Record ID No. |
183 |
Author(s) |
Aquino M.T., Plassard C. , 2004 |
Affiliation |
INRA, UMR 1222, 2 Pl Viala,Batiment 13, Agro M, F-34060 Montpellier 01, France |
Title |
Dynamics of ectomycorrhizal mycelial growth and P transfer to the host plant in response to low and high soil P availability |
Source. Vol.(no):Page |
Fems Microbiology Ecology. 48(2): 149-156 p. |
Categories |
Ectomycorrhiza |
Subjects |
Soil plant relations |
Sub-subjects |
Nutrition |
Host |
Pinus pinaster |
Organism |
Hebeloma cylindrosporum |
Country |
France, Europe |
Abstracts |
The aim of this work was to investigate the quantitative relationships between the rates of fungal soil
exploration and their effects on plant growth and phosphorus (P)
nutrition in soil with varying P availability. Ectomycorrhizal
associations were established between Pinus pinaster and the
basidiomycete Hebeloma cylindrosporum. Plants were grown for 4
and 6 months in mini-rhizoboxes filled with a 0.5 mm soil layer
with two contrasting P levels (-P and +P soils), containing 3 or
50 mg of bicarbonate extractable P per kg of dry soil,
respectively. Surface areas of the soil layers colonised by the
roots and the hyphae were estimated using image analysis.High P
availability decreased the rates of fungal soil colonisation,
calculated as 0.92 +/- 0.19 cm(2) day(-1) plant(-1) in the -P
soil and 0.42 +/- 0.1 cm(2) day(-1) plant(-1) in the +P soil
over the 4-6 months period. Four-month old mycorrhizal plants
accumulated lower amounts of biomass and total P than
non-mycorrhizal plants, regardless the level of P availability.
By contrast, 6-month old mycorrhizal plants were larger and
contained more P than non-mycorrhizal plants, especially in the
+P soil. However, mycorrhizal plants were always different from
non-mycorrhizal P-deficient plants, which had an increased root
surface and root P allocation. To explain these contradictory
results, we propose that P accumulation by mycorrhizal plants
derives mainly from fungal P uptake. The net P transfer from the
fungus to the plant was estimated as 0.36 and 0.66 mumol of P
per cm(2) of mycelium in -P and +P soil, respectively. Our data
demonstrated that, despite the inhibitory effect of the high
soil P availability on the rates of fungal soil colonisation,
the ectomycorrhizal symbiosis was more efficient to improve host
plant P nutrition in these conditions.
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