In the plant - model Arabidopsis thaliana, the state of dormancy is maintained by the endosperm, a single cell layer within the seed coat surrounding the embryo, which synthesizes and continuously releases ABA towards the embryo.
The mature ovule in most flowering plants, including Arabidopsis thaliana, contains a seven - celledembryo sac consisting of two synergid cells, one egg cell, one central cell and three antipodal cells.