1008 EXPERIMENT STATION RECORD. 



reserve material in the tubers of the potato, rhizomes of arum and iris, 

 and the tubers of colchicum, and Ranunculus consists almost entirely 

 of starch. Dextrin and sugar were present, but in very small quantities. 

 In the tubers of Ophrys, the bulbs of lily, tulip, and hyacinth the 

 reserve material consists of starch mixed with dextrin, or a mucilagi- 

 nous substance more or less soluble in water. In the tubers of Ficaria 

 the reserve consists of starch, dextrin, and nonreducing sugars. In the 

 dahlia, which may be compared with the tulip bulbs, the starch is 

 replaced by inulin and the dextrin by levulin. In the artichoke inulin, 

 levulin, and nonreducing sugars are present. In the onion and asphodel 

 mixtures of reducing and nonreducing sugars form the greater part of 

 their reserve material. 



In the reaction which takes place in the using up of the reserve 

 material by the plant the starch is transformed into dextrin, then into 

 nonreducing sugars, and later into reducing sugars. Dextrin is trans- 

 formed into nonreducing and reducing sugars. Inulin is reduced simi- 

 larly to starch, but levulin takes the place of dextrin, and the last form 

 present is levulose and not glucose. The carbohydrate materials are 

 directly or indirectly transformed into reducing sugar or glucose, in 

 which form they are assimilated, the only exception in the material 

 studied being the reserve in Stachys. In this galactan is present and 

 seems to be directly assimilable. 



The formation of the reserve material is muchinore complicated, 

 since the action of diastases and the living protoplasm must be con- 

 sidered. It seems impossible to accelerate the formation of reserve 

 material or to increase the proportion of intermediary products. The 

 investigator must be content to establish the presence of compounds in 

 the reserve organs from which the reserve material is formed. As an 

 example, young tulip bulbs contain dextrin and nonreducing sugar. 

 The sugar and afterwards the dextrin diminishes as the starch increases 

 and from this it would be concluded that sugar is transformed into 

 dextrin and dextrin into starch, but this transformation so far has not 

 been reproduced by experiment. In most of the other plants which 

 have starch as reserve material similar observations can be made. The 

 sugars, especially the nonreducing sugars and dextrin, generally pre- 

 cede the formation of starch. On the other hand, in potatoes and arum 

 the young tubers do not contain much sugar or dextrin and here it 

 seems possible that the starch may be formed directly, or it may de- 

 pend on substances other than sugar. Inulin and levulin are formed 

 apparently in a somewhat similar manner to starch and dextrin. The 

 galactan of Stachys, which is directly assimilated, is also directly 

 formed. 



The influence of mineral salts on the form and structure of 

 plants, C. DASSONVILLE {Rev. Gen. Bot., 10 (1898), Ko. 109, pp. 15-25; 

 110, pp. 59-68; 111, pp. 102-124; 112, pp. 161-170; 113. pp. 193-199; 114, 

 pp. 238-260; 115, pp. 289-3(4; 116, pp. 335-344; and 117, pp. 370-380, 



