14.2 plant growth factors

Question 1

what’s an example of plant growth factor?

Answer 1

IAA (indoleacetic acid)

Question 2

what does plant growth factor do?

Answer 2

affects growth

Question 3

what type of response is plant growth factors?

Answer 3

tropism response to directional stimuli

Question 4

what is the effect of IAA on roots & shoots?

Answer 4

inhibits root cell elongation & causes elongation of shoot cells

Question 5

explain how plant growth factors causes phototropism. (5)

Answer 5

1) cells in shoot tip produces IAA & is transported down the shoot
2) IAA initially transported evenly throughout all regions
3) light causes IAA to move from light side -> shaded side of shoot
4) increased IAA concentration on shaded side of shoot -> cell elongation occurs more
5) shoot tip bends towards light

Question 6

explain how plant growth factors cause gravitropism. (5)

Answer 6

1) cells in root tip produces IAA & is transported down the shoot
2) IAA initially transported to all sides of the root
3) gravity influences movement of IAA from upper to lower side of root
4) increased IAA concentration on lower side of root -> inhibits cell elongation
5) root tip bends towards gravitational force