Transcript No Slide Title

Slide 1
Structure
of
Plants
Slide 2
1.
2.
3.
A. Functions of Roots
Anchor & support
plant in the ground
Absorb water &
minerals
Hold soil in place
Root Hairs
Fibrous Roots
Slide 5
A. Functions of Stems
1.Support system for plant body
2.Transport system carries
water & nutrients
3.Holds leaves & branches
upright
Looking at the
Each light and dark
picture
the left:
tree ringtoequals
one
year of annual growth.
What
years
had
Light rings for fast
the
most
rain?
spring
growth,
dark for
slow summer growth.
What
Smalleryears
rings tell of
experienced
the
past droughts that
have occurred.
worst
drought?
Slide # 6
A. Functions of Leaves
1. Main photosynthetic organ
2. Broad, flat surface increases
surface area for light
absorption
3. Have systems to prevent
water loss
• Stomata open in day but
close at night or when hot
to conserve water
• waxy cuticle on surface
4. System of gas exchange
• Allow CO2 in and O2 out of
leaf
Elephant Ear Plant
Slide # 7
B. Leaf Structures
Leaf Cross-Section
1.Cuticle: waxy layer;
covers upper surface
Cuticle
Mesophyll
• Protects leaf against
water loss
2.Veins: transports water,
nutrients and food
• Made of xylem and
phloem
3.Mesophyll: contains
cells that perform
photosynthesis
b/c they contain
Chloroplasts.
Veins
Stoma
(Opening)
2 Guard
Cells
Surround
each
Stoma
Stoma- singular
Stomata-plural
Slide # 18
Chapter 25
Plant
Responses
and
Adaptations
Slide #19
Hormone Action on Plants
A. Plant cells can produce
hormones: which are
chemical messengers that
travel throughout the plant
causing other cells called
target cells to respond.
B. In plants, hormones
control:
Movement
of hormone
Hormoneproducing
cells
Target
cells
1. Plant growth &
development
2. Plant responses to
environment
Cells in one blooming
flower signals other blooms
using hormones to open.
Slide # 20
C. Plant cells will send signals
to one another to tell them:
1. When trees to drop their leaves.
2. When to start new growth.
3. When to cause fruit to ripen.
4. When to cause flowers to bloom.
5. When to cause seeds to sprout.
Tree
Budding
Fruit
Ripening
Cactus
Blooming
Leaf Drop
Sprouting
Corn Seeds
Slide # 21
D. Ethylene causes
Fruit to Ripen
1.Fruit tissues release a
small amount of ethlyene
2.Causes fruits to ripen.
3.As fruit become ripe, they
produce more and more
ethlyene, accelerating
the ripening process.
Ethylene released
by apples and
tomatoes causes
fruit to age quickly.
Slide # 22
Plant Tropisms
1. Tropism: the way a plant grows in response to
stimuli in the environment.
a.Phototropism: growth response to light
-Plants bend towards light
a.Geotrophism: growth response to gravity
-plant roots grow down with gravity, shoots (stems) grow
up against gravity and out of the soil.
a.Thigmotropism: growth response to touch
-vines grow up around trees, venus flytrap closes when
leaves are touched
Slide # 23
What type of tropism is shown in these pictures?