Question

In angiosperms, during development of embryo the suspensor cells develop from
a. Oospore
b. Integument
c. Endosperm
d. Cotyledon

Answer 1

Hint: After the fertilization of male and female gametes, a zygote is formed which then develops an embryo. During the development of the embryo, the zygote enlarged in size and divided by a transverse division resulting in the formation of two unequal cells. The larger one is called the suspensor cell.

Complete answer:
• The angiosperms show a phenomenon of double fertilization in which one male gamete is fused with the egg to form a zygote and the other male gamete fuses with the two polar nuclei.
• The diploid zygote finally developed into an embryo which is called Embryogeny.
•During Embryogeny, the zygote enlarges in size, secretes its cellulose cell wall, and divides by a transverse division resulting in the formation of two unequal cells. The basal cell larger in size is called the suspensor cell which is found at the micropylar end of the embryo sac.
• The suspensor cell divides by transverse division to form a tetrad. The cells formed through division in the suspensor cell then divide by a number of transverse divisions to form a long suspensor consisting of a row of seven to eight cells.
• A suspensor cell is the type of a cord that suspends the embryo and is attached to the radicle in the young stage.

Hence, the correct answer is option (A).

Note: Oospore is a fertilized female zygote having a thick cellulose wall. The suspensor cell situated at the terminal end of the suspensor is called the hypophysis which undergoes numerous divisions and the cell then later on forms the initials of the radicle, root protoderm, and root cap.