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XL 



OXYDASES AND THEIR INHIBITORS IN PLANT TISSUES. 

 PART III: THE LOCALIZATION OF OXYDASES AND 

 CATALASB IN SOME MARINE ALG^. 



By W. R. G. ATKINS, Sc.B., A.LC, 

 Assistant to the Professor of Botany, Trinity College, Dublin. 



[Read December 16, 1913. Published January 31, 1914.] 



Notwithstanding the large amount of work which has been done in recent 

 years in connection with the distribution of oxydases in plants, the problem 

 of their localization in marine algse has hitherto attracted little attention or 

 7ione at all. In the present paper a short account is given of such work ; 

 and it is hoped that further details will soon be forthcoming. 



For the detection of oxydases, very dilute solutions of guaiaouin resin, 

 benzidine, and a-naphthol in aqueous alcohol were employed ; if no direct 

 action appeared, a few drops of neutral four-volume hydrogen peroxide were 

 added. It may be remarked that the above reagents for oxydases yield 

 respectively a blue colour — a blue changing to brown, and a purple when 

 oxidized. The addition of alcohol alone causes an evolution of gas-bubbles 

 from algal tissue. Probably this may be accounted for by the forcing out of 

 solution of dissolved air, because the same effect is produced by mixing 

 alcoliol and water. Whether this is a quantitatively sufficient explanation 

 has not been tested. There remains the possibility that it is due in part to 

 Liberation of oxygen by reducing substances, which on the death of the proto- 

 plasm come into contact with easily reduced compounds. An example of 

 this type is the action of hydrogen peroxide upon moist silver hydroxide. 

 2AgOH + HA = 2Ag + '2J1,0 + 0^. 



Accordingly, to avoid thi.s error in testing fur catalase, hydrogen peroxide 

 alone was added to the mashed algal tissue. Algae which have been boiled 

 fail to bring about the decomposition of the peroxide. Whether the 

 browning of benzidine is in every case due to oxydase action will be 

 considered later on. 



Maieria/. 

 The algae tested were collected by tlie author in Cork Harbour towards 

 the end of September and early in October, and kept in sea-water in the open 



SCIENT. PROC, E.D.S., VOL. XIV., NO. XI. 2 H 



^# %; 



MAY 18 1914 



