BIO FINAL EXAM CH. 39 PLANT HORMONES Flashcards
What is the source of the plant hormone AUXIN
Stem apical meristems & young leaves
- one way polar transport (tip -> base)
What are the two major effects of the plant hormone Auxin
- cell elongation, acid growth hypothesis
- interacts with other hormones
Aging leafs produce _____ and more _____
less auxin and more ethylene
What is Auxins practical use?
stimulates growth of adventitious roots & promotes fruit development.
What is the source of the plant hormone CYTOKININS.
Roots some in embryos or fruits.
What are the three major effects of the plant hormone CYTOKININS.
- stimulate cytokineses (cell division)
- anti-aging
- interacts with auxins to control cell division, differentiation and apical dominance.
What about Apical Dominance?
Removal of apical buds increase sugar availability but decreases axuxins
What is the source of the plant hormone GIBBERELLINS.
apical meristems (roots & shoot), young leaves and seeds.
What are the three major effects of the plant hormone GIBBERELLINS.
- stem elongation (grows straight up)
- fruit growth (makes grapes larger)
- seed germination
What is the source of the plant hormone ABSCISIC ACID (ABA)?
everywhere
What are the three major effects of the plant hormone ABA?
- slows growth
- seed dormancy and drought tolerance (increase the likelihood the the seed will germinate in optimal conditions.)
What is the hormone ethylene?
Stress hormone in which responds to stress (drought, flooding, etc…)
produced during fruit ripening and programmed cell death.
Ethylene is produced when
a seedling tip pushes against an obstacle (rock)
What is the triple response of ethylene?
- slows stem elongation
- thickens the stem
- grows horizontally
what is Senescence?
Programmed cell death of certain organs, or the entire plant.
A burst of ____ is associated with onset of _____, programed cell death.
Ethylene, apoptosis
What is the relationship between Auxin and Cytokinin?
- stem apical dominance
- auxin< shoot buds develop
- auxin> roots
What is the relationship between Auxin and Gibberellin?
- Fruit development
What is the relationship between Auxin and Ethylene?
Leaf abscission (detachment of parts of the leaf)
What is the relationship between Gibberellins and ABA?
- seed germination
Reversible phytochrome system
Flashes of light at night… what happens… why?
Plants response to gravity is called?
gravitropism.
- roots show positive tropism and grow downward.
- shoots show negative gravitropism and grow upward.
Plants may detect gravity by the settling of
Statoliths
What is thigmomorphogenesis
mechanical disturbances changes a plants form such as rubbing a young plants stems makes them shorter.
