TY - JOUR

T1 - High sensitivity of Lobelia dortmanna to sediment oxygen depletion following organic enrichment

AU - Møller, Claus Lindskov

AU - Jensen, Kaj Sand

N1 - © 2010 The Authors. New Phytologist © 2010 New Phytologist Trust.

PY - 2011

Y1 - 2011

N2 - • 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.

AB - • 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.

KW - Anaerobiosis

KW - Cell Hypoxia

KW - Chlorophyll

KW - Circadian Rhythm

KW - Geologic Sediments

KW - Iron

KW - Linear Models

KW - Lobelia

KW - Nitrogen

KW - Organic Chemicals

KW - Oxygen

KW - Partial Pressure

KW - Phosphorus

KW - Photosynthesis

KW - Plant Leaves

KW - Plant Roots

KW - Time Factors

KW - Water

U2 - 10.1111/j.1469-8137.2010.03584.x

DO - 10.1111/j.1469-8137.2010.03584.x

M3 - Journal article

C2 - 21175638

VL - 190

SP - 320

EP - 331

JO - New Phytologist

JF - New Phytologist

SN - 0028-646X

IS - 2

ER -