Agricultural Research Management Information System

Home
Research Summary
Search
About Us
- ARMIS
- Brochure
Contact Us
Report
User Request
Data Input
Help
- Operation Manual
  - PDF
  - Video
- Program Area & Commodity
We have reached 37600 number of research entries at this moment.

- Logout

Research Detail

Home
Research
Detail

Screening and Characterization of Phosphorus Solubilizing Bacteria and Their Effect on Rice Seedlings

Md. Shahinur Rahman
Department of Agricultural Chemistry, Faculty of Agriculture, Bangladesh Agricultural University, Mymensingh 2202, Bangladesh

Quazi Forhad Quadir
Department of Agricultural Chemistry, Faculty of Agriculture, Bangladesh Agricultural University, Mymensingh 2202, Bangladesh

Atiqur Rahman
Department of Agricultural Chemistry, Faculty of Agriculture, Bangladesh Agricultural University, Mymensingh 2202, Bangladesh

Moonmoon Nahar Asha
Department of Agricultural Chemistry, Faculty of Agriculture, Bangladesh Agricultural University, Mymensingh 2202, Bangladesh

Md. Abul Khair Chowdhury
Department of Agricultural Chemistry, Faculty of Agriculture, Bangladesh Agricultural University, Mymensingh 2202, Bangladesh

Abstract/ Executive Summary:

An experiment was carried out to isolate, screen and characterize bacteria collected from an industrially polluted site of Bhaluka under the Mymensingh district and to evaluate their phosphorus (P) solubilizing capacity. About ten plant and soil samples from six different spots were collected from the site. Thirty four bacterial isolates were screened and pure cultures of the different bacterial isolates were prepared. Among the bacterial isolates 25 were gram negative and 9 were gram positive. About 31 bacterial isolates had catalase producing capacity and remaining 3 were negative to catalase test. Bacterial isolates were grown on a NBRIP media to determine their phosphorus solubilizing capacity. About 25 bacterial isolates were shown P solubilizing capacity. Isolate SB8 gave the highest result about 11.42 PSI (phosphorus solubilizing index), whereas other bacterial isolates showed moderate P solubilizing capacity (PSI 1.75-6.35). A plant trial with selected isolates (SB₈, SB₁₅, SB₂₅) were also done and SB8 achieved 10% higher P content in comparison with control which supports the in vitro P solubilization assays.

Keywords: Screening, Phosphorus fixation, Bacteria, Rice

Location: Department of Agricultural Chemistry, Faculty of Agriculture, Bangladesh Agricultural University, Mymensingh

Start Date: 00-00-2013

End Date: 00-00-2013

Program Area: Crop-Soil-Water Management

Commodity: Rice

Objectives:

1. To screen potential PSB from industrially polluted soils of Seedstore, Bhaluka, Mymensingh for agricultural use and evaluate their physical and biochemical characteristics, and 2. To determine their efficiency on the content and uptake of P in a rice seedling.

Methodology:

Collection of samples - To isolate rhizospheric bacteria from plant root, ten plant samples with their roots and soil samples from six different spots were collected from an industrially contaminated site Seedstore, Bhaluka under Mymensingh district. Immediately after collection, each sample was kept in labeled air tight plastic zipper bag and stored at 4°C. Isolation of the bacterial strains - To isolate bacterial isolates from each plant roots, all plant roots were washed with sterilized distilled water in a test tube. A series of dilution (10-1, 10-2 and 10-3) were made to reduce the density of the bacterial population. Each diluted sample was allowed to culture separately on a 9 cm petri dish containing a solid nutrient rich agar medium having sucrose, nutrient broth and agar at the rate of 10, 10, 15 gL^-1 , respectively. The pH of the medium was 6.5. Each media was autoclaved at 121°C with 15 psi for 20 minutes before inoculation. After inoculation the samples were spreaded with the help of a sterile spreader and incubated in an incubator at 28°C for 2 days. Again bacterial isolate from soil samples were isolated using a liquid nutrient rich media prepared in a 500 mL conical flask and autoclaved at 121°C with 15 psi for 20 minutes. Exactly 200 mL broth media was inoculated with approximately 2g soil inoculums and incubated in an incubator at 28°C for 2 days. Then bacterial suspension was produced in the conical flask and then this suspension was spread in a solid nutrient agar medium with desired dilution. In this isolation each media was autoclaved at 121°C with 15 psi for 20 minutes before inoculation. After inoculation the samples were spread with the help of a sterile spreader and then incubated in an incubator at 28°C for 2 days. After 2 days of the incubation morphologically different sized and shaped bacterial isolates were selected for the further culture with the help of a toothpick and pin pointed sterile needle. Pure cultures of the bacterial isolates were obtained by repeated sub-culture method. In this method, the bacterial isolates were grown repeatedly until a pure culture of a strain is obtained. Screening of the PSB - Mineral phosphate solubilization activities of isolated bacterial isolates were tested by plate assay. Phosphorus solubilizing bacteria screening were done using NBRIP medium. Phosphate solubilizing capacity was calculated in terms of phosphate solubilization index, PSI (PSI=A/B, where A is the total diameter of the halo zone, and B is the colony diameter). The isolates showing PSI > 2 have been considered as phosphate solubilizing bacteria. Performance of selected PSB isolate on the rice seedling - The bacterial isolates were selected to examine their performance on a test crop rice variety Iratom 24. On the basis of their PSI values three bacterial isolates were selected eg one with highest PSI (SB₈), one with moderate PSI (SB₁₅) and one with lowest PSI (SB₂₅) and inoculated with the plant roots before transplanting. Seeds of Iratom 24 were surface sterilized by using 70% ethanol for 10 minutes, and 100% ethanol for five minutes, respectively. After every step seeds were washed by distilled water for five times. The seeds were then soaked in the bacterial suspension for 3 hours. The bacteria coated seeds were placed on petri dish containing sand for germination. Ten days old seedlings were transplanted in earthen pots and allowed to grow for 30 days. Every pot contained 10 kg soil was treated with recommended dose of urea, MoP, gypsum and TSP. The dose of TSP varied according to the treatments. Total P content and P concentration was determined after harvesting of seedlings. Treatments under investigations - The conducted experiment was a two factor experiment viz. three PSB inoculants and different P doses. The nutrient broth containing no bacterial isolate was used as control. Sample collection and processing - Thirty days after transplanting one plant was sampled from each pot and labeled properly and sent directly to the laboratory for further processing and chemical analysis. Plant samples were washed several times with tap water followed by distilled water. After air drying (48 hours) and oven drying (48 hours at 60°C) the samples were subjected to grinding (0.2 mm sieve). The ground plant samples were then digested using HNO₃ and H₂O₂ to obtain the plant extract for the determination of P content. Statistical analysis - The statistical analysis of the experimental data was carried out using MS Excel and Mini Tab data analysis software. Statistical differences between treatments were carried out by Tukey’s range test.

Source of Information: Res. Agric., Livest. Fish. Vol. 1, No.1, December 2014: 27-35; ISSN : P-2409-0603, E-2409-9325

Article Link (Online Journal):

Funding Source:

Total Budget (Tk.) :

Achievement/Findings:

Bacterial isolates were grown on a NBRIP media containing Ca₃(PO₄)₂ for seven days to determine their phosphorus solubilizing capacity and their PSI was determined. Twenty five bacterial isolates were identified as PSB among which Strain SB8 showed highest PSI about 11.42 and rest of the strains PSI ranged from 1.75 to 6.36. On the basis of PSI, three strains were selected such as one highest PSI, one moderate PSI strain and one no PSI strain i.e. SB₈, SB₁₅ and SB₂₅, respectively and they were treated with zero P and half P of the recommended doses of P and a control (without any bacterial isolate) treated with zero P, half P and full P of the recommended doses of P to determine their effect on the growth and P uptake of test crop rice cv. Iratom 24. Though there was no significant difference was found on the shoot and root length, number of tillering and shoot dry weight but significant difference was observed on the P content and P uptake among the treatments. The highest P content was observed in treatment S₄P₂ about 0.3% and second highest was in S₁P₁ and S₂P₁ about 0.2% and lowest was in S₃P₀ about 0.1%. Similarly highest P uptake was observed in S₁P₁ about 0.5 g plant^-1 and second highest was observed in S₄P₂ and S2P1 about 0.4 g plant^-1 and lowest was in S₃P₁ about 0.2 g plant^-1 which revealed that strain SB₈ achieved 10% higher P than control.

Knowledge Management: Journal