Lateral root initiation by asymmetrical transverse divisions of pericycle cells in four plant species:Raphanus sativus, Helianthus annuus, Zea mays, andDaucus carota

PROTOPLASMA ◽  
1995 ◽  
Vol 188 (1-2) ◽  
pp. 49-58 ◽  
Author(s):  
P. J. Casero ◽  
Ilda Casimiro ◽  
P. G. Lloret
Development ◽  
1995 ◽  
Vol 121 (10) ◽  
pp. 3303-3310 ◽  
Author(s):  
M.J. Laskowski ◽  
M.E. Williams ◽  
H.C. Nusbaum ◽  
I.M. Sussex

In both radish and Arabidopsis, lateral root initiation involves a series of rapid divisions in pericycle cells located on the xylem radius of the root. In Arabidopsis, the number of pericycle cells that divide to form a primordium was estimated to be about 11. To determine the stage at which primordia are able to function as root meristems, primordia of different stages were excised and cultured without added hormones. Under these conditions, primordia that consist of 2 cell layers fail to develop while primordia that consist of at least 3–5 cell layers develop as lateral roots. We hypothesize that meristem formation is a two-step process involving an initial period during which a population of rapidly dividing, approximately isodiametric cells that constitutes the primordium is formed, and a subsequent stage during which meristem organization takes place within the primordium.


PROTOPLASMA ◽  
1993 ◽  
Vol 176 (3-4) ◽  
pp. 138-144 ◽  
Author(s):  
P. J. Casero ◽  
I. Casimiro ◽  
L. Rodr�guez-Gallardo ◽  
G. Mart�n-Partido ◽  
P. G. Lloret

2010 ◽  
Vol 89 (2-3) ◽  
pp. 236-241 ◽  
Author(s):  
Yan Liu ◽  
Inga von Behrens ◽  
Nils Muthreich ◽  
Wolfgang Schütz ◽  
Alfred Nordheim ◽  
...  

2019 ◽  
Vol 116 (17) ◽  
pp. 8597-8602 ◽  
Author(s):  
Priya Ramakrishna ◽  
Paola Ruiz Duarte ◽  
Graham A. Rance ◽  
Martin Schubert ◽  
Vera Vordermaier ◽  
...  

In plants, postembryonic formation of new organs helps shape the adult organism. This requires the tight regulation of when and where a new organ is formed and a coordination of the underlying cell divisions. To build a root system, new lateral roots are continuously developing, and this process requires the tight coordination of asymmetric cell division in adjacent pericycle cells. We identified EXPANSIN A1 (EXPA1) as a cell wall modifying enzyme controlling the divisions marking lateral root initiation. Loss ofEXPA1leads to defects in the first asymmetric pericycle cell divisions and the radial swelling of the pericycle during auxin-driven lateral root formation. We conclude that a localized radial expansion of adjacent pericycle cells is required to position the asymmetric cell divisions and generate a core of small daughter cells, which is a prerequisite for lateral root organogenesis.


2012 ◽  
Vol 367 (1595) ◽  
pp. 1525-1533 ◽  
Author(s):  
Leentje Jansen ◽  
Ianto Roberts ◽  
Riet De Rycke ◽  
Tom Beeckman

In Arabidopsis thaliana , lateral-root-forming competence of pericycle cells is associated with their position at the xylem poles and depends on the establishment of protoxylem-localized auxin response maxima. In maize, our histological analyses revealed an interruption of the pericycle at the xylem poles, and confirmed the earlier reported proto-phloem-specific lateral root initiation. Phloem-pole pericycle cells were larger and had thinner cell walls compared with the other pericycle cells, highlighting the heterogeneous character of the maize root pericycle. A maize DR5::RFP marker line demonstrated the presence of auxin response maxima in differentiating xylem cells at the root tip and in cells surrounding the proto-phloem vessels. Chemical inhibition of auxin transport indicated that the establishment of the phloem-localized auxin response maxima is crucial for lateral root formation in maize, because in their absence, random divisions of pericycle and endodermis cells occurred, not resulting in organogenesis. These data hint at an evolutionarily conserved mechanism, in which the establishment of vascular auxin response maxima is required to trigger cells in the flanking outer tissue layer for lateral root initiation. It further indicates that lateral root initiation is not dependent on cellular specification or differentiation of the type of vascular tissue.


2013 ◽  
Vol 25 (4) ◽  
pp. 1304-1313 ◽  
Author(s):  
Eric D. Vincill ◽  
Arielle E. Clarin ◽  
Jennifer N. Molenda ◽  
Edgar P. Spalding

2011 ◽  
Vol 191 (4) ◽  
pp. 970-983 ◽  
Author(s):  
Joseph G. Dubrovsky ◽  
Selene Napsucialy-Mendivil ◽  
Jérme Duclercq ◽  
Yan Cheng ◽  
Svetlana Shishkova ◽  
...  

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