Tropism Flashcards
What is tropism
Growth of a plant towards a directional stimulus
Plants do respond to stimuli
What are auxin
Plant hormones
Where is auxin produced
The the ends / tips of root & shoots
Where is auxin located
Dissolves in cell solution
Diffuses backwards and concentrates on the darker & lower side
Difference between auxin in roots and shoots
Roots: inhibit growth
Shoots: stimulates growth
What is phototropism
Is it positive or negative negative in shoots and roots
What happens when there’s a unidirectional light
What happens when the light intensit is equal in all directions
Growth towards light from 1 direction
Shoots: positive // roots: negative
Stimulate cells to elongate, bend towards the direction of light
Same auxin diffusion rate, equal growth
There’s a hormone produced at the tip of the shoot which stimulates bending
The hormone causes cells to elongate
What are mica sheets and agar block
Mica sheet: impermeable to chemicals
Agar blocks: permeable to chemicals
What is geotropism
Growth towards gravity
Why are shoots negatively geotropic
Grow towards light for photo
For glucose to respire
Why are roots positively geotropic
Grows towards soil to obtain water and mineral ions + anchor plant
