Chapter 16- Plant responses

Question 1

Describe the roles of auxins in plant responses

Answer 1

• Control of cell elongation
• Prevent leaf fall
• Maintain apical dominance
• Involved in tropism
• Stimulates the release of ethene

Question 2

Suggest the functions of gibberellins

Answer 2

• Stem elongation
• Trigger mobilisation of food stores in seed at germination
• Stimulates pollen tube growth in fertilisation

Question 3

What is the effect of ethene>

Answer 3

Causes fruit ripening, promotes abscission in deciduous trees

Question 4

Describe the roles of abscisic acid

Answer 4

• Maintain dormancy of seed +bud
• Stimulates cold protective responses (anti-freeze)
• Stomatal closing