Classification of Classification of PlantsPlants

CHAPTER 28 CHAPTER 28

Plant Kingdom

Flowering Plants

Non-flowering Plants

3 groups

FernsFernsMossesMosses GymnospermsGymnosperms

Non - flowering Plants

Do NOT produce flowers

A plant can be divided into 3 partsA plant can be divided into 3 parts

Examples of Examples of MossesMosses

spores

Spore-producing capsule

No true roots, No vascular tissues (no transport)

Characteristics of Characteristics of MossesMosses

Simple stems & leaves

Have rhizoids for anchorage

Spores from capsules (wind-dispersal)

Damp terrestrial land

Simplest plants

underground stem

root

A leaf (finely divided into small parts)

roots, feathery leaves & underground stems

Characteristics of Ferns

have vascular tissuesvascular tissues (transport & support)

DampDamp & shadyshady places

Spore-producing organSpore-producing organ on the underside of leaves (reproduction)

needle-shaped leaves

Male cones (in clusters)

Female cones (scattered)

roots, woody stems

Characteristics of Characteristics of GymnospermsGymnosperms

needle-shaped leaves

tall evergreen trees

cones with reproductive structures

dry places

vascular tissues (transport)

naked seeds in female cones

2 2 groupsgroups

MonocotyledonsMonocotyledons DicotyledonsDicotyledons

Flowering Plants

roots, stems, leaves

vascular tissues (transport)

flowers, fruits (contain seeds)

MonocotyledonMonocotyledonss

Parallel veins

one seed-leaf

Characteristics of Characteristics of MonocotyledonsMonocotyledons

leaves have parallel veins

herbaceous plants

e.g. grass, maize

DicotyledonDicotyledonss

Veins in network

two seed-leaves

Characteristics of Characteristics of DicotyledonsDicotyledons

leaves have veins in network

e.g. trees, sunflower, rose

Plant Plant ClassificationClassificationNon-flowering

Plants

Flowering

Spore-bearing

Naked seeds

No roots

with roots

Mosses Ferns

Gymnosperms

1 seed-leaf

2 seed-leaves

Monocots Dicots

Plant Structure and

Function

CHAPTER 29

Stem

The main body of the portion above ground of a tree, shrub or herb.

The ascending plant axis. Have buds.

Stem Functions

Support of other plant organs. Ps. Storage (water and food).

Modified Stems

1. Rhizomes

2. Stolons

3. Tubers

4. Tendrils

Rhizome

An elongated underground horizontal stem.

Ex: Iris, many grasses

Stolon

An elongated above-ground horizontal stem.

Ex: Strawberries Airplane Plant

Tuber

A much-enlarged, short, fleshy underground stem tip.

Ex: Dahlia, Potato

Leaf

Lateral outgrowths of the stem axis.

Primary photosynthetic organs. Function:

Photosynthesis Storage

Leaf Modifications

1. Tendrils: for support Ex: Peas

2. Bulbs: for food storage Ex: Onion

3. Insect Catching Ex: Carnivorous Plants

4. Flowers: thought to be modified leaves.

Tendrils Spines

Succulent Leaves Bracts

Other Modifications of Leaves

Root

The descending axis of a plant, normally below ground.

Functions: Anchorage. Absorption of water and minerals. Storage.

Root Types

Taproot - one main root. Ex: carrot

Fibrous Roots - many small roots of equal size. Ex: grass roots

Other Root Types

Sexual Organs

1. Flowers

2. Fruits

3. Seeds

Flowers

Modified leaves grouped together on a stem.

Sexual reproductive organs. Function:

Sexual Reproduction

Fruit

A mature ovary, sometimes including other floral parts.

Function: Seed dispersal Seed protection

Fruits

Seed

Mature ovule containing the embryo and nutrient tissues.

Function: Dispersal unit in sexual

reproduction.

Main Tissue Systems

1. Dermal

2. Vascular

3. Ground

Dermal Tissue

Epidermis or "skin" of the plant.

Often has a cuticle, a waxy coating to prevent water loss.

Functions: Prevent water loss. Water absorption (root hairs).

Vascular Tissue

Made of Xylem and Phloem. Functions:

Transport and support Xylem - Water Phloem - Food

Phloem

Phloem

Sieve Cell – alive when functioning, but lacks a nucleus.

Companion Cell – alive, controls itself and the sieve cell.

Root Hairs Extensions of the epidermis to

increase surface area for water absorption.

Not a true tissue. Comment - root hairs are very

delicate and must be continually replaced.

Root Hairs

Leaves

Stem outgrowths for Ps. Leaf Morphology:

1. Gross

2. Fine

Gross Morphology

Blade - the flattened portion of a leaf.

Petiole - stalk of a leaf.

Blade

Petiole

Axillary Buds

Blade/Leaf Types Simple - 1 blade. Compound - Several blades.

Nodes and Internodes

Node - stem area where a leaf and bud are attached.

Internode - stem area between nodes.

Nodes

Internode}

Fine Morphology

The tissues within a leaf.

1. Upper Epidermis

2. Mesophyll

3. Lower Epidermis

4. Veins

Upper Epidermis

Cuticle present. Usually 1 cell layer thick. Cells w/o chloroplasts . Function: protects the

mesophyll.

Mesophyll

1. Palisade upright cells.

2. Spongy loosely organized cells with air spaces.

Function: major sites for Ps.

Epidermis

Epidermis

Lower Epidermis

Cuticle present. Usually 1 cell layer. Cells w/o chloroplasts. Stomata present for gas

exchange.

Stomata (mouth)

Regulated by Guard Cells which have chloroplasts.