Question

What is endosperm? Describe free nuclear endosperm and cellular endosperm.

Answer 1

Endosperm is a tissue inside the seeds of the angiosperms which appears after fertilization. It provides nutrition to the embryo. In angiosperms, endosperms are of three types: nuclear, cellular and helobial endosperm.

(i) Nuclear type: It is the most common type of endosperm formation. In this type the primary endosperm nucleus gives rise to a number of free nuclei which remain as a peripheral layer and a large central vacuole appears in the embryo sac. Cell wall formation takes later leading to the formation of cellular endosperm. For example, Coconut, Areca.
(ii) Cellular type: In it, first and subsequent divisions of primary endosperm nucleus are accompanied by wall formation, hence endosperm is cellular from the very beginning. For example, Petunia, Datura.