A cabbage plant is kept in a warm room for two years…
Contributed by StemPy LabTry it on paper first. A hint, the key idea and the worked solution are here when you need them.
A cabbage plant is kept in a warm room for two years. It makes a fine head of leaves but never flowers. A gardener learns that it needs weeks of cold.
- Why has it not flowered?
- Give two ways to make it flower.
- The plant was moved to a cold store, and has spent days there. How many days are needed in all, and how many more days must it stay?
- A day before the end of the cold treatment it is moved to a hot room for a long time. What might happen, and what is this 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) Cabbage is a biennial. It needs a cold period before it flowers, and the warm room never gave it one.
Step 2. (b) Give it the cold treatment, or spray it with gibberellic acid, which can take the place of the cold in some biennials.
Step 3. (c) weeks is days. It has spent days, so more days are needed.
Step 4. (d) A hot spell soon after the cold can undo the effect. This is devernalisation. The plant may then fail to flower.
Answer: (a) it had no cold; (b) cold treatment or gibberellic acid; (c) days in all and days more; (d) devernalisation.
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