This is a presentation about Plant responses and movements to external environment factor or external stimulus. Prepared by Aram omer sorkan University of Sulaimani School of Science Department of Biology

1. Prepared by: Aram Omer Sorkan & Karzan Sdiq
Plant Responses & Movments
University of Sulamani
School of Science
Department of Biology

2. Purposes
 In this presentation, we want to describe the Responses and Movements of the plant.
Describe tropisms as Plant Response. Describe Nastic Movements as Plant Movement.

3. Plant Response:Tropism
 A tropism is a biological phenomenon, indicating growth or turning movement of a
biological organism, usually a plant, in response to an environmental stimulus.
 OR , The responses of plants to their environment.
 OR , a plant's directional growth response to a physical stimulus.
Types of Tropism
1.Phototropism
2.Gravitropism
3.Thigmotropism
4.Chemotropism
5.Hydrotropism
6.Thermotropism

4. 1.Phototropism
 Phototropism is the growth response of a plant in response to light direction.
 Positive Phototropism Vs Negative Phototropism

5. 2.Gravitropism
 Geotropism is the growth response of a plant in response to gravity.
 Positive Geotropism Vs Negative Geotropism

6.  Thigmotropism is the growth response of a plant to physical contact (touch).
 Positive Thigmotropism Vs Negative Thigmotropism
3.Thigmotropism

7. 4.Chemotropism
 Chemotropism is the growth response of a plant to a particular chemical, Roots
grow toward useful minerals in the soil but away from acids.
 Positive Chemotropism Vs Negative Chemotropism

8. 5.Hydrotropism
 Hydrotropism is the growth response of a plant to water.
 Roots exhibit Positive Hydrotropism.

9. 6.Thermotropism
 Thermotropism is the movement of plant or their parts in response to changes in the
external stimulus of temperature.
Example:Rhododendron
Cold temperature
Hot temperature

10. NASTIC MOVEMENTS
 The non-directional movements of the plant in response to external stimuli are
called nastic movement.
 The direction of the movement is determined by the structure of the plant organ
itself, It is not determined by an external stimulus.

11. Types of nastic movements:
1-Nyctinasty or Nyctinastic (sleep movements)
a. Photonasty
b. Thermonasty
c. Epinasty & Hyponasty
2-Seismonastic movements
3-Haptonastic or Thigmonastic movements
NASTIC MOVEMENTS

12. 1-Nyctinasty Movement
 This is induced by diurnal variations in light and temperature,The diurnal movements.
 *Photonasty:The principle stimulus of Photonasty is the photoperiod.
Day Night
Example:Oxalis triangularis (Shamrock flower)

13. *Photonasty:
1-Nyctinasty Movement
Example: Cestrum nocturnum (Night Jasmine)
Day Night

14. **Thermonasty:It takes place due to temperature changes.
1-Nyctinasty Movement
Example: Tulipa clusiana (Tulip flower)
Rise Temperature Low Temperature

15. 1-Nyctinasty Movement
Epinasty Vs Hyponasty
Epinasty Hyponasty

16. 2-Seismonastic movements
 The shock movement.
 Movement in plants in response to touch as well
as other forms of physical contact or mechanical
disturbance such as shaking, wounding, wind,
raindrops, and intense heat or burning.
 In the case of the sensitive plant (Mimosa pudica),
a leaflet, leaf or group of leaves rapidly folds
and bends in response to the external stimulus.

17. 3-Haptonastic Movement
 Haptonastic occurs due to stimulus of touch.
 plant movement in response to touch or physical contact without regard to the
direction of the stimulus. Thigmonastic movements are exemplified by the closing of
the insect-eating plant Venus’s flytrap (Dionaea muscipula) and the bending of the
glandular hairs of sundew (Drosera sp.) as a result of contact with an insect.
Sundew Venus’s FlytrapCarnivorous Plant

18. References
http://biologyboom.com/nastic-movements/
http://www.preservearticles.com/2011121918563/different-types-of-nastic-
movements-movement-plants.html
http://www.cropsreview.com/plant-movements.html
MOORE R, CLARK WD, VODOPICH DS. 2003. Botany. 2nd ed. New York, NY:
McGraw-Hill. p. 443-454
http://leavingbio.net/plant%20responses.htm

19. Thank You….Any Question ?
Any Question? Any Question?