Abstract
Seed dormancy, defined as the failure of intact seeds to germinate under favorable conditions, is thought to be an important adaptive trait in many plant species. Seed dormancy is established during seed maturation phase and subsequently released by after-ripening (dry storage of matured seeds), cold stratification, or nitrate treatment. In Arabidopsis, Cape verde islands-0 (Cvi-0), a naturally occurring genetic variation, has been a tool to study seed dormancy, because this accession exhibits significantly higher level of seed dormancy than commonly used accessions such as Columbia-0 and Landsberg erecta. We found that embryos isolated from 4-weeks after-ripened Cvi-0 seeds could germinate (or start growing), suggesting that seed dormancy of Cvi-0 largely depends on the seed coat. We identified several hyper-"embryo dormant" accessions that sustain embryo dormancy after 4 weeks of after-ripening. Factors that determine different types of dormancy, embryo dormancy and seed coat dormancy, will be discussed in the context of global gene expression and phytohormone metabolism.
