Question

Entry of pollen tube through micropyle is
a. Chalazogamy
b. Misogamy
c. Porogamy
d. Pseudogamy

Answer 1

Hint: The tubular structure produced by the male gametophyte of seed plants is called a pollen tube. The elongation of the pollen tube takes place in the integral stage of the plant life cycle. The tiny opening in the ovule in a seed plant is called the micropyle. The main function of micropyle is to absorb water in the seed and make it available for embryo germination.

Complete answer:
> Option C:
The process of entering of pollen tube through a micropyle in the ovule is called Porogamy. It is common in angiosperms. Some studies say that porogamy is directed by the filiform apparatus. The common plant examples which show porogamy is Lily.

> Option A:
The entrance of the pollen tube through chalaza or the integument is called Chalazogamy. Treub was the one who discovered the process of chalazogamy. For example – Casuarina. In the plant of Ulmus, partial chalazogamy is seen.

> Option B:
The fertilization type which is observed in all the Cucurbit plants is called misogamy. For example – pumpkin, ridge gourds, bitter gourd, etc. In this, entering of the pollen tube takes place through the integuments or middle part of the ovule.

> Option D:
The asexual reproduction in which there are no union gametes involves is called Pseudogamy. It is referred to as parthenogenesis in zoology and asexual reproduction form in botany. In zoology pseudogamy or parthenogenesis is the process in which stimulation of sperm occurs in the egg cell to develop the embryo but the main thing is that from the male no gene is being inherited.

Hence, the correct answer is option (C).

Note: Thus, we have discussed the different processes in which the pollen tube enters the embryo from different parts of the embryo sac. Pollen tubes germinate to go inside the embryo and fertilize the ovule. The pollen tube is the male gametophyte and the ovule is the female gametophyte. The micropyle, chalaza is the different regions from where the pollen tube can enter.