الفهرس 
Introduction and Literature ReviewOnly 14 pages are availabe for public view
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Abstract
The pH of the Egyption soils are slightly alkaline and most of
the Egyptian soils are poor in nutrients and require adequate amount
of fertilization to sustain and improve high plant productivity.
Monohydrogen phosphate (available form of phosphorus for plant)
react with calcium in neutral and alkaline soils and precipitated
strongly to the surface of the soil particles this reaction remove available
phosphorus from soil solution. Fortunately, there are groups of soil
microorganisms (phosphate solubilizing fungi) that can solubilize
unavailable phosphorus forms. The need for effective and environmentally biofertilizers for agriculture as alternative way for using chemical fertilizers was increased.
The present study involved three aims, the first aims is the
isolation, identification and solubilization potential of phosphate
solubilizing fungi from different habitats. Thirty soil samples were
collected from different localities and different habitats in Beni-Suef
governorate, Egypt. Total fungal counts were recorded by using
dilution plate methods on Pikovskaya,s medium (PVK). Phosphate
solubilizing fungi (PSF) were selected by formation of halo zone
around fungal colony on (PVK) agar plate after 4 days of incubation.
Out of the 146 fungi taxa isolated from different soil samples,
only ten isolates showed significant zone of phosphate solubilization
on PVK agar medium. The physico - chemical properties of the soil
containing PSF were determined. PSF were identified morphologically
and the most common genera were Aspergillus and Penicillium and
Trichoderma. Trichoderma spp. have different mechanism in phosphate
solubilization and not produce clear zone on agar plate like
Aspergillus and Penicillium. Five species of Trichoderma were
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isolated and screened on broth medium to be phosphate solubilizing
fungi. Only thirteen soil samples from thirty soil samples collected
from different localities in Beni-Suef governorate possessed PSF and
this indicate that the low count of (PSF) in Egyptian soil. The
isolation of PSF from saline soil refers to the ability of these
isolates to high salinity tolerance and any microorganism that
acidifies its external medium will show some level of phosphorus
solubilizing activity. All isolates exhibit different levels of phosphate
solubilizing activity on (PVK) broth medium containing tri-calcium
phosphate (TCP) as sole phosphorus source. Final pH of the medium,
solubilized P and dry weights of fungi were recorded. Aspergillus
niger 2, Penicillium variabile and T. harzianum 301 showed solubilization
activity 1.67, 0.55% and 0.32% respectively whereas the pH values
of the culture filtrates were 3.6, 4.3 and 5.0 respectively.
The role of mycorrhizae in phosphorus acquisition cannot be
denied. Isolation and characterization of arbuscular mycorrhizal spores
from different habitats in Beni-Suef governorate is the second aim of
the study. Fourteen Plants collected from different localities in Beni-
Suef governorate were found to be belonging to nine families. Two
plant species were identified as member of liliaceae namely Allium
cepa and Allium sativum and four plant species of Gramineae were
identified as Triticum vulgaris, Zea mays, Sorghum sp. and Ehrharta
calycina. Solanum tuberscum and Lycopersicon esculatium were
collected and identified as member of solanaceae collected during this
investigation. Leguminoseae, Chenopodiaceae, sclepiadceae, Umbelliferae,
Onagraceae and Portulacaceace were represented by single species.
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The study showed that the counts of (AM) spores were
affected by plant species and location. Trifolium alexanderinum,
Cynancum acutum, Sorghum sp., Zea mays, Anathum graveolans,
Ehrharta calycina, Ludwigia stolonifera and Allium cepa showed the
highest number of spores compared to other samples (40000-110000
spores Kg-1soil). In contrast Lycopersicon esculatium, Solanum tuberscum,
Allium sativum, Triticum vulgaris, Portulaca oleraceae and Beta
vulgaris var rapa gave the lowest density of mycorrhizal spores
(17000-37000 spores Kg-1soil). Glomus was the most abundant genus
during the study, it was isolated from all soil samples. Gigaspora
was the second important genus, it was extracted and sieved from
nine soil samples out of fourteen. Acaulospora was the third important
genus, it was isolated from seven soil samples out of fourteen. Seven
species were isolated and identified during the investigation Glomus
fasciculatus, Glomus mosseae, Glomus etunicatus, Gigaspora nigra,
Gigaspora calospora, Aculospora laevis and Entrophospora infrquens.
The application of this study was conducted in pot experiment
which is the third aim of the work. The aim of this experiment to
evaluate the efficiency of phosphate solubilizing fungi on growth of
Hordeum vulgare in prescence and absence of rock phosphate in
unsterilized soil. Aspergillus niger 2, Trichoderm harzianum 301 and
arbuscular mycorrhizal spores were put as individual inocula in pots.
Morphological and physiological parameters were recorded on
Hordeum vulgare in addition to microbiological studies on the soil of
the experiment as total bacterial and fungal counts. Also, dehydrogenase
enzyme activity was estimated as an important factor for microbial
activity. All the previous parameters were measured at two growth
intervals (30 and 60 days). The results revealed that the growth of
Hordeum vulgare increased in presence of rock phosphate and
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inoculated with PSF than non rock phosphate amended soil
inoculated with PSF. T. harzianum 301 stimulated the growth of
Hordeum vulgare in both case of rock phosphate and non rock phosphate amended soil. The AMF treatment showed significant increase in nitrogen, potassium and phosphorus percent when compared with other treatments. from the previous results it was concluded that rock phosphate can be added as a crude phosphate fertilizer in the soil with phosphate solubilizing fungus Trichoderma harzianum. The application of P solubilizing fungi is recommended as a sustainable way for increasing plant growth.