Isolation and Identification of Rhizobacteria from Paddy Land and Their Benefit as a Biofertilizer
Biological nitrogen fixation (BNF) studies have been emphasized following the problem faced in the application of chemical nitrogen fertilizer in wetland rice cultivation. Among fertilizer inputs, nitrogen is the major limiting nutrient for crop production. Besides energy intensive, chemical nitr...
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| Format: | Thesis |
| Language: | English English |
| Published: |
2001
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| Subjects: | |
| Online Access: | http://psasir.upm.edu.my/id/eprint/10542/1/FP_2001_2.pdf |
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| Summary: | Biological nitrogen fixation (BNF) studies have been emphasized following
the problem faced in the application of chemical nitrogen fertilizer in wetland
rice cultivation. Among fertilizer inputs, nitrogen is the major limiting nutrient
for crop production. Besides energy intensive, chemical nitrogen fertilizer
also cause groundwater pollution. One of the approaches to alleviate this
problem is by isolating the beneficial rhizobacterial from wetland rice which
have the capability to fix nitrogen biologically and produce plant growth
hormones, indole-3-acetic acid (1M) in vitro.
The study consisted of three experiments. Experiment I was the isolation and
identification of rhizobacterial strains from paddy land and their reactions
toward several biochemical tests. Experiment II was the determination of 1M
production by the rhizobacterial using modified colorimetric methods. Experiment III was to determine the effects of 1M production by
rhizobacterial isolates on growth of rice variety MR 211, the colonization of these isolates on rice roots and nitrogenase activity of rhizobacteria through
Acetylene Reduction Assay.
From the isolation procedures, several strains of bacterial were isolated from
the rice rhizosphere. The population of these rhizobacterial ranged from 105
to 109 cfu/mL. By using Biolog Identification System, these rhizobacterial
have been identified as Corynebacterium spp., Proteus mirabilis and
Spirillum spp., which showed their unique characteristics to Gram staining,
pellicle formation, motility, starch hydrolysis, catalase, antibiotic test and
carbohydrate fermentation with different carbon sources.
The experimental results indicate that Corynebacterium spp., Proteus
mirabilis and Spirillum spp. were able to produce 1M in culture medium
supplemented with L-tryptophan as a precursor, which ranged between 1-10
J-lg/mL. The presence of precursor was essential for detection of 1M
production by the bacteria. 1M production increased in the presence of 0.1
mg/L, 10 mg/L and 100 mg/L of precursor. |
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