TOLERANCE OF FRESH WATER BY MARINE PLANTS 



AND ITS RELATION TO ADAPTATION 



W. J. V. OSTERHOUT 



Some effects of distilled water on r 



asm 



have been 



the 



Further investigations on this 



remarkable dmerences between marine 



tolerance of fresh water. 



p and 



the same plant, with respect to their 

 ese differences are interesting from 



their 



a physico-chemical standpoint, and significant because of 

 bearing on the theory of adaptation. 



It is commonly supposed that most marine plants are killed 

 by exposure to fresh water. 2 Some instances have recently come 



rapidity 

 violacea. 



observation in which death occurs with g 

 example of this is furnished by Polysiph 



within a minute 



:n pure distilled water, many of the cells 

 This is clearly shown by the fact that 

 if they are replaced in sea water at the end of a minute they become 

 disorganized and never recover. This effect of distilled water is 

 not due to the presence of toxic substances acquired during distilla- 



the 



Spirogy 



hairs. Moreover, the same effect is produced by water taken 

 directly from ponds, rivers, and springs. 



On the other hand, there are species which are quite tolerant 

 of fresh water. Some years ago the writer 3 found marine algae 



growing along the sides of a steamboat 



xposed 



some 



They were also exposed daily to concentrated sea water and to 

 strong sunlight, under which they reached a relatively high tempera- 



ture, 

 blue- 



included representatives of the red, 

 lgae, and were associated with a 



somew 



1 Bot. Gaz. 55:446. 1913. 



2 Cf. Pfeffer, Pflanzenphysiologie 1:415 



3 Univ. Calif. Publ. Botany 2:227. 1906. 



Botanical Gazette, vol. 63] 



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