TY - JOUR
T1 - Root aeration via aerenchymatous phellem
T2 - three-dimensional micro-imaging and radial O2 profiles in Melilotus siculus
AU - Verboven, Pieter
AU - Pedersen, Ole
AU - Herremans, Els
AU - Ho, Quang Tri
AU - Nicolaï, Bart M.
AU - Colmer, Timothy David
AU - Teakle, Natasha
PY - 2012/1
Y1 - 2012/1
N2 - • Internal root aeration enables waterlogging-tolerant species to grow in anoxic soil. Secondary aerenchyma, in the form of aerenchymatous phellem, is of importance to root aeration in some dicotyledonous species. Little is known about this type of aerenchyma in comparison with primary aerenchyma. • Micro-computed tomography was employed to visualize, in three dimensions, the microstructure of the aerenchymatous phellem in roots of Melilotus siculus. Tissue porosity and respiration were also measured for phellem and stelar tissues. A multiscale, three-dimensional, diffusion-respiration model compared the predicted O 2 profiles in roots with those measured using O 2 microelectrodes. • Micro-computed tomography confirmed the measured high porosity of aerenchymatous phellem (44-54%) and the low porosity of stele (2-5%) A network of connected gas spaces existed in the phellem, but not within the stele. O 2 partial pressures were high in the phellem, but fell below the detection limit in the thicker upper part of the stele, consistent with the poorly connected low porosity and high respiratory demand. • The presented model integrates and validates micro-computed tomography with measured radial O 2 profiles for roots with aerenchymatous phellem, confirming the existence of near-anoxic conditions at the centre of the stele in the basal parts of the root, coupled with only hypoxic conditions towards the apex.
AB - • Internal root aeration enables waterlogging-tolerant species to grow in anoxic soil. Secondary aerenchyma, in the form of aerenchymatous phellem, is of importance to root aeration in some dicotyledonous species. Little is known about this type of aerenchyma in comparison with primary aerenchyma. • Micro-computed tomography was employed to visualize, in three dimensions, the microstructure of the aerenchymatous phellem in roots of Melilotus siculus. Tissue porosity and respiration were also measured for phellem and stelar tissues. A multiscale, three-dimensional, diffusion-respiration model compared the predicted O 2 profiles in roots with those measured using O 2 microelectrodes. • Micro-computed tomography confirmed the measured high porosity of aerenchymatous phellem (44-54%) and the low porosity of stele (2-5%) A network of connected gas spaces existed in the phellem, but not within the stele. O 2 partial pressures were high in the phellem, but fell below the detection limit in the thicker upper part of the stele, consistent with the poorly connected low porosity and high respiratory demand. • The presented model integrates and validates micro-computed tomography with measured radial O 2 profiles for roots with aerenchymatous phellem, confirming the existence of near-anoxic conditions at the centre of the stele in the basal parts of the root, coupled with only hypoxic conditions towards the apex.
U2 - 10.1111/j.1469-8137.2011.03934.x
DO - 10.1111/j.1469-8137.2011.03934.x
M3 - Journal article
C2 - 22029709
SN - 0028-646X
VL - 193
SP - 420
EP - 431
JO - New Phytologist
JF - New Phytologist
IS - 2
ER -