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Assimilation and isotopic fractionation of nitrogen by mycorrhizal and nonmycorrhizal subarctic plants
Author(s) -
Emmerton K. S.,
Callaghan T. V.,
Jones H. E.,
Leake J. R.,
Michelsen A.,
Read D. J.
Publication year - 2001
Publication title -
new phytologist
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.742
H-Index - 244
eISSN - 1469-8137
pISSN - 0028-646X
DOI - 10.1046/j.1469-8137.2001.00179.x
Subject(s) - subarctic climate , botany , biology , shoot , abundance (ecology) , ecology
Summary• Discrimination between 14 N and 15 N isotopes during assimilation of nitrogen (N) from inorganic (NO 3 , NH 4 ) and organic (glutamic acid, glycine) sources by subarctic ecotypes of Eriophorum vaginatum, Luzula wahlenbergii. Betula nana and Vaccinium vitis‐idaea was studied under axenic laboratory conditions. • Ectomycorrhizal B. nana and ericoid mycorrhizal V. vitis‐idaea assimilated significant amounts of all the N sources, whereas nonmycorrhizal E. vaginatum and L. wahlenbergii used mineral N but had very limited abilities to use amino acids. • Root, shoot and whole‐plant 15 N abundance frequently differed from the sources and were influenced by mycorrhizas, indicating that plant 15 N abundance is not a reliable guide to that of the N source used. • This study establishes that differences in leaf 15 N abundance between coexisting plants may result from species‐specific differences in isotopic fractionation of N. This challenges the view that 15 N abundance in shoots of different plant functional types directly reflects their utilization of isotopically distinct soil N pools.