The impact of Sinorhizobium meliloti and Pseudomonas fluorescens on growth, seed yield and biochemical product of fenugreek under water deficit stress

Bacteria that colonize plant roots and promote plant growth are referred to as plant growth-promoting rhizobacteria (PGPR). For a long-serving period, the PGPRs have been applied as biofertilizers in crops culture. Recent studies indicated the importance of PGPR for controlling the water deficit. The present study investigates the effects of two different PGPRs on some morphophysiological characteristics in fenugreek under water deficit stress. The first factor was application of four PGPR levels including (1. Sinorhizobium meliloti, 2. Pseudomonas fluorescens, 3. combination of S. meliloti and P. fluorescens and 4. control without bacterial inoculation) and four levels of soil water content including 40%, 60%, 80% and 100% of field capacity (FC) was considered as second factor. The results showed that leaf area, shoot fresh and dry weight, nitrogen, phosphorus and potassium content, and water use efficacy (WUE) were significantly improved by PGPR inoculation and individual use of PGPR was more effective. Decreasing of soil water content up to 0.40 FC and inoculation of two bacteria led to increase of secondary metabolites such as nicotinic acid and trigonelline. However seed yield was decreased in PGPR treated plants