Recommend Plant Signaling & Behavior (PS&B) to your librarian for 2008. Download form here.

Sign up for Table of Contents Alerts!

PS&B is the official journal of the Society for Plant Neurobiology. Full membership ($60 annually) and student membership ($30 annually) include online access to the journal. Click here to join.

Email this page

Print this page

Article Addendum

Outstanding Lobelia dortmanna in iron armour

Kaj Sand-Jensen, Claus Lindskov Møller and Ane Løvendahl Raun

Purchase article for $19

Subscribe to this journal for $79/year

Lobelia dortmanna leads a group of small, highly-valued rosette species that grow on coarse, nutrient-poor soils in temperate softwater lakes. They acquire most CO₂ for photosynthesis by root uptake and efficient gas transport in large air channels to the leaves. Lobelia is the only species that releases virtually all photosynthetic oxygen from the roots and generates profound day-night changes in oxygen and CO₂ in the sediment pore-water. While oxygen release from roots stimulates decomposition and supports VA-mycorrhiza fungi, the ready gas exchange presents a risk of insufficient oxygen supply to the distal root meristems as sediments accumulate organic matter from lake pollution. So the plant with the greatest oxygen release from roots is also the most sensitive to oxygen depletion in sediments and it dies or losses anchorage by shortening the roots from 10 to 2 cm at even modest contents (2.4%) of degradable organic matter. Coatings of oxidized iron on roots in organically enriched sediments reduce radial oxygen loss and, thereby, increase internal concentrations and supply of oxygen to root tips. Oxidized iron is also a redox buffers which may prevent the ingress of sulfides and other reduced toxic solutes during nights. Controlled experiments are under way to test if iron enrichment can help survival of rosette species threatened by lake pollution or whether removal of organic surface sediments is required.

Addendum to: Møller CL, Sand-Jensen K. Iron plaques improve the oxygen supply to root meristems of the freshwater plant, Lobelia dortmanna. New Phytol 2008; In press.

Authors

Kaj Sand-Jensen

Freshwater Biological Laboratory; Biological Institute; University of Copenhagen; Hillerød, Denmark

Claus Lindskov Møller

Freshwater Biological Laboratory; Biological Institute; University of Copenhagen; Hillerød, Denmark

Ane Løvendahl Raun

Freshwater Biological Laboratory; Biological Institute; University of Copenhagen; Hillerød, Denmark

Purchase article for $19

Subscribe to this journal for $79/year