chapter 31 Flashcards
plants rely o n3 types of sensory receptors
- photoresptors
- mechanical receptors
- chemical
tropism
Biological phenomenon indicating growth, bending, or turning of an organism in response to an external signal
phototropism
movement in response to light
movement in response to gravity
gravitropism
movement in respond to the sun
heliotropism
moment in response to temp
thermotropism
movement in response to water
hydrotropism
movement in response to chemicals
chemotropism
movement in response to touch or contact
thigmotropism
tip of plant covered =
no growth towards light
only tip of plant exposed =
growth towards sun
when tip is separated by mica=
no growth towards light
when tip is separated by gelatin
growth towards light
auxin redistributed to _____ side
shaded
high auxin concentration _____rate of cell elongation in root
decrease
high auxin concentration triggers production of ______
ethylene
roots bend away from light
negative respiration
to germinate under shade of another plant is ______
maladaptive
what is the mechanism for light detection
phytochrome
what is phytochrome
a photoreceptor that switch back and forth between two stable forms depending on light exposure
when root caps detect low water condition _____ is produced
aba
_______ slows root elongation by influencing cellulose in celll wall, expanding in diameter rather than length