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A winter variety of wheat is kept for different weeks at 4 °C before sowing…
Contributed by StemPy LabTry it on paper first. A hint, the key idea and the worked solution are here when you need them.
A winter variety of wheat is kept for different weeks at before sowing. The table shows the days from sowing to flowering.
| Weeks of cold | Days to flower |
|---|---|
| 0 | no flowers |
| 2 | no flowers |
| 4 | 94 |
| 6 | 80 |
| 8 | 68 |
| 10 | 66 |
- How many days sooner does it flower after weeks of cold than after weeks?
- What is the average gain in days for each extra week between and weeks?
- What does the small change between and weeks suggest?
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) After weeks the plants flower in days, and after weeks in days. That is days sooner.
Step 2. (b) The extra weeks are . The average gain is days for each week.
Step 3. (c) From to weeks the gain is only days. The effect of the cold is nearly complete at about weeks, and more cold adds very little.
Answer: days; days for each week; the effect reaches a limit.
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