6.1 pmt Flashcards
internal and external stimuli are detected and lead to a response
1
Q
what are plant growth factors and where are they produced?
A
-chemicals that regulate plant growth response to directional stimuli
-produced in plant growing regions(apical meristems)
-diffuse from cell to cell/phloem mass transport
2
Q
explain why shoots show positive phototropism.
A
1.IAA diffuses to shaded side of shoot tip
2.as IAA diffuses down shaded side, it causes active transport of H+ ions into cell wall.
3.disruption to H-bonds between cellulose molecules and action of expansions make cell more permeable to water.(acid growth hypothesis)
4.cells on shaded side elongate faster due to higher turgor pressure.
5.shoot bends towards light
3
Q
A
