Bryophyta: Funaria - External, Internal Structure and Reproduction

Bryophyta

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Bryophyta: Funaria - External, Internal Structure and Reproduction

Bryophyta: Funaria - External, Internal Structure and Reproduction

Funaria:

It is cosmopolitan in distribution, mostly found in moist soil, rock, walls, and tree trunks.

External structures:

Gametophyte:

Plant is small about 1-3 cm long, stem is erect and branched. It is differentiated into rhizoids, axis, and leaves. The rhizoids are multicellular and branched. The axis is aerial, erect, and branched. The leaves are simple, small, and spirally arranged. The upper leaves are large and lower leaves are crowded.

Internal structure:

funaria structures

Stem: The outermost layer is epidermis contain chloroplast. Below the epidermis there is multilaered parenchyma called cortex. In the centre there is compact and narrow cells without protoplast called central cylinder which factions as conducting tissue.

Leaves: The leaf lamina consists of single layered parenchyma rich in chloroplast and the midrib contains central strand.

Reproduction:

reproduction of funaria

Asexual method of reproduction takes place by following method

  • By primary protonema: The spores germinate to give rise small filament called primary protonems, which contains small buds from where new plant is produced.
  • By secondary protonema: The filament can grow from stem, leaves, or rhizoids called secondary Protonems. They bear small buds and which are capable to give rise new plant.
  • By gemmae: The small multicellular structures develop on leaves and axis, which develop into new plant.
  • By bulbil: The gammae like structures developed on the rhizoids are called bulbils which grow into new plant.

Sexual reproduction:

Funaria is monoecious female organs develop or separate branch of same plant autocious.

Male branch - the branch with male sex organs id called male branch.

  • The male sex organs - Antheridia develop in group at the apex of shoot
  • They are mixed with hair like structure paraphysis.
  • Antheridia and paraphysis are surrounded by leaves called perichaetial leaves.

Each antneridiuim is stalked, club-shaped, surrounded by jacket; two apex cells are large/thick called operculum. With the help of water, the operculum ruptures and androcytes come out and change into antherozoids (spermatozoids).

Female branch – The branch with female sex organs.

  • The female sex organ – Archegonia are developed at the apex of shoot.
  • The archegonia are mixed with hair like sterile structures called paraphysis.
  • Both surrounded by perichaetial leaves.

Each archegonium is flask shaped, stalked, and contains broad Venter and long neck. The Venter contains an egg, Venter canal cell, double layered wall. Neck contains neck canal cells.

Fertilization:

In pressure of water antherozoid reach to archegonia tip. Neck canal/Venter canal cells degenerate. antherozoids enter through neck and only one free with egg to form zygote.

Sporophyte:

The zygote secrets thick wall around it called oospore, which grows into a saprophyte. The mature saprophyte consists of foot\seta\capsule

  • Foot – it is barrel, conical shaped, embedded in apex of a branch.
  • Seta – it is very long, twisted, and slender.
  • Capsule- pear-shaped in structure and it consists of
  1. Apophysis – it is multicellular thick basal portion of the capsule
  2. Columella- it is central portion of the capsule surrounded by spore sac.
  3. Spore sac- it is a sac containing spores on either side of columella. On the outer side of the spore sac air spaces are present separated by partition wall.
  4. Operculum – apical region of capsule. It is conical lid of the capsule. It consists of small teeth called peristome.

Dehiscence of capsule: At maturity annulus breaks and the operculum is thrown away. The spores are liberated out.

Spore germination: Under favorable condition the spore, germinate to produce small filament. The filament branches freely called primary protonema. The primary protonema gives small buds. Each bud gives rise into new Funaria plant.

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