The Mechanisms of Seed Dormancy
In this chapter and the next, the phenomenon of dormancy, as defined on p. 6 and excluding imposed dormancy, will be considered, first of all with respect to the mechanisms of dormancy and secondly by discussing the ways in which dormancy may be broken. Since it has been by studying the breaking of dormancy that much of our understanding of the mechanisms of dormancy has been obtained, this order of treatment is not wholly logical. Furthermore, at a time when new advances in molecular biology are announced almost daily, we have to confess that our understanding of the molecular basis of seed dormancy is so fragmentary that there is no plant species for which there exists an adequate account of its dormancy in cellular and molecular terms. The most comprehensive survey of the literature of seed dormancy may be found in the second volume of the monograph by Bewley and Black (1982), in which about 400 species are listed for which substantial research contributions on seed dormancy have been made, but the authors point out that they have omitted very many contributions and presumably many species. Table 5.1 lists the species and genera whose seed dormancy seems to have received most attention from research workers. In addition to those species in which dormancy has been studied, there are many more species which are known or reliably suspected to possess dormant seeds.
KeywordsSeed Dormancy Sugar Maple Mechanical Restriction Intact Seed Germination Inhibitor
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