Effect of three commercial bio-fertilizers prepared with Pseudomonas on yield and morphophysiological traits of lettuce (Lactuca sativa L.)

Bio-fertilizers are microbial inoculants or a combination of carriers of effective microbial strains with high efficiency to provide one or more nutrients needed by the plant, which are important materials as reducing agents to reduce the environmental damage of chemical fertilizers, to reduce diseases, to improve the soil structure, to stimulate plant growth and to increase the quantity and quality of the crops. This study was conducted to investigate the effect of three commercial bio-fertilizers, including Pseudomonas aeruginosa, P. putida, and P. fluorescens, on some morphological and physiological traits of lettuce under greenhouse conditions. The experiments were held on Nuclear Agriculture Research School in a completely randomized design (CRD) with four replications. The results indicated that inoculation of lettuce at growth stage with these biological fertilizers caused a significant increase in plant growth components such as plant height, leaf number, plant diameter, dry and fresh weights. In the case of physiological indicators, the use of bio-fertilizers increased expression of total protein, and also improved the production of oxidative enzymes (peroxidase and polyphenol oxidase) in the leaf compared to the control. According to the results of this study, it can be concluded that the use of bio-fertilizers contributes to the development of organic agriculture which in turn improves the quantity and quality of the product.