The key difference between embryo sac and endosperm is that embryo sac is a structure present in the ovule of flowering plants, while endosperm is a structure present in the seeds of flowering plants.
Embryo sac and endosperm are two important structures present in flowering plants. Embryo sac produces an egg cell for the purpose of fertilization, while endosperm forms due to double fertilization when the sperm fuses with the binucleate central cell.
CONTENTS
1. Overview and Key Difference
2. What is Embryo Sac
3. What is Endosperm
4. Similarities – Embryo Sac and Endosperm
5. Embryo Sac vs Endosperm in Tabular Form
6. Summary – Embryo Sac vs Endosperm
What is an Embryo Sac?
The embryo sac is a structure present in the ovule of flowering plants. The ovule is a structure in plants that encloses the reproductive cells in females. It contains the nucleus, integument, and female gametophyte. The embryonic sac is the female gametophyte that is oval in shape. The embryo sac produces an egg cell for the purpose of fertilization.
The female gametophyte of flowering plants or embryo sac is a tiny structure that contains only a few nuclei (normally eight). The cytoplasm is associated more or less directly with these nuclei, and it is not portioned by the cell walls. Moreover, one of the several nuclei of the embryo sac serves as the egg in the sexual reproduction of flowering plants. This nuclei (egg) unites with one of the two sperm nuclei delivered by the pollen tube. On the other hand, two other nuclei of the embryo sac fuse with the second sperm nucleus from the pollen tube and give rise to the endosperm.
What is Endosperm?
Endosperm is a structure present in the seeds of flowering plants. It is formed when two nuclei of the embryo sac fuse with the second sperm nucleus from the pollen tube. Therefore, endosperm forms due to double fertilization. It is triploid in nature in angiosperm or flowering plants. Endosperm is also the multicellular food storage tissue in the seed.
Endosperm surrounds the embryo and provides nutrients in the form of starch. However, endosperm also contains oil and protein. Because of this, animals use endosperm as a source of nutrition in their diet. For example, wheat endosperm (that is ground into flour), barley endosperm (the main source of sugars in beer production), coconut meat, coconut water, and corn are all nutritional sources in the animal diet. However, some plants, such as orchids, do not have an endosperm in their seeds.
What are the Similarities Between Embryo Sac and Endosperm?
- The embryo sac and endosperm are two important structures present in flowering plants.
- The embryonic sac is involved in the formation of the endosperm.
- Both structures have peculiar functions.
- These structures are extremely important for the survival of plants.
What is the Difference Between Embryo Sac and Endosperm?
The embryo sac is present in the ovule of flowering plants, while the endosperm is present in the seeds of flowering plants. Thus, this is the key difference between embryo sac and endosperm. Furthermore, the embryo sac develops before fertilization, while the endosperm develops after fertilization.
The following table summarizes the difference between embryo sac and endosperm.
Summary – Embryo Sac vs Endosperm
The embryo sac and endosperm are two important structures found in flowering plants. Two of the nuclei in the embryo sac unite with sperm and give rise to endosperm. Therefore, the embryo sac develops before fertilization, and the endosperm develops after fertilization. Moreover, the embryo sac is a structure present in the ovule of flowering plants. In contrast, the endosperm is a structure present in the seeds of flowering plants. It develops after fertilization. So, this summarizes the difference between embryo sac and endosperm.
Reference:
1. “Endosperm – An Overview.” ScienceDirect Topics.
2. “Embryo SAC.” Unacademy.
Image Courtesy:
1. “Angiosperm embryo sac diagram” By BlueRidgeKitties (CC BY 2.0) via Flickr
2. “Coconut layers” By Kerina yin – Own work (CC BY-SA 3.0) via Commons Wikimedia