Bio 103: Fundamentals in Plant Biology. This is a powerpoint presentation discussing about different types of plant movements.

1. QuizQuiz
1. Gametophyte
a. Fern
b. Male angiosperms
c. Female angiosperms
2. Protective covering of the sorus.
3. Nurse cells
4. Do flowers undergo secondary growth? Yes/No (3pts)
5. Structure that holds pollen among gymnosperms
6. Define double fertilization
7. Define pollination
8-10. Functions of flowers

2. Label the following

3. Label the following
a b c d

4. ESSAYESSAY
Compare and contrast
reproduction of angiosperms,
gymnosperms and bryophytes.

6. .
There are many types of tropisms :
• Phototropism
• Geotropism
•Thigmotropism
• Hydrotropism
• Chemotropism
• Thermotropism
TROPISM
Plant growth in response to a
stimulus
(“tropo” – ”turn”)
!!
Tropisms allow plants to seek
out the best conditions for
survival

7. TROPISM
POSITIVEPOSITIVE
 If the plant
moves TOWARD
the stimulus
NEGATIVENEGATIVE
 If the plant
moves AWAY
from the stimulus

8. GEOTROPISM
Geotropism is the growth
of a plant in response to
gravity.
Positive Geotropism
It is the growth of a plant towards the
center of the earth-down with gravity.
Ex. roots growing down
Negative Geotropism
It is the growth of a plant away
from the center of the earth-
opposite from the pull of gravity
Ex. stems grow up
Positive Geotropism
Negative Geotropism
(“Geo” – Earth)

9. IMPORTANCE OF
GEOTROPISM
• Pulls roots down to anchor a plant
• Roots can get needed water and
minerals if they stay in the soil

10. PHOTOTROPIS
MThe growth response of a plant in
response to light direction is
called phototropism.
(“Photo” – light)
Ex. Stems growing toward the window to get
to the light

11. THIGMOTROPISM
Thigmotropism is the growth
of a plant in response to
touch/contact.
NEXT
(“Thigmo” – “touch”)
Tendrils on a sweet pea
Photo by Christopher Meloche
Vines growing on a wall or fence

12. HYDROTRHYDROTR
OPISMOPISMHydrotropism is the growth in
response to water. Ex. roots
growing toward moisture
NEXT
(“hydro” – “water”)
THERMOTROPISM
Thermotropism is the tendency of plants or other
organisms to bend toward or away from heat.
Ex. curling of Rhododendron leaves in response to
cold temperatures.
Chemotropism
Chemotropism is movement caused by chemical stimuli.
Ex. Growth of a pollen tube is always towards the ovules
so that reproduction can occur
(“Therm” – “heat”)
(“Chemo” – chemical”)

13. MOVEMENTS

14. Nastic
Movement
¤ Nastic Movements are plant movements that
are in response to a stimulus (non-directional)
¤Examples:. Temperature,
Humidity, & Light Irradiance
¤ The movement can be caused by turgor or
changes in growth

15. Plants
That
Have
Nastic
Moveme
nt
Prayer Plant (Flat) Prayer Plant (Vertical)
Due to Daytime Due to Nighttime

16. Nastic
Movement
vs.
Tropic
Movement
¤Nastic Movements differ from Tropic
Movements in that the direction of
Tropic Responses depend on the
direction of the stimuli, whereas the
direction of Nastic Movements are
independent of the stimuli.

17. NASTICNASTIC
RESPONSESRESPONSES¤ The frequency of these responses increases as intensity of the
stimulus increases.
¤ Example of Nastic Response: Opening and closing of
flowers (Photonastic response)
¤ Nastic Responses are usually associated with plants:
1. Photonasty: Response to light
2. Nyctinasty: Movements at night or in the dark
3. Chemonasty: response to chemicals or nutrients
4. Hydronasty: response to water
5. Thermonasty: Reponse to temperature
6. Geonasty/Gravinasty: Response to gravity
7. Thigmonasty/Seismonasty/Haptonasty: Response to touch
¤ Notice that the Nastic Responses are named with the suffix “-
nasty” and have prefixes that depend on the stimuli

18. PHOTOPERIODIPHOTOPERIODI
CITYCITY
¤ Photoperiodicity is the physiological reaction of
organisms to the length of day or night.
¤ Examples:
1. Shortday plants-Morning Glory, Tulip
2. Longday plants-Potato, Poppy
3. Day Neutral-Tomato, Dandelion, Corn

19. -The term auxin is derived from the Greek word auxein which
means to grow.
- Auxins were the first plant hormones discovered
Functions of Auxins:
-Stimulates cell elongation
-Stimulates cell division in the cambium
-Stimulates differentiation of phloem and xylem
-initiates response of bending in response to gravity and light
HORMONES

20. 
Coleoptile or stem tip
Agar block
prevents the
movement of
auxins in the
stem
If auxins cannot move through the stem than the stems ability to
respond to, say light ,is inhibited. This means that the plant will not be
able to grow towards the light as it normally would. Place the tip back
on the plant and all is well!!
EFFECTS OF AUXIN

21. If the agar block is
placed partially on the
stem than the response
would be as shown.
As the auxin (which is
in the agar block)
diffuses into that side of
the coleoptile, it
stimulates cell
elongation and the
coleoptile bends away
from the block.

22. Cytokinin Functions:
-Stimulates cell division
Ethylene :
-Ethylene, unlike the rest of the plant hormone
compounds is a gaseous hormone
- stimulates the ripening of the fruit
Gibberellins:
- Gibberellins affect:
The rate of cell division
Flowering
Increase in size of leaves and fruits
Seed and bud dormancy
Induction of growth at lower temperatures

23.  Abscisic acid :
-causes trees to lose their leaves in response to
winter -buds to go dormant