Tropism:The Way Plants

Respond to Stimuli

Presentation Created by Mr. M. Barr, Kleb Intermediate School

With Adaptations by D. Tresten, Schindewolf

Certain materials are included under the fair use exemption of the U.S. Copyright Law and have been prepared according to the

multimedia fair use guidelines and are restricted from further use.

 

Stimulus (pl. Stimuli):Cause

Response:Effect

LightAll plants respond to lightStems and leaves grow toward light

Response to light is phototropism

Gravity We do not need to worry about which way to

plant a seed because the root grows down and the stem grows up. Why does this happen? It happens because plants respond to the pull of gravity.

Root cells grow toward the pull of gravity; stem and leaf cells grow away from the pull of gravity.

The response to gravity is called geotropism (or gravitropism)

WaterA plant’s roots grow toward water (not very strongly; plant must be touching water)

Growth of a plant’s roots toward water is called hydrotropism

TouchSome plants respond when they are touched

Grapevines,etc. have tendrils which allow a plant to grow around an object

Response of a plant to touch is thigmotropism

ColorPlants respond to different colors of light

Response of a plant to color is chromotropism

HeatPlants respond to different temperatures

Response of a plant to temperature changes is called thermotropism

ExamplesView the following slides for examples of tropism (some of which are also called nastic movements)

View videos of

Tropism

Go tohttp://sunflower.bio.indiana.edu/~rhangart/plantmotion/earlygrowth/photomorph/photomorph.html

View animation of Phototropism

http://www.landscapemodeling.org/html/animations/plant-growth.htm

REVIEW

Forms of Tropism Know these for the test:

PHOTOTROPISM -- response to light. GEOTROPISM -- response to earth contact or gravity. THERMOTROPISM -- response to heat. HYDROTROPISM -- response to moisture. CHROMOTROPISM -- response to colors. THIGMOTROPISM -- response to touch.

Source: http://www.afpmb.org/mpmh/chap2.htm

Name the Types of Tropisms that we

LearnedClue: Water VS No water

Clue: Heat VS Cold

Clue: Close VS Far from Earth

Clue: Touch with a toothpick

Clue: Blue light VS Red light

Clue: Dim light VS Bright light

Hydrotropism

Thigmotropism

Thermotropism

Chromotropism

Phototropism

Geotropism/Gravitropism

Click when you know the answer:

Tropism Definition:Response to lightResponse to heatResponse to gravityResponse to moistureResponse to touchResponse to colors

Phototropism

Thermotropism

Gravitropism or Geotropism

Hydrotropism

Thigmotropism

Chromotropism

Try again:

Tropism Definition:Response to touchResponse to waterResponse to colorsResponse to coldResponse to gravityResponse to too little light

Thigmotropism

Hydrotropism

Chromotropism

Thermotropism

Gravitropism or Geotropism

Phototropism

Hydrotropism

Thigmotropism

Thermotropism

Chromotropism

Phototropism

Geotropism/Gravitropism

Name the type of Tropism that each of

the following investigations is

testing…

Investigation What form of tropism is being

tested?Mesh Divider (Inserted to bottom of pan)

Seeds =

Dry Soil Watered Soil

#

•Chromotropism •Geotropism•Hydrotropism•Phototropism •Thigmotropism

InvestigationWhat form of tropism is being

tested?

Plant APlant B

#

•Chromotropism •Geotropism•Hydrotropism

•Phototropism •Thigmotropism•Thermotropism

InvestigationWhat form of tropism do you think

the scientist is meaning to test? What’s wrong with the idea?

#

•Chromotropism •Geotropism•Hydrotropism•Phototropism •Thigmotropism•Thermotropism

InvestigationWhat form of tropism is being

tested?

#

•Chromotropism•Geotropism

•Hydrotropism

•Phototropism •Thigmotropism•Thermotropism

Purple light

WhiteLight

InvestigationWhat form of tropism is being

tested?

#

•Chromotropism •Geotropism•Hydrotropism•Phototropism •Thigmotropism•Thermotropism

InvestigationWhat form of tropism is being

tested?Plant in the space shuttle

Same kind of plant in a building on

Earth

#

•Chromotropism •Geotropism•Hydrotropism•Phototropism •Thigmotropism

Roots grow inevery direction

Roots growdownward

InvestigationWhat form of tropism is being

tested?

#

•Chromotropism •Geotropism•Hydrotropism•Phototropism •Thigmotropism•Thermotropism

InvestigationWhat form of tropism is being

tested?

#

•Chromotropism •Geotropism•Hydrotropism•Phototropism •Thigmotropism•Thermotropism

Investigation

See animation and more facts: http://biology.kenyon.edu/edwards/project/steffan/b45sv.htm

What form of tropism is being tested?

#

•Chromotropism •Geotropism•Hydrotropism•Phototropism •Thigmotropism•Thermotropism

InvestigationWhat form of tropism is being

tested?Are there too many variables in this

test?

#

•Chromotropism •Geotropism•Hydrotropism•Phototropism •Thigmotropism•Thermotropism

InvestigationWhat form of tropism is being tested?Could there be more than one variable

affecting the outcome of this test?

#

•Chromotropism •Geotropism•Hydrotropism•Phototropism •Thigmotropism•Thermotropism

QuizNumber from 1 – 15 Identify the types of tropism

This is an example of which form of tropism?

#1

•Chromotropism •Geotropism•Hydrotropism•Phototropism •Thigmotropism•Thermotropism

Mimosa plants

contract when

touched. This is an

example ofwhat form

of tropism?

http://www.dickinson.edu/~nicholsa/Romnat/mimosa.htm

#2

•Chromotropism •Geotropism•Hydrotropism•Phototropism •Thigmotropism•Thermotropism

Venus fly traps close around insects that “irritate” them. This is an example ofwhat form of tropism?

For a Humorous Animation of “Venus Pie Trap,” go to

http://www.siggraph.org/artdesign/gallery/S99/animation/venus_pie.html

Source & For more information, go to: http://florawww.eeb.uconn.edu/acc_num/198501413.html

#3

Investigation What form of tropism is being

tested if this bag is taped to a wall?

Staples to keep beans from moving

Paper Towel, moist

Ziplock baggie, open at top

1 of 2 seeds1 is right side up/

other is upside down (lima beans, peas, corn)

#4

•Chromotropism •Geotropism•Hydrotropism•Phototropism •Thigmotropism

Data for Investigation 1:What evidence suggests

geotropism?

Close-up View

#5

Investigation What form of tropism is being

tested?Mesh Divider (Inserted to bottom of pan)

Seeds =

Dry Soil Watered Soil

#6

•Chromotropism •Geotropism•Hydrotropism•Phototropism •Thigmotropism

InvestigationWhat form of tropism is being

tested?

Plant A Plant B

#7

•Chromotropism •Geotropism•Hydrotropism

•Phototropism •Thigmotropism•Thermotropism

InvestigationWhat form of tropism is being

tested?

#8

•Chromotropism •Geotropism•Hydrotropism•Phototropism •Thigmotropism•Thermotropism

InvestigationWhat form of tropism is being

tested?

#9

•Chromotropism •Geotropism•Hydrotropism

•Phototropism•Thigmotropism•Thermotropism

InvestigationWhat form of tropism is being

tested?

#10

•Chromotropism •Geotropism•Hydrotropism•Phototropism •Thigmotropism•Thermotropism

Investigation

See animation and more facts: http://biology.kenyon.edu/edwards/project/steffan/b45sv.htm

What form of tropism is being tested?

#11

•Chromotropism •Geotropism•Hydrotropism•Phototropism •Thigmotropism•Thermotropism

InvestigationWhat form of tropism is being

tested?

#12

•Chromotropism •Geotropism•Hydrotropism•Thigmotropism•Thermotropism

Investigation:What form of tropism is being

tested?

#13

•Chromotropism •Geotropism•Hydrotropism•Phototropism •Thigmotropism•Thermotropism

InvestigationWhat form of tropism is being

tested?

Plant in the space shuttle

Same kind of plant in a building on

Earth

#14

•Chromotropism •Geotropism•Hydrotropism•Phototropism •Thigmotropism•Thermotropism

InvestigationWhat form of tropism is being

tested? It’s hard to tell, isn’t it? Too many variables!

Plant on the moon

•Chromotropism •Geotropism•Phototropism •Thigmotropism•Thermotropism

InvestigationWhat form of tropism is being

tested?

#15

•Chromotropism •Geotropism•Hydrotropism•Phototropism •Thigmotropism•Thermotropism