Skill:
• Design of experiments to test hypotheses about factors affecting germination
Germination is the process by which a seed emerges from a period of dormancy and begins to sprout
For germination to occur, a seed requires a combination of:
- Oxygen – for aerobic respiration (the seed requires large amounts of ATP in order to develop)
- Water – to metabolically activate the seed (triggers the synthesis of gibberellin)
- Temperature – seeds require certain temperature conditions in order to sprout (for optimal function of enzymes)
- pH – seeds require a suitable soil pH in order to sprout (for optimal function of enzymes)
Additionally, certain plant species may require additional conditions for germination:
- Fire – some seeds will only sprout after exposure to intense heat (e.g. after bushfires remove established flora)
- Freezing – some seeds will only sprout after periods of intense cold (e.g. in spring, following the winter snows)
- Digestion – some seeds require prior animal digestion to erode the seed coat before the seed will sprout
- Washing – some seeds may be covered with inhibitors and will only sprout after being washed to remove the inhibitors
- Scarification – seeds are more likely to germinate if the seed coat is weakened from physical damage
Experiments can be developed using any of these factors as an independent variable
- Germination can be measured by the rate of seed growth over a set period of time
Factors Affecting Germination
