Question

Assertion : Nuclear endosperm is formed by subsequent nuclear division without wall formation.

Reason : Coconut is an example of such endosperm, where the endosperm remains nuclear throughout the development of the fruit.

(a) Both A and R are true and R is the correct explanation of A

(b) Both A and R are true but R is not correct explanation of A

(c) A is true but R is false

(d) A and R are false

Answer 1

Correct option (c) A is true but R is false

Explanation :

In nuclear endosperm, first and further divisions of primary endosperm nucleus are not followed by cytokinesis or wall formation and thus these free nuclear divisions lead to formation of a large number of free nuclei in embryo sac. At maturity, centripetal wall formation may occur to make the tissue partly cellular. Endosperm of coconut is unique in sense that it is both nuclear and cellular. Here the primary endosperm nucleus undergoes a number of free nuclear divisions. When the fruit is about 50 mm long the embryo sac remains filled with a watery fluid or milk containing free nuclei and fine cytoplasmic particles. At a later stage when the fruit becomes about 100 mm in length the liquid shows in addition to free nuclei, several cells each enclosing variable number of nuclei. Thus coconut has multicellular endosperm (called coconut meat) in the outer part and free nuclear as well as vacuolate endosperm (called coconut milk) in the centre.