'/ vv 



. 



EFFECT OF SALTS UPON OXIDASE ACTIVITY OF 



APPLE BARK 



CONTRIBUTIONS FROM THE HULL BOTANICAL LABORATORY 263 



D. H. Rose, Henry R. Kraybill, and R. C. Rose 



(WITH FIVE FIGURES) 



Introduction 



In an earlier paper (21) one of the authors showed that there is a 

 marked difference in the action of the salts of the alkali metals upon 

 the fire-holding capacity of tobacco, even when the salts have 

 similar anions. For instance, the carbonates of potassium, 

 rubidium, and caesium promote the combustion of tobacco to a 

 very much greater extent than the carbonates of sodium and 

 lithium. The chlorides of sodium, lithium, and potassium retard 

 the combustion, but the chloride of potassium is not nearly so 

 effective as the chloride of sodium or lithium. In general, the 

 salts of potassium, rubidium, and caesium are much more favor- 

 able to combustion than those of sodium and lithium. 



It has been known for a long time that potassium is an essential 



element for the higher plants. Numerous attempts have been 



made to replace potassium by sodium, and, while apparently sodium 



can fulfil some of the functions of potassium, attempts to replace 



potassium entirely by sodium have been unsuccessful. The fact 



that potassium seems to have such a marked property of promoting 



the combustion of tobacco, and sodium does not, suggests that this 



particular property of potassium may have a relation to certain 



functions in the plant, which cannot be fulfilled by sodium. These 



facts suggested that a study of the effect of the alkali salts upon 



oxidase activity might be of interest. The work reported in 



this paper was done in 191 7. More extended studies were 



_ planned, but, since it has been impossible to carry them out com- 



JJpletely at the present time, it seemed wise to report the results 



*"" obtained. 



^ Botanical Gazette, vol. 69] [218 



— 3 



