Plant Growth Responses Flashcards
What three things do plants respond to?
Light
Gravity
Water
What is light need for?
Light is needed for photosynthesis
What is gravity need for?
Gravity is needed for the plant to be anchored in the soil
What is water need for?
Water is needed in photosynthesis and other metabolic processes
What are the hormone-like substances in plants called?
Plant Growth Factors
Where are these plant growth factors made?
In cells throughout the plant
What does IAA control in the roots and shoots?
Controls cell elongation in shoots
and inhibits cell elongation in roots
Describe the process of growth in the shoot due to IAA
Cells at the tip of the shoot produce IAA
Initally IAA is transported evenly 2 all regions down the shoot
Light causes the IAA 2 move from the light to the shaded side
A greater con. of IAA builds in the shaded side
Which causes a a greater rate of cell elongation in the shaded than the light side
So the shoot bends towards the light
This is positive phototrophism
What type of tropism is in the roots?
Positive geotropism
Describe the process of growth in the root due to IAA?
Cell in tip of root produces IAA and transports it along the root
Initally IAA is transported evenly 2 all regions down the root
Gravity causes the IAA 2 move from the upper to the lower side
A greater con. builds on the lower side
As IAA inhibits cell elongation, the upper side grows more and the root bends downwards
What roles does IAA have?
Increases placticty in plants
Controls cell elongation in shoots
and inhibits cell elongation in roots
What is the name of the theory 2 explain that plasticity in the plant?
Acid Growth Hypothesis
What is a simularity between taxis and tropism?
involves movemnt towards or away froma stimulus
What is a difference between taxis and tropism?
taxis involves organism moving and a trophism is is growth response
