Root Apical Meristems

Ji‐Young Lee, Duke University, Durham, North Carolina, USA
Philip N Benfey, Duke University, Durham, North Carolina, USA

Published online: April 2007

DOI: 10.1002/9780470015902.a0020121

Root apical meristems are populations of cells at the root tip that divide and form all the tissues of the root. The fate of divided cells is determined by positional signals. The iterative process of cell division, elongation and differentiation promotes root growth. An important aspect of growth is balancing the rate of cell division and differentiation, which is regulated by the quiescent centre.

Keywords: root; apical meristem; plant growth factors; positional signals

Figure 1. The atlas of the root tip of Arabidopsis thaliana as a representative root meristem. The organization of the root apical meristem is enlarged and major tissues are colour-coded. The first T-shape arrangement of divided cells (marked in bold lines) indicates the formative cell division.
Figure 2. Gene regulatory pathways for formative cell divisions and tissue specification. Gene regulatory pathways of (a) epidermis (b) endodermis and cortex (c) xylem and phloem and (d) QC are shown. , positive regulation; intcal , negative regulation; protein movement.
Figure 3. Regulation of root apical meristem organization by growth factors. (a) Stem cell maintenance by auxin and the gravitropic response by auxin and cytokinin. Green and blue lines respectively indicate the flow of auxin and cytokinin. The relative amounts are indicated by the line thickness. (b) The cytokinin regulation pathway and stele development.
close
 References
    Aida M, Beis D, Heidstra R et al. (2004) The PLETHORA genes mediate patterning of the Arabidopsis root stem cell niche. Cell 119: 109–120.
    Blilou I, Xu J, Wildwater M et al. (2005) The PIN auxin efflux facilitator network controls growth and patterning in Arabidopsis roots. Nature 433: 39–44.
    Bonke M, Thitamadee S, Mahonen AP, Hauser MT and Helariutta Y (2003) APL regulates vascular tissue identity in Arabidopsis. Nature 426: 181–186.
    Clowes FAL (1961) Duration of the mitotic cycle in a meristem. Journal of Experimental Botany 12: 283–293.
    Clowes FAL (1981) The difference between open and closed meristems. Annals of Botany 48: 761–767.
    Clowes FAL (2000) Pattern in root meristem development in angiosperms. New Phytologist 146: 83–94.
    Helariutta Y, Fukaki H, Wysocka-Diller J et al. (2000) The SHORT-ROOT gene controls radial patterning of the Arabidopsis root through radial signaling. Cell 101: 555–567.
    Mahonen AP, Bishopp A, Higuchi M et al. (2006) Cytokinin signaling and its inhibitor AHP6 regulate cell fate during vascular development. Science 311: 94–98.
    Motose H, Sugiyama M and Fukuda H (2004) A proteoglycan mediates inductive interaction during plant vascular development. Nature 429: 873–878.
    Schiefelbein J (2003) Cell fate specification in the epidermis: a common patterning mechanism in the root and shoot. Current Opinion in Plant Biology 6: 74–78.
    Wildwater M, Campilho A, Perez-Perez JM et al. (2005) The RETINOBLASTOMA-RELATED gene regulates stem cell maintenance in Arabidopsis roots. Cell 123: 1337–1349.
 Further Reading
    Abas L, Benjamins R, Malenica N et al. (2006) Intracellular trafficking and proteolysis of the Arabidopsis auxin-efflux facilitator PIN2 are involved in root gravitropism. Nature Cell Biology 8: 249–256.
    Birnbaum K, Shasha DE, Wang JY et al. (2003) A gene expression map of the Arabidopsis root. Science 302: 1956–1960.
    Cano-Delgado A, Yin Y, Yu C et al. (2004) BRL1 and BRL3 are novel brassinosteroid receptors that function in vascular differentiation in Arabidopsis. Development 131: 5341–5351.
    Friml J, Wisniewska J, Benkova E, Mendgen K and Palme K (2002) Lateral relocation of auxin efflux regulator PIN3 mediates tropism in Arabidopsis. Nature 415: 806–809.
    Gunning BES, Hughes JE and Hardham AR (1978) Formative and proliferative cell divisions, cell differentiation, and developmental changes in the meristem of Azolla roots. Planta 143: 121–144.
    Kenrick P and Crane PR (1997) The origin and early evolution of plants on land. Nature 389: 33–39.
    Mahonen AP, Bonke M, Kauppinen L et al. (2000) A novel two-component hybrid molecule regulates vascular morphogenesis of the Arabidopsis root. Genes and Development 14: 2938–2943.
    book Steeves TA and Sussex IM (1989) Patterns in Plant Development, 2nd edn. Cambridge, UK: Cambridge University Press.
    Torrey JG and Feldman LJ (1977) The organization and function of the root apex. American Scientist 65: 334–344.
    van den Berg C, Willemsen V, Hendriks G, Weisbeek P and Scheres B (1997) Short-range control of cell differentiation in the Arabidopsis root meristem. Nature 390: 287–289.

Related Sub-Topics:

Genes, Molecules and Cellular Processes | Cell Differentiation and Stem Cells | Roots and Root Systems | Plant Development | Meristems
Contact Editor close
Submit a note to the editor about this article by filling in the form below.

* Required Field

Article Title: Root Apical Meristems
 
How to Cite close
Lee, Ji‐Young, and Benfey, Philip N(Apr 2007) Root Apical Meristems. In: eLS. John Wiley & Sons Ltd, Chichester. http://www.els.net [doi: 10.1002/9780470015902.a0020121]