S4.5.8 For the adult
Plant responses
Seedlings grow in a closed box with one hole in its side. Which way will their shoots grow?
What this chapter teaches
Plants respond to light and gravity by growing. Auxin, made in the shoot tip, moves to the shaded side of a shoot, and the cells there grow longer, so the shoot bends towards the light. Shoots grow up and roots grow down in response to gravity.
Three questions to ask
There is no one right wording. Listen for the idea.
- Which way do the shoots in a box with one hole bend, and why?
- Where is auxin made, and what does it do to the cells?
- Which way does a root grow, and which way does a shoot grow, and what sets this?
After the chapter, the learner can
- Explain how auxin makes shoots grow towards light
- Show seedlings bending towards light in a box with one hole
What they copy into their notebook
Light from one side: auxin moves to the shaded side, the cells there grow longer, the shoot bends towards the light. Gravity: shoots grow up, roots grow down.