Kingdom Plantae
 What are the 4 main characteristics of the
Kingdom Plantae?
 Eukaryotic
 Multicellular
 Autotrophic
 Cell Wall Present

4 Additional Characteristics
 1) Cuticle
 2) Stomata
 3) Secondary Products
 4) Starch Storage

1) Cuticle
 Waxy layer on stems and leaves to prevent water loss.
 Necessary for plants to survive in terrestrial environments.
 Problem: Cuticle blocks CO
2 and O
2 gas exchanges between the cells and the environment. Solution:
2) Stomata
 Pores on plant surfaces for gas exchange.
 Comment – plants must balance need for CO
2 uptake with H
2
O loss.

 3) Secondary Products
 Materials not produced by the primary metabolic pathways.
 Examples:
 cuticle waxes
 Lignin (wood)
 Sporopollenin (pollen grains)
 4) Starch Storage
 Most plants store extra food as starch.
 Ex: chloroplasts amyloplasts

Plant Life Cycle
 Alternation of
Generations.
 Plants exist in two body forms.
 Sporophyte (2N)
- makes spores.
 Gametophyte
(1N) - makes gametes.

Spores
 Produced by meiosis.
 Grows directly into a gametophyte by mitosis.

Gametophyte
Produces gametangia by mitosis.
 Gametes protected by a jacket of "sterile" cells.

Sterile cells
Antheridia
Sperm
 Male gametangia.
 Produce sperm (may be flagellated).
Archegonia
 Female gametangia.
 Produce eggs.
Egg
Sterile Cells

Plants: 4 Evolutionary Trends
1. Reduction of Gametophyte.
2. Change from flagellated sperm to pollen.
3. Development of seeds, flowers, and fruits.
4. Development of vascular tissues.

Evolution of Plants
 From green algae called Charophytes.

Origin of two body forms?


May have been an adaptation or delay of meiosis due to the lack of water.
Comment – primitive plants have swimming sperm and depend on water for fertilization.
 Movement from water to land
 Modern Charophytes grow in shallow water. This may have allowed them to be pre-adapted to move to land.

Plant Taxonomy
 Class = Division
 - phyta : suffix for the division name.

Plant Emphasis
1. Examples
2. Characteristics
3. Life History
4. Importances

Divisions: Examples
 Bryophyta - Mosses
 Hepatophyta - Liverworts
 Anthocerophyta - Hornworts
 ~17,000 species

Nonvascular Seedless Land Plants

The "Bryophytes”
 Ex: Mosses, Liverworts, Hornworts

Moss Leaf
Characteristics
 No vascular tissue (in most).
 No seeds, flowers or fruits.
 Flagellated sperm.
 Gametophyte dominant.
 Often found in wet habitats Why?
 Reasons:
 Water uptake by osmosis only.
 Need water for sperm to swim.
 Are never more than 10 cm tall. Why?
 No wood or support tissue
 Can’t move water up against gravity (no xylem or phloem).

Life History
 Gametophyte dominant.
 Sporophyte parasitic on gametophyte.

Gametophyte
 Photosynthetic
 Produces antheridia and archegonia.
 Needs rain for sperm dispersal.
Antheridia
Archegonia

Sporophyte
 Produces spores in a sporangium or capsule.
 Parasitic on the gametophyte.
Sporangium
Spores

Bryophytes -Importances
 Peat Moss (many uses).
 Soil Formation.

Pteridophytes:
Seedless Vascular Plants
 Examples Divisions:
 Psilophyta – Wisk ferns
 Lycophyta - Club Mosses
 Sphenophyta - Horsetails
 Pterophyta - Ferns
 ~13,000 species, mostly ferns

Pteridophytes:
Seedless Vascular Plants
 The ferns and fern allies.
 A collection of several different plant divisions.

Characteristics:
 True vascular tissue.
 Xylem – water.
 Phloem – food.
 No seed, flowers or fruits.
 Flagellated sperm.
 Sporophyte dominant.

Life History:
 Sporophyte dominant.
 Gametophyte reduced, but usually independent from the sporophyte.

Life Cycle

Spore Types
 Homosporous - one kind of spore (most fern allies).
 Hetrosporous - two kinds of spores.
 Microspores  males  sperm
 Megaspores  females  eggs

Psilotum – a Wiskfern
 Oldest known vascular plant.
 Has dichotomous branching (a primitive character).
 True stems only, no roots or leaves.
Sporangia

Lycopodium - a Club Moss
 Spores are in clusters of sporangia called a strobilus, which is a primitive type of cone.
Strobilus

Equisetum - Horsetails
 Have silica in cell walls.
 Also called scouring rushes.
 Have strobili on some stems.
Strobilus

True Ferns
 Most diverse division.
 Forms range from aquatic to tree-like.
 Spores formed in sporangia called a sorus.

Ferns
 Leaf called a frond.
 Often have underground stems called rhizomes.

Fern – Life cycle
 Sporophpyte  Sori on fronds

Fern – Life Cycle
 Sorus  Sporangium

Fern – Life Cycle
 Germinating Spore  Gametophytes

Young Sporophytes

Importances
 Psilophyta:
 1 form eaten.
 1st true vascular plant.

Importances
 Lycophyta:
 Christmas decorations.
 Terrarium plants.
 Spores used as baby powder.

Importances
 Sphenophyta:
 Scouring rushes.
 Tinker toy plants.

Importances
 Pterophyta:





Landscaping and houseplants.
Food (limited).
Lumber (limited).
Home for nitrogen-fixing cyanobacteria.
Coal.

Summary
 Know the general characteristics of plants.
 Know the alternation of generations for plants.
 What are the evolutionary trends in plants?

Summary
 For each plant division, know:
 Examples
 Characteristics
 Life History
 Importances