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)
4.
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. • seed plants that do not have
flowers or fruit
• gymnosperm seeds are usually Gymnosperms
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
9.
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. • Most roots are
underground Roots
• 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
13.
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
20.
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
23.
24. Confused with parts of the flower?
• Stamen = Pistil =
STAY MEN Girl with pistol (girl
power!)
The male part of the The female part of the
flower flower
