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Iron plaques improve the oxygen supply to root meristems of the freshwater plant, Lobelia dortmanna
Author(s) -
Møller Claus Lindskov,
SandJensen Kaj
Publication year - 2008
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.1469-8137.2008.02506.x
Subject(s) - oxygen , botany , oxygen transport , root cap , meristem , chemistry , horticulture , biology , biophysics , shoot , organic chemistry
Summary• High radial oxygen loss (ROL) from roots of aquatic plants to reduced sediments is thought to deplete the roots of oxygen and restrict the distribution of those species unable to form a barrier to oxygen loss. Metal precipitates with high iron content (Fe‐plaques) frequently form on roots of aquatic plants and could create such a diffusion barrier, thereby diverting a larger proportion of downward oxygen transport to the root meristems. • To investigate whether Fe‐plaques form a barrier to oxygen loss, ROL and internal oxygen concentrations were measured along the length of roots of the freshwater plant Lobelia dortmanna using platinum sleeve electrodes and Clark‐type microelectrodes. • Measurements showed that ROL was indeed lower from roots with Fe‐plaques than roots without plaques and that ROL declined gradually with thicker iron coating on roots. The low ROL was caused by low diffusion coefficients through root walls with Fe‐plaques resulting in higher internal oxygen concentrations in the root lacunae. • By diverting a larger proportion of downward oxygen transport to root meristems in L. dortmanna , the presence of Fe‐plaques should diminish root anoxia and improve survival in reduced sediments.