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Translocation of 15 N indicates nitrogen recycling in the mat‐forming lichen Cladonia portentosa
Author(s) -
Ellis C. J.,
Crittenden P. D.,
Scrimgeour C. M.,
Ashcroft C. J.
Publication year - 2005
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 - 10.1111/j.1469-8137.2005.01524.x
Subject(s) - chromosomal translocation , lichen , nitrogen , biology , botany , chemistry , genetics , gene , organic chemistry
Summary• Nitrogen translocation was measured in Cladonia portentosa during 2 yr growth in Scottish heathland. Translocation was predicted to occur if N is resorbed from senescent basal tissue and recycled within the thallus. • 15 N was introduced into either the lower (TU thalli) or upper (TD thalli) 25 mm of 50‐mm‐long thalli as 15 N‐NH 4 + , 15 N‐NO 3 − or 15 N‐glycine. Labelled thalli were placed within intact lichen cushions, either upright (TU) or inverted (TD). Vertical distribution of label was quantified immediately following labelling and after 1 and 2 yr. • Independently of the form of introduced label, 15 N migrated upwards in TU thalli, with new growth being a strong sink. Sink regions for 15 N during year 1 (including new growth) became sources of 15 N translocated to new growth in year 2. Upward migration into inverted bases was minimal in TD thalli, but was again marked in new growth that developed from inverted apices. • Relocation of N to regions of growth could facilitate internal N recycling, a process postulated to explain the ecological success of mat‐forming lichens.