Lifecycle of Moss and Bryophytes

Introduction to Moss

Mosses are part of a plant group known as bryophytes.
Bryophytes include mosses and liverworts, commonly found in moist, shaded areas.
Known as the "amphibians" of the plant kingdom due to their dependence on water for reproduction.
Plant body is more differentiated than algae but lacks true roots, stems, or leaves.
Mosses grow in dense green clumps, often in damp or shady locations.

Structure:
- Talus-like and prostrate or erect.
- Attached to the substratum by unicellular or multicellular rhizoids.
Reproduction:
- Dependent on water for sexual reproduction.
Morphology:
- Lack true roots, stems, or leaves, but may have structures that resemble them.

Protonema Stage
- Develops directly from a spore.
- Creeping, green, branched, and often filamentous.
Leafy Stage
- Develops from the secondary protonema as a lateral bud.
- Consists of upright, slender axes with spirally arranged leaves.
- Attached to soil through multicellular, branched rhizoids.
- Bears multicellular sex organs.

Male Sex Organ: Antheridium, produces flagellate antherozoids.
Female Sex Organ: Archegonium, flask-shaped, produces a single egg.
Fertilization:
- Antherozoids travel through water to reach archegonium.
- Fusion of antherozoid and egg forms a zygote.
Sporophyte Formation:
- Zygote forms a multicellular body called sporophyte, which remains attached to gametophyte.
- Sporophyte undergoes meiosis to produce haploid spores.
Germination:
- Spores germinate to produce new gametophyte.

Question: Dominant gametophyte stage in plant groups?
- Answer: Bryophytes (Option 1).
Question: Antherozoids in bryophytes?
- Answer: Flagellate (Option 1).

Highlight the importance of understanding the two stages of the moss life cycle for exams.
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