meristem

 

  • The shoot apical meristem consists of four distinct cell groups: • Stem cells • The immediate daughter cells of the stem cells • A subjacent organizing center • Founder cells
    for organ initiation in surrounding regions These four distinct zones are maintained by a complex signalling pathway.

  • [28][29] Secondary meristems There are two types of secondary meristems, these are also called the lateral meristems because they surround the established stem of a plant
    and cause it to grow laterally (i.e., larger in diameter).

  • Division of meristematic cells provides new cells for expansion and differentiation of tissues and the initiation of new organs, providing the basic structure of the plant
    body.

  • Differentiated plant cells generally cannot divide or produce cells of a different type.

  • Rice also contains another genetic system distinct from , that is involved in regulating stem cell number.

  • [19] Root apical meristem and tissue patterns become established in the embryo in the case of the primary root, and in the new lateral root primordium in the case of secondary
    roots.

  • This allows a constant supply of new cells in the meristem required for continuous root growth.

  • This process known as mericloning, has been shown to reduce or eliminate viruses present in the parent plant in multiple species of plants.

  • Evidence suggests that the QC maintains the surrounding stem cells by preventing their differentiation, via signal(s) that are yet to be discovered.

  • It harbors two pools of stem cells around an organizing center called the quiescent center (QC) cells and together produces most of the cells in an adult root.

  • One of these indications might be the loss of apical dominance and the release of otherwise dormant cells to develop as auxiliary shoot meristems, in some species in axils
    of primordia as close as two or three away from the apical dome.

  • Often several branches will exhibit this behavior after the removal of apical meristem, leading to a bushy growth.

  • [21] Diversity in meristem architectures[edit] The SAM contains a population of stem cells that also produce the lateral meristems while the stem elongates.

  • [citation needed] Cells of the inner or outer cortex in the so-called “window of nodulation” just behind the developing root tip are induced to divide.

  • Cells at the shoot apical meristem summit serve as stem cells to the surrounding peripheral region, where they proliferate rapidly and are incorporated into differentiating
    leaf or flower primordia.

  • Cells of this zone have a stem cell function and are essential for meristem maintenance.

  • Medullary tissue There are two types of apical meristem tissue: shoot apical meristem (SAM), which gives rise to organs like the leaves and flowers, and root apical meristem
    (RAM), which provides the meristematic cells for future root growth.

  • [25] Also, it has been proposed that the mechanism of KNOX gene action is conserved across all vascular plants, because there is a tight correlation between KNOX expression
    and a complex leaf morphology.

  • [26] Primary meristems Apical meristems may differentiate into three kinds of primary meristem: • Protoderm: lies around the outside of the stem and develops into the epidermis.

  • All plant organs arise ultimately from cell divisions in the apical meristems, followed by cell expansion and differentiation.

  • Primary growth gives rise to the apical part of many plants.

  • [citation needed] There are three types of meristematic tissues: apical (at the tips), intercalary or basal (in the middle), and lateral (at the sides also known as cambium).

  • [10] acts to promote cellular differentiation by repressing WUS activity outside of the central zone containing the stem cells.

  • [citation needed] Recent investigations into apical dominance and the control of branching have revealed a new plant hormone family termed strigolactones.

  • It turns out that the mechanism of regulation of the stem cell number might be evolutionarily conserved.

  • [9] Another important gene in plant meristem maintenance is WUSCHEL (shortened to WUS), which is a target of CLV signaling in addition to positively regulating CLV, thus forming
    a feedback loop.

  • This process involves a leaf-vascular tissue located LRR receptor kinases , peptide signalling, and interaction, similar to that seen in the system.

  • Indeterminate growth of meristems Though each plant grows according to a certain set of rules, each new root and shoot meristem can go on growing for as long as it is alive.

  • In many plants, meristematic growth is potentially indeterminate, making the overall shape of the plant not determinate in advance.

  • Their growth is limited to the flower with a particular size and form.

  • In Arabidopsis thaliana, 3 interacting CLAVATA genes are required to regulate the size of the stem cell reservoir in the shoot apical meristem by controlling the rate of cell
    division.

  • The corpus and tunica play a critical part of the plant physical appearance as all plant cells are formed from the meristems.

  • As a result, the plant will have one clearly defined main trunk.

  • In that sense, the meristematic cells are frequently compared to the stem cells in animals, which have an analogous behavior and function.

  • Intercalary meristems are capable of cell division, and they allow for rapid growth and regrowth of many monocots.

  • At the meristem summit, there is a small group of slowly dividing cells, which is commonly called the central zone.

  • The primary meristems in turn produce the two secondary meristem types.

  • In contrast, nodules on pea, clovers, and Medicago truncatula are indeterminate, to maintain (at least for some time) an active meristem that yields new cells for Rhizobium
    infection.

  • The mechanism of apical dominance is based on auxins, types of plant growth regulators.

  • Primary growth leads to lengthening of the plant body and organ formation.

  • Thus, soybean (or bean and Lotus japonicus) produce determinate nodules (spherical), with a branched vascular system surrounding the central infected zone.

  • Recent findings indicate that QC can also act as a reservoir of stem cells to replenish whatever is lost or damaged.

 

Works Cited

[‘1. Galun, Esra (2007). Plant Patterning: Structural and Molecular Genetic Aspects. World Scientific Publishing Company. p. 333. ISBN 9789812704085
2. ^ Jump up to:a b c d Fletcher, J. C. (2002). “Shoot and Floral Meristem Maintenance in Arabidopsis”.
Annu. Rev. Plant Biol. 53: 45–66. doi:10.1146/annurev.arplant.53.092701.143332. PMID 12221985.
3. ^ Clark SE, Williams RW, Meyerowitz E (1997). “The CLAVATA1 gene encodes a putative receptor kinase that controls shoot and floral meristem size in
Arabidopsis”. Cell. 89 (4): 575–85. doi:10.1016/S0092-8674(00)80239-1. PMID 9160749. S2CID 15360609.
4. ^ Jeong S, Trotochaud AE, Clark S (1999). “The Arabidopsis CLAVATA2 gene encodes a receptor-like protein required for the stability of the CLAVATA1
receptor-like kinase”. Plant Cell. 11 (10): 1925–33. doi:10.1105/tpc.11.10.1925. PMC 144110. PMID 10521522.
5. ^ Fletcher JC, Brand U, Running MP, Simon R, Meyerowitz EM (1999). “Signaling of cell fate decisions by CLAVATA3 in Arabidopsis shoot
meristems”. Science. 283 (5409): 1911–14. Bibcode:1999Sci…283.1911F. doi:10.1126/science.283.5409.1911. PMID 10082464.
6. ^ Jump up to:a b J. Mark Cock; Sheila McCormick (July 2001). “A Large Family of Genes That Share Homology with CLAVATA3”.
Plant Physiology. 126 (3): 939–942. doi:10.1104/pp.126.3.939. PMC 1540125. PMID 11457943.
7. ^ Jump up to:a b Karsten Oelkers, Nicolas Goffard, Georg F Weiller, Peter M Gresshoff, Ulrike Mathesius and Tancred Frickey (3 January 2008). “Bioinformatic
Analysis of the CLE signalling peptide family”. BMC Plant Biology. 8: 1. doi:10.1186/1471-2229-8-1. PMC 2254619. PMID 18171480.
8. ^ Valster, A. H.; et al. (2000). “Plant GTPases: the Rhos in bloom”. Trends in Cell Biology. 10 (4): 141–146. doi:10.1016/s0962-8924(00)01728-1.
PMID 10740268.
9. ^ Jump up to:a b Stone, J. M.; et al. (1998). “Control of meristem development by CLAVATA1 receptor kinase and kinase-associated protein phosphatase interactions”. Plant Physiology. 117 (4): 1217–1225. doi:10.1104/pp.117.4.1217.
PMC 34886. PMID 9701578.
10. ^ Jump up to:a b Mayer, K. F. X; et al. (1998). “Role of WUSCHEL in Regulating Stem Cell Fate in the Arabidopsis Shoot Meristem”. Cell. 95 (6): 805–815. doi:10.1016/S0092-8674(00)81703-1. PMID 9865698. S2CID 18995751.
11. ^
Sheen, Jen; Hwang, Ildoo (September 2001). “Two-component circuitry in Arabidopsis cytokinin signal transduction”. Nature. 413 (6854): 383–389. Bibcode:2001Natur.413..383H. doi:10.1038/35096500. ISSN 1476-4687. PMID 11574878. S2CID 4418158.
12. ^
Lohmann, Jan U.; Kieber, Joseph J.; Demar, Monika; Andreas Kehle; Stehling, Sandra; Busch, Wolfgang; To, Jennifer P. C.; Leibfried, Andrea (December 2005). “WUSCHEL controls meristem function by direct regulation of cytokinin-inducible response regulators”.
Nature. 438 (7071): 1172–1175. Bibcode:2005Natur.438.1172L. doi:10.1038/nature04270. ISSN 1476-4687. PMID 16372013. S2CID 2401801.
13. ^ Kieber, Joseph J.; Ecker, Joseph R.; Alonso, Jose M.; Schaller, G. Eric; Mason, Michael G.; Deruère, Jean; Ferreira,
Fernando J.; Haberer, Georg; To, Jennifer P. C. (2004-03-01). “Type-A Arabidopsis Response Regulators Are Partially Redundant Negative Regulators of Cytokinin Signaling”. The Plant Cell. 16 (3): 658–671. doi:10.1105/tpc.018978. ISSN 1040-4651. PMC
385279. PMID 14973166.
14. ^ Jurgens, G.; Berger, J.; Mayer, K. F.; Laux, T. (1996-01-01). “The WUSCHEL gene is required for shoot and floral meristem integrity in Arabidopsis”. Development. 122 (1): 87–96. doi:10.1242/dev.122.1.87. ISSN 0950-1991.
PMID 8565856.
15. ^ Jackson, David; Simon, Rüdiger; Je, Byoung Il; Somssich, Marc (2016-09-15). “CLAVATA-WUSCHEL signaling in the shoot meristem”. Development. 143 (18): 3238–3248. doi:10.1242/dev.133645. ISSN 0950-1991. PMID 27624829.
16. ^ Gordon,
S. P.; Chickarmane, V. S.; Ohno, C.; Meyerowitz, E. M. (2009-08-26). “Multiple feedback loops through cytokinin signaling control stem cell number within the Arabidopsis shoot meristem”. Proceedings of the National Academy of Sciences. 106 (38): 16529–16534.
Bibcode:2009PNAS..10616529G. doi:10.1073/pnas.0908122106. ISSN 0027-8424. PMC 2752578. PMID 19717465.
17. ^ Sebastian, Jose; Lee, Ji-Young (2013). “Root Apical Meristems”. eLS. doi:10.1002/9780470015902.a0020121.pub2. ISBN 978-0470016176.
18. ^
Bennett, Tom; Scheres, Ben (2010). “Root development-two meristems for the price of one?”. Current Topics in Developmental Biology. 91: 67–102. doi:10.1016/S0070-2153(10)91003-X. ISBN 9780123809100. PMID 20705179.
19. ^ Heidstra, Renze; Sabatini,
Sabrina (2014). “Plant and animal stem cells: similar yet different”. Nature Reviews Molecular Cell Biology. 15 (5): 301–12. doi:10.1038/nrm3790. PMID 24755933. S2CID 34386672.
20. ^ Jump up to:a b c Lohmann, J. U. et al. (2001) A Molecular Link
between Stem Cell Regulation and Floral Patterning in Arabidopsis Cell 105: 793-803
21. ^ “Branching out: new class of plant hormones inhibits branch formation”. Nature. 455 (7210). 2008-09-11. Retrieved 2009-04-30.
22. ^ Taguchi-Shiobara; Yuan,
Z; Hake, S; Jackson, D; et al. (2001). “The fasciated ear2 gene encodes a leucine-rich repeat receptor-like protein that regulates shoot meristem proliferation in maize”. Genes & Development. 15 (20): 2755–2766. doi:10.1101/gad.208501. PMC 312812.
PMID 11641280.
23. ^ Jump up to:a b Suzaki T.; Toriba, T; Fujimoto, M; Tsutsumi, N; Kitano, H; Hirano, HY (2006). “Conservation and Diversification of Meristem Maintenance Mechanism in Oryza sativa: Function of the FLORAL ORGAN NUMBER2 Gene”. Plant
and Cell Physiol. 47 (12): 1591–1602. doi:10.1093/pcp/pcl025. PMID 17056620.
24. ^ Golz J.F.; Keck, Emma J.; Hudson, Andrew (2002). “Spontaneous Mutations in KNOX Genes Give Rise to a Novel Floral Structure in Antirrhinum”. Curr. Biol. 12 (7): 515–522.
doi:10.1016/S0960-9822(02)00721-2. PMID 11937019. S2CID 14469173.
25. ^ Hay and Tsiantis; Tsiantis, M (2006). “The genetic basis for differences in leaf form between Arabidopsis thaliana and its wild relative Cardamine hirsuta”. Nat. Genet. 38 (8):
942–947. doi:10.1038/ng1835. PMID 16823378. S2CID 5775104.
26. ^ Bharathan G, et al. (2002). “Homologies in Leaf Form Inferred from KNOXI Gene Expression During Development”. Science. 296 (5574): 1858–1860. Bibcode:2002Sci…296.1858B. doi:10.1126/science.1070343.
PMID 12052958. S2CID 45069635.
27. ^ Jump up to:a b Evert, Ray, and Susan Eichhorn. Raven Biology of Plants. New York: W. H. Freeman and Company, 2013. Print.
28. ^ Baucher, Marie; AlmJaziri, Mondher; Vandeputte, Olivier. “From primary to secondary
growth: origin and development of the vascular system”. academic.oup.com. Retrieved 2023-03-18.
29. ^ Tognetti, Vanesa B.; Bielach, Agnieszka; Hrtyan, Mónika (October 2017). “Redox regulation at the site of primary growth: auxin, cytokinin and ROS
crosstalk: Apical meristems plasticity in response to stress”. Plant, Cell & Environment. 40 (11): 2586–2605. doi:10.1111/pce.13021. PMID 28708264.
30. ^ Adams, Alexa (April 2013). “Elimination of viruses from the hop (Humulus lupulus) by heat therapy
and meristem culture”. Journal of Horticultural Science. 50 (2): 151–160. doi:10.1080/00221589.1975.11514616. Retrieved 24 January 2023.
31. ^ Alam, I; Sharmin, SA; Naher, MK; Alam, MJ; Anisuzzaman, M; Alam, MF (April 2013). “Elimination and detection
of viruses in meristem-derived plantlets of sweetpotato as a low-cost option toward commercialization”. 3 Biotech. 3 (2): 53–164. doi:10.1007/s13205-012-0080-6. PMC 3597136. PMID 8324570.
32. ^ Mackenzie, K.A.D; Howard, B.H (1986). “The Anatomical
Relationship Between Cambial Regeneration and Root Initiation in Wounded Winter Cuttings of the Apple Rootstock M.26”. Annals of Botany. 58 (5): 649–661. doi:10.1093/oxfordjournals.aob.a087228.
2. Plant Anatomy Laboratory from University of Texas;
the lab of JD Mauseth. Micrographs of plant cells and tissues, with explanatory text.
3. Schoof, Heiko; Lenhard, M; Haecker, A; Mayer, KF; Jürgens, G; Laux, T (2000). “Arabidopsis shoot meristems is maintained by a regulatory loop between Clavata
and Wuschel genes”. Cell. 100 (6): 635–644. doi:10.1016/S0092-8674(00)80700-X. PMID 10761929. S2CID 8963007.
4. Scofield and Murray (2006). The evolving concept of the meristem. Plant Molecular Biology 60:v–vii.
Photo credit: https://www.flickr.com/photos/the-o/2294116183/’]