602 TRANSLOCA TION 



the tartaric acid of grapes is neutralized but the malic acid decomposed, 

 and Erlenmeyer states that the disappearance of the glycolic acid present 

 in unripe grapes is brought about in the same manner. Mach and Haas 

 found that the percentage of tannin decreases during ripening 1 . The 

 marked accumulation of organic substances in the flesh of fruits is as a 

 general rule of bionomical importance, and not as in the seed for the 

 purpose of storing up nutrient reserve-materials. 



Sugars and starch often occur in the translocatory channels leading 

 to fruits, and in the case of olives mannite may perhaps take part 

 in translocation, and synanthrose in cereals 2 . Amides seem always to be 

 present in flowers and young fruits, and nitrogenous materials probably 

 reach the fruits partly in the form of proteid and partly as amides, for 

 certain observations of Borodin's 3 indicate that asparagin is transferred 

 to the fruits and seeds of Prnmts padus, Cornus sanguined, Sambiicns 

 raccmosa, &c. 4 



Trees. The plastic assimilatory products from the leaves accumulate 

 mainly in the roots, and then spread upwards to the permanent parts 

 of the stem, while sufficient food-materials are stored in the winter buds 

 for the first stages of their development. A certain provision of nutrient 

 materials is always present in the younger branches, and hence when 

 removed these are able to form new roots and shoots to a limited extent 

 in the absence of any photosynthetic assimilation 5 . 



As a general rule the reserve-materials arc stored up in the living 

 cells of the wood, cortex, and in some cases of the medulla also. The 

 medullary rays are especially adapted for the transverse distribution of 

 the plastic products brought by the phloem n , and Gris 7 has observed that 



1 Mach, Bot. Jahrcsb., 1877, p. 716 ; Haas, Chem. Centralbl., 1878, p. 700. Buignet apparently 

 observed a similar diminution in many fruits (Ann. d. chim. et d. phys., 1861, iii. ser., T. LXI, p. 281). 



2 Miintz, Ann. d. sci. nat., 1886, vii. ser., T. Ill, p. 61. Cf. Sachs, Jahrb. f. wiss. Bot., 1863, 

 Bd. in, p. 230 ; Hilger, Versuchsst., 1874, Bd. xvn, p. 245 (grapes) ; Dahmen, Jahrb. f. wiss. Bot., 

 1892, Bd. xxiii. pp. 453, 460; Mesnard, Ann. d. sci. nat., 1893, vii. ser., T. xvni, p. 316. 



3 Bot. Zeitung, 1878, p. 812; also Dahmen, I.e.; Fortes, Compt. rend., 1876, T. LXXXIII, 

 p. 922 ; 1877, T. LXXXIV, p. 1401. 



4 Macro-chemical researches on fleshy fruits in different stages of development are : Apples and 

 pears: O. Pfeiffer, Chem. Unters. iiber d. Reifen d. Kernobstes, 1876; Pfeil, Bot. Jahresb., 1880, 

 p. 869; Kulisch, ibid., 1892, p. 437; Lindet, Compt. rend., 1893, T. cxvil, p. 696. Cherries: 

 Amthor, Zeitschr. f. physiol. Chem., 1883, Bd. vii, p. 197. Grapes : Hilger-Gross, Versuchsst., 1887, 

 Bd. xxxin, p. 170; Muller-Thurgan, Landw. Jahrb., iSSS, Bd. xvn, p. 84. Bilberries: Omeis, 

 Bot. Centralbl., 1890, Bd. XLIII, p. 84. Additional literature by Konig, Chemie d. Nahr.- u. Genuss- 

 mittel, 1889, p. 769. 



5 Sachs, Flora, 1862, p. 331; J. Schroder, Jahrb. f. wiss. Bot,, 1869-70, Bd. vii, p. 305; 

 A. Fischer, ibid., 1891, Bd. xxn, p. 125. On the reserve-materials jn the buds of Abies, cf. Bnsse, 

 Flora, 1893, p. 157 ; in bud-scales, Schaar, Bot. Jahresb., 1890, p. 666. 



6 For anatomical details, cf. de Bar)', Comp. Anat. of Phanerogams and Ferns ; Haberlandt, 

 Physiol. Anat., 1896, 2. Aufl., pp. 263, 345, 490; Strasburger, Leitungsbahnen, 1891. 



7 Gris, Compt. rend., 1866, T. LXX, p. 603. Cf. de Bary, 1. c., p. 536 ; Gris, Ann. d. sci. nat., 

 1872, v. ser.. T. xiv, p. 71 ; de Bary, 1. c., p. 418. 



