Ask A Scientist© Biology Archive

Author:      janicehu
Text:        Why do some plants freeze and others do not?

Response #:  1 of 1
Author:      Jim Murray
Text:        The main reason some plants freeze and others do not is that some 
plants do not have much water in them.  Pine tree leaves have little water and 
are therefore difficult to freeze.  Another reason is that some plants make 
chemicals to put into their fluids that reduce the freezing temperature.  
Salts and oils are some.  The polyunsaturated fats found in many plants freeze 
at a lower temperature than the saturated fats found in many animals.  
Therefore plant fats are liquid (oils) at room temperature, and animal fats 
are solid.  Plants could not use so many saturated fats as warm blooded 
animals do or they would freeze up solid at higher temperatures.  I know 
little of plants but many animals can make ethylene glycol to keep themselves 
from freezing.  Ethylene glycol is the active ingredient in car anti-freeze.