Traits of the Truly Terrestrial Plants

G. Land plants must have a root system.

1. For anchorage and structural support.

2. For absorption of water and minerals.

Traits of the Truly Terrestrial Plants

H. Land plants must have protection from drying out.

This is usually accomplished by a thick cuticle or bark.

Classification of Land PlantsAll land plants are either

vascular plants or nonvascularplants.

1. Vascular plants have vascular tissue and nonvascular plants do not have vascular tissue.

a) Vascular tissue is tissue that conducts food and water throughout the plant.

b) Phloem: Carries food down the plant from the leaves.

c) Xylem: Carries water up the plant from the roots.

Vascular plants are referred to as “tracheophytes.”

These are the true land plants.

Nonvascular plants are referred to as “bryophytes.”These are the “in-between” plants.

They are still tied to a watery existence. They do not have vascular tissue and they are not

well suited to life on land. The bryophytes include mosses and liverworts.

Tracheophytes (Vascular Plants) are further subdivided into "Seed Plants" and "Seedless Plants".

The seed plants do produce seeds

The seedless plants do not produce seeds.

Seedless plants include the ferns.

Angiosperms are the flowering plants.

Gymnosperms are the cone-bearing plants.

The Angiosperms are divided into:monocots and dicots.

Corn is a Monocot.

Oak trees are dicots.

The differences between monocot and dicots will be discussed later in the lesson.

Kingdom Plantae

Nonvascular Plants(Bryophytes)

Liverworts and Mosses

Vascular Plants(Tracheophytes)

Seedless Plants Seed Plants

Ferns

Gymnosperms(cone-bearing)

Angiosperms(flowering)

DicotsMonocots

Let’s summarize this information on the

flow chart.

The Bryophytes: Mosses and other nonvascular plants have life cycles dominated by

gametophytes.

Characteristics of the Bryophytes:

1. Bryophytes are called the "in-between" plants. They live on land, but are not well suited to life as a terrestrial plant.

Liverworts

Hornworts

Mosses

Bryophytes produce _____________, and must have _____ to reproduce.

During part of their life cycle, they produce _____ that must _____ through water to reach the egg. They must live in places

where there is rainfall or dew for at least part of

the year.

motile gametes water

spermswim

Bryophytes have no……true roots, stems and

leaves.

Although bryophytes do not have true roots, they do

possess rhizoids. Rhizoids are root-like

structures that anchor the plant to the ground. Rhizoids are capable of:

absorbing water and minerals from the soil. Water moves from cell

to cell through the rhizoids and into the

rest of the plant.

Bryophytes….

Bryophytes are nonvascular plants. This means they have no…… vascular tissue (xylem or phloem). These plants can draw up water by osmosisonly a few centimeters above the ground. This prevents them from growing very big.Bryophytes have multicellular reproductive structures.

NOTE: In bryophytes, the gametophyteis the dominant, recognizable stage of the life cycle and is the stage that carries out most of the plant’s photosynthesis.

Bryophytes have alternation of generations.

In tracheophytes, the sporophyte is the dominant, recognizable stage of the life cycle and is the stage that carries out most of the plant’s photosynthesis.

As members of the plant kingdom, they

do possess chlorophyll and

carry out photosynthesis.

Characteristics of Liverworts Include:

The liverworts have thin, leathery leaves that lie flat against the surface of the

ground.

They are anchored by rhizoids on the lower side. (Rhizoids are root-like structures that are used for anchorage and absorption. Rhizoids are not true roots since they contain no vascular tissue.)

The plant body is called a thallus.

Liverworts reproduce asexually by producing gemmae.

Gemmae are small reproductive structures that are often produced inside

a gemmae cup. When washed out of the cup, the

gemmae can divide by mitosis to produce a new individual.

Liverworts can reproduce both:

asexually and sexually.

Liverworts also have alternation of

generations, with the gametophyte

generation being the dominant generation.

Life cycle of the LiverwortLabel the numbered structures seen in the drawing to the right:

1 – thallus2 – rhizoids3 – gemmae cup4 – antheridial ray (male

gametophyte)5 – archegonial ray (female

gametophyte)6 – archegonium7 – egg8 – antheridium9 – sperm10 – sporophyte plant11 – old archegonium12 – spores

This area enlarged.

This area enlarged.

Sperm swims in water to reach egg.

This area enlarged after fertilization

Female Gametophyte

Male Gametophyte

Archegonial Ray

Antheridial Ray

Archegonium

Antheridium

sperm egg

zygoteSporophyte(inside old archegonium)

sporangium

spores

Sperm swims through water to reach egg.

meiosis

2N2N2N

1N 1N 1N

1N 1N

1N

mitosis

Flow Chart for the Liverwort life cycle

Note: Concerning alternation of generations in the

liverworts:➢ The gametophyte

generation is dominant.➢ The sporophyte is

completely parasitic on the gametophyte.

➢ Flagellated sperm must swim through water to reach the egg inside the archegonium. This is a disadvantage to plants living on land.

1. The moss plant grows upright. 2. It does not have true roots, stems, and

leaves.3. Mosses are found in moist, shady

places. The moss plant goes into a dormant stage when water supply is low. It grows for only a few days after each rain.

4. The sporophyte generation is more advanced than in the liverworts, but the gametophyte generation is still the dominant generation.

Characteristics of Mosses

Life cycle of the moss.

Gametophyte plant

Gametophyte plant

1 – leaf like structure2 – stalk3 – rhizoids4 – archegonium5 – egg6 – antheridium7 – sperm8 – zygote9 – young sporophyte

plant10 – seta11 – capsule12 – spores13 – protonema

(young gametophyte plant)

Sperm swims in

water.

Sperm swims down to egg.

Fertilization occurs.

Zygote grows by mitosis

Gametophyte plant

Sporophyte plant

Protonema matures and grows into adult plant.

Female Gametophyte

Male Gametophyte

Archegonium

Antheridium

sperm egg

zygoteSporophyte(seta and capsule)

sporangium

spores

Sperm swims through water to reach egg.

meiosis

2N2N2N

1N 1N

1N 1N

1N

mitosis

Flow Chart for the Moss life cycle

protonema1N

Mosses: A recap

Gametophyte: Upright, leafy looking, with rhizoids.

Sporophyte: Grows out of the old archegonium. It cannot live independently.

Sporophyte Plant

Gametophyte Plant

The protonema is produced when a _____ germinates and grows into a tangled mass of ______________. The protonema grows into the ___________ plant.

Protonema:The protonema is

the young gametophyte

plant.

spore

green filamentsgametophyte

The sporophyte consists of a foot, a seta (or stalk), and a sporangium. The foot is embedded in the archegonium and is used to absorb nutrients from the gametophyte plant.

The capsule is the sporangium and produces spores.

The Seedless Vascular Plants

Evolution of Vascular Tissue

In the bryophytes, the only method of moving water through the plant body is for the water to move from cell to cell by osmosis. This limits the growth of the plant. Bryophytes are small and grow close to the ground because they have no way to transport water large distances.

The fossil record indicates that about 420 million years ago, the small moss-like plants that inhabited the landmasses were joined by…..…..plants that were taller and grew to the size of small trees.