628 EXPERIMENT STATION RECORD. 



A new method of so-called water culture, II, L. Hiltnee (Prakt. Bl. 

 Pflanzenhau u. Schutz, n. ser., 12 (1914), No. 5, pp. 40-55, figs. 2). — These ex- 

 periments, continuing those previously reported with serradella (E. S. R., 28, p. 

 817), show the value of rock phosphate in nutritive solutions for use in growing 

 oats as preventive of dry spot and tipburn and also as supplementary to or as 

 replacing other nutritive components. 



Antagonism and balanced solutions, R. H. True [Science, n. ser., Jfl {1915), 

 No. 1061, pp. 653-656). — The author discusses the terms antagonism and balanced 

 solutions as used by a number of investigators aud claims that there appears to 

 be no reason to limit the use of the term balanced solutions as is commonly done. 



On the osmotic pressure of the juices of desert plants, J. A. Harris, J. V. 

 Lawrence, and R. A. Gortner (Science, n. ser., 4i (1915), No. 1061, pp. 656-658, 

 fig. 1). — A series of cryoscopic determinations on the spring flora of the 

 vicinity of Tucson, Ariz., with comparisons on species of spring and early sum- 

 mer plants in the vicinity of the Station for Experimental Evolution on Long 

 Island have been made to test the results given by E. and Hilda Drabble 

 (E. S. R., 18, p. 824) and Fitting (E. S. R., 25, p. 430). 



The authors were unable to find pressures as high as those described by 

 Fitting, but they do not claim that they do not occur. Pressures of 10.5 at- 

 mosplieres or lower were obtained for about 50 per cent of the Cold Spring 

 Harbor series, wliereas in the desert plants 50 per cent of the pressures were 

 15.7 atmospheres or hi?;her. 



Relations between osmotic pressure and regulation of stomata, W. S. 

 iLJiN (Bot. CentU., Beihefte, 32 (1914), 1. AM., No. 1, pp. 15-35, figs. S).— 

 Reporting details of experimentation on the behavior of leaf stomata under 

 varying conditions the author claims that stomatal regulation, which is related 

 to transpiration conditions, shows also a close relation to change in starch 

 content, and this in itself shows a close relation witli variations in osmotic 

 pressure. 



Regulation of the stomata is dependent directly upon physiological processes. 

 Variation in total water content in a plant acts as a stimulating factor, condi- 

 tioning the a,ctivation of certain enzyms which determine the state of the starch 

 material. Alternations of osmotic properties and of turgor also result, the 

 latter influencing the degree of stomatal opening. 



The changes ob.served are not purely mechanical, but dependent upon the 

 activity of living protoplasts under the influence of external stimuli, for ex- 

 ample, alterations or differences in intensity of illumination, which seem to 

 affect the osmotically influential contents of the guard cells. 



The problems in a comparative study of transpiration in plants, W. S. Iljin 

 (Bot. CentU., Beihefte, 32 (1914), 1. AU., No. 1, pp. 36-65, figs. 27).— Results 

 of studies on various types of plants are given, but they are considered to show 

 that it is not yet possible by a study of the transpiration curves alone to ascer- 

 tain the degree of protection enjoyed by types biologically different. The pres- 

 ent work aims not so much to give exact results for individual .species or plants 

 as to mark out lines along which study may proceed in order to ascertain which 

 plants may be expected to survive under given conditions or to win out in 

 competition. 



Increased carbon dioxid concentration in relation to transpiration and 

 development in plants, N. Kisselew (Bot. Centbl., Beihefte, 32 (1914), 1- AM., 

 No. 1, pp. 86-96. pis. 2, figs. 3). — The author describes experimentation relative 

 to the effects of increased carbon dioxid supply on plants somewhat similar to 

 that reported by Brown and Escombe (E. S; R., 14, p. 546) and by Fischer 

 (E. S. R., 28, p. 837). The results agreed with Fischer's conclusions, inasmuch 



