Plant Responses Flashcards Preview

Gd 12 LS 2018 > Plant Responses > Flashcards

Flashcards in Plant Responses Deck (27):
1

Apparatus used to nullify the effects of gravity or unidirectional light

Clinostat

2

Mechanical defences against herbivores

  • Thorns and prickles
  • Thorns housing mutualistic bacteria that cause gangrene in herbivores
  • Galls housing mutualistic ants that release chemicals that burn herbivores' lips/ snouts

3

Function of Abscisic Acid

  • Protects plants during stress periods (e.g. drought, winter)
  • Promotes leaf senescence
  • Closes stomata

4

Auxin response to gravity in roots is...

positive: it moves towards gravity, or downwards.

5

Indolacetic Acid (IAA)

Example of auxin

6

Initial response to infection

cells at site of infection die to create barrier around infection that stops spread of micro-organism

7

phototropism

plant growth towards light

8

Gibberellic Acid

Example of gibberellins

9

Clinostat

Apparatus used to nullify the effects of gravity or unilateral light

10

auxin is produced in...

apical meristem (tips of roots and shoots)

11

plant growth towards gravity

Gravitropism (geotropism)

12

response to night time (closing up of leaves or flowers)

nastic movement

13

If the tip of a plant is removed...

it will grow broader, but not taller (makes a hedge)

14

Auxin response to light in shoots is...

negative: it is destroyed by light, or moves away from light.

15

Functions of auxin

  • promotes apical dominance
  • cell elongation and enlargement resulting in phototropism in shoots
  • inhibition of cell growth resulting in geotropism in roots
  • prevents leaf senescence
  • delays fruit ripening

16

Example of auxin

Indolacetic Acid (IAA)

17

nastic movement

response to night time (closing up of leaves or flowers)

18

Commercial uses for auxins

  • Causing cuttings to root
  • induce flowering
  • induce fruit setting (creating seedless fruits)
  • herbicides (weed killers)

19

Systemic Acquired Resistance

Production of Salicylic Acid at site of infection which travels to rest of plant in inactive form to make rest of plant resistant to infection

20

plant growth towards light

phototropism

21

geotropism

plant growth towards gravity

22

Example of gibberellins

Gibberellic Acid

23

Sequence the events resulting in phototropism

  1. Auxins produced in apical meristem.
  2. They move away from light to dark side of shoot.
  3. Auxins cause cell elongation in cells on dark side.
  4. Uneven growth between light and dark sides causes shoot to bend towards the shorter, light side.
  5. Plant grows towards the light source.

24

Plants' first line of defence to prevent infection

  • Waxy cuticle
  • Lignin
  • Sticky gum that seals wounds

25

Sequence the events resulting in geotropism

  1.  Auxins produced in apical meristem.
  2. They move towards gravity, to the lower side of the root.
  3. Auxins inhibit cell elongation in cells on lower side.
  4. Uneven growth between upper and lowers sides causes root to bend towards the shorter, lower side.
  5. Roots grow down, towards gravity.

26

'Stress' chemicals produced that make plants unpalatable to herbivores

  • tannins
  • alkaloids
  • essential oils (e.g. menthol in lemons) u
  • rushiol (the 'poison' in Poison Ivy)
  • glycosides in foxgloves

27

Function of gibberellins

  • increase internode length
  • promotes seed germination
  • promotes fruit setting