Which external (environment) and internal (seed) factors may lead to dormancy in seeds?

Question

Which external (environment) and internal (seed) factors may lead to dormancy in seeds?

Answer 1

Before a seed leaves the mother plant, it prepares for dormancy by dehydrating and increasing its level of abscisic acid (ABA).  ABA is a stress hormone that inhibits seed germination.  These are internal factors that initiate dormancy.

Many plants automatically energy a dormancy phase.  So, environmental factors do not lead to initiating dormancy.  This is called Primary Dormancy.

Secondary Dormancy occurs when the seeds is released from the mother plant in an undormant state but enter dormancy because environmental factors are not proper for germination.  These environmental factors include temperature (too hot or too cold), moisture (too dry or too wet),  anerobic (no oxygen), or low light.