AGRICUI<TURAT, BOTANY, CIIKMISTRY AND PHVSTOT.OOY OF PI^ANTS IO93 



much smallei proportions than in the alcoholic ferment. This jjhenomenon 

 still remains unexplained. 



5) Just as in the zymase of yeasts, the presence of NeuberCt's 

 carboxylase is also recorded in the zymase of potato and sugar beet. 



6) The fact that a product acting exclusively on pyrotartaric acid was 

 obtained, but leaving the sugar solution intact, a property peculiar to 

 carboxylase, shows that the latter may also be extracted from the zj^mase of 

 the potato and sugar beet. 



7) In the same way as the carboxylase of j^easts, the carboxylase of 

 the potato and sugar beet is much less sensitive to a high temperature and 

 to different antiseptics than the other zymases. 



851 - Investigations into the Part played by the Amylase in Potato Tubers. — 



I. BODNAR J. (Royal Station of Plant Physiol(jgy and Pathology, Budapest), Relation 

 between the amylase and sugar content in stored potato tubers, in Kiserleto^yi 

 Kozlemenyek (Bulletin of the Agricultural Stations of Hungary), Vol. XVIII, Part 4, 

 pp. 789-795. Budapest, 1915. — II. Doby G. and BodnAr J., Amylase in healthy potatoes 

 and in those suffering from leaf curl, Ibid. Vol. XVIII, Part 5-6, pp. 956-968, 4 ta- 

 bles, 1915. 



I. — Accoiding to the enquiries of W. Henneberg, the content of 

 sugar in the potato influences its keeping powers, those kinds which are 

 poor in sugar exhibiting greater resistance to bacterial decomposition than 

 those with a relatively large sugar content. A high sugar content thus seems 

 to constitute a predisposition to rot, and it is of great importance from 

 the practical point of view to know this content. 



The object of the present work was to examine the possibility of find- 

 ing a relation between the sugar content of stored potato tubers in the rest- 

 ing state and one of its regulating agents (enzymes) ; in other words to de- 

 termine, from the proportion of the corresponding enzyme, the total quantity 

 of sugar forming in the tubets in the resting state, and concluding from this 

 whether or not the tubers are adapted for storing. In the total quantity 

 of sugar in the tubers, there was also included the sugar consumed by the 

 respiratory process, because from the point of view of stoiage, it is important 

 to ascertain the loss of starch occasioned b}'' the respiration of the tubers. 



The experiments carried out were for the purpose of determining whe- 

 ther the proportion of sitgar in the tubei in a state of rest can be brought 

 into relationship with the activity of the amylase present. The result of the 

 following determinations are given : proportion of amjdase in 9 tubers, pro- 

 portion of reducing sugai (glucose), proportion of non-reducing sugar (^sac- 

 charose), and total sugar content of these tubers. The experiments, which 

 are summarised in several tables, gave the following results. 



Maltase was present in the tubers in a state of rest. 



There is no regular relation between the proportion of reducing sugar 

 (glucose) in the tuber and the activity of the amylase present ; the quantity 

 of reducing sugar does not always increase in proportion with the acti- 

 vity of the amylase. 



On the contrary, certain relation can be found between the activity 

 of the amylase and the proportion of non-reducing sugar (saccharose). 



