Plant Structure

Structure of plants

Roots

Stem

Leaves

Pkant tissue

Roots

Organ to anchor the plant in the soil.

Absorbs water and minerals.

Stores carbohydrates.

Types of roots

Tap root

Fibrous root system

Modified roots

Taproot

Main root in dicots.

Lots of rain.

Lateral roots: branch roots.

Adapted to find water deep underground.

Fibrous system root

No main root in monocots.

Mat of thin roots spreading below soil surface.

Shallow roots adapted to absorb water at the surface.

Root hairs

Increase surfce area to absorb water.

Diacot and monocot.

Root cap

Protects apical meristem

Modified roots

Prop roots

Storage roots

Strangling aerial roots

Buttress roots

Pneumatophores

Prop roots

Above groud structure to brace and support top-heavy trees.

Storage roots

Store water and food.

Strangling aerial roots

Wrap around host plant extending toward the ground.

Buttress root

Above- ground, architectural structure to hold up large trees.

Pneumatophores

Air roots, acquire air for underwater root systems.

Stems

Organ that raises leaves and reproductive structures.

Stems’ structure

Nodes

Internode

Apical meristem

Axillary meristem

Nodes

Point where leaves are attached.

Internode

Space in between nodes

Apical meristem

Growing point at the top/bottom (terminal bud).

Axillary meristem

Growing point at nodes on the sides forms brances (lateral bud).

Apical dominance

Axillary buds close to the apical buds are inhibited.

Cut off apical bud to release axillary buds to grow.

*Pruning a tree/bush makes it grow wider instead of taller.

Modified stems

Rhizome

Bulb

Stolon

Tuber

Rhizome

Horizontal shoot that grows underground.

*Ginger, turmeric, lotus

Bulb

Underground storage structure, short stem with fleshy leaves

*Onion, garlic, lily, tulip

Stolon

Runner, horizontal shoot for asexual reproduction.

*Strawberry, aspen

Tuber

Enlarged ends of stolons or rhizomes for storing food

*Potato: eyes of the potato are axillary buds at the nodes.

Leaves

Main photosynthetic organ

Leaves’ structure

Blade

Petiole

Blade

Flat part

Petiole

Leaf stalk

Types of leaves

Simple

Compound

Doubly compound

Simple

Single undivided blade

Compound

Blade is divided into multiple leaflets (pinnate).

Doubly compound

Leaflets are divided into smaller leaflets (bipinnate).

Modified leaves

Tendrils

Spines

Storage leaves

Reproduction leaves

Bracts

Tendrils

Clings to surfaces to allow a vine to climb.

Spines

Sharp needles for protection for protection

Storage leaves

Store water

*Aloe

Reproduction leaves

Plantlete for asexual reproduction.

Bracts

Brightly coloured to attract pollinators to flowers.

Plant tissue

Dermal tissue

Vascular tissue

Ground tissue

Growth

Leaf tissue

Dermal tissue

Epidermis

Cuticle

Trichomes

Epidermis

Layer of cells on the outside

Cuticle

Waxy coating on the epidermis

Trichomes

Hairy defense mechanism against herbivores.

*Can secrete sticky or toxic substances.

Vascular tissue

Xylem

Phloem

Stele

Xylem

Conducts water and dissolved minerals.

Nitrogen: nucleic acids, protein

Potassium: enzyme cofactor

Magnesium: chlorophyll

Phosphorous: nucleic acids, phospholipids, ATP

Phloem

Transport organic material (carbohydrates, proteins)

Stele

Vascular bundle in the roots

*Dicots

*Monocots

Dicots

Xylem in the shape of a cross, phloem is in between

Monocots

Inner ring of xylem, outer ring of phloem

Ground tissue

Pith (medulla)

Cortex

Pith (medulla)

Soft, spongy middle filler tissue.

Function: fill space.

Cortex

Outer filler layer below epidermis

Growth

Interminate growth

Determinate growth

Interminate growth

Always growing (roots, shoots?

Determinate growth

Stop growing after reaching a certain size (flowers, leaves)

Leaf tissue

Stomata

Dicot mesophyll

Bundle sheath cells

Stomata

Guard cells: two cells that control opening/closing of stoma

Dicot Mesophyll

Palisade mesophyll

Spongy mesophyll

Palisade mesophyll

Tall mesophyll cells on top side (absorb light)

Spongy mesophyll

Loosely arranged shorter cells (CO2 and O2 circulation)

Bundle sheath cells

Surround vascular tissue (surround xylem and phloem)