Plant Hormones Flashcards
What is plant tropism?
Growing towards or away from a stimulus
What is phototropism?
When a plant would grow away or towards light
What is geotropism?
When a plant would grow away or towards gravity
What is hydrotropism?
When a plant would grow away or towards water
What hormone controls where the plant grows towards?
Auxin
What tropisms does a shoot of a plant do?
Positive Phototropism
Negative Geotropism
What tropisms does the roots of a plant do?
Negative Phototropism
Positive Geotropism
Describe how auxin affect the shoot of the plant when the sun is to one side?
- Auxin is made in the tip
- Light is detected by cells at the tip
- Auxin diffuses down to the dark side
- Where auxin moves the cells elongate
- Shoot now bends towards the light
What happen when the sun is directly on top of the shoot?
Auxin will diffuse equally downwards causing a taller shoot as auxin elongates lower down in the shoot
What happens when there is no light on the shoot?
Shoot will still grow but not much as it is limited due to no photosynthesis
What happens when the tip of the shoot is taken off?
No growth will occur as no auxin is present in the shoot
What tropisms do roots to? (Pos and Neg)
Positive geo and hydrotropism
Negative phototropism
What hormone allows roots to grow downwards?
Auxin
How do roots move down by auxin?
Auxin will move away from the light. It moves to the lower side of the roots. The roots elongate where the auxin ISN’T present and means it moves down.
What 3 thing are needed for seeds to germinate?
Water
Oxygen
Warmth
Why is water needed for seed germination?
Used to activate the enzymes
Why is oxygen needed for seed germination?
Aerobic Respiration
Why is warmth needed for seed germination?
Enzymes optimum temperatures
