Enhancing Drought Resistance in Red Clover (Trifolium pratense L.) using Growth-Promoting Bacteria

Aims: Arid environments present significant constraints on plant development, with water scarcity being a primary impediment. In this study, we investigated whether plant growth-promoting microorganisms (PGPRs) are effective in reducing the negative effects of water deficit on red clover (Trifolium pratense L.).Materials & Methods: A factorial test, using a completely randomized design, investigated the effect of PGPRs on seed germination, growth, and plant nutrient uptake under water deficit conditions. Three soil moisture regimes were established: field capacity ۱۰۰% (FC۱۰۰), ۷۰% (FC۷۰), and ۴۰% (FC۴۰). Experimental treatments comprised inoculation with Azotobacter vinelandii (AV), a consortium of Pantoea agglomerans and Pseudomonas putida (PA+PP), and AV+PA+PP.Findings: Germination rate varied considerably, with AV×FC۷۰ exhibiting the highest percentage (۹۳%) and control+FC۷۰ the lowest (۶۰%). Synergistic applications of AV, PA, and PP were less effective at mitigating drought stress than single treatments. Root length (۱۰.۷۹cm), shoot length (۱۸.۸۹cm), and dry biomass (aboveground: ۰.۹۸g.plant-۱; belowground: ۱.۸۸g.plant-۱) reached their maxima under AV×FC۴۰, whereas (PA+PP)×FC۴۰ yielded the minimal measurements. PA+PP demonstrated no statistically significant impact on water deficit reduction (p<۰.۰۱). AV×FC۴۰ maximized potassium uptake. Iron and manganese were highest in (PA+PP)×FC۷۰, while zinc was maximum in (AV+PA+PP)×FC۱۰۰. Minimum uptake of iron, zinc, and manganese occurred with (AV+PA+PP)×FC۷۰, (AV+PA+PP)×FC۴۰, and AV×FC۱۰۰, respectively.Conclusion: Typically, inoculation of red clover with A. vinelandii has demonstrated efficacy in enhancing drought tolerance, offering a biotechnological strategy for forage production in water-limited environments. Nevertheless, a comprehensive understanding of the mechanisms by which rhizobacteria confer drought resilience to host plants necessitates further investigation.

کلیدواژه ها:

Azotobacter ، Environmental Stress ، Nutrient uptake ، PGPRs ، Rhizosphere