Question

Refer to the following figure regarding Division Bryophytes
i) ‘A’ are the androcytes of other cells of the antheridium, which give rise to a large number of biflagellate male gametes.
ii) ‘B’ is the antheridial chamber and “C” is the multicellular stalk of antheridium.
iii) ‘D’ and ‘E’ respectively represent venter canal cells and neck canal cell of the female sex organ.
iv) ‘F’ is the egg cell of the archegonium, which usually possesses several female gametes.
Which of the following combinations of above statements is incorrect?

a) (i) and (ii)
b) (iii) and(iv)
c) (ii) and (iii)
d) (i) and (iv)

Answer 1

Hint: Reproduction in the bryophytes occurs either through vegetative propagation or through sexual reproduction. As A Sexually they reproduce using gemma, tubers, bulbils, regeneration and through many more ways. The male and female sex organs are known as antheridia and archegonia.

Complete answer:
- ‘A’ in the given diagram is the androcytes where pollen grains are formed. The wall covering it provides protection to the androcytes. It is the main centre for the production of male gametophytes.
- ‘B’ in the given diagram is the antheridial cavity that encloses the androcyte.
- ‘C’ in the given diagram is the stalk that holds the antheridium in place.
- ‘D’ in the given diagram is the neck canal cell of the archegonia.
- ‘E’ is the ventral canal cell.
- ‘F’ is the egg of the archegonia.

Additional information: The sex organs present in bryophytes are well covered and multi-layered. Antheridium is a stalked structure that encloses androcytes. Androcytes give rise to the biflagellate antherozoid. Archegonium is a stalked and flask-shaped female sex organ that consists of neck canal cells and ventral canal cells. It has a swollen base structure called a venter. Antherozoids are attracted to the archegonia because of chemical substances released by neck canal cells and ventral canal cells. The fertilized egg marks the beginning of the sporophyte stage. The zygote undergoes repeated division to form a zygote. The embryo develops into the sporophyte. The sporophyte remains attached to the parent plant body for nutrition. The sporophyte is differentiated into foot, capsule, and seta. Capsule functions to produce spores by the division of spore mother cells. They further divide to form a tetrad of spores.
So the answer is ‘b) iii and iv’

Note: In the female sex organ the neck-like elongated structure consists of the neck canal cells and at the end is the small portion of ventral canal cells. The female produces a single egg whereas the male produces a large number of spores.