|PLUSKOTA, WIOLETTA - Oregon State University|
|NONOGAKI, HIROYUKI - Oregon State University|
Submitted to: Book Chapter
Publication Type: Book / Chapter
Publication Acceptance Date: 8/22/2009
Publication Date: 4/15/2010
Citation: Martin, R.C., Pluskota, W., Nonogaki, H. 2010. Seed Germination. In: Eng-Chong Pua and Michael Davey. Plant Developmental Biology - Biotechnological Perspectives Volume 1. Springer Heidelberg. Chapter 19:383-404.
Interpretive Summary: This book chapter discusses the structure of seeds and the regulatory mechanisms involved in seed germination. The roles of the testa, or seed covering, the endosperm and the embryo in the regulation of seed germination are discussed. Mechanisms involved in regulating the levels of ABA and GA, the interactions between these two hormones, and the effect of light and temperature on their regulation are presented. Receptors of ABA and GA are also important in maintaining or releasing seeds from dormancy. The role of other genes not directly related to GA and ABA that affect dormancy and germination are also discussed.
Technical Abstract: Initiation of seed germination is a critical decision for plants. It is important for seed populations under natural conditions to spread the timing of germination of individual seeds to maximize the probability of species survival. Therefore, seeds have evolved the multiple layers of mechanisms that repress or delay germination including dormancy. Physicochemical properties of seed covering tissues such as testa and endosperm affect the occurrence or the timing of seed germination. Physiological repression may be present in the embryo itself in some species. Plant hormones such as abscisic acid and gibberellin affect the physiological status of the embryo. The repression imposed by abscisic acid can be overcome by gibberellin or other environmental factors such as light and cold temperature. Gibberellin can also affect abscisic acid levels in seeds. Understanding the mechanisms of repression and de-repression in seeds is crucial for the development of new biotechnology to improve seed performance.