The Environment and Plant Responses

1
The Environment and Plant Responses

• SWBAT differentiate between positive and negative
  tropisms describe phototropism and gravitropism
  give an example of photoperiodism in plants
  discuss nastic movement in plants

2
Tropisms

• Tropism
• The growth response of a plant to its environment
  
• What is positive tropism?
• When a plant grows toward a factor
• What is negative tropism?
• When a plant grows away from a factor

3
Tropisms

• Phototropism
• A plants growth response to light
• Why is tropism necessary?
• Plants need to be able to respond and change
  their growth if they are knocked over, or a
  factor changes. It is important to survival
• Gravitropism
• A plants growth response to gravity

4
Photoperiodism

• Photoperiodism
• A plants response to the length of time it is
  exposed to light
• List and describe the 3 types of plants that
  bloom according to photoperiodism.
• Short day plants
• Bloom when the days are short and nights are long
• Long day plants
• Require long periods of light and short periods
  of darkness
• Day neutral plants
• The bloom whenever conditions such as moisture
  and temperature are right. Light has no effect on
  it.

5
Facets of Botany Moving Plants

• What are nastic movements?
• Nasic movements refer to reversible, repeatable
  plant movements such as a venus flytrap catching
  a bug, or a flower opening and closing its
  petals.
• These movements are produces by changes in turgor
  pressure

6
Facets of Botany Scheduling Poinsettias

• What is the main concept of this facet?
• Organisms respond to their environments, but
  these responses can be fooled or manipulated by
  man controlling certain factors.

7
In your lab group

• Share the measurements you took on Friday of your
  stem movement lab and answer the questions on
  page SA 132 in your lab notebook
• When you finish start your homework
• Page SA 127 13C