Question

Which of the following statements are incorrect?

• A. The generative cell divides and forms the two male gametes.
• B. If the female parent produces unisexual flowers, then there is no need for emasculation for artificial hybridisation.
• C. The ability of the pistil to recognise the pollen followed by its acceptance or rejection is the result of a continuous dialogue between pollen grain and the egg cell.
• D. One of the male gametes moves towards the egg cell and fuses with its nucleus thus completing the syngamy.

Answer 1

The correct option is C The ability of the pistil to recognise the pollen followed by its acceptance or rejection is the result of a continuous dialogue between pollen grain and the egg cell.

The statement in option C is incorrect because the continuous dialogue for the recognition of the pollen grain occurs between the pollen grain and the pistil. No chemical dialogue for the recognition of pollen occurs between the pollen and the egg cell. Infact, by the time male gamete reaches the egg cell, the pollen pistil interaction is over. The pollen pistil interaction starts from the time of pollen deposition on the stigma until the pollen tube enters the ovule.

The generative cell in the pollen grain divides to form the male gametes. Out of the two male gametes released by the pollen tube, one male gamete fuses with the egg cell to form the zygote, whereas the other fuses with the polar nuclei to form the primary endosperm nucleus.

Emasculation is the process of removing the anthers from bisexual flower. This is done during artificial hybridisation. Emasculation helps in preventing self pollination. Since in unisexual flower only the male or female reproductive structure is present, there will be no self-pollination. Therefore emasculation is not required in unisexual flowers.