Question

Give an example of an exalbuminous seed.

Answer 1

Hint: A fertilized ovule is called a seed. Now, seeds are broadly classified into three main types:
1. Albuminous Seeds or ‘Endospermic’ seeds
2. Exalbuminous Seeds or ‘Non-endospermic’ seeds
3. Perispermic seeds
A seed contains a typical type of tissue called endosperm. This tissue is formed of triple fusion during fertilization and is filled with reserve food materials that nourish the seeds during their dormancy period and during germination.

Complete answer:
Now there are certain seeds where the endosperm is either completely consumed during development or remains of endosperm persists. The types of seeds according to endosperm availability are listed above. Now a brief explanation of the types are as follows:
1. Albuminous Seeds or ‘Endospermic’ seeds: These are the seeds where the endosperm still persists after development till maturity. Examples are wheat, maize, barley, sunflower, coconut, castor, etc.
2. Exalbuminous Seeds or ‘Non-endospermic’ seeds: In this type, the endosperm is completely consumed during development. Examples are Pea, bean, groundnut, etc.
3. Perispermic seeds: This is the third type of seed where the remains of the nucellus are seen. This residual and persistent nucellus is termed perisperm. Examples are black pepper and beet.

Note:
Sometimes many people get confused between exalbuminous and non-endospermic, or between albuminous and endospermic seeds. It should be remembered that both words mean the same and exalbuminous seeds are also known and categorized as non-endospermic seeds. Simultaneously, albuminous seeds are also known as endospermic seeds.
The perispermic seeds don’t fall under the category of seeds that are classified on the basis of endosperm presence or absence.