86 



BOTANICAL GAZETTE 



[august 



The conductivity of the juice from the leaves is shown to be 

 double that obtained from the root, and the amount of crude 

 ash is in accord with this fact, although the juice from the leaves 

 has a little more than twice as much crude ash as is found in the 

 juice from the roots. Since perfectly pure water may be con- 

 sidered as practically a non-conductor, it is evident that the 

 conductivity of the juice obtained is due to the substances that 

 were dissolved in the cell sap. From the results obtained for 

 the specific conductivity of the solution containing the ash, it 

 will be seen that the conductivity is due in large measure to the 

 dissolved salts, and that the organic products have played only 

 a slight part if any. 



It may be noted here that these facts are in accord with the 

 general statements in regard to the ash content of plants:^ '*that 

 the proportion of ash increases from the root upwards to the 

 leaves/' The different varieties of Beta vulgaris analyzed by 

 Wolffs showed that the leaves contained a much larger amount 

 of crude ash than the roots. It would seem then that the con- 

 ductivity measurements are here a rough estimate of the rela- 

 tive amounts of ash present in roots and leaves. It must not be 

 forgotten, however, that the juice obtained would not contain all 

 the ash, since some constituents of the ash exist in the plant in 

 the form of insoluble compounds/'' 



2, SoLA^^UM TUBEROSUM. 



Young vigorous plants grown on a heavy black loam were 

 used and measurements made for the juice extracted from the 

 leaves, the a^^rial stems, and the tubers. The results obtained 

 were as follows : 



Leaves 



Aerial stems 

 Tuber 



Sp. cond. of juice 



0.01959 

 0.02449 



0.01505 



Crude ash from 5CC Sp. cond. of ash sol 



0.0906 

 0.0781 

 0.0623 



0.01857 



0.02031 

 O.OT516 



■Vines, Physiology of plants, p. 130, 1886. 



9 Wolff, Aschenanalysen, pp. 76-77. 



^° Vines, Physiology of plants, p. 131. 1886. 



