ISOLATION, CHARACTERIZATION AND EFFICACY OF PHOSPHATE SOLUBILISING BACTERIA
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Date
2016
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Division of Microbiology, Faculty of Basic Sciences, Sher-e-Kashmir University of Agricultural Sciences & Technology of Jammu
Abstract
The present investigation was carried out with the objectives to explore rhizospheres for isolation of
phosphate solubilizing bacteria vis a vis evaluation of the efficient isolated phosphate solubilizers in
maize (Zea mays). Eight locations viz. R.S. Pura, Burj Tanda, Chakrohi, Kaili mandi, Chatha farm-I,
Chatha farm-II, Gurha slathian and Rakh Dhiansar were surveyed for rhizosphere soil sample
collection. Soil varied in pH, E.C, O.C, available N and available P between 6.68 – 7.12, 0.10 – 0.19
E.C μS cm-1, 0.41-.53%, 112-166 kg ha-1 and 10-14.2 kg ha-1, respectively. The different isolated PSB
showed the clearing zones from 0.95 mm to 7.79 mm whereas the phosphorus solubilizing efficiency
determined was between 38.56 % and 78.52 %. The total culturable bacteria from the locations showed
the peak values on the 6th day of incubation varying between 6.13×106 to 8.93×106 cfu g-1 soil, whereas
the PSB population from the locations showed the peak values on 7th day of incubation and varied
between 2.50×108 - 8.86×108 cfu g-1 soil. PSB induced the pH changes in the Pikovskaya broth and
showed a drop of pH from 6.47 (Control) to 3.63 (PSB1). The optimum temperature for PSB survival
has been found to vary between 25-350C. Maximum phosphatase activity in 24 hrs varied between
12.9-36.8 μg PNPP ml-1h-1 whereas the maximum phytase activity was observed in 72 hrs and varied
between 4.2-10.2 μg P ml-1 h-1. The three phosphorus solubilizing efficient bacterial cultures were
subjected to the 16S rRNA sequence analysis, two cultures were identified as Bacillus pumilus (PSB1
and PSB4), and one as Bacillus atrophaeus (PSB7). These isolates were blended in a sterile carrier
maintaining the population from 10-9 to 10-10 were evaluated for their efficiency in promoting the dry
matter yield of Maize (Zea mays) variety CM-135 in the pot experiment and showed a significant
increase in dry matter yield of the Zea mays as compared to the control. A present investigation
revealed diverse PSB population in the rhizospheric soil samples of different areas of Jammu that
showed their potential role as biofertilizers for growth promotion of crop plants. Endeavours needed to
be directed to identify, screen and characterize PSB from more niches in Jammu region for their
ultimate application under field conditions. So that, the successful implementation in use of PSB to
exploit soil fixed P that can be an alternative sustainable strategy for management of soil to optimize P
bioavailability.
Description
M.Sc. Dissertation
Keywords
PHOSPHATE SOLUBILISING BACTERIA, SOLUBILIZATION, RHIZOSPHERE, BACILLUS PUMILUS, BACILLUS ATROPHAEUS. MAIZE, 16S RRNA, PHOSPHOROUS