Difference Between Fruit and Seed

The key difference between fruit and seed is that fruit is the developed ovary of angiosperms after fertilization while seed is a fertilized ovule of plants.

Pollination is the process of transferring pollen from anthers to the stigma of the flowers. And, it can be self-pollination or cross-pollination. Once pollens land on the stigma, they start to germinate upon stimulation by the sugary fluid on the stigma. Then, the intine of the pollen grain grows out through a small pore in the extine to produce the pollen tube. Subsequently, the pollen tube grows down and enters the ovule through the micropyle. Next, the apex of the pollen tube degrades in order to release two male nuclei inside the ovary.

Moreover, double fertilization takes place by the fusion of one male nucleus with the egg cell nucleus, giving rise to the diploid zygote. Here, the fusion of the other male nucleus with the diploid secondary nucleus gives rise to the triploid primary endosperm nucleus. After the fertilization, the ovule becomes the seed, and the ovary becomes the fruit.

CONTENTS

1. Overview and Key Difference
2. What is a Fruit 
3. What is a Seed
4. Similarities Between Fruit and Seed
5. Side by Side Comparison – Fruit vs Seed in Tabular Form
6. Summary

What is a Fruit?

Fruits are a unique feature of angiosperms. After fertilization, an ovary of a flower becomes a fruit. Moreover, there are three types of fruits: simple fruits, aggregate fruits, and multiple fruits. In simple fruits, there is only one ovary. They may contain one or more seeds. Also, they may be fleshy or dry. Berry is a popular example for a simple fruit. Whereas, an aggregate fruit develops from a single compound flower and contains many ovaries. Blackberry is an example of aggregate fruits. On the other hand, multiple fruits are a result of multiple flowers with fused ovaries.

The pericarp of the fruit has three layers: exocarp (peel), mesocarp and endocarp (pith). Exocarp is the outermost layer of the pericarp. It is more like a tougher outer skin. Mesocarp is the fleshy middle layer located in between the exocarp and the endocarp. Endocarp is the innermost layer of the pericarp that surrounds the seeds. The endocarp may be membranous or thick and hard.

What is a Seed?

Both angiosperms and gymnosperms produce seeds. Some seeds are naked while some are enclosed by fruits. Seed is the structure that develops from the fertilized ovule. The two integuments of the ovule become the two seed coats, which are outer seed coat (testa) and the inner seed coat (tegmen).

Some seeds contain only one seed coat. After fertilization, funicle develops into the stalk of the seed. The nucellus is generally used up completely but, in some seeds, it may remain as a thin layer. After fertilization, the egg cell gives rise to the embryo, and synergid and antipodal cells get completely disorganized after fertilization.

What are the Similarities Between Fruit and Seed?

• Fruit and seed are results of sexual reproduction in angiosperms.
• Most fruits contain seeds.
• Also, fruits play an important role in seed dispersal by attracting animals.

What is the Difference Between Fruit and Seed?

Fruit is the ripened ovary of angiosperms while seed is a fertilized ovule of both angiosperms and gymnosperms. So, this is the key difference between fruit and seed. Only angiosperms produce fruits while both angiosperms and gymnosperms produce seeds. Also, another difference between fruit and seed is their outer layer. Exocarp is the outer layer of fruit, while testa is the outer layer of seed.

Moreover, a vital difference between fruit and seed is that without the seeds, the fruit cannot grow into a new plant. But, without the fruit, the seed can grow into a new plant.

Summary – Fruit vs Seed

Fruit and seed are two important structures of certain plant groups. Angiosperms produce true fruits. Both angiosperms and gymnosperms produce seeds. In angiosperms, fruits bear seeds. True fruit is the ripened ovary while seed is the fertilized ovule. Fruits help in seed dispersal by attracting animals while seeds can grow into a new plant. Thus, this is the summary of the difference between fruit and seed.

Reference:

1.“Fruit.” Wikipedia, Wikimedia Foundation, 5 May 2019, Available here.
2. Lambers, Hans. “Seed.” Encyclopædia Britannica, Encyclopædia Britannica, Inc., 24 May 2018, Available here.

Image Courtesy:

1.  “FruitArrangement” By Rei at English Wikipedia (CC BY-SA 3.0) via Commons Wikimedia
2. “2728867” (CC0) via Pixabay