486 



Scorching of Foliage. 



[Aug., 



doubtful. Assuming a case in which wind causes severe wilting 

 of the leaves, the cell-sap will become concentrated, and may 

 eventually reach a stage at which the concentration of the salts 

 dissolved in the cell-sap will be sufficient to cause *' salting out " 

 of proteids, thus injuring or killing the protoplasm.* This stage 

 would be reached earlier (i.e., with less loss of water) when the 

 percentage of salts in the cells has been increased by the absorp- 

 tion of salt from spray. In this way salt may be occasionally 

 among the factors responsible for damage to foliage. The action 

 of salt spray in extracting water from leaves would tend in the 

 same direction, especially when the spray on the leaves becomes 

 gradually more concentrated by evaporation, f the water 

 extracted from the leaf being a loss to be added to that due to 

 transpiration. On the other bond, cuticular transpiration would 

 be stopped wherever liquid is present on the cuticle, and it must 

 also be remembered that where spray is being evaporated the 

 wind will be rendered less dry. 



Conclusion. — The general conclusion from the foregoino- con- 

 siderations is that the scorching of foliage by sea-winds is chiefly 

 due to the drying action of the wind, but that salt may perhaps 

 occasionally contribute towards the production of an injurious 

 effect. 



* Blackman, Vegetation and Fros<, New rhytolog'ist, Vol. 8 (1909), p. 358. 

 t Since reabsorption of water by the leaf tissues from the film of salt water on 

 the surface of the leaf might thereby be preventod. 



