Record ID No. |
176 |
Author(s) |
Ortas I., Rowell D. L., Harris P. J. , 2004 |
Affiliation |
Cukurova University, Faculty of Agricultural, Department of Soil Science, Adana, Turkey |
Title |
Effect of mycorrhizae and pH change at the root-soil interface on phosphorus uptake by Sorghum using a rhizocylinder technique |
Source. Vol.(no):Page |
Communications in Soil Science and Plant Analysis. 35(7-8): 1061-1080 p |
Categories |
Arbuscular Mycorrhiza |
Subjects |
Soil plant relations |
Sub-subjects |
Soil reaction |
Host |
Sorghum, Sorghum biocolor |
Organism |
Glomus mosseae |
Country |
Turkey, Asia |
Abstracts |
Sorghum (Sorghum bicolor) was grown for 40 days in.
rhizocylinder (a growth container which permitted access to rh
zosphere and nonrhizosphere soil), in two soils of low P status.
Soils were fertilized with different rates of ammonium and
nitrate and supplemented with 40 mg phosphorus (P) kg(-1) and
inoculated with either Glomus mosseae (Nicol. and Gerd.) or
nonmycorrhizal root inoculum. N-serve (2 mg kg(-1)) was added to
prevent nitrification. At harvest, soil from around the roots
was collected at distances of 0-5, 5-10, and 10-20 mm from the
root core which was 35 mm diameter. Sorghum plants, with and
without mycorrhiza, grew larger with NH4+ than with NO3-
application. After measuring soil pH, 4 3 suspensions of the
same sample were titrated against 0.01 M HCl or 0.01 M NaOH
until soil pH reached the nonplanted pH level. The acid or base
requirement for each sample was calculated as mmol H+ or OFF
kg(-1) soil. The magnitude of liberated acid or base depended on
the form and rate of nitrogen and soil type. When the plant root
was either uninfected or infected with mycorrhiza., soil pH
changes extended up to 5 mm from the root core surface. In both
soils, ammonium as an N source resulted in lower soil pH than
nitrate. Mycorrhizal (VAM) inoculation did not enhance this
difference. In mycorrhizal inoculated soil, P depletion extended
tip to 20 mm from the root surface. In non-VAM inoculated soil P
depletion extended up to 10 mm from the root surface and
remained unchanged at greater distances. In the mycorrhizal
inoculated soils, the contribution of the 0-5 mm soil zone to P
uptake was greater than the core soil, which reflects the hyphal
contribution to P supply. Nitrogen (N) applications that caused
acidification increased P uptake because of increased demand;
there is no direct evidence that the increased uptake was due to
acidity increasing the solubility of P although this may have
been a minor effect.
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