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Response of phosphomonoesterase activity in the lichen Cladonia portentosa to nitrogen and phosphorus enrichment in a field manipulation experiment
Author(s) -
Hogan E. J.,
Minnullina G.,
Sheppard L. J.,
Leith I. D.,
Crittenden P. D.
Publication year - 2010
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.1469-8137.2010.03221.x
Subject(s) - phosphomonoesterase , thallus , nitrogen , lichen , phosphorus , botany , deposition (geology) , chemistry , ammonium , environmental chemistry , zoology , biology , phosphatase , biochemistry , paleontology , phosphorylation , organic chemistry , sediment
Summary• Effects of nitrogen (N) enrichment on the heathland lichen Cladonia portentosa were quantified to test the hypothesis that modified N : phosphorus (P) relationships observed in this species in N‐polluted natural environments are a direct effect of increased N deposition, and to evaluate potential confounding effects of N form and P availability. • Cladonia portentosa was harvested from experimental plots in lichen‐rich peatland vegetation (background total N deposition of 8 kg N ha −1 yr −1 ) treated for 4 yr with additional wet N deposition at 0, 8, 24 and 56 kg N ha −1 yr −1 as either NH 4 + or NO 3 − , and with or without P added at either 0.6 or 4 kg P ha −1 yr −1 . • Nitrogen enrichment increased thallus N concentration, N : P mass ratio and phosphomonoesterase (PME) activity by factors of up to 1.3, 1.4 and 1.7, respectively, effects being independent of N form. Phosphomonoesterase activity was tightly related to thallus N : P ratio with additions of P at 4 kg ha −1 yr −1 depressing PME activity by a factor of 0.4. • Nitrogen enrichment induces P‐limitation in C. portentosa with attendant changes in chemical and physiological characteristics that could be used as sensitive biomarkers with which to detect low levels of N pollution.