Coordination and Control in Plants Flashcards
Name 4 photoreceptors:
Light intensity
Light duration
Direction of light
Wavelength
What are some benefits of phototropism?
Receive the maximum amount of light for photosynthesis and development at the appropriate time of year
Where are auxins produced?
Apical Meristem
What is the growth effect that takes place with auxins?
Elongation of cells in zone of elongation
Where are Cytokinins produced?
Actively dividing tissues
What is the growth effect that takes place with cytokinins?
Cell division
Where are gibberellins produced?
Apical buds and leaves
What is the growth effect that takes place with gibberellins?
Elongation of intermodal regions
What are the characteristics of cells that divide by mitosis?
Small
Thin walls
Prominent nuclei
Lack large vacuoles
What happens to the cells in the zone of elongation?
Cells develop small vacuoles
Absorb water by osmosis
During auxin action what does the membrane pump out?
Pumps out hydrogen ions into the cellulose of the cell wall
What does effect do this hydrogen have?
Loosens linkages between cellulose microfibrils - wall is more flexible
How do cells absorb water?
By osmosis
More auxin =
more cell expansion
What is phytochrome?
A pigment found in the leaves of flowering plants
What are the 2 interchangeable forms of phytochrome?
Phytochrome 660
Phytochrome 730
What is phytochrome 660?
Absorbs red light and rapidly converts to p730
What is phytochrome 730?
Absorbs light in the far-red region of the spectrum, rapidly converts to p660
A phytochrome =
protein + pigment
What is photoperiodism?
A major influence on the timing of flowering in many plants is the length of day
What is an example of a long day plant?
Poppy
What is a long day plant also known as?
Short night plants
What are long day plants?
Only flower if the length of day exceeds 12 hours - usually summertime
What is an example of a short-day plant?
Chrysanthemum
