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Deposition of nitrogen in ectomycorrhizae of Norway spruce
(Picea abies (L.) Karst.) on NH4
+-
fertilized sites in the Black Forest, Germany
TALK Session 3 "Mycorrhizae in Stressed Ecosystems"
BECKMANN, SUSANNE & INGRID KOTTKE
Eberhard-Karls-Universität, Tübingen, Botanisches
Institut, Spezielle Botanik und Mykologie, Auf der
Morgenstelle 1, 72076 Tübingen, Germany
ICOM1 Abstract
A nitrogen-fertilization experiment has been carried out on
two plots of the ARINUS-Projekt, Schluchsee and Villingen and
the Nitrogen-deposition in ectomycorrhizae of Norway spruce
was studied. The survey indended to prove wether accumulation
of nitrogen containing granules takes place in field material
as was shown as in vitro. Different mycorrhizal types and
observation sites were compared. Proof and relative
quantification of N-accumulation was aided by EELS, Electron
Energy Loss Spectroscopy. Compared to the vacuole, the N-
content was up to 53 times increased in the granules. All of
the investigated types of mycorrhizae were able to form the
granules, though to a different extend. The number of
granules per mm2 of hyphal mantle increased after
fertilization. The increase depended on the mycorrhizal type
and more marked on the Schluchsee plot. Xerocomus badius
mycorrhizae and Cenococcum geophilum showed already high
amounts of granules on the control plot. The N-content of the
granules of Xerocomus badius was always high. In contrast,
Tylospora fibrillosa contained a higher number of granules
and higher N-contents of the granules only after the
fertilization. Only Tylospora fibrillosa showed clear
differences among the soil horizons. In conclusion
mycorrhizal types reacted differently. Apart from mediating
the N-nutrition of the host trees, ectomycorrhizae are shown
to play a role in the regulation of the nitrogen household of
forest soils because of their capacity of N-accumulation.