Question

Which one of these does not require external water for fertilization?

• A. Ferns
• B. Algae
• C. Cycads
• D. Bryophytes

Answer 1

The correct option is C Cycads

• Ferns, algae, and bryophytes find water as an essential element for fertilisation to take place. Because they are in need of water for the movement of sperms, etc. Whereas the condition is not similar in the case of Cycas.

Fertilization in Cycas;

• The pollen tube grows towards the archegonium of the female gametophyte. There, the end of the pollen tube bursts and discharges its contents into the archegonia chamber.
• The spermatozoids are set free in the archegonia chamber. They swim towards the neck of the archegonium and make their way down to the egg cell. One of the spermatozoids fuses with the egg uncles i.e. oosphere.

Fertilization is thus effected.

• The fertilized oosphere is subsequently surrounded by a wall to form oospores (2n).