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)