Editing Dormancy (section)

=== Seeds ===
When a mature and viable [[seed]] under a favorable condition fails to germinate, it is said to be dormant. [[Seed dormancy]] is referred to as ''' embryo dormancy''' or '''internal dormancy''' and is caused by endogenous characteristics of the embryo that prevent [[germination]] (Black M, Butler J, Hughes M. 1987). Dormancy should not be confused with seed coat dormancy, external dormancy, or hardheadedness, which is caused by the presence of a hard seed covering or [[seed coat]] that prevents water and oxygen from reaching and activating the [[embryo]]. It is a physical barrier to germination, not a true form of dormancy (Quinliven, 1971; Quinliven and Nichol, 1971).

Seed dormancy is desired in nature, but the opposite in the agriculture field. This is because agricultural practice desires rapid germination and growth for food whereas in nature, most plants are only capable of germinating once every year, making it favorable for plants to pick a specific time to reproduce. For many plants, it is preferable to reproduce in spring as opposed to fall even when there are similar conditions in terms of light and temperature due to the ensuing winter that follows fall. Many plants and seeds recognize this and enter a dormant period in the fall to stop growing. The grain is a popular example in this aspect, where they would die above ground during the winter, so dormancy is favorable to its seedlings but extensive domestication and crossbreeding has removed most dormancy mechanisms that their ancestors had.<ref name=":0">{{Cite journal|last1=Barrero|first1=José M.|last2=Jacobsen|first2=John V.|last3=Talbot|first3=Mark J.|last4=White|first4=Rosemary G.|last5=Swain|first5=Stephen M.|last6=Garvin|first6=David F.|last7=Gubler|first7=Frank|date=January 2012|title=Grain dormancy and light quality effects on germination in the model grass Brachypodium distachyon|journal=New Phytologist|volume=193|issue=2|pages=376–386|doi=10.1111/j.1469-8137.2011.03938.x|pmid=22039925|doi-access=free|bibcode=2012NewPh.193..376B }}</ref>

While seed dormancy is linked to many genes, abscisic acid (ABA), a plant hormone, has been linked as a major influencer to seed dormancy. In a study on rice and tobacco plants, plants defective in zeaxanthin epoxidase gene, which are linked to ABA-synthesis pathway. Seeds with higher ABA content, from over-expressing zeaxanthin epoxidase, led to an increased dormancy period while plants with lower numbers of zeaxanthin epoxidase were shown to have a shorter period of dormancy. A simple diagram can be drawn of ABA inhibits seed germination, while gibberellin (GA, also plant hormone) inhibits ABA production and promotes seed germination.<ref name=":0" /><ref>{{Cite journal|last1=Koornneef|first1=Maarten|last2=Bentsink|first2=Leónie|last3=Hilhorst|first3=Henk|date=2002-02-01|title=Seed dormancy and germination|journal=Current Opinion in Plant Biology|volume=5|issue=1|pages=33–36|doi=10.1016/S1369-5266(01)00219-9|pmid=11788305|bibcode=2002COPB....5...33K |issn=1369-5266|hdl=11858/00-001M-0000-0012-36A6-C|s2cid=27054888 |hdl-access=free}}</ref>