92 



LIVING PLANTS 



Relation of 

 the organism 

 to cold 



Death above 

 freezing point 



The formation of ice in the plant does not 

 imply its death. If the temperature falls to a 

 certain point characteristic of each species a 

 disorganization of the protoplasm will ensue, 

 and the plant dies regardless of subsequent 

 treatment. On the other hand it is well 

 known that many plants may be frozen and 

 recover normal appearance, and that the 

 death of others may be averted by practices 

 known to the gardener. Thus some frozen 

 plants, if submerged in water a few degrees 

 above freezing and allowed to thaw, will en- 

 tirely recover. If such plants are placed in 

 warm air to recover, the ice in the intercellu- 

 lar spaces gradually melts and a large pro- 

 portion of it evaporates into the air, while 

 the protoplasm absorbs only a small amount. 

 All of this ice w^as in the cell originally, and 

 its return is necessary for the welfare of the 

 cell and the plant. A frozen plant, thawed in 

 the open air, therefore, is sometimes killed by 

 loss of water which might be prevented if the 

 plant were immersed in a vessel of the fluid. 

 If ice be actually formed inside the cells, 

 however, the plant dies whether thawed 

 slowly or quickly, in dry or moist media. 



The death of plants by low temperature 

 above freezing point is due to related causes. 

 Acanthus, coleus, basils, melons, tobacco 

 plants, etc., blacken and die if exposed to a 



