WSU BIO 1501 Lab Chapter 6: Introduction to Plants

Plants

Multicellular eukaryotes, most of which produce their own food through photosynthesis and have adapted to life on land in one spot, and produce gametes by growing an external structure

Autotrophic

An organism capable of synthesizing its own food from inorganic substances, using light or chemical energy. Green plants, algae, and certain bacteria are autotrophs.

Photosynthesis

Process by which plants and some other organisms use light energy to convert water and carbon dioxide into oxygen and high-energy carbohydrates such as sugars and starches

Male Antheridia

Male reproductive structures found in the haploid gametophyte stage of non-flowering plants like mosses, ferns, and liverworts. They produce and release sperm cells, which require water to swim and fertilize an egg

Female Archegonia

Female reproductive structures found in the haploid gametophyte stage of non-flowering plants like mosses, ferns, and most gymnosperms. An archegonium produces and houses a single egg cell and is typically flask-shaped

True or False: Gametophyte stage is haploid (n), so it produces gametes by mitosis

True

Alternation of Generations

The alternation between the haploid gametophyte and the diploid sporophyte in a plant's life cycle

Gametophyte

Haploid (n) 1 set of chromosomes, multicellular structures, produces gametes by mitosis

Sporophyte

Diploid (2n), 2 sets of chromosomes, or spore-producing via meiosis, phase of an organism

Syngamy

The fusion of two cells, or of their nuclei, in reproduction

Sporangium

A structure within the diploid sporophyte stage of a plant's life cycle that produces and houses haploid spores via meiosis. These spores are crucial for the reproduction and dispersal of the plant

Spore Mother Cell

Also called a sporocyte, is a diploid (2n) cell found within the sporangia of plants. It is the specific cell type that undergoes meiosis to produce haploid (n) spores.

Phylum Hepatophyta

Known as Liverwarts, they are limited in size and restricted to moist environments because they lack a vascular system and require water for reproduction

Phylum Hepatophyta Thallus (n)

The body of a plant-like organism that is not divided into leaves, roots, or stems. It houses the gemma cups with gemmae (n)

Phylum Hepatophyta Rhizoids

A thin, rootlike structure that anchors a moss and absorbs water and nutrients.

Phylum Hepatophyta Gemma Cups

Structures that house gemmae, tiny lens-shaped pieces of thallus that are a form of asexual reproduction in liverworts

Phylum Hepatophyta Gemmae

A form of asexual reproduction found in some species of liverworts. They are small, multicellular, haploid discs of tissue produced inside specialized, cup-shaped structures called gemma cups on the surface of the thallus, which is the liverwort's main body

Phylum Hepatophyta Archegoniophore

A specialized, stalk-like structure found in certain thalloid liverworts. It is part of the haploid gametophyte and bears the female reproductive organs, the archegonia, looks like a palm tree.

Phylum Hepatophyta Antheridiophore

A specialized, stalk-like structure found in certain thalloid liverworts, that bears the male reproductive organs (the antheridia). It is part of the haploid gametophyte stage and is crucial for sexual reproduction in these plants, looks like a flattened flower

True or False: The sporophyte phase in Phylum Hepatophyta is not microscopic

False

Phylum Hepatophyta Sexual Reproduction

1. A gametophyte produces male or female stalks (antheridiophores or archegoniophores).

2. Rainwater splashes sperm from a male stalk to a female stalk.

3. The sperm fertilizes the egg, forming a zygote.

4. The zygote grows into a tiny sporophyte, which lives on the female gametophyte.

5. The sporophyte produces spores through meiosis.

6. The spores are released and grow into new gametophytes.

Phylum Hepatophyta Asexual Reproduction

1. Rainwater splashes tiny pieces of tissue called gemmae from cups on the gametophyte.

2. Each gemma can grow into a new, genetically identical gametophyte.

Phylum Bryophyta

Commonly known as a moss, it lacks vascular tissue, true roots, stems, and leaves. The gametophyte stage is the dominant stage of life, and requires water for sperm transport, meaning it reproduces via spores

True or False: Sexual reproductive structures are not housed at the tips of the mature gametophyte filaments?

False

Phylum Bryophyta Antheridia

Within the phylum Bryophyta (mosses), the antheridium is the multicellular, sac-like male reproductive organ. Its primary function is to produce and hold numerous sperm cells, which are required for sexual reproduction. Shaped like long ovals.

Phylum Bryophyta Archegonia

Within the phylum Bryophyta (mosses), the archegonium is the multicellular female reproductive organ. Its primary function is to produce and house a single egg cell, which, upon fertilization, will give rise to the diploid sporophyte generation, look like bowling pins

Phylum Bryophyta Stalk

Known as the seta, the role of the seta is to elevate the spore-containing capsule high above the dense mat of the leafy gametophyte. This elevation is crucial for effective spore dispersal, allowing wind or water to carry the spores away to new locations for germination

Phylum Bryophyta Capsule

The terminal, spore-producing structure of the diploid sporophyte. Also known as a sporangium, its primary function is to create and disperse the spores necessary for the moss life cycle to continue. The capsule is located at the top of the seta (stalk), which elevates it for better spore dispersal

Phylum Bryophyta Sexual Reproduction

1. A moss must be wet for its life cycle to continue. Male mosses release sperm that swim through a film of water to reach the eggs on a female moss plant.

2. After a sperm fertilizes an egg, a new structure called a sporophyte starts to grow out of the female moss. It consists of a stalk with a small capsule on top. The sporophyte is dependent on the green, leafy moss plant for nutrients.

3. Inside the capsule, cells divide to produce millions of tiny spores. When the capsule is mature and the air is dry, it opens to release the spores, which are then carried away by the wind.

4. If a spore lands in a moist area, it germinates and grows into a new green, leafy moss plant, starting the cycle all over again.

Phylum Bryophyta Asexual Reproduction

1. A small piece of the moss plant—like a fragment of a leaf or stem—simply breaks off.

This can happen naturally from wind, animals brushing against it, or heavy rain.

2. Some mosses and liverworts produce tiny buds called gemmae in special cups on their surface.

Raindrops splash into these cups and scatter the gemmae, which then grow into new plants.

3. If a detached fragment or gemma lands in a moist, suitable spot, it will begin to grow.

The new growth forms a complete new moss plant that is a genetic copy of the parent.

Phylum Pterophyta

Known as ferns, they have vascular tissue, roots, stems, and leaves. They reproduce via spores, and the sporophyte stage is the dominant stage life.

Phylum Pterophyta Frond

(2n) The large, complex leaves of ferns. They grow from an underground or above-ground stem called a rhizome and are the most visible part of the fern

Phylum Pterophyta Rhizome

A creeping, underground, horizontal stem from which the roots and fronds of the fern grow. It is the most common form of stem in ferns, though some species may have upright or above-ground stems

Phylum Pterophyta Sori

Clusters of sporangia, which are the spore-producing sacs of a fern. They are typically located on the underside of a fern's fronds and are a key feature for identifying different fern species

Phylum Pterophyta Fiddlehead

The tightly coiled, young frond (shoot) of a fern as it emerges from the ground. The coiled shape, which resembles the scroll of a violin or fiddle

Phylum Pterophyta Sexual Reproduction

1. The leafy fern you recognize is the sporophyte. On the underside of its fronds are clusters of spore cases called sori.

2. When mature, the sori release haploid spores into the air.

3. A spore lands on moist ground and grows into a small, heart-shaped plantlet called a prothallus (the gametophyte).

4. The prothallus produces both sperm and eggs. When water (like rain or dew) is present, the sperm swim to fertilize an egg.

5. The fertilized egg grows into a new sporophyte, which eventually becomes the large, familiar fern plant. The tiny prothallus withers away as the new fern grows.

Phylum Pterophyta Asexual Reproduction from the Rhizome

1. Rhizomes are underground stems that grow horizontally away from the parent fern.

2. New ferns can sprout from different points along the rhizome, creating a colony of genetically identical plants.

3. Division can also happen naturally when an older part of the rhizome dies and breaks away, leaving behind separate, independent plants

Phylum Pterophyta Asexual Reproduction from the Frond

1. Walking ferns grow new, tiny plantlets, or bulbils, directly on the tips of their fronds.

2. These fronds "walk" across the forest floor as they bend down and touch the ground, where the plantlet takes root and grows into a new fern.

Phylum Pterophyta Prothallus

A tiny, heart-shaped, independent gametophyte, or sexual generation, of a fern. It is a short-lived, delicate, and often inconspicuous structure that arises from a germinating spore

Which of the following is the dominant, free-living, and photosynthetic generation in the liverwort life cycle?

Gametophyte

Asexual reproduction in some liverworts, such as Marchantia, is accomplished by the production of gemmae within what structures?

Gemmae Cups

Which statement is true about the sporophyte of a liverwort?

It is very small and dependent on the gametophyte

In the liverwort life cycle, what is the ploidy level (1n or 2n) of the gametophyte?

Haploid (1n)

In sexual reproduction, the female reproductive organ that produces an egg in a liverwort is called a(n)?

Archegonium

What is the dominant, independent, photosynthetic stage in the life cycle of a moss?

Gametophyte

The tiny, root-like structures that anchor a moss plant to its substrate are called?

Rhizomes

The diploid sporophyte of a moss grows from the gametophyte and produces what via meiosis?

Spores

Where does meiosis occur in the moss life cycle?

In the sporangium (Capsule)

What is the dominant, independent, and photosynthetic generation in the life cycle of a fern?

Sporophyte

In ferns, the clusters of sporangia, which are found on the underside of the leaves (fronds), are called?

Sori

The tiny, heart-shaped, free-living, and haploid gametophyte of a fern is known as the?

Prothallus

Which part of the fern produces the male reproductive organs (antheridia) and female reproductive organs (archegonia)?

Prothallus

How do ferns reproduce sexually?

By dispersing spores that germinate into a gametophyte