MATERIAL TRANSFORMATIONS IN Till. PLANT 187 



cane sugar is there any transformation of the latter into starch; Böhm obtained 

 quite analogous results by artificially supplying sugar to the plant. 



§10. Glucosides. 1 ' — Glucosides 1 are chemical combinations of glucose (some- 

 times of other sugars) with various other substances, and they are split into their 

 component parts by the action of acids or glucoside-splitting enzymes. For 

 example, under the influence of emulsin, arbutin takes up water and produces 

 hydroquinone and glucose. This reaction is shown below: 



О 

 CH 2 OH— CHOH— CH—CHOH— CHOH— CH— OC 6 H 4 OH (arbutin) + 



О 

 H 2 (water) = CH 2 OH— CHOH— CH—CHOH— CHOH— CHOH (glucose) + 

 НОСеНЮН (hydroquinone). 



Indican, a glucoside of the indigo plant, etc., forms glucose and indoxyl, 

 with the taking up of water: 



C 7 H 6 NC— О— С 6 Нц0.5 (indican) + H 2 (water = 



СОН 

 C 6 H 12 6 (glucose) + С 6 Н/ ),CH (indoxyl). 



Indoxyl oxidizes in the air, forming dark blue indigotin (indigo blue) and water: 



2CsH 7 ON + 2 = 2H0O + C 16 H 10 O 2 N 2 . 

 Indigotin has the structural formula, 



CO /C 



c 6 h/ )c=c( )c 6 h 4 . 



As a third example may be mentioned amygdalin, an a-ß glucoside of almond, 

 peach, etc., which takes up water and splits into glucose, benzaldehyde and 

 hydrocyanic acid: 



O— 

 CH 2 OH— CHOH— CH—CHOH— CHOH— CH— 0— CH 2 — CHOH— 

 C 6 H 5 



I 



CH—CHOH— CHOH— CH—O—CH (amygdalin) + H 2 (water) = 2C 6 H 12 6 



-o- 



CN 

 (glucose) + C 6 H b — CHO (benzaldehyde) + HCN (hydrocyanic acid). 



Glucosides may undergo autolysis in the tissues. Thus, if leaves of Polygo- 

 num tindorium are exposed to an atmosphere saturated with chloroform 

 vapor (which kills the cells), blue indigotin is formed in the tissues. The chlor- 

 ophyll may then be extracted by alcohol, leaving the leaves blue. When 



1 Rijn, van, 1900. [See note 2, p. 333.] 



r This section appears for the first time in the 7th Russian edition. — Ed. 



w For this and similar statements of formulas and reactions, see Haas and Hill, 1013. [See 

 note 3, p. 6.] Also see works on organic chemistry; an excellent short treatise for physio- 

 logical students is Bernthsen, A., A text-book of organic chemistry. Translated and edited 

 by J. J. Sudborough. New York. 1907. — Ed. 



