( 370) 



Botany. — "The action of the respLratory enzymes of Sauromatum 

 venosum Schotf', By Dr. Th. Weevers (Communicated by Prof. 

 F. A. F. C. Went). 



(Communicated in the meeting of September 30, 1911). 



The production of beat in the spadix of Aroideae has been long- 

 known; it was first observed by Lamarck in 1777. Since it has 

 been repeatedly investigated '} and was found to be a process invol- 

 ving absorption of oxygen. Khaus ^) showed that in the tissue starch 

 and sugar are used up, whilst CO, and sometimes organic acids are 

 produced. 



In 190J Hahn '), in a short paper, stated that in the press juice 

 of Arum macvlatum an enzyme is present, which decomposes glucose 

 Avith formation of carbon dioxide. After removal of the CO, by 

 l)oiling, the litpiid still had an acid reaction. He observed neither 

 formation of alcohol in the air, nor in a hydrogen atmosphere, al- 

 though in the latter case also the glucose was decomposed and CO^ 

 was formed. 



Tliis short note was not followed by any detailed communication, 

 so that it seemed to me desirable to investigate wliether the interest- 

 ing results of Hahn's inquiry were confirmed with other objects. 



Sauromatum venosum Schott appeared to me to be suitable for 

 investigation on account of its size and the ease with which it can 

 be obtained. 



For the purpose of orientation, I rubbed up in a mortar the fertile 

 as well as the sterile part of a spadix, and made the pulp up to 

 250 c.c. with water. One half of this was at once boiled for 5 

 minutes; to the other half a few drops of toluene were added and 

 after the flask had been closed by a plug of cotton- wool it remained 

 for 48 hours at 16° C. Its contents were then boiled, a certain 

 amount was filtered off from both halves and the reducing sugar as 

 well as the organic acids were determined in the filtrate. (Indicator 

 phenolphtalëine, which gave a sharp endpoint.) 



In the flask in w^hich autolysis had taken place were found 10 mg. 

 glucose and 8,0 c.c. 0,1 N. acid, in the control flask 80 mg. glucose 

 and 0,5 c.c. 0,1 N. acid. 



^) Saussure, Ann. sc. nat. 18:22. 



Vrolik and de Vriese, Ann. Sc. nat. 1836. 



Garreau, Ann. Sc. nat. 1851. 



2j G. Kraus, Abh. naturf. Ges. Halle, 1882. Ann. Jard. bot. 1S9G. 



«) M. Hahn, Ber. chem. Ges. Bd. 33, 1900. 



