi-traits bacteria stimulated overall plant growth, including sugar content, root and leaf yield and the leaf chlorophyll contents, and macro- and micro-nutrient uptake, which might partly contribute to the activation of the processes involved in the alleviation of the effect of water stress. According to the results, at the level of 75, 50 and 25% of WHC under water constraint, beet yield parameters BF4, BF6, Bio-organic and mineral fetilizer was found effective. As an average of the five water regimes, bacterial formulations increased dry storage root weight by 6.5-27.7% and 9.1-27.3% and dry leaf weight by 6.1-26.7% and 3.9-25.8% at the first and second trials, whereas, mineral fertilizers (NP) and bio-organic fertilizers increased dry storage root weight by 24.5% and 9.3-15.5% and 20.2 and 9.2-15.2%, and dry leaf weight by 23.5% and 11.7-23.2% and 22.2% and 3.3-21.9%, respectively, compared with control. Moreover, water stress in sugar beet plants was alleviated partially by the inoculation with bacterial strains. Our results provide strong evidence that the role of bacteria in the performance of sugar beet plants in stressful environment of soils not only the improved plant growth, yield, and macro- and micro-nutrient content, but also the alleviation of water deficit and waterlogging stress.