Kids: How plants chill out
Photo: Flickr user Mr. Greenjeans
You might wonder, how do plants adapt to colder temperatures in fall and winter?
For a plant to survive really cold weather, its cells have to be protected from the formation of ice crystals during freezing. As they grow, these ice crystals act like miniature needles. They pierce the living part of a plant’s cell – the cytoplasm and nucleus – and keep the cells from functioning again when temperatures rise.
Fortunately for some plants, the onset of cold weather is usually gradual. That’s why an unseasonable freeze can devastate plants that are normally cold hardy. If the weather cools off gradually, specialized genes are activated in plants. These genes may be responding to cold, dehydration, or certain plant hormones, and the plant may respond by creating a kind of antifreeze to block ice formation.
Plants have other survival mechanisms, too. For example, some trees gradually dehydrate during the autumn months. By winter, there’s very little moisture left to freeze within the cells of the tree. And some plants keep water in their cell walls but not in the living part of the cell – the cytoplasm and the nucleus – where ice can form – and kill the plant.
