Response of phosphomonoesterase activity in the lichen Cladonia portentosa to nitrogen and phosphorus enrichment in a field manipulation experiment.
New Phytol
; 186(4): 926-933, 2010 Jun.
Article
em En
| MEDLINE
| ID: mdl-20345638
ABSTRACT
*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.
Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Fósforo
/
Monoéster Fosfórico Hidrolases
/
Líquens
/
Nitrogênio
Idioma:
En
Revista:
New Phytol
Assunto da revista:
BOTANICA
Ano de publicação:
2010
Tipo de documento:
Article
País de afiliação:
Reino Unido