BOTANY. , r )23 



The formation of mannan in Amorphophallus konjak, M. Tsuk- 

 amoto (Imp. Univ. Col. Agr. [Tokyo] Bui., vol. 2, No. 7, pp. 406-408). — 

 The tuber of this araeeous plant is used in Japan as an article of 

 diet and is of interest on account of its containing no starch but a 

 very large amount of mannan. Examinations made of the leaves of 

 the plant showed very small quantities of starch, some maunose, but 

 neither pentosans nor galaetaus. 



Investigations made to determine whether maunose as such occurred 

 iu the leaf showed that the slimy mannan was present in the cells of 

 the leaf, making it probable that it plays to some extent the role of 

 starch in assimilation, but the exact role of mannose is not yet deter- 

 mined. The presence of mannose as such in the petioles of the leaves 

 is highly interesting, it being the first time it has been so reported. 



The formation of asparagin in plants under different condi- 

 tions, U. Suzuki (Imp. Univ. Col. Agr. [To/17/0] Bttl, vol.2, No. 7, pp. 

 409-457). — A series of experiments with a number of different plants 

 was conducted in which the formation of asparagin was investigated. 

 The methods of experimentation and the analytical data from which 

 the conclusions are drawn are given in detail. 



As a result of his observations the author concludes that asparagin 

 in plants has two sources (1) from the decompositions of proteids and 

 (!') as a synthetical product of ammonia salts, urea, and nitrates. 



It is formed in full-grown plants not only in the dark, but under some 

 conditions in the light. The synthetic formation of asparagin is possi- 

 ble only when sugar is present and some condition for protein formation 

 is wanting. Excess of sugar prevents the formation of asparagin from 

 proteids, but stimulates its synthetic production. 



Ammonia as such is seldom found stored in plants, it usually being 

 quickly transformed into innocuous compounds. When the necessary 

 sugar for this transformation is wanting, small quantities remain in the 

 plant, but large amounts of ammonia are injurious. 



Ammonium salts are better than sodium nitrate for asparagin pro- 

 duction. Of the ammonium salts tested the chlorid is the most favor- 

 able to asparagin formation and the phosphate least. Urea was in 

 most experiments better than ammonium salts for this purpose. 



For the conversion of nitrates a high temperature and presence of 

 sugar are necessary. For the conversion of asparagin into proteids 

 sulphates are necessary. 



Etiolated plants were unable, unless sugar was present, to convert 

 sodium nitrate into asparagin, but readily transformed urea. 



Can old leaves produce asparagin by starvation ? T. Miyachi 

 (Imp. Univ. Col. Agr. [ToTcyo] Bid., vol. 2, No. 7, pp. 458-464).— The 

 production of asparagiu in plants, commonly thought to be restricted 

 to young plants, was investigated by the author, and it was found that 

 by starving old plants of Peonia albiflora the leaves were able to pro- 

 duce asparagin from proteids. 



