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Planta (2010) 232:12071218 DOI 10.1007/s00425-010-1239-1
ORIGINAL ARTICLE
The tensor-based model for growth and cell divisions of the root apex. II. Lateral root formation
Joanna Szymanowska-Puka Jerzy Nakielski
Received: 31 March 2010 / Accepted: 19 July 2010 / Published online: 14 August 2010 Springer-Verlag 2010
Abstract In this work, the formation of the virtual lateral root (VLR) is shown. The VLR is formed using the 2D simulation model of growth and cell divisions based on the concept of growth tensor, specied for radish. Growth is generated by the eld of growth rates of an unsteady type (GT eld). Principal directions of growth (PDGs) are assumed to dene the orientation of cell divisions. Temporal sequences of the VLR formation are a result of an application of the GT eld to the polygon meshwork representing cell pattern of already initiated primordium. The computer-generated lateral root (LR) develops realistically, and its cell pattern is vivid and similar to that observed in anatomical sections. The real and virtual LRs show similar cellular organization, both originate from a small group of cells situated in two-cell layers of the pericycle and both layers are engaged in the LR development. The LR formation seems to be controlled at the tensor level and individual cells presumably detect PDGs and obey them in the course of the cell divisions. PDGs are postulated to affect the cellular organization of the LR. Using the method of computer simulations, cellular aspects of the LR morphogenesis are discussed.
Keywords Growth tensor modeling Lateral root
formation Principal directions of growth Radish Virtual
primordium
AbbreviationsGT Growth tensorIL Inner layerOL Outer layerLR Lateral rootVLR Virtual lateral rootQC Quiescent centerPDGs Principal directions of growthRERGl Relative elemental rate of linear growth
R-NCS Root-natural coordinate system 2D Two dimensional
Electronic supplementary material The online version of this article (doi:http://dx.doi.org/10.1007/s00425-010-1239-1
Web End =10.1007/s00425-010-1239-1 ) contains supplementary material, which is available to authorized users.
J. Szymanowska-Puka (&) J. Nakielski
Department of Biophysics and Plant Morphogenesis, University of Silesia, Katowice, Polande-mail: [email protected]
J. Nakielskie-mail: [email protected]
Introduction
Lateral roots (LRs) develop above the zone of differentiation (Fahn 1990) from a subset of pericycle cells situated at the periphery of the stele (or endodermis in ferns), deeply inside the parent root (Malamy and Benfey 1997). In Arabidopsis thaliana, they are...