Transcript Plant Tropisms

Plants Move
TROPISM
is a biological
phenomenon,
indicating growth
or turning
movement a plant
in response to an
environmental
stimulus
TROPISM
POSITIVE
 If
the plant moves
TOWARD the
stimulus
NEGATIVE
 If
the plant moves
AWAY from the
stimulus
Phototropism
Movement of plants toward light
Why?
Maximize amount of sun for photosynthesis to make their
food.
Phototropism
http://www.youtube.com/watch?NR=1&v=KQOC_bPrqFs&s
afety_mode=true&persist_safety_mode=1
Gravitropism
Movement of plants in
response to gravity
Positive is toward gravity
(roots grow down)
Negative is away from
gravity (shoot, stems, and
leaves grow up)
Why?
Allows plants to grow
properly and get nutrients
and sunlight
http://www.youtube.com/watch?v=mYZXax8V_L0&feature=related&safety_m
ode=true&persist_safety_mode=1
Hydrotropism
Movement by plants toward water.
Why?
Roots search for and grow toward
water, because it is needed for
photosynthesis and to support cell
structure.
http://virtualastronaut.tietronix.com/textonly/act25/text-plants.html
Thigmotropism
Plants moving in response to touch.
Positive is toward touch (vines wrap around
structures)
Negative is away from touch (some plants
close up when touched)
Why?
to support leaves as they
grow higher to reach the
sun to make more food
(photosynthesis).
http://www.youtube.com/wat
ch?v=8HeedWWe6VA&featur
e=related&safety_mode=true
&persist_safety_mode=1
Gravitropism

Gravity causes a response in plant growth

In the picture above, which part of the plant
exhibits positive tropism, and which exhibits
negative tropism?
Hydrotropism

The way a plant grows or bends in response to
water

Why would it be important for some parts of a
plant to be pulled toward water?
Thigmotropism
 Plants
 What
bend and grow because of touch.
are some other ways a plant can be
“touched”?
Phototropism

The way a plant grows or bends in response to
light.

Why do you think sunflowers were given their
nickname?
Hydroptropism
Gravitropism
Phototropism
Gravitropism
Phototropism
Thigmotropism
TROPISM QUIZ
Identify the type
of tropism in the
following pictures
1
2
3
4
5
6
7
 http://www.youtube.com/watch?v=Ze8N
V7cvW8k&feature=results_main&playnext
=1&list=PL5464C68C7644DD4D&safety_mo
de=true&persist_safety_mode=1
8
9
10
 http://www.youtube.com/watch?v=8SkK
uwbmR5Y&feature=related&safety_mode
=true&persist_safety_mode=1
11
 http://www.youtube.com/watch?v=9sgg
QQuBU40&feature=related&safety_mode
=true&persist_safety_mode=1
12
13
 http://www.youtube.com/watch?v=mYZX
ax8V_L0&safety_mode=true&persist_safet
y_mode=1
14
15
 http://www.youtube.com/watch?v=8Hee
dWWe6VA&feature=fvsr&safety_mode=tr
ue&persist_safety_mode=1
16
 http://www.youtube.com/watch?v=FC5e
BkDJbMs&feature=BFa&list=PL5464C68C7
644DD4D&lf=results_main&safety_mode=tr
ue&persist_safety_mode=1
17
18
 http://www.youtube.com/watch?v=Zq3U
uHlPLQU&feature=related&safety_mode=
true&persist_safety_mode=1
19
20
 http://www.youtube.com/watch?v=frmyz
IhD29Q&safety_mode=true&persist_safety
_mode=1