The Meristem and Quiescent Centre in Cultured Root Apices of the gib-l Mutant of Tomato (Lycopersicon esculentum Mill.)*

Barlow, PW

doi:10.1093/oxfordjournals.aob.a088383

Cited by 42 publications

(34 citation statements)

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“…This indicates that the requirement of GA for CMT ordering is a very early feature of cellular development. In accordance with this, Barlow (1992) reported that cultured root apices of the GA-deficient 9ib-1 mutant of tomato exhibited shorter and wider meristematic cells when compared with wild-type root meristems. Moreover, the cellular organization of the gibberellin-deficient 9ib-l-tomato root apices underwent a profound reconstruction in the region of the quiescent centre, indicating that GAs are involved in the morphogenetic control of root development.…”

Section: Discussionsupporting

confidence: 70%

A role for gibberellic acid in orienting microtubules and regulating cell growth polarity in the maize root cortex

Baluška

Parker

Barlow

1993

Planta

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Abstract. The role of gibberellins and cortical microtubules in determining the polarity of cell growth in the root cortex of maize (Zea mays L.) was examined. Inhibition of gibberellin biosynthesis, either naturally through mutation (d5 mutant) or by means of chemicals such as 2S,3S paclobutrazol, caused thickening of root apices and increased their starch content. Immunofluorescence microscopy of cortical microtubules, coupled with a comparison of cell widhts, lengths and shapes, indicated that the meristem and immediate post-mitotic zone were the targets of gibberellin deficiency. Cortical cells in these regions were impaired in their ability to develop highly ordered transversal arrays of cortical microtubules. Consequently, the cells became wider and shorter. Application of gibberellic acid re-established the arrangements of cortical microtubules and the polarity of cell growth characteristic for roots having normal levels of gibberellins, it also decreased the starch content. These results indicate that gibberellins are morphogenetically active substances, not only in shoots but also in roots of maize.

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Section: Discussionsupporting

confidence: 70%

A role for gibberellic acid in orienting microtubules and regulating cell growth polarity in the maize root cortex

Baluška

Parker

Barlow

1993

Planta

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“…Alternatively, the constant number of dividing cells may occur as a consequence of the inhibited elongation rate of cells in the zone of rapid elongation. Although cell division and elongation can be uncoupled (Haber and Foard, 1964), feedback regulation between the two probably occurs (Barlow, 1993). For cell division, coupling needs to be exerted not only on the duration of the cell cycle but also on the number of cycling cells.…”

Section: Control Of the Number Of Dividing Cellsmentioning

confidence: 99%

“…By contrast, moderate salt stress (Zhong and Lauchli, 1993) and low temperature (Pahlavanian and Silk, 1988) have been shown to decrease strain rates uniformly throughout the elongation zone. Barlow (1993) pointed out that the organization of the root meristem is highly stabilized against somatic mutations and developmental changes. Therefore, truncation of the elongation zone from its basal end may reflect one of a small number of general pathways for regulating root growth.…”

Section: Apical and Basal Portions Of The Zone Of Rapid Elongationmentioning

confidence: 99%

STUNTED PLANT 1, A Gene Required for Expansion in Rapidly Elongating but Not in Dividing Cells and Mediating Root Growth Responses to Applied Cytokinin

Baskin¹,

Cork²,

Williamson³

et al. 1995

Plant Physiol.

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To understand the control of spatial patterns of expansion, we have studied root growth in wild type and in the stunted planf 1 mutant, stpl, of Arabidopsis thaliana. We measured profiles of cell length and calculated the distribution of elongation rate. Slow growth of stpl results both from a failure of dividing cell number to increase and from low elongation rates in the zone of rapid expansion. However, elongation of dividing cells was not greatly affected, and stpl and wild-type callus grew at identical rates.*Thus, rapid cellular expansion differs in mechanism from expansion in dividing cells and is facilitated by the STPl gene. Additionally, there was no difference between stpl and wild-type roots for elongation in response to abscisic acid, auxin, ethylene, or gibberellic acid or for radial expansion in response to ethylene; however, stpl responded to cytokinin much less than wild type. In contrast, both genotypes responded comparably to hormones when explants were cultured; in particular, there was no difference between genotypes in shoot regeneration in response to cytokinin. Thus, effects on root expansion mediated by cytokinin, but not effects mediated by other hormones or effects on other cytokinin-mediated responses, require the STPl locus.How is the expansion of plant organs regulated? In the growing zones of most organs, expansion rate is not a constant quantity; rather, there is a well-defined spatial pattern of expansion rate. Although we have learned a considerable amount about how certain compounds, such as auxin, modify overall expansion rate, we have learned less about the control of spatial patterns of expansion rate. Spatial patterns of expansion rate might reflect underlying profiles of concentration of (or sensitivity to) one or more growth-regulating substances, but, in general, this simple explanation has not been validated. Furthermore, expansion in an organ includes dividing cells. Although "growth by cell expansion" is commonly contrasted with

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“…Além disso, a aplicação de giberelina reduz a taxa de regeneração no controle e no mutante ga4 e a aplicação de paclobutrazol (PBZ) aumenta essa taxa em doses não-letais (EZURA; HARBERD, 1995). Os níveis endógenos de giberelina podem ser parcialmente responsáveis pela lenta taxa de crescimento e proliferação celular no centro quiscente (CQ) de tomateiro (BARLOW, 1992). A análise da aplicação exógena de GA3 e de PBZ mostrou ainda que o CQ do mutante gib-1 (gibberellin deficiente 1) tratado com GA3 assemelha-se ao CQ do controle não tratado e que o CQ do mutante gib-1 não tratado assemelha-se ao CQ do controle tratado com PBZ, formando um grupo com níveis normais de giberelinas e outro com reduzidos níveis deste hormônio (BARLOW et al, 1992).…”

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“…Os níveis endógenos de giberelina podem ser parcialmente responsáveis pela lenta taxa de crescimento e proliferação celular no centro quiscente (CQ) de tomateiro (BARLOW, 1992). A análise da aplicação exógena de GA3 e de PBZ mostrou ainda que o CQ do mutante gib-1 (gibberellin deficiente 1) tratado com GA3 assemelha-se ao CQ do controle não tratado e que o CQ do mutante gib-1 não tratado assemelha-se ao CQ do controle tratado com PBZ, formando um grupo com níveis normais de giberelinas e outro com reduzidos níveis deste hormônio (BARLOW et al, 1992). Em tomateiro, o mutante MT-pro (procera), o qual apresenta resposta constitutiva a giberelina, reduz a formação tanto de gemas caulinares quanto de raízes em explantes cotiledonares, mostrando um possível papel da giberelina na fase de aquisição de competência (LOMBARDI-CRESTANA et al, 2012 GREENBOIM-WAINBERG et al, 2005;JASINSKI et al, 2005).…”

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Competência organogênica in vitro das linhagens MT-Rg1 e MT-pro em tomateiro (Solanum lycopersicum L. cv Micro-Tom)

Azevedo¹

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The Meristem and Quiescent Centre in Cultured Root Apices of the gib-l Mutant of Tomato (Lycopersicon esculentum Mill.)*

Cited by 42 publications

References 0 publications

A role for gibberellic acid in orienting microtubules and regulating cell growth polarity in the maize root cortex

A role for gibberellic acid in orienting microtubules and regulating cell growth polarity in the maize root cortex

STUNTED PLANT 1, A Gene Required for Expansion in Rapidly Elongating but Not in Dividing Cells and Mediating Root Growth Responses to Applied Cytokinin

Competência organogênica in vitro das linhagens MT-Rg1 e MT-pro em tomateiro (Solanum lycopersicum L. cv Micro-Tom)

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