Bryophytes Lecture Notes

These flashcards cover key concepts related to bryophytes, including their structure, reproduction, ecological roles, and human relevance.

What are bryophytes?

Bryophytes are non-vascular plants that include mosses, liverworts, and hornworts, and have around 23,000 species.

What are the three main adaptations plants developed for living on land?

1. Development of a fatty cuticle to reduce water loss. 2. Multicellular gametangia and sporangia. 3. Development of multicellular embryos.

What is the structure of moss gametophytes?

Leaves are usually one-cell thick except at midrib, contain chloroplasts, and have a stem-like axis without xylem or phloem.

What are the components of a mature moss sporophyte?

A mature moss sporophyte consists of a capsule, seta, and foot.

How do mosses reproduce sexually?

Mosses reproduce sexually through gametangia forming at apices, where sperm swim to archegonia to fertilize the egg.

What is calyptra in mosses?

Calyptra is the cap that forms on top of the sporophyte after the top of the archegonium splits off.

What is the function of operculum in mosses?

Operculum, at the tip of the capsule, covers the peristome and opens or closes in response to humidity.

What ecological role do peat mosses play?

Peat mosses are ecologically important as they help retain moisture in bogs and provide habitats.

What distinguishes liverworts from mosses?

Liverworts have flattened, lobed thalli and lack true xylem and phloem.

What are the features of hornworts?

Hornworts have a thallus with one large chloroplast per cell, and mature sporophytes that resemble miniature roots.

What human applications do peat mosses have?

Peat mosses are used as soil conditioners, poultice materials, and fuel due to their high absorptive capacity and antiseptic properties.

What type of environments can bryophytes colonize?

Bryophytes can colonize a variety of habitats including damp banks, bare rocks, and alpine slopes.

What are the three main adaptations plants developed for living on land?

1. Development of a fatty cuticle to reduce water loss. 2. Multicellular gametangia and sporangia. 3. Development of multicellular embryos.

What is the structure of moss gametophytes?

Leaves are usually one-cell thick except at midrib, contain chloroplasts, and have a stem-like axis without xylem or phloem.

What are the components of a mature moss sporophyte?

A mature moss sporophyte consists of a capsule, seta, and foot.

How do mosses reproduce sexually?

Mosses reproduce sexually through gametangia forming at apices, where sperm swim to archegonia to fertilize the egg.

What is the function of operculum in mosses?

Operculum, at the tip of the capsule, covers the peristome and opens or closes in response to humidity.

What are the features of hornworts?

Hornworts have a thallus with one large chloroplast per cell, and mature sporophytes that resemble miniature roots.

What type of environments can bryophytes colonize?

Bryophytes can colonize a variety of habitats including damp banks, bare rocks, and alpine slopes.

What is the function of the fatty cuticle in land plants?

The fatty cuticle helps to reduce water loss from the plant's surface.

What are multicellular gametangia and sporangia in land plants?

Multicellular gametangia are structures that produce gametes, while sporangia are structures that produce spores.

Why is the development of multicellular embryos an important adaptation for land plants?

Multicellular embryos are protected and nourished by the parent plant, increasing their survival rate in terrestrial environments.

What is the function of the capsule in a moss sporophyte?

The capsule is the part of the moss sporophyte that contains and releases spores.

What is the seta in a moss sporophyte?

The seta is the stalk that elevates the capsule, aiding in spore dispersal.

What is the foot in a moss sporophyte?

The foot is embedded in the gametophyte and absorbs nutrients for the sporophyte.

How are peat mosses used as soil conditioners?

Peat mosses improve soil structure and enhance its water retention capacity.

Why were peat mosses historically used as poultice materials?

They were used due to their high absorptive capacity and antiseptic properties, making them suitable for wound dressing.

Can peat mosses be used as fuel?

Yes, dried peat mosses can be harvested and used as a source of fuel, particularly in regions where they are abundant.

What is an apice?

Apice (plural: apices) refers to the tip or highest point of an organ or part, such as the apex of a stem or root in a plant.

What is an archegonia?

The female gametangia in bryophytes that produce egg cells; in sexual reproduction, sperm swim to the archegonia to fertilize the egg.

What is an antheridia?

The male gametangia in bryophytes that produce sperm cells; during sexual reproduction, sperm released from antheridia swim to archegonia to fertilize the egg.

What is a thallus? (plural: thalli)

A plant body that is not differentiated into true roots, stems, and leaves. It is the main body of a bryophytic plant and carries out photosynthesis and nutrient absorption.

Where are gametangia found?

True for both antheridia and archegonia, it’s found at the apice of a gametophyte stalk.

Where is the sporangia found?

The tip of the seta, producing and decimating spores for reproduction.

How does a plant enter the sporophyte generation?

Gametes fuse during fertilization in gametangia, forming a diploid (2n) zygote that develops into the sporophyte generation, staying attached to the gametophyte for nutrition.

What is the ploidy of the sporophyte generation?

It is diploid (2n), resulting from the fusion of gametes during fertilization.

What is the ploidy of the gametophyte generation?

It is haploid (n), developed from spores through mitosis and responsible for producing gametes.

How does a plant enter the gametophyte generation?

This begins when spores (2n) undergo meiosis to form haploid (n) spores. Mature spores are released from the sporangium and, in the right environment, germinate & develop through mitosis into a new gametophyte.

What is the peristome?

“Teeth” at the tip of the capsule that are hygroscopic, releasing spores at the correct humidity.