Plant Kingdom Test - 71

Correct Option: A

Explanation:

• The structure of Bryopsida mainly mosses consists of two body parts including gametophyte and sporophyte.
•  The spore capsule has a supporting branch which is the sporophytic part of moss and this part arises from the protonema part known as a gametophyte. The leaf, stem, gametophore, and protonema together form the gametophyte.

Hence, the correct option is (A) - Sporophyte, (B)- Gametophyte

 

• In bryophytes, fertilization occurs by chemotaxis, that is movement of antherozoids towards the egg due to a chemical substance called malic acid. 
• This chemical is released by the mature archegonia into the surrounding water, sensing which the antherozoids swim towards it. Therefore water is essential for fertilization in bryophytes and hence, they are usually found in damp and shaded areas.

In bryophytes, the sporophyte is parasitic (partially or wholly) on the gametophyte as it is organically attached and is nutritionally dependent upon the gametophyte.

Asexual reproduction in liverworts takes place by fragmentation of thalli, or by the formation of specialised structures called gemmae.

In Marchantia, the plant body consists of a dorsoventrally flattened, prostrate and dichotomously branched thallus. The thalli are conspicuous, the apex of each thallus is notched. Along the mid-rib are present characteristic, prominent goblet or cup-shaped structures, the gemma cups, with smooth, dentate or frilled margins. These cups enclose asexual reproductive bodies called gemma.So the correct option is B.

• In bryophytes fertilization and post fertilization changes take place in the archegonium, anchored by gametophyte.
• The diploid zygote formed after fertilization of the antherozoids and the egg cell undergoes development to form the diploid sporophyte, meiosis takes place in the sporophyte to produce haploid spores that on germination produce the protonema of the gametophyte.

Asexual reproduction in liverworts takes place by fragmentation of thalli, or by the formation of specialised structures called gemmae.

• Peat forms when plant material does not fully decompose in acidic and anaerobic conditions.
  
• Sphagnum moss forms peat, for this reason, Sphagnum is also called peat moss. 
  
• Peat is used as fuel and manure.

Gemmae are green multicellular asexual buds, which develop in small receptacles called gemma cups located on the thalli. Gemmae become detached from the parent body and germinate to form new individuals.