Question

List and describe the parts of the female gametophore of Marchantia. What is the structure in which the eggs are produced? List and describe its parts.

Answer 1

Answere :

The sex organs in Marchantia are produced on special stalked receptacles or branch called gametophores. The receptacle bearing male (antheridium) sex organ is called antheridiophore.

The receptacle bearing female (archegonium) sex organ is called archegoniophore (female gametophore). It is a special lateral, erect modified branch and extension of vegetative thallus.

It consist of a stalk and a disc that bears 9 rays. In the early stage, the archegonia develop on the upper (dor­sal) side of the disc. About 12-14 archegonia are arranged in a single row on each ray of the disc.

The stalk of the archegoniophore begins to elongate just after fertilisation and its margins of disc pushed downwards. The archegonia are hanging upside down on disc— the youngest one being nearer the stalk while the older ones towards the periphery.

Rays on disc are long, stout and green finger-like projections that give the mature female receptacle an umbrella-like appearance. The archegonia become inverted by the curvature of the disc.

Archegonium is a structure in which eggs are produced. It is a female reproductive organ. Mature archegonium is a flask-shaped structure. It remains attached to the archegonial disc by a short stalk.

It consists upper elongated slender neck and basal globular portion called venter. The neck consists of six vertical rows enclosing eight neck canal cells. Four cover cells are present at the top of the neck. Venter has a large egg cell and venter cell surrounded by venter wall cells.

Venter acts as site of fertilization in archegonium.

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