Review the key concepts, formulae, and examples before starting your quiz.
🔑Concepts
Germination is the process by which a dormant seed begins to grow into a young plant called a seedling.
Water () is essential as it softens the seed coat (testa), allowing the embryo to break through, and activates enzymes needed for growth.
Air () is required for the process of respiration, which allows the seed to produce energy from the food stored in the cotyledons.
Warmth (suitable temperature) is necessary because the chemical reactions within the seed occur optimally at specific temperatures (usually between and ).
The seed consists of an embryo which has two main parts: the radicle (future root) and the plumule (future shoot).
The cotyledons or 'seed leaves' store food for the developing embryo until the first true leaves can perform photosynthesis using and sunlight.
📐Formulae
💡Examples
Problem 1:
Why do seeds placed in a dry cupboard fail to germinate even if there is plenty of air and warmth?
Solution:
The seeds lack moisture ().
Explanation:
Without , the seed coat remains hard, and the internal enzymes required to convert stored starch into energy remain inactive.
Problem 2:
Describe the change in the radicle and plumule during the early stages of germination.
Solution:
The radicle grows downwards into the soil, and the plumule grows upwards towards the light.
Explanation:
The radicle develops into the root system to absorb and minerals, while the plumule develops into the shoot system to begin producing food.
Problem 3:
A student places seeds in a beaker filled completely with boiled and cooled water, then adds a layer of oil on top. Will the seeds germinate?
Solution:
No, the seeds will not germinate.
Explanation:
Boiling the water removes dissolved oxygen (), and the oil layer prevents any further from the air from dissolving into the water. Respiration cannot occur without .