Required Practical - Plant Hormones
Biology: Cambridge International GCSE Supplement, topic 14.5.3
Light Investigation
The effect of light on seedlings can be demonstrated with mustard or cress seeds. Complete the following steps:
Step 1
- Place the seeds in petri dishes with damp cotton wool, and leave them in a warm place to germinate (develop).
Step 2
- Randomly divide the petri dishes into three groups and assign each group to one of the following light conditions:
- Full sunlight in a windowsill
- Darkness
- Partial light
Step 3
- Measure the height of the plants daily for a week.
Step 4
- Draw and label biological drawings to show the effects.
Step 5
- The independent variable is the lighting conditions.
- The dependent variable is the growth of the plant.
Step 6
- Phototropism can also be demonstrated by placing a seedling in a container that is open only on one side.
Test yourself on Required Practical - Plant Hormones
To investigate the effect of light and gravity on plant growth, which three conditions should we place the plants in?
Light Investigation