669 



however, an excessive increase of turgidity in the tissue can be ascribed to 

 this since, according tolDe Vries, it is especially the plant acids which condi- 

 tion the turgidity of the cells. 



The experiments of Viala and Pacottet^ on hlack rot (Guignardia 

 BidzvelUi) show how very^ determinative this acid content can often be. 

 Infection experiments in young berries are successful only so long as the 

 acid content exceeds the sugar content. Not only the content in organic 

 acids is increased but also the indifferent ash material is changed by the 

 changed absorption of nutrition. This is shown by Andre's experiments- 

 He tried to excite etiolated plants to unusual activity 'by increasing the tem- 

 perature (30 degrees), but found only an unusual increase in the absorption 

 of silicic acid, with an exclusion of other mineral elements. 



The decomposition and counter building of the proteins in the plant 

 celP also stand in the closest connection with the above described processes 

 of the formation and oxidation of the carbohydrates. 



In the germination and sprouting of buds on branches, roots and tubers, 

 we find products of the decomposition of proteins which are similar to those 

 of artificial protein decomposition, i. e., asparagin, glutamin, leucin, tyrosin, 

 occur in very large amounts. According to Borodin's investigations* these 

 amido compounds occur more abundantly, the fewer the elements present 

 which are free from nitrogen (especially the grape sugar) and which can 

 be used for the breaking down of the proteins. 



Since in etiolated plants, as well as in others grown in the light but in 

 air free from carbon dioxid, the new production of carbohydrates is sup- 

 pressed and since these are used up by day in respiration, an accumulation 

 of asparagin will take place. Among the more recent observers, we wi!l 

 mention Zaleski (cf. next page) who found an increase of asparagin in 

 seedlings of Allium Cepa. The above mentioned work by Schulze and 

 Castoro° should be especially considered, from which it is seen that, for 

 example, in etiolated seedlings of Lupinus Alb us the content in protein 

 substances decreases ; that in aspargin constantly increases. Tyrosin and 

 leucin decrease. 



As a matter of fact, E. Schulze found more than half of the whole 

 nitrogen content in 20 day old etiolated lupin seedlings in the form of 

 asparagin". If now the nitrogen free part of the protein molecule is used 

 up in respiration and no new elements, lacking nitrogen, are present to 

 reconstruct normal protein in the protoplasm, the cell will undergo the most 



1 Viala, P., et Pacottet, P., Sur le developpement du Black Rot. Compt rend 

 1904. CXXXIX, p. 152. 



2 Andre, G., Wirkung der Temperatur auf die Absorption der Mineralstoffe bei 

 etiolierten Pflanzen. Compt. rend. 1902; cit. Biedermann's Centralbl f Agrikul- 

 turchemie 1903, Part 2. 



3 Pfeffer in Jahrb. f. wissensch. Bot. 1872, Vol. 8, p. 548. Tagebl. d Naturf 

 Vers. z. Wiesbaden. 



4 Bot. Zeit. 1878, p. 802 ff. 



5 Schulze, E., und Castoro, N., Beitrage zur Kenntnis der Zusammensetzung- u. 

 des Stoffwechsels der Keimpflanzen: cit. Bot. Centralbl. 1904, Vol. XCVI, p. 540. 



6 Schulze, E., Uber den Eiweissumsatz im Pflanzenorganismus. Landwirtsch. 

 Jahrbiicher. 1880, p. 1-60. 



