Transcript PLANT REPRODUCTION

PLANT DIVERSITY
Plants have an alternation of generations:
the diploid spore-producing plant
(sporophyte) alternates with the haploid
gamete-producing plant (gametophyte).
ANGIOSPERMS (flowering
plants)
FLOWER SEED
FLOWER AGAIN
*Bright colored
petals/attractive
scent attract
*Flower has many
parts
*Sepal, petals,
stamen, stigma,
ovary
Sepals
sepal
• The sepals protect
the flower before
it opens.
Petals
• The petals
attract
pollinating
insects with
their bright
colour and
attractive
scent.
Stamens
stamens are
the male part of
the flower.
• The plant makes
pollen in the top
part of the
stamen, called
the anther.
• The
stigma
The Stigma
• The stigma is the
top of the female
part of the flower.
• The pollen from
another flower
collects on the
stigma’s sticky
surface.
The Ovary
• The ovary protects
the ovules.
• Pollen travels to
the ovules and
fertilization takes
place.
• Now the ovules will
develop into seeds.
Pollination
• Insects visit
flowers to search
for nectar –
their food.
• But the flowers use
the insects for
their own purposes!
• As the insect probes
for nectar, its body
rubs against the
stamens.
• Pollen gets stuck on
the insect’s legs.
• You can often see bees
with a heavy load of
yellow pollen on their
hind legs.
Pollination
When the insect
visits another
flower of the same
type, the pollen will
stick to the stigma.
This is called
pollination.
Fertilization
The pollen travels
to the ovary, where
it joins with an
ovule.
This is called
fertilization.
Seeds
• The seeds develop
inside the ovary,
which grows to
become the seed
pod or fruit.
Seed Dispersal
• The seeds are
dispersed; some by
animals, some by
the wind, some by
explosion and some
by water.
Angiosperms have 2 divisions
Angiosperm Life Cycle
The sporophyte is the dominant generation, but multicellular male and female gametophytes are
produced within the flowers of the sporophyte. Cells of the microsporangium within the anther
undergo meiosis to produce microspores. Subsequent mitotic divisions are limited, but the end
result is a multicellular pollen grain. The megasporangium is protected by two layers of
integuments and the ovary wall. Within the megasporangium, meiosis yields four megaspores—
three small and one large. Only the large megaspore survives to produce the embryo sac.
Fertilization occurs when the pollen germinates and the pollen tube grows toward the embryo sac.
The sporophyte generation may be maintained in a dormant state, protected by the seed coat
Gymnosperms
• Gymnosperms include
gnetophytes, cycads,
ginkgoes, and conifers
• Cone bearing plants
Bryophytes
• Bryophytes have life cycles that
depend on water for reproduction.
Lacking vascular tissue, these plants
can draw up water by osmosis only a
few centimeters above the ground
• they are low-growing plants that can be
found in moist, shaded areas.
• mosses, liverworts, and hornworts
Bryophyte Life Cycle
Seedless Vascular Plants
• Ferns & Horsetails
• Like other vascular plants,
ferns and their relatives
have true roots, leaves, and
stems. Roots are
underground organs that
absorb water and minerals
Seedless Vascular Plants Life
Cycle
REVIEW
a. seed
b. zygote
c. sporophyte
d. microspores
e. megaspore
f. microgametophyte
g. Megagametophyte
h. Ovary
i. anther
b. Sporophyte c. megaspores
d. microspores
a. Epidermis
b. Cortex
c. Vascular bundle/xylem
d. Pith
e. Phloem
f. Bark
g. .
h. .
a. Epidermis
b. Palisade mesophyll
c. Leaf vein
d. Spongy mesophyll
e. Epidermis
f. Stomate
g. Guard cell
h. Leaf veins
i. Cuticle
A, B and C
j. Stomates
k. Palisade mesophyll
l. Spongy mesophyll
a. Pressure
b. Osmotic
c. Higher
d. Higher
e. turgid
a. Anther
b. Filament
c. Stamen
d. Pollen
e. Stigma
f. Style
g. Ovary
h. Pistil
i. Petal
j. Sepal
k. Ovule
l. Pollen tube
a.
b.
c.
d.
e.
f.
g.
h.
i.
j.
k.
l.
Zone of cell
division
Zone of elongation
Zone of
maturation
endodermis
pericycle
phloem
xylem
cortex
epidermis
Root hair
Vascular cylinder
Root cap
1.
The sun causes water to
evaporate at leaves
2.
Negative pressure
3.
Water molecules cling to
one another (cohesion) and
to sides of vessels
(adhesion)
4.
Negative pressure potential
5.
Cohesion refers to water
molecules clinging together
and tension refers to
negative pressure potential.
Water flows upward along
the length of the plant
Plant Adaptations to Life On
Land
• Drying out: waterproof surfaces
• Gas exchange: stomata (above
ground)/swim bladder
• Support: vacuole/cell walls
• Conduction: xylem and phloem/conducting
cells
• Reproduction: moist surfaces/specialized
delivery systems (pollen tubes)