GBRIEFER ARTICLES 
EVIDENCE FOR THE GENERAL rr Tete a OF 
OXIDASES IN PLANT 
If the oxidases play the essential réle in respiration which recent 
theories have attributed to them, they must be present in all living 
cells. Two types of tissues, however, have been reported to be without 
oxidases, namely, tissues markedly acid in reaction and some tissues 
said to contain large amounts of reducing substances. 
Recently it has been pointed out by the writer’ that in some of the 
most acid plant tissues, the citrus fruits, the reported absence of oxidases 
was due to the methods of investigation. By separating out the carpel 
Sacs in such a way that the acid juice and the ferment were kept apart, 
as is normally the case in the living tissue, good oxidase reactions were 
obtained; whereas in former methods the tissue was ground in an at- 
tempt to extract the ferment, and the latter was then inhibited by the 
action of the aci 
Tissues soporte to be free of oxidases on account of the presence 
of reducing substances include a few organs of some higher plants and 
the algae as a group (with but two definite exceptions), so far as they 
have been investigated. 
Examining a few representative forms from the algae with a number 
of reagents, results as indicated in the accompanying table were obtained. 
The material was freed from foreign matter as far as possible, ground, 
or in the case of the large brown forms simply torn up and added to the 
Solutions of the reagent. The formation of oxidation products was then 
followed by color changes as compared with checks containing boiled 
material. 
The results indicated in the table were further confirmed in the case 
of the filamentous forms by following the reactions in individual cells. 
The material was placed in a one-half per cent watery solution of para- 
phenylenediamine, or equal parts of one-half per cent solution of para- 
phenylenediamine and alpha napthol (Spitzer’s reagent); and in each 
* Bor. Gaz. 57: 528. 1914. 
hae Sci. Proc. Roy. Dublin Soc. 14:11; DuGcar and Davis, Science N.S. 
39: 260. 
407] [Botanical Gazette, vol. 59 
