Agriculture Reference
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4.5.3.3 Trichoderma, Mortierella and Galactomyces
A total of 14 strains of Trichoderma isolated from the forest tree rhizospheres of
Pinus, deodar, bamboo, guava and oak using Trichoderma -specific medium were
evaluated for P-solubilizing activity employing National Botanical Research Insti-
tute Phosphate (NBRIP) broth containing TCP as the sole P source and were
compared with a standard culture of T. Harzianum (Kapri and Tewari 2010 ).
Even though all fungal cultures could solubilize TCP, the degree of solubilization
differed among fungal isolates which varied between 111.5
g/ml
in the culture filtrates of Trichoderma . In a similar study, Habte and Osorio ( 2012 )
evaluated the effect of N (NH 4 + and/or NO 3 ) on the dissolution of RP by a PSF
Mortierella sp. In the presence of NH 4 Cl or NH 4 NO 3 , the pH of the medium was
significantly decreased from an initial value of 7.6 to 3.4 and 3.7, respectively. In
the presence of KNO 3 , the pH went down only to 6.7. As a result, significantly more
P was detected in the presence of NH 4 Cl (129.65 mg/l) than in the presence of
NH 4 NO 3 (109.25 mg/l), while the concentration of P in the presence of KNO 3 was
only 0.08 mg/l. Yingben et al. ( 2012 ) observed that Galactomyces geotrichum P14,
isolated from soil of phosphate mines, demonstrated maximum solubilization of
insoluble P (1252.13 mg/l) within 40 h in a modified phosphate growth medium
supplemented with TCP.
μ
g/ml and 404.07
μ
4.5.3.4 Mixed Group
Pradhan and Sukla ( 2005 ) tested two fungal isolates for their TCP-solubilization
efficiency on solid and in liquid medium. The fungal Isolates were identified as
Aspergillus sp. and Penicillium sp. on the basis of their colony morphology and
microscopic characteristics. Phosphate solubilization was coupled to pH decrease
mediated by growth of fungus in medium containing glucose as C source. Asper-
gillus sp. solubilized 480 g P/ml, while Penicillium sp. solubilized 275 g P/ml from
0.5 % TCP after 4 and 3 days of growth, respectively. High P-solubilization activity
of Aspergillus sp., Penicillium sp. and Fusarium sp. isolated from saline area of
Purna river basin was reported by Rajankar et al. ( 2007 ). Of the total 107 soil
samples collected from saline affected area, 31 % samples had P-solubilizing fungi
wherein 87 % were identified as Aspergillus spp., 8.7 % as Penicillium spp. and
4.3 % as Fusarium spp. Xiaoa et al. ( 2008 ) conducted a similar experiment for RP
solubilization by PS fungi, Candida krissii , P. expansum and Mucor ramosissimus ,
isolated from phosphate mines (Hubei, PR China). The content of soluble P was the
highest when the initial pH for RP solubilization was 5.5 in the medium inoculated
with C. krissii , which was different from that of 7 in the medium inoculated with
P. expansum and 7.5 in the medium inoculated with M. ramosissimus . Mittal
et al. ( 2008 ) isolated 6 PSF (2 strains of A. awamori and 4 of P. citrinum ) from
various rhizosphere. The P-solubilizing activity of PSF in liquid varied from 38 to
760
μ
g/ml for TCP and 28-248
μ
g/ml for MRP among all isolates. Phosphate-
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