Cell division and regeneration in primary root meristems of Zea mays recovering from cold treatment

Barlow, Peter W.; Rathfelder, Erica L.

doi:10.1016/0098-8472(85)90028-0

Cited by 37 publications

(13 citation statements)

References 23 publications

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“…The changed appearance of the cells shortly before root emergence is probably caused by water uptake; whether it is also accompanied by deposition of additional wall material, particularly at the ends of each cell, was not studied. A somewhat similar obliteration of packet boundaries is found in young roots of Zea exposed to low temperature (Barlow & Rathfelder, 1985).…”

Section: The Origin Of Cell Packets and Estimates Of Cell Cycle Durationsupporting

confidence: 72%

“…These three features of packets -rates, numbers and orientations of divisions -have assisted analyses of both normal root development (the present study) and development that has been perturbed by experimental treatment (e.g. Barlow & Pilet, 1984;Barlow & Rathfelder, 1985). The relative thickness of the partition walls and their positions within the packet make it possible to deduce the sequence of earlier divisions (Risueno et al, 1968;Gavaudan & Chazelas, 1969).…”

Section: Cellular Packets In the Meristem Of Zea Mays 47 Discussionmentioning

confidence: 99%

“…Cells that serve as initials (i.e. those that border the QC) have a longer proliferative future, but they, too, will eventually be displaced from the meristem when they are supplanted by cells from the QC; this occurs both spontaneously and as a result of environmental perturbation (Barlow & Rathfelder, 1985). Where successive rounds of division in the cortex and stele were followed, no increase was found in the median interdivisional period as the packets approached the proximal margin of the meristem.…”

Section: The Origin Of Cell Packets and Estimates Of Cell Cycle Durationmentioning

confidence: 99%

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CELLULAR PACKETS, CELL DIVISION AND MORPHOGENESIS IN THE PRIMARY ROOT MERISTEM OF ZEA MAYS L.

Barlow

1987

New Phytologist

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SUMMARYDormant meristematic cells of the unemerged radicle contained within the caryopsis oi Zea mays L. are arrested in either the Gj or G^ phase of the mitotic cycle. Following germination and the resumption of root growth, each of these cells divides repeatedly to form multicellular groups, or 'packets'. The thickened cell walls that bound each packet correspond to the walls of the formerly dormant mother cell, while the thinner walls that partition the packet correspond to walls laid down when the successive rounds of division are completed. The relative thickness of these partition walls corresponds to their age, the most recently inserted wall being the thinnest. The packets thus give evidence of not only the number of divisions that have occurred since germination, but also the sequence in which these divisions took place. In addition, the elongation of the packets during root growth allows their displacement away from the root tip into the zone beyond the margin of the meristem to be measured.Using roots fixed at different times during early growth, the kinetics of packet development has been followed in cells occupying different positions within the meristem at the start of root growth. By counting the number of cells in the packets at frequent intervals during root growth, the period between each round of division has been found to be fairly constant, even as the cells are displaced towards the margin of the meristem. Variability in the interdivisional period within a packet is insufficient to cause extensive overlapping of the different rounds of division. Exceptions are found in cortical and stelar cells around the quiescent centre, where the more distal cells in a packet often divide at up to half the rate of the more proximal cells. This is evidence of a steep gradient of cell extension rate near the quiescent centre; such a gradient does not occur along packets elsewhere in the meristem. In the quiescent centre itself, cells of its cortical portion divide more rapidly than cells of its stelar portion.Cells in the cortex (but not in the stele) often divide unequally at their first transverse division; the distal (apical) daughter is usually the longer of the two daughter cells. Asymmetric transverse division also occurs in some cells during the next rounds of division. The more rapid entry into mitosis of the longer daughter cell results in packets with particular sequences of division. Asymmetric, longitudinal (periclinal) divisions also occur in the cortex, the inner daughter cell being wider than the outer daughter cell. These periclinal divisions occur in the distal portion of the cortex near its inner and outer borders with the stele and epidermis, respectively. At the start of root growth, periclinal divisions commence sooner in the outer cortex than in the inner cortex but do not persist, and the number of cell files across the width of the cortex declines. A concurrent loss of files also occurs in the stele. The first two rounds of penchnal divisions in the innermost file of the cortex show...

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Section: The Origin Of Cell Packets and Estimates Of Cell Cycle Durationsupporting

confidence: 72%

Section: Cellular Packets In the Meristem Of Zea Mays 47 Discussionmentioning

confidence: 99%

Section: The Origin Of Cell Packets and Estimates Of Cell Cycle Durationmentioning

confidence: 99%

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CELLULAR PACKETS, CELL DIVISION AND MORPHOGENESIS IN THE PRIMARY ROOT MERISTEM OF ZEA MAYS L.

Barlow

1987

New Phytologist

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“…Considering the potential functions of plant MAPK cascades (Hirt 1997;Mizoguchi et al 1997;Jonak et al 1999), the maize primary root provides a unique system in which to investigate the physiological role of the ZmMEK1-containing MAPK cascade. Meristematic, elongating and dierentiating cell populations are spatially separated along the longitudinal axis of the maize primary root (Feldman 1994), and these processes can be regulated in the intact organ by low-temperature exposure (Clowes and Stewart 1967;Barlow and Rathfelder 1985;Barlow and Adam 1989;BalusÏ ka and Barlow 1993;Kerk and Feldman 1994;BalusÏ ka et al 1995). We are interested in the molecular events governing cell cycle transitions in the maize primary root and its coordination with environmental conditions (Hardin and Wolniak 1998;Hsieh and Wolniak 1998).…”

Section: Introductionmentioning

confidence: 99%

Expression of the mitogen-activated protein kinase kinase ZmMEK1 in the primary root of maize

Hardin

Wolniak

2001

Planta

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We have analyzed changes in the distribution and abundance of a mitogen-activated protein kinase kinase (MAPKK) enzyme (EC 2.7.1.37) known as ZmMEK1. in root apices of Zea mays L. under normal growth conditions, and after treatments that alter patterns of proliferation, as a means to assess the potential physiological role of the MAP kinase cascade in growth and development. The ZmMEK1 protein is most abundant within immature tissues such as the roots and leaves of seedlings, and is nearly undetectable in mature leaf tissue. Along the longitudinal axis of growing roots, ZmMEK1 mRNA and protein are abundant throughout the apical 12 mm. Two anti-ZmMEK1 antibody-reactive proteins can be resolved within the apical 4 mm of the root, spatially coinciding with the meristem and distal elongation zone. Phosphatase treatments suggest that both immunoreactive bands are forms of ZmMEK1 that differ in their state of phosphorylation. Expression of ZmMEK1, histone H4 and cyclin-dependent protein kinase (CDK) in roots after 7 days of exposure to low temperature and during a 48-hour recovery period was monitored during the coincident alterations in growth. Levels of ZmMEK1 mRNA and protein within these roots were indistinguishable from those of control roots. However, a slower-migrating form of ZmMEK1 temporally coincided with the observed increase in CDK levels during the transition into proliferative activity. We demonstrate that the ZmMEK1 MAPK activator is expressed and is differentially phosphorylated within the root meristem and distal elongation zone. We suggest that post-translational modifications of the protein regulate the function of ZmMEK1 within the root. Changes in ZmMEK1 phosphorylation state correlate with changes in proliferation in the root apex.

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“…If roots bend in response to tropic study because it can be clearly traced to its origin as stimuli, the tip distal to the developing curve remains the boundary layer between cells on the acroscopic straight and is pushed smoothly sideways into its face of the quiescent centre and the root-cap initials new direction despite the opposing force from the (e.g. see Barlow & Rathfelder, 1985). In an early surrounding soil.…”

Section: Introduction Rr^ - T • I -I J I -Imentioning

confidence: 99%

The epidermal surface of the maize root tip

Abeysekera

McCully

1993

New Phytologist

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SUMMARYThe surface of the meristematic epidermis of maize roots is tri-partite. A helicoidal primary wall follows the contours of the tops of the columnar epidermal cells and is continuous with their buttressed anticlinal walls. Two overlying layers form a smooth covering over the root which obscures the cell outlines. This compound surface is similar architecturally to outer epidermal surfaces of shoots. The two outer layers are distinct structurally and in their staining properties from the wall and are together here referred to as the pellicle. Both pellicle layers are fibrillar but not helicoidal. Their development begins in the boundary between the cap and the root proper and they reach maximum thickness over the meristematic region. The outer layer then disintegrates and is absent from the elongation zone. The inner layer thins irregularly as the columnar cells elongate to their final tabular form and usually persists only over the groove above anticlinal walls and at the base of root hairs. The cell wall thins to about half its maximum thickness during this elongation. Emerging root hairs broach the pellicle and the original primary wall. Remnants of both these layers form a short, tight collar at the base of each hair; this collar adheres to the primary wall of the hair which is continuous with a new, thin wall which is formed interior to the original outer wall of the parent cell.Failure to recognize the complex structure and transitory nature of the epidermal pellicle has led to confusion in the literature regarding the nature of root-surface and rhizosphere mucilaginous components and their origin. These interpretations are compared with those arising from this study.

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Cell division and regeneration in primary root meristems of Zea mays recovering from cold treatment

Cited by 37 publications

References 23 publications

CELLULAR PACKETS, CELL DIVISION AND MORPHOGENESIS IN THE PRIMARY ROOT MERISTEM OF ZEA MAYS L.

CELLULAR PACKETS, CELL DIVISION AND MORPHOGENESIS IN THE PRIMARY ROOT MERISTEM OF ZEA MAYS L.

Expression of the mitogen-activated protein kinase kinase ZmMEK1 in the primary root of maize

The epidermal surface of the maize root tip

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