EXPERIMENT STATION RECORD. 333 



AGEICULTTJRAL BOTANY. 



Physiology of the intake of material by the living plant cell. — H, Changes 

 produced by potassium cyanid in the permeability of the vegetable plasma- 

 membrane, M. KJiEHAN {Internal. Ztschr, Phys. Chem. Biol., 1 {1914) y No. 3-4, 

 pp. 189-259, figs. 9; abs. in Jour. Chem. Soc. [Londoyi], 108 {1915), No. 629, I, 

 pp. 108, 109). — Summarizing the more general results of the tests detailed, the 

 autlior states that the point of concentration at which plasmoylsis of plant 

 cells occurs in solutions of certain salts named is raised above that which is 

 normal to the plant by the addition of potassium cyanid in suitable proportions. 

 The effectiveness varies with its concentration and the length of exposure 

 thereto, the effects being reversible after use of the less concentrated solutions. 

 This elevation is not due to retention within the cell of osmotically-active sub- 

 stances caused by the limiting influence of potassium cyanid on respiration, 

 but is due partly to its influence on the colloids of the plasma membrane 

 and partly to the increased permeability of the membrane for certain solutes 

 of the external medium. 



Physiology of the intake of material by the living plant cell. — III, Influ- 

 ence of neutral salts and some nonelectrolytes on the injurious effects of 

 alcohols on plant cells, Helene Nothmann-Zuckeekandl {Internat. Ztschr. 

 I'hys. Chem. Biol., 2 {1915), No. 1, pp. 19-41; abs. in Jour. Chem. Soc. [London], 

 108 {1915), No. 630, I, pp. 199, 200).— Following up the report of Krehan 

 noted above, the author states that the exosmosis from leaves of Echeveria, 

 Saxifraga ^armentosa, and Tradescantia discolor in aqueous solutions of the 

 lower alcohols is augmented by the addition of neutral salts. The increase is 

 due, apparently, not to an altered solubility of the alcohol but to the summa- 

 tion of the tendencies separately shown by the dissolved substances. 



With higher alcohols, however, the osmotic effect of the solutions is usually 

 reduced by addition of the salts. It is thought that in this case the alcohol 

 and the salt obstruct each other in entering by the same path, this view being 

 confirmed by experiments employing plasmolysis. Entrance is thought to be 

 afforded by the hydrocolloids of the plasma. 



Tannic or aspartic acids or peptone increase the action of the various alco- 

 hols, but glycin, tyrosin, sucrose, and maltose are inactive. 



The influence of salts on heliotropism, Ines Maecolongo {Bui. Orto Bot. R. 

 Univ. Napoli, 4 {1914), PP- 211-221). — Describing the effects of various admix- 

 tures of equimolecular solutions of certain potassium, sodium, calcium, and mag- 

 nesium salts on seedlings of oat, bean, and mustard, the author states that all 

 these salts increase the readiness and degree of the heliotropic response of 

 etiolated, but lower those of the normally growing, plantlets. 



It is thought that the effects observed may be ascribed to the chemical action 

 of the nutritive salts without excluding a physico-chemical influence related 

 to the concentration of the solution. 



A bibliography is appended. 



A three-salt nutrient solution for plants, J. W. Shive {Amer. Jour. Bot., 

 2 {1915), No. 4, PP- 157-160). — The author gives a preliminary report on his 

 experimentation with wheat and buckwheat in attempting to devise and use 

 a simpler nutrient solution than the 4-salt mixture used by Tottingham (E. S. R., 

 31, p. 425), potassium nitrate being omitted from the Knop formula as used 

 by that investigator. 



From the results as tabulated it is claimed that the 3-salt mixture, in proper 

 proportions, is eminently suitable for plant development. It gave a markedly 

 better growth of tops than the 4-salt solution, at least with a total osmotic con- 



