Phosphate-solubilization activity of bacterial strains in soil and their effect on soybean growth under greenhouse conditions

Abstract

The efficiency of 13 phosphate-solubilizing bacteria (PSB; four Burkholderia sp., five Enterobacter sp., and four Bradyrhizobium sp.) was assessed in a soil plate assay by evaluating soil phosphorus (P) availability. A commercial argentine strain, Pseudomonas fluorescens, was used for comparing solubilizing activity. Burkholderia sp. PER2F, Enterobacter sp. PER3G, and Bradyrhizobium sp. PER2H strains solubilized the largest quantities of P in the soil plate assay after 60 days as compared with the other strains, including the commercial one. The effect of PSB inoculation on growth and nutrient uptake of soybean plants was also studied under greenhouse conditions. Plants inoculated with Burkholderia sp. PER2F had the highest aerial height and showed an appropriate N/P ratio. However, none of the PSB increased P uptake by plants. This suggests that PSB inoculation does not necessarily improve P nutrition in soybean, nor was there any relationship between P availability in the soil plate assay and P content in the soybean shoot in the greenhouse. We concluded that the selection of efficient PSB strains as possible inoculation tools for P-deficient soils should focus on the integral interpretation of soil assays, greenhouse experiments, and field trials.

Evaluation of rice–legume–rice cropping system on grain yield, nutrient uptake, nitrogen fixation, and chemical, physical, and biological properties of soil

“…2004). Similarly, PSB strains were reported to vary in phosphate solubilization activity and 389 stimulating growth of soyabean (Fernández et al 2007). Reddy and Raju (2006) found that 390 application of PSB with PR produced rice yields statistically at par with that produced by SSP 391 application @ 30 kg ha -1 .…”

Phosphate solubilizing bacteria: Assessment of their effect on growth promotion and phosphorous uptake of mung bean (Vigna radiata [L.] R. Wilczek)

“…Increased growth and P uptake of several crop plants due to PSB inoculation have been reported in a number of studies conducted under both growth chamber and greenhouse conditions (Dey et al, 2004;Fernández et al, 2007;Vikram and Hamzehzarghani, 2008;Hariprasad and Niranjana, 2009;Yu et al, 2011). The increase in shoot length, root length, shoot dry weight, and root dry weight of mung bean plants inoculated with PSB strains could be attributed to a greater absorption of nutrients, especially P. Compared with single inoculation, co-inoculation showed higher growth performances and P uptake; this suggests that both strains acted synergistically with each other to promote mung bean plant growth.…”

“…Screening of potential phosphate solubilizing isolates, which can be used as bio-inoculants to increase plant growth and yield, is recognized as an area of interest because such microbial inoculants could substantially reduce the chemical fertilizer requirement. There are several previous reports dealing with the application of phosphate solubilizing bacteria (PSB), either individually or combined, to assess their effects on the growth and biomass production of several crops (Fernández et al, 2007;Mittal et al, 2008;Vikram and Hamzehzarghani, 2008;Hariprasad and Niranjana, 2009;Jain et al, 2010). In the present study, we isolated and identified PSB strains and assessed their effect on the growth and nutrient uptake of mung bean plants cultivated under greenhouse conditions.…”

Effect of P- Solubilizing Bacteria on Microbial Biomass P and Phosphatase Activity in Groundnut (Arachis hypogaea L) Rhizosphere

“…Sterilized seeds were then placed in glass Petri dish and coated with bacterial suspension (OD 620nm 0.9). Three inoculated seeds were sown per 10 kg of unsterilized soil in earthen pots (Fernández et al, 2007).…”