High sensitivity of Lobelia dortmanna to sediment oxygen depletion following organic enrichment.
New Phytol
; 190(2): 320-31, 2011 Apr.
Article
em En
| MEDLINE
| ID: mdl-21175638
ABSTRACT
⢠Lobelia dortmanna thrives in oligotrophic, softwater lakes thanks to O(2) and CO(2) exchange across roots and uptake of sediment nutrients. We hypothesize that low gas permeability of leaves constrains Lobelia to pristine habitats because plants go anoxic in the dark if O(2) vanishes from sediments. ⢠We added organic matter to sediments and followed O(2) dynamics in plants and sediments using microelectrodes. To investigate plant stress, nutrient content and photosynthetic capacity of leaves were measured. ⢠Small additions of organic matter triggered O(2) depletion and accumulation of NH(4)(+), Fe(2+) and CO(2) in sediments. O(2) in leaf lacunae fluctuated from above air saturation in the light to anoxia late in the dark in natural sediments, but organic enrichment prolonged anoxia because of higher O(2) consumption and restricted uptake from the water. Leaf N and P dropped below minimum thresholds for cell function in enriched sediments and was accompanied by critically low chlorophyll and photosynthesis. ⢠We propose that anoxic stress restricts ATP formation and constrains transfer of nutrients to leaves. Brief anoxia in sediments and leaf lacunae late at night is a recurring summer phenomenon in Lobelia populations, but increased input of organic matter prolongs anoxia and reduces survival.
Texto completo:
1
Coleções:
01-internacional
Temas:
Geral
Base de dados:
MEDLINE
Assunto principal:
Compostos Orgânicos
/
Oxigênio
/
Sedimentos Geológicos
/
Lobelia
Tipo de estudo:
Diagnostic_studies
/
Prognostic_studies
Idioma:
En
Revista:
New Phytol
Assunto da revista:
BOTANICA
Ano de publicação:
2011
Tipo de documento:
Article
País de afiliação:
Dinamarca