Morphological and Histochemical Studies of Primary Root Meristem of Rauwolfia vomitoria

1965 ◽  
Vol 126 (3) ◽  
pp. 204-208 ◽  
Author(s):  
Abdul J. Mia ◽  
Suman M. Pathak
Development ◽  
1999 ◽  
Vol 126 (7) ◽  
pp. 1387-1395 ◽  
Author(s):  
T. Hamann ◽  
U. Mayer ◽  
G. Jurgens

In Arabidopsis embryogenesis, the primary root meristem originates from descendants of both the apical and the basal daughter cell of the zygote. We have isolated a mutant of a new gene named BODENLOS (BDL) in which the primary root meristem is not formed whereas post-embryonic roots develop and bdl seedlings give rise to fertile adult plants. Some bdl seedlings lacked not only the root but also the hypocotyl, thus resembling monopteros (mp) seedlings. In addition, bdl seedlings were insensitive to the auxin analogue 2,4-D, as determined by comparison with auxin resistant1 (axr1) seedlings. bdl embryos deviated from normal development as early as the two-cell stage at which the apical daughter cell of the zygote had divided horizontally instead of vertically. Subsequently, the uppermost derivative of the basal daughter cell, which is normally destined to become the hypophysis, divided abnormally and failed to generate the quiescent centre of the root meristem and the central root cap. We also analysed double mutants. bdl mp embryos closely resembled the two single mutants, bdl and mp, at early stages, while bdl mp seedlings essentially consisted of hypocotyl but did form primary leaves. bdl axr1 embryos approached the mp phenotype at later stages, and bdl axr1 seedlings resembled mp seedlings. Our results suggest that BDL is involved in auxin-mediated processes of apical-basal patterning in the Arabidopsis embryo.


Plant Direct ◽  
2019 ◽  
Vol 3 (2) ◽  
pp. e00116 ◽  
Author(s):  
Mouli Ghosh Dastidar ◽  
Andrea Scarpa ◽  
Ira Mägele ◽  
Paola Ruiz-Duarte ◽  
Patrick von Born ◽  
...  

Development ◽  
1995 ◽  
Vol 121 (1) ◽  
pp. 53-62 ◽  
Author(s):  
B. Scheres ◽  
L. Di Laurenzio ◽  
V. Willemsen ◽  
M. T. Hauser ◽  
K. Janmaat ◽  
...  

The primary root of Arabidopsis thaliana has a remarkably uniform cellular organisation. The fixed radial pattern of cell types in the mature root arises from proliferative divisions within the root meristem. The root meristem, in turn, is laid down during embryogenesis. We have analysed six mutations causing alterations in the radial organisation of the root. Embryonic phenotypes resulting from wooden leg, gollum, pinocchio, scarecrow, shortroot and fass mutations are described. While mutations in the fass gene affect morphogenesis of all cells, the five other mutations cause alterations in specific layers. Wooden leg and gollum mutations interfere with the proper organisation of the vascular tissue. Shortroot, scarecrow and pinocchio affect the endodermis and cortex. The layer- specific phenotypes caused by all five mutations are also apparent in the hypocotyl. All these phenotypes originate from defects in the radial organisation of the embryonic axis. Secondary roots, which are formed post-embryonically, also display layer-specific phenotypes.


2010 ◽  
Vol 64 (5) ◽  
pp. 764-774 ◽  
Author(s):  
Hanma Zhang ◽  
Woong Han ◽  
Ive De Smet ◽  
Peter Talboys ◽  
Rakesh Loya ◽  
...  

2009 ◽  
Vol 59 (3) ◽  
pp. 426-436 ◽  
Author(s):  
Carole L. Thomas ◽  
Dominik Schmidt ◽  
Emmanuelle M. Bayer ◽  
Rene Dreos ◽  
Andrew J. Maule

2019 ◽  
Vol 71 (3) ◽  
pp. 934-950 ◽  
Author(s):  
Carlos Hernán Barrera-Rojas ◽  
Gabriel Henrique Braga Rocha ◽  
Laura Polverari ◽  
Diego Armando Pinheiro Brito ◽  
Diego Silva Batista ◽  
...  

Abstract Root growth is modulated by different factors, including phytohormones, transcription factors, and microRNAs (miRNAs). MicroRNA156 and its targets, the SQUAMOSA PROMOTER BINDING PROTEIN-LIKE (SPL) genes, define an age-dependent pathway that controls several developmental processes, including lateral root emergence. However, it remains unclear whether miR156-regulated SPLs control root meristem activity and root-derived de novo shoot regeneration. Here, we show that MIR156 and SPL genes have opposing expression patterns during the progression of primary root (PR) growth in Arabidopsis, suggesting that age cues may modulate root development. Plants with high miR156 levels display reduced meristem size, resulting in shorter primary root (PRs). Conversely, plants with reduced miR156 levels show higher meristem activity. Importantly, loss of function of SPL10 decreases meristem activity, while SPL10 de-repression increases it. Meristem activity is regulated by SPL10 probably through the reduction of cytokinin responses, via the modulation of type-B ARABIDOPSIS RESPONSE REGULATOR1(ARR1) expression. We also show that SPL10 de-repression in the PRs abolishes de novo shoot regenerative capacity by attenuating cytokinin responses. Our results reveal a cooperative regulation of root meristem activity and root-derived de novo shoot regeneration by integrating age cues with cytokinin responses via miR156-targeted SPL10.


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