A farmer sows two bags of wheat, once in autumn and once in spring…
Contributed by StemPy LabTry it on paper first. A hint, the key idea and the worked solution are here when you need them.
A farmer sows two bags of wheat, once in autumn and once in spring.
| Bag | Sown in | Result |
|---|---|---|
| X | autumn | flowers in the next spring |
| X | spring | green plants, no flowers |
| Y | autumn | flowers in the next spring |
| Y | spring | flowers in summer |
- Which bag holds a winter variety, and which a spring variety?
- What does the winter variety need, which the spring variety does not?
- What is this need called?
Need a reminder? The key ideaShow
Vernalisation is the promotion of flowering by a period of low temperature, sensed by the shoot apex. Winter varieties and biennials need it. A warm spell soon after the cold can undo it (devernalisation). Gibberellic acid can take the place of the cold in some biennials.
The worked solution
Have you tried it?
Work it out on paper first. It is fine to get stuck or make a mistake: that is how we learn. When you are ready, go through the solution one step at a time, and check each step against your own.
Step 1. (a) Bag X fails to flower when it is sown in spring, so it is the winter variety. Bag Y flowers either way, so it is the spring variety.
Step 2. (b) The winter variety needs a cold winter before it flowers. Sown in autumn, it gets one.
Step 3. (c) The need for cold is vernalisation.
Answer: (a) X is winter and Y is spring; (b) a cold period; (c) vernalisation.
Discussion (0)
Log in to join the discussion.
Loading…