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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  and
Jerry M. Baskin
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
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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.

Keywords

evolution of seed dormancyDrosera anglicaCampanula americanaLobelia appendiculataLobelia spicataSabatia angularismorphophysiological dormancy
Type
Short Communication
Information
Seed Science Research , Volume 15 , Issue 4 , December 2005 , pp. 357 - 360
Copyright
Copyright © Cambridge University Press 2005

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