324 EXPERIMENT STATION RECORD. 



acter of a special semipermeable membrane, according to the conception of J. 

 de Rufz de Lavison (E. S. R., 25, pp. 730, 731). 



Respiration of plants as hydrolytic oxidation, W. Palladin {Ber. Deut. 

 Bot. GeseU., 31 (1913), No. 2, pp. 80-82). — Continuing work previously noted 

 (E. S. R., 27, p. 632), the author makes the following statements: 



Alkaline solutions containing chromogens eagerly absorb atmospheric oxygen, 

 at the same time forming brownish red pigments. During alcoholic fermenta- 

 tion compounds are formed which readily give up to the respiratory pigments 

 their hydrogen, which is oxidized by the absorbed oxygen, the result being a 

 pigment and water. Hydrogen is said to be separated in considerable quantity 

 in an alkaline solution of formaldehyde in the presence of copper mouoxid, 

 formic acid being produced therein as the result. 



Absorption of oxyg'en by the respiratory chromogens of plants, W. Pal- 

 ladin and Z. TOLSTAJA (Biochem. Ztschr., ^9 (1913), No. 5, pp. 381-397, figs. 

 2). — In connection with the work noted above, the authors report the conclu- 

 sions resulting from another series of investigations substantially as follows: 



Respiratory chromogens maybe extracted from plants by means of methyl alco- 

 hol. Alkaline solutions of these chromogens absorb oxygen from the air, form- 

 ing brownish red pigments. The protoplasm in which such absorption occurs 

 possesses an alkaline reaction. These chromogens may also be oxidized by 

 means of peroxidase and by hydrogen peroxid. Aqueous extracts of plants 

 also contain chromogens which, after addition of alkali, absorb atmospheric 

 oxygen, but this capability is diminished or suspended on boiling. 



Chromogens extracted with wood alcohol are scarcely at all oxidized by 

 atmospheric air, but such chromogens from plants subjected for several days to 

 autolysis in an acid-free medium absorb oxygen energetically from air with the 

 formation of pigments. Such altered chromogens are called reduced, as dis- 

 tinguished from ordinary chromogens, which by autolysis with yeast may be 

 changed to the reduced form. Plants which yield on autolysis in an acid-free 

 medium a chromogen quickly turning dark in air yield no trace whatever of 

 pigment under like treatment in a medium containing acid. 



During alcoholic fermentation (and therefore during the first anaerobic 

 stage of respiration) products are formed which readily give up their hydro- 

 gen to the respiratory pigments by which the hydrogen is oxidized to water. 

 Boiling does not prevent such products from giving up their hydrogen to the 

 chromogen. The i-espiratory chromogens resemble the leucoplasts in giving 

 up their hydrogen to the absorbed oxygen, the result being pigment and water. 

 The oxygen absorbed during respiration is utilized after removal of the 

 hydrogen from the plant. 



Periodical daily fluctuations of respiration in foliag'e leaves in darkness 

 and their probable relation to carbon dioxid assimilation, II, A. Meyeb and 

 N. T. Deleano (Ztschr. Bot., 5 (1913), No. ^, pp. 209-320, figs. 36).— As the re- 

 sult of a long series of investigations with attached leaves of beet in continu- 

 ance of the work done with separated leaves previously noted (E. S. R., 26. 

 p. 822), the authors state that no direct effect or certain afterinfluence of 

 light upon the production of carbon dioxid could be established. 



The variations observed are thought to be related to assimilation changes 

 resulting from illumination, these consisting partly in a sudden increase in 

 carbohydrate content of the cells, which is said to correspond to increased 

 capacity for respiration. Such variations did not occur in well grown etiolated 

 leaves. The periodicity of the leaves is pointed to as evidence of a somewhat 

 mechanical character of the cells, certain factors, such as changes in assimila- 

 tion, transportation, etc.. acting as excitants to such machinery of stimulation. 

 Further investigations are contemplated. A bibliogi-aphy is appended. 



