plant hormones. Flashcards
define geotropism.
ability for shoots to grow up (negative geotropism) and roots to grow down (positive geotropism.)
define phototropism.
ability for shoots to grow towards the light (positive phototropism.) and roots to grow away from the light (negative phototropism.)
type of tropism: geotropism.
positive or negative?
effect?
shoots and roots.
shoots: negative.
grow up.
roots: positive.
grow down.
type of tropism: phototropism.
positive or negative?
effect?
shoots and roots.
shoots: positive.
grows towards the light.
roots: negative.
grows away from the light.
what are auxins?
family of hormones found in plants.
where are auxins mostly made?
in the tips of the shoots and roots.
what can auxins do ?
diffuse to other parts of shoots or roots.
change the rate of elongation in plant cells, controlling how long they become.
how do shoots respond to a high concentration of auxin?
cells in shoots grow more.
how do roots respond to high concentration of auxin?
cells in roots grow less.
what is geotropism?
gravity pulls on the auxin causing it to gather at the bottom of the roots and shoots that are running horizontally.
what does geotropism cause?
roots to grow down and shoots grow up.
how does positive geotropism work?
auxins produced at the tip of root and accumulates at bottom due to gravity.
auxins will stop growth of root cells so will cause opposite sides to continue to grow and elongate.
how does negative geotropism work?
auxins produced at tip of stem and accumulates at the bottom due to gravity.
auxins increase growth of stem cells so will cause underside to continue to grow and elongate.
what does phototropism cause?
makes sure stem is always growing more on the shady side and tilts leaves towards the sun.
how does positive phototropism work?
auxins will accumulate on shaded side.
