THE OXIDASES IN RELATION TO PLANT PATHOLOGY 297 

 TABLE LXVIII. 



JUICE PRESSED FROM DIFFERENT PARTS OF A SINGLE HEALTHY PLANT. 



Oxidase Units. 



Roots, lower half 0-237 



Roots, upper half . . . . . . . . 0-144 



Stem .. 0-022 



Pedicels and midribs of leaves . . . . . . 0-173 



Leaves 0-230 



Seeds (groups of calyxes, each containing 



several seeds) . . . . . . . . . . 0-590 



On the whole these results seem to indicate that oxidase 

 activity is greatest in those portions of the plant in which 

 the cells are young, and the vacuoles, as a consequence, are 

 small. 



Having quantitatively examined the oxidase content 

 of normal beet plants, Bunzel turned his attention to 

 plants suffering from curly-top, and to those which 

 were, from drought or unknown causes, stunted in 

 their growth. Some of his results are shown in the tables 

 on p. 298. 



From the following tables it is clear that plants which are 

 small because of retarded growth have much larger quan- 

 tities of oxidase in their leaves than have normal plants in 

 either their fully developed or immature leaves. Diseased 

 plants resemble stunted and " trotzer " plants in having 

 an increased oxidase content. The term " trotzer " is 

 applied to those plants which fail to develop a seed stem 

 and fail entirely to flower. Between the roots of the 

 various types no well-marked difference in oxidase content 

 appears to exist, as the values found for each sort var 

 within fairly wide limits. 



Though Bunzel's experiments have not thrown any 

 direct light upon the cause of the disease, they are none 

 the less of great interest, and bring out in a very striking 

 manner the relationship between morphology and chemical 



