Seed plants

1. Seed
Plants

2. Characteristics of Seed Plants
•produce seeds
•sperm of seed plants
do not need water;
they form inside tiny
structures called
pollen
–pollen is
transported by
wind or animals
•seed plants are the
most common plants
on Earth today

3. The Structure of Seeds
•A seed forms after
fertilization, when the
sperm and eggs are
joined
•Seed has three parts:
–young plant
(sporophyte)
–stored food in the
cotyledon (seed
leaves of the young
plant)
–seed coat (surrounds
and protects young
plant)

5. •Seed plant has some
advantages over
seedless plant:
–young plant uses
stored food when it
begins to grow
–seeds can be
spread by animals,
which is more
efficient than
spores being
spread by the wind

6. Gymnosperms
•seed plants that do not have
flowers or fruit
•gymnosperm seeds are usually
protected by a cone
•economically important because the
wood is used for building materials
and paper products
•pine trees produce resin, which is
used to make soap, turpentine,
paint, and ink
•Some conifers are used to make an
important anticancer drug
•Fertilization
–2 kinds of cones: male and
female
–pollination transfer of pollen
from male reproductive
structures to the female
structures of seed plants

7. •Angiosperms
•produce flowers and fruit; most abundant plants today
•flowers help angiosperms reproduce some use
wind for pollination, others use flowers to attract
pollinators
•fruits surround and protect seeds; fruits also attract
animals who eat the fruit and dispose of the seeds
along the way

8. •Two kinds of angiosperms
–(1) monocots: one
cotyledon, leaves with
parallel veins, flower parts
in threes, bundles of
vascular tissue are
scattered
–(2) dicots: two
cotyledons, leaves with
branching veins, flower
parts in four or fives,
bundles of vascular tissue
are in a ring

10. Structure of Seed Plants
•Two kinds of vascular tissue:
–Xylem: transports water and minerals from
the roots to the shoots
–Phloem: transports food molecules to all
parts of a plant

11. Roots
•Most roots are
underground
•Three main functions of
roots:
–Roots supply plants
with water and
dissolved minerals.
–Roots hold plants
securely in the soil.
–Roots store surplus
food made during
photosynthesis.

12. •Root Structure
–Epidermis: layer of cells that covers
the surface of roots
–Root hairs: some cells of epidermis
extend from the roots and increase the
surface area
–Roots grow larger at their tips
–Root cap: group of cells that protect
the tip of the root; produces a slimy
substance that helps root to push
through soil as it grows

14. Root Systems
•Two kinds of root systems:
–Taproot systems
•One main root
(taproot)
•Grows downward
•Many smaller roots
branch off or taproot
•Can reach water deep
underground

15. –Fibrous root systems
•Several roots that
spread out from
plant’s base
•Roots are usually
same size
•Usually get water
from close to the soil
surface.
•Monocots usually
have fibrous roots

16. Stems
•Stem Functions:
–Support the plant body
–Hold up flowers, which helps
pollinators see the flowers
–Transport materials between root
system and shoot system
–Some stems store materials stems of
cactuses are adapted for water storage

17. •Herbaceous Stems
–Soft, thin, and flexible
stems
–Examples of plants with
herbaceous stems:
•Wildflowers
•Clovers
•Poppies
•Beans
•Tomatoes
•Corn

18. •Woody Stems
–Trees and shrubs with rigid
stems made of wood and bark
–In areas with cold winters,
large xylem cells are produced
at beginning of growing
season. As fall approaches,
smaller xylem cells are
produced, which appear
darker
–The cycle begins again next
spring they form growth
rings

19. Leaves
•Leaf Functions:
–Main function is to make food for plant
•Leaf Structure:
–Outer surface covered by cuticle to prevent
water loss
–Stomata: tiny openings in epidermis that let
carbon dioxide enter the leaf
–Guard cells open and close the stomata
–Most photosynthesis takes place in middle of
leaf
–Cells in upper layer (palisade layer) contain
many chloroplasts

21. •Leaf Adaptations:
–Leaves of many cactuses are
modified as spines, which keep
animals from eating plant
–Leaves of sundew modified to catch
insects

22. Flowers
•Flowers usually have the following basic parts:
–Sepals: modified leaves that make up
outermost ring of flowers parts and protect
the bud
–Petals: broad, flat, thinlike parts of a flower
that attract insects or other animals
–Stamens: male reproductive structure of
flower: has a thin stalk called a filament,
topped by an anther
–Pistils: found in center of flower; female
reproductive structure. Tip of pistil is called
stigma
•Base of stigma contains ovary

24. •Stamen =
STAY MEN
The male part of the
flower
Pistil =
Girl with pistol (girl
power!)
The female part of the
flower
Confused with parts of the flower?