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Underdeveloped embryos in dwarf seeds and implications for assignment to dormancy class

Published online by Cambridge University Press:  22 February 2007

Carol C. Baskin*
Affiliation:
Department of Biology, University of Kentucky, Lexington, KY 40506-0225, USA Department of Plant and Soil Science, University of Kentucky, Lexington, KY 40546-0312, USA
Jerry M. Baskin
Affiliation:
Department of Biology, University of Kentucky, Lexington, KY 40506-0225, USA
*
*Correspondence: Email: ccbask0@uky.edu

Abstract

Studies were conducted to determine if small embryos (i.e. low embryo length:seed length ratio) in mature dwarf seeds (0.2–2 mm) are underdeveloped. In this case, they would grow (inside the seed) prior to germination, and seeds would have morphological or morphophysiological dormancy. Prior to radicle emergence, embryo length in seeds of Drosera anglica (Droseraceae), Campanula americana, Lobelia appendiculata, L. spicata (Campanulaceae) and Sabatia angularis (Gentianaceae) increased 0, 103, 182, 83 and 57%, respectively. Since embryo growth did not occur in seeds of D. anglica prior to germination, embryos, although small, are fully developed; seeds have only physiological dormancy. The underdeveloped embryo in seeds of C. americana has little or no physiological dormancy; thus, seeds have morphological dormancy. On the other hand, underdeveloped embryos in seeds of L. appendiculata, L. spicata and S. angularis are physiologically dormant, and seeds have morphophysiological dormancy. Therefore, since small embryos in dwarf seeds may or may not be underdeveloped, assignment of seeds to a dormancy class requires that studies be done to determine if embryos grow inside the seed before germination can occur. Such information is important in understanding the evolutionary relationship of the different kinds of seed dormancy.

Type
Short Communication
Copyright
Copyright © Cambridge University Press 2005

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References

Angiosperm Phylogeny Group (2003) An update of the Angiosperm Phylogeny Group classification for the orders and families of flowering plants: APG II. Botanical Journal of the Linnean Society 141, 399436.CrossRefGoogle Scholar
Bailey, I.W., Swamy, B.G.L. (1948) Amborella trichopoda Baill., a new morphological type of vesselless dicotyledon. Journal of the Arnold Arboretum 29, 245254. + plates I–VCrossRefGoogle Scholar
Baskin, C.C. and Baskin, J.M. (1998) Seeds: Ecology, biogeography, and evolution of dormancy and germination. San Diego, Academic Press.Google Scholar
Baskin, C.C., Milberg, P., Andersson, L. and Baskin, J.M. (2001) Seed dormancy-breaking and germination requirements of Drosera anglica, an insectivorous species of the Northern Hemisphere. Acta Oecologica 22, 18.CrossRefGoogle Scholar
Baskin, J.M. and Baskin, C.C. (1979) The ecological life cycle of the cedar glade endemic Lobelia gattingeri. Bulletin of the Torrey Botanical Club 106, 176181.CrossRefGoogle Scholar
Baskin, J.M. and Baskin, C.C. (1984) The ecological life cycle of Campanula americana in northcentral Kentucky. Bulletin of the Torrey Botanical Club 111, 329337.CrossRefGoogle Scholar
Baskin, J.M. and Baskin, C.C. (1990) Germination ecophysiology of seeds of the winter annual Chaerophyllum tainturieri: A new type of morphophysiological dormancy. Journal of Ecology 78, 9931004.Google Scholar
Baskin, J.M. and Baskin, C.C. (2004) A classification system for seed dormancy. Seed Science Research 14, 116.CrossRefGoogle Scholar
Boesewinkel, F.D. and Bouman, F. (1995) The seed: Structure and function Seed development and germination 124. in Kigel, J.;, Galili, G.New York, Marcel Dekker.Google Scholar
Grushvitzky, I.V. (1967) After-ripening of seeds of primitive tribes of angiosperms, conditions and peculiarities. pp. 329336. in Borriss, H.Physiologie, Ökologie und Biochemie der Keimung. Griefswald, Ernst-Moritz-Arndt-Universität.Google Scholar
Martin, A.C. (1946) The comparative internal morphology of seeds. The American Midland Naturalist 36, 513660.CrossRefGoogle Scholar
Nikolaeva, M.G. (1969) Physiology of deep dormancy in seeds. Leningrad, Russia, Izdatel'stvo ‘Nauka’. (Translated from Russian by Z., Shapiro, National Science Foundation, Washington, DC.)Google Scholar
Nikolaeva, M.G. (2004) On criteria to use in studies of seed evolution. Seed Science Research 14, 315320.CrossRefGoogle Scholar