Transcript Plant Adaptations

 Desert

Root system


Cactus needles—reduced surface area
Thick stems


Shallow to obtain water
Reduced leaves


Plants
To store water
Dormant Seeds

Germinate only when enough moisture
present
 Life



in the water:
Have tissues with large air-filled
spaces through which oxygen can
diffuse down the stem
Seeds that float and delay
germination
Specialized air roots that allow O2 to
get to the roots down in the mud
 Salty

conditions:
Specialized cells in the leaves that
pump the salt out of the plant tissue
onto the leaf surface where rain
washes it off
The leaves of water lillies float on the surface, so that oxygen can enter
through their stoma and travel down to the roots, which are under water.
Venus Fly
Trap
 Poor

soil:
If the soil can’t provide N2,
plants trap and digest insects
that release (Nitrogen) N2
 Plants


without Roots:
Live on body of another plant
No roots live in a humid
environment to retain/store
water from rainfall
Spanish
Moss
Spanish Moss
Orchids
 Fighting

Make/secrete chemicals that are
toxic if eaten
 Need

insects:
Milkweed
for Pollination
Plants will mimic a pollinators mate
Wasp
attempting
to mate with
the flower
Ophrys
speculum
mimics a
female
wasp
Auxins
– Hormones found in plants that are
responsible for growth in stem height.
 These
hormones
are located at the
tips of stems
(at the apical
meristems).
 Are important
for response to
gravitropism and
phototropism.
Auxins
– Responsible for growth in stem
height
 Cutting
the
apical meristems (tips)
off of branches
will cause
growth in side
branches.
Cytokinins
–
Hormone that
stimulates cell
division and
growth of lateral
buds (side
branches).
 It
also causes
dormant seeds to
sprout.
Gibberillins-
Plant hormone that produces
dramatic increases in size mostly in stems and
fruits.
Ethylene- Plant hormone that causes fruits to
ripen.
 Ethylene
is released in response to auxin.
The
way in which plants grow in response to
stimuli in their environment are called
tropisms.
Main Types of Tropisms:
1.
Geotropism or Gravitropism Response to gravity
1.
Phototropism - Response to
light
1.
Thigmotropism - Response
to touch
 Causes
the shoot of a
germinating seed to
grow out of the soil
(against gravity).
 Also causes the roots of
a plant to grow with the
force of gravity and into
the soil.
Causes
a plant to grow
towards a light source
This
experiment shows the importance of
apical meristems to the growth of stems
towards a light source.
Apical
Meristem Region of cells
capable of division
and growth at root
and shoot tips
A
plant can be affected
by touch in many ways –
 Plants
touched regularly could
have stunted growth
 Vines
and climbing plants form structures that
attach themselves to things they touch.


Some climbing plants have long,
twisting leaf tips, or petioles that
wrap tightly around small objects.
Other plants have extra growths
called tendrils that emerge near the
base of the leaf and wrap tightly
around any object.