Question

The germination of pollen on stigma is _________ type.
(a) In vitro
(b) In vivo
(c) In situ
(d) Ex situ

Answer 1

Pollens give rise to the male gametophyte. After pollination, these pollen land on stigma which is the part of the pistil where the pollen germinates. The pollen germinates inside the pistil.

Complete solution:
The processes that occur outside the body of a living organism are termed in vitro.
The processes that occur inside the body of a living organism are termed in vivo.
The germination of pollen grain on stigma happens in ‘in vivo’ conditions.
According to biology, in situ means examining an organism in its natural place. In-situ, the organism is not moved out from its natural environment.
Ex-situ means examining an organism outside its natural environment.

Additional information:
The pollen germination starts when the pollen grain lands on the stigma. The pollen grain cell divides into two cells of different sizes. The bigger one is called a tube cell (vegetative cell). The intine grows through the germ pore and forms the pollen tube. The pollen tube grows, passes through the style and reaches the ovary. The tube nucleus degenerates and the generative nucleus divides and forms two male gametes.
The male gametes are released after the pollen tube bursts. One of the two male gametes unites with the egg cell.

So, the correct answer is ‘In vivo’.

Note:
The germination of pollen grain on stigma happens only in biological cell conditions. It is a natural process that starts as soon as a compatible pollen lands on the stigma. The pollen tube grows inside the body and transfers the male gamete to the ovary for fertilization.
In vivo should not be confused with in situ. In situ means examining an organism in its natural place.