Class 11 Biology Plant Physiology Plant Growth and Development
State the types of exogenous and endogenous dormancy.
Solution: Seed dormancy is the state in which seed is unable to germinate even under favourable environmental conditions. Seed dormancy can be broken by providing favourable conditions. There are two types of seed dormancy, namely exogenous and endogenous. Exogenous dormancy is caused due to unfavaourable conditions outside of the seed's embryo. An example of exogenous dormancy is when the moisture cannot enter the seed and thus preventing germination. Endogenous dormancy occurs due to chemical changes within the seed’s embryo. An example of endogenous dormancy is when embryo is not yet fully developed. It could also happens due to endogenous chemical inhibitors.