Abstract
Non-destructive scanning electron microscopy allows one to visualize changing patterns of individual cells during epidermal development in single meristems. Cell growth and division can be followed in parallel with morphogenesis. The method is applied here to the shoot apex of Anagallis arvensis L. before, during, and after floral transition. Phyllotaxis is decussate; photoperiodic induction of the plant leads to the production of a flower in the axil of each leaf. As seen from above, the recently formed oval vegetative dome is bounded on its slightly longer sides by creases of adjacent leaf bases. The rounded ends of the dome are bounded by connecting tissue, horizontal bands of node cells between the opposed leaf bases. The major growth axis runs parallel to the leaf bases. While slow-growing at the dome center, this axis extends at its periphery to form a new leaf above each band of connecting tissue. Connecting tissue then forms between the new leaves and a new dome is defined at 90° to the former. The growth axis then changes by 90°. This is the vegetative cycle. The first observed departure from vegetative growth is that the connecting tissue becomes longer relative to the leaf creases. Presumably because of this, the major growth axis does not change in the usual way. Extension on the dome continues between the older leaves until the axis typically buckles a second time, on each side, to form a second crease parallel to the new leaf-base crease. The tissue between these two creases becomes the flower primordium. The second crease also delimits the side of a new apical dome with the major axis and growth direction altered by 90°. During this inflorescence cycle the connecting tissue is relatively longer than before. Much activity is common to both cycles. It is concluded that the complex geometrical features of the inflorescence cycle may result from a change in a biophysical boundary condition involving dome geometry, rather than a comprehensive revision of apical morphogenesis.
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Abbreviations
- SEM:
-
scanning electron microscopy, micrograph
References
Ball, E. (1972) The surface histogen of living shoot apices. In: Dynamics of meristem cell populations, pp. 75–97, Miller, M.N., Kuhnert, C.C., eds. Plenum Press, New York
Ballard, L.A.J. (1969) Anagallis arvensis L. In: The induction of flowering, pp. 376–392, Evans, L.T., ed. MacMillan, Melbourne
Bernier, G. (1988) The control of floral evocation and morphogenesis. Annu. Rev. Plant Physiol. Plant Mol. Biol. 39, 175–219
Bernier, G., Kinet, J.-M., Sachs, R.M. (1981) The physiology of flowering, vol. II. CRC Press, Boca Raton, Fla., USA
Brulfert, J., Fontaine, D., Imhoff, C. (1985) Anagallis arvensis. In: Handbook of Flowering, vol. 1, pp. 434–449, Halevy, A.A., ed. CRC Press, Boca Raton, Fla., USA
Coen, E. (1991) The role of homeotic genes in flower development and evolution. Annu. Rev. Plant Physiol. Mol. Biol. 42, in press
Davis, E.L., Rennie, P., Steeves, T.A. (1979) Further analytical and experimental studies on the shoot apex of Helianthus annuus: variable activity in the central zone. Can. J. Bot. 57, 971–980
Evans, L.T. (1971) Flower induction and the florigen concept. Annu. Rev. Plant Physiol. 22, 365–391
Gordon, J.E. (1978) Structures: or why things don't fall down (Appendix 4). Da Capo Press (Plenum Publishing Co.), New York
Green, P.B. (1988) A theory for inflorescence development and flower formation based on morphological and biophysical analysis in Echeveria. Planta 175, 153–169
Green, P.B. (1989) Shoot morphogenesis, vegetative through floral, from a biophysical perspective. In: Plant reproduction: From floral induction to pollination, Lord, E., Bernier, G., eds. Am. Soc. Plant Physiologists Symp. Ser., vol, 1. pp. 58–75
Green, P.B., Linstead, P. (1990) A procedure for SEMs of complex shoot structures applied to the inflorescence of snapdragon (Antirrhinum). Protoplasma 158, 33–38
Haughn, G.W., Somerville, C.R. (1988) Genetic control of morphogenesis in Arabidopsis. Devel. Genet. 9, 73–89
Hernández, L., Havelange, A., Bernier, G., Green, P.B. (1991) Growth behavior of single epidermal cells during flower formation: sequential SEMs provide kinematic for Anagallis. Planta, in press
Kutschera, U. (1989) Tissue stresses in growing plant organs. Physiol. Plant. 77, 157–163
Lyndon, R.F. (1990) Plant development. The cellular basis. Unwin Hyman, London
Lyndon, R.F., Francis, D. (1984) The response of the shoot apex to light generated signals from the leaves. In: Light and the flowering process, pp. 171–189, Vince-Prue, D., Thomas B., Cockshull, K.E., eds. Academic Press
Marc, J., Palmer, J.H. (1982) Changes in mitotic activity and cell size in the apical meristem of Helianthus annuus L. during the transition to flowering. Am. J. Bot. 69, 768–775
Melchers, G. (1937). Die Wirkung von Genen, tiefen Temperaturen und blühenden Pfropfpartnern auf die Blühreife von Hyoscyamus niger. Biol. Zbl. 57, 568–614
Nelson, A.J. (1990) Net alignment of cellulose in the periclinal walls of the shoot apex surface cells in Kalanchoe blossfeldiana. I. Transition from vegetative to reproductive morphogenesis. Can. J. Bot. 68, 2668–2677
Newman, I.V. (1956) Pattern in meristems of vascular plants. 1. Cell partition in living apices and in the cambial zone in relation to the concepts of initial cells and apical cells. Phytomorphology 6, 1–19
Prusinkiewicz, P., Lindenmayer, A. (1990) The algorithmic beauty of plants. Springer, New York Berlin
Schwarz-Sommer, Z., Huijser, P., Nacken, W., Saedler, H., Sommer, H. (1990) Genetic control of flower development by homeotic genes in Antirrhinum majus. Science 250, 931–936
Weberling, F. (1989) Morphology of flowers and inflorescences, Cambridge (UK) University Press
Went, F.W. (1957) The experimental control of plant growth, pp. 78–81. Chronica Botanica, Waltham, Mass., USA
Williams, M.H., Green, P.B. (1988) Sequential scanning electron microscopy of a growing plant meristem. Protoplasma 147, 77–79
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Use of the SEM facility of Professor G. Goffinet, Institute of Zoology, University of Liège, is greatly appreciated. We thank Dr. R. Jacques, C.N.R.S., Le Phytotron, Gif-sur-Yvette, France, for providing the experimental material, and Mr. Philippe Ongena for expert photography. Support was from grants from the U.S. Department of Agriculture and National Science Foundation as well as from the Fonds National de la Recherche Scientifique, Fonds de la Recherche Fondamentale et Collective, and the “Action de Recherche Concertée” of Belgium.
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Green, P.B., Havelange, A. & Bernier, G. Floral morphogenesis in Anagallis: Scanning-electron-micrograph sequences from individual growing meristems before, during, and after the transition to flowering. Planta 185, 502–512 (1991). https://doi.org/10.1007/BF00202959
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DOI: https://doi.org/10.1007/BF00202959