Abstract:

Stomata of various sizes are produced on the primary root of Ceratonia siliqua L. Most are generated during embryogenesis, prior to seed desiccation. They can be detected on the dry embryo in a wide zone just above the root tip. Initially, large stomata are formed. These have the ability to induce divisions of their neighbouring cells, creating particular cell patterns around them. Later, small perigenous stomata are generated. As the root grows following seed germination, the stomatal zone overlaps with that of the root hairs. Although root stomata of C. siliqua undergo a structural differentiation that seems almost identical to that of the elliptical stomata formed on leaves, they are unable to move and remain permanently open. Polarizing microscopy of fully differentiated stomata and young stomata at the stage of stomatal pore formation revealed deposition of radial cellulose microfibril systems on their periclinal walls. However, these systems were less developed than those on leaf stomata, a feature that might he responsible for their inactivity. Besides, plastids of the root guard cells (GCs) do not differentiate into chloroplasts but function solely as amyloplasts. Root stomata have a short life span. During rapid and intense root growth, GCs cannot keep pace with the elongation of their neighbouring rhizodermal cells. They therefore split in their mid-region, transversely to the stoma axis. The two parts of the transversely torn stoma are dragged apart and a large opening is formed on the root surface, just above the substomatal cavity. The root stomata, together with these openings, may facilitate increased gaseous exchange during respiration and/or an increased transfer of some nutrients and water in the rapidly growing primary root. © 2002 Annals of Botany Company.

Notes:

Cited By :11Export Date: 7 February 2017CODEN: ANBOACorrespondence Address: Christodoulakis, N.S.; Department of Botany, University of Athens, Athens 15784, Greece; email: nchristo@biology.db.uoa.grChemicals/CAS: Cellulose, 9004-34-6References: Apostolakos, P., Galatis, B., Probable involvement of cytoskeleton in stomatal pore formation in Asplenium nidus L. (1998) Protoplasma, 203, pp. 48-57;Apostolakos, P., Galatis, B., Microtubule and actin filament organization during stomatal morphogenesis in the fern Asplenium nidus. Guard cells (1999) New Phytologist, 141, pp. 209-223; Aylor, D.E., Parlange, J.-Y., Krikorian, A.D., Stomatal mechanics (1973) American Journal of Botany, 60, pp. 163-171; Christodoulakis, N.S., Structural diversity and adaptations in some Mediterranean evergreen sclerophyllous species (1992) Environmental and Experimental Botany, 32, pp. 295-305; Christodoulakis, N.S., Psaras, G.K., Stomata on the primary root of Ceratonia siliqua (1987) Annals of Botany, 60, pp. 295-297; Esau, K., (1965) Plant anatomy, , New York, London: John Wiley & Sons Inc; Fahn, A., (1982) Plant anatomy, , Oxford, New York: Pergamon Press; Galatis, B., Microtubules and guard cell morphogenesis in Zea mays (1980) Journal of Cell Science, 45, pp. 211-244; Galatis, B., Apostolakos, P., Microtubule organization and morphogenesis of stomata in caffeine-affected seedlings of Zea mays (1991) Protoplasma, 165, pp. 11-26; Galatis, B., Mitrakos, K., The ultrastructural cytology of the differentiating guard cells of Vigna sinensis (1980) American Journal of Botany, 67, pp. 1243-1261; Galatis, B., Apostolakos, P., Katsaros, Chr., Microtubules and their organizing centres in differentiating guard cells of Adiantum capillus veneris (1983) Protoplasma, 115, pp. 176-192; Jang, C.-J., Nakajima, N., Kondo, N., Disruption of microtubules by abscisic acid in guard cells of Vicia faba L. (1996) Plant Cell Physiology, 37, pp. 697-701; Jarvis, P.G., Mansfield, T.A., (1981) Stomatol physiology, , Cambridge, UK: Cambridge University Press; Lefebvre, D.D., Stomata on the primary root of Pisum sativum L. (1985) Annals of Botany, 55, pp. 337-341; Meidner, H., Mansfield, T.A., (1968) Physiology of stomata, , London: McGraw-Hill; Palevitz, B.A., The stomatal complex as a model of cytoskeletal participation in cell differentiation (1982) The cytoskeleton in plant growth and development, pp. 345-376. , Lloyd CW, ed. London, UK: Academic Press; Sack, F.D., The development and structure of stomata (1987) Stomatal function, pp. 59-89. , Zeiger E, Farquhar GD, Cowan IR, eds. Stanford, CA, USA: Stanford University Press; Tarkowska, J.A., Wakowska, M., The significance of stomata on seedling roots (1988) Annals of Botany, 61, pp. 305-310; Tietz, A., Urbasch, I., Spaltöffnungen an der keimwurzel von Helianthus annuus (1977) Naturwissenschaften, 63, p. 10

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