© 2007 Heron Publishing—Victoria, Canada
Pattern of secondary thickening in a Quercus cerris root system
Antonino Di Iorio (1, 3), Bruno Lasserre (2), Gabriella S. Scippa (2) and Donato Chiatante (1)
1. Department of Chemical and Environmental Sciences, University of Insubria, Via Valleggio 11, 22100 Como, Italy / 2. Department of Environment and Territory Sciences and Technologies, University of Molise, Via Mazzini 8, 86170 Isernia, Italy / 3. Corresponding author (antonino.diiorio@uninsubria.it) / Received March 1, 2006; accepted May 16, 2006; published online December 1, 2006
Summary
We investigated changes in the pattern of secondary thickening along first-order lateral roots of Quercus cerris L. (turkey oak), a dominant species in the mixed forests of the Mediterranean basin. The eccentricity of radial growth was
analyzed relative to the gravimetric center of the root, a measure that is unaffected by year-to-year variation in growth
ring width. In cross sections collected at the taproot–lateral root junction, radial growth was greatest on the upper side
of the root. However, at a distance of 10 cm from the taproot–lateral root junction, radial growth was greatest on the lower
side of the root. With increasing distance from the taproot–lateral root junction, the direction of the vector of radial growth
eccentricity changed in an anti-clockwise direction as viewed from the distal face of the root cross section. These findings
applied to all lateral roots of the studied root system, irrespective of root size, depth of origin and axial growth direction.
Ring analysis indicated that most first-order lateral roots grew to a length of 1 m in the first year.
Keywords:
downward growth, eccentric growth, gravimetric and geometric center, three-dimensional analysis, woody root eccentricity.
