The post fertilization change in embryo sac.
(i) Fertilization: The process begins with the fusion of male and female gametes, resulting in the formation of a diploid zygote (2N). This zygote is the first cell of the future embryo.
(ii). Zygote Development: After fertilization, the zygote undergoes mitotic divisions. These divisions lead to the formation of a multicellular structure known as the proembryo.
(iii). Formation of Globular Embryo: The proembryo develops into a globular embryo through further cell divisions. This stage is characterized by the embryo taking on a rounded shape.
(iv). Heart-Shaped Embryo: As development continues, the globular embryo transforms into a heart-shaped embryo. This shape is significant as it indicates further differentiation of the embryo.
(v). Maturation of Embryo: The heart-shaped embryo matures into a fully developed embryo. During this stage, structures such as the suspensor, cotyledons, and embryonic axis are formed.
(vi). Formation of Suspensor: The suspensor is a structure that supports the embryo and helps in nutrient transfer from the parent plant. It plays a vital role in anchoring the embryo and facilitating its growth.
(vii). Development of Embryonic Structures: The mature embryo consists of three main parts:
(a)Radicle: The lower part that will develop into the root.
(b) Plumule: The upper part that will develop into the shoot.
(c) Cotyledons: These are the seed leaves that provide nutrition to the developing plant.
(viii). Seed Formation: Finally, the mature embryo, along with the surrounding tissues, forms a seed. In dicots, two cotyledons are typically present, which are crucial for the seed's development.
