Image Source – Cold-tolerant Wood Frog
Wood frogs (Rana sylvatica) are found in the northern parts of North America where the temperature can get very cold. When the wood frog experiences chilly conditions, a chemical signal is sent through it’s boy which prepares the frog to be frozen. The frog can remain frozen solid for the whole winter. The frog’s heart stops beating during this time also. It feels rock hard and looks dead but is not. When the weather starts to get warmer in the spring, the frog thaws out just in time for mating season. The frog can stay frozen without dying because of the way it stores glucose, which lowers the freezing point of water. The frog is able to build up the concentration of glucose in it’s cells, so that the cytoplasm doesn’t freeze, even when the interstitial water freezes. Two-thirds of the water in the frog’s body can freeze into ice crystals.
(Student post from an article in “Scientriffic” by Priyanka Shewpersad)
Image Source – Winter vegetable garden
Winter vegetables, such as broccoli, cabbage, cauliflower and brussel sprouts, are also frost-tolerant. These plants have genes that allow “antifreeze proteins” to be produced, which prevent the plant cells from being damaged by frost.