Structures of

Seed Plants

Quick ReviewWhat are the two kinds of vascular tissue and what are their jobs?

What are the four groups of plants and the example for each?

Why do seeds provide a survival advantage? (2 things)

Why are flowers & fruits advantageous?

What is the structure on all plants that helps them avoid drying out?

What lives in the pollen grain?

Explain the life cycle of all plants.

Plant Systems

** Just like we have body systems to different jobs (circulatory, respiratory, etc.), so do plants

1. Root System - made up of only roots

2. Shoot System - stems and leaves

** The vascular tissues of the two systems are connected so the water/food go through the whole plant

Roots - Functions

Mostly underground

Supply plants with water and dissolved

minerals from the soil (move up xylem)

Hold plants securely in the soil

Store extra food (sugar) made during

photosynthesis (moved down the

phloem)

Roots - Structure

Outer layer of cells - Epidermis

Center of root holds vascular tissue

Water diffuses from epidermis to xylem

Tip of root - Root Cap

Root cap produces slime to help root push

through the soil as it grows longer

Roots - 2 Types

Taproot (found mostly in dicots)

– one main root growing downward

with tiny small roots that branch out

– get water deep underground (carrot)

Fibrous (found mostly in monocots)

– several roots spread out from the base of

the stem

– they’re all about the same size

– get water close to the surface (grass)

Stems - Function

Usually located above ground

Connects the roots to leaves and

flowers

Supports the plants body

Leaves get better sunlight

Flowers are off the ground to be closer to

animals for seed dispersal/pollination

Some stems store materials (cactus)

Stems - 2 Types

Herbaceous Stems

– soft, thin and flexible

– Ex: beans, wildflowers, clovers

Woody Stems

– rigid stems made of wood and bark

– Ex: trees and shrubs

Leaves - Function

Make food for the plant (sugar)

Absorb Carbon Dioxide (CO2)

*Photosynthesis Equation*

Water + CO2 + light energy --> sugar +O2

Leaves - Structure

Outer surface - covered in a cuticle to prevent water loss

Epidermis - single layer of cells beneath the cuticle (light can pass through)

Stomata: openings in the epidermis that let CO2

into the leaf

Guard Cells: open and close the stomata

Palisade Layer - one of the middle layers that has many chloroplasts (for photosynthesis!)

Spongy Layer - where xylem & phloem are found

Leaf Diagram

Gas Exchange in Leaves

CO2 enters the plant’s leaves through the stomata

Stomata: holes in the leaf’s epidermis; surrounded by guard cells which open and close the stomata

Water can also escape through these stomata (BAD!). This loss of water from leaves is called Transpiration.

Flowers - Function

Adaptations for sexual

reproduction

Colorful flowers attract

animals for pollination

Flowers produce

nectar, which animals

drink and thus pollinate

the plant

Flowers - Basic Parts

4 Basic Parts:

Sepal - modified leaves that make up the outermost ring of flower to protect the bud

Petal - broad, flat, thin leaf-like parts of a flower; attract animals to pollinate

Stamen - male reproductive structure; made up of a filament and an anther

Pistil - female reproductive structure on a flower; made up of the stigma, style and ovary

Flower Diagram

Pollination & Fertilization

Pollination: the transfer of pollen from

the male to female structure on a plant

Fertilization: when a sperm fuses with

an egg inside an ovule

Pollination & Fertilization

Flower to Fruit to Seed

From Seed to Plant

Seeds can be dormant (inactive) for

long periods of time if the environment

is not suitable.

Once they are planted in a good

environment (water, air, warmth), the

seeds germinate (sprout)