AGEICULTUEAL BOTANY. 323 



28 (1912), 1. AM., No. 3, pp. Ji22-^52, figs. 6).— As a result of studies carried 

 out with cultures of L. sativum, Helianthus annuus, Vida faba, Trifolium 

 repens, and Sctaria italica in alum solutions,' tlie author states that roots 

 lacking starch showed no geotropic response even when capable of growth, 

 and that in several cases the degree of geotropism was observed to show increase 

 corresponding to the increase in starch content. 



Symbiosis of plants as a chemical problem, J. Zellneb (Bot. Centbl., 

 Beihefte, 28 (1912), 1. AM., No. 3, pp. 473-4S6; abs. in Bot. Centbl, 122 (1913), 

 No. 11, pp. 229, 230). — The author reports on a study of the relations between 

 plants associated in various degrees as symbionts or as host and parasite in 

 regard to their chemical likenesses and differences, their absorption, excretion, 

 and exchange of dissolved substances, and the transformations that take place 

 . in each. A considerable number of details, qualitative and quantitative, are 

 given in regard to lichens, smut and grain, mistletoe and its hosts, etc. It 

 would seem that the chemical composition, reactions, etc., of symbiont or para- 

 site are determined by its systematic position rather than by the chemical 

 characters of its associate or host. 



The influence of manganese on the formation of chlorophyll, Eva Mameli 

 (Atti Soc. Ital. Prog. Sci. [Rome'\, 5 (1911), pp. 793-799; abs. in Bot. Centbl., 

 122 (1913), No. 10, p. 200).— It is stated that several plants (Protococcus 

 viridis, Spirogyra majuscula, Vaucheria sp., Zea mays, Polygonum fagopyrum, 

 Helianthus annuus, and Torenia fournieri) in a nutritive medium lacking 

 manganese remain colorless, or very pale, but that addition of manganese in 

 increasing proportion leads to a correspondingly increasing show of green 

 color. The author notes the agreement of this finding with the results of 

 Willstatter's investigations (E. S. R., 24, pp. 329, 628). 



On the state of chlorophyll in plants and colloidal chlorophyll, A. Heb- 

 LiTZKA (Arch. Ital. Biol, 58 (1912), No. 3, pp. 388-392) .—The author submits 

 the results of experiments and spectroscopic examinations of colloidal solu- 

 tions of chlorophyll, of solutions of alcohol and acetone, and of the expressed 

 juice of leaves. 



It is stated that the colloidal solutions showed spectra and behavior in 

 general similar to those observed in case of living leaves and expressed juices, 

 and unlike those from alcoholic solutions. These results are held to agree 

 with those previously announced (E. S. R., 27, p. 227), and to show that in 

 living leaves chlorophyll exists in a colloidal state. 



The distribution of ions within the plant body in relation particularly to 

 the localization of protein formation, C. Acqua (Ann. Bot. [Rome], 11 (1913), 

 No. 2, pp. 281-312, pis. 3). — Continuing work previously noted (E. S. R., 24, 

 p. 531), the author studied the effects produced upon wheat, corn, beans, peas, 

 and white mustard when grown in solutions, more or less concentrated, of 

 manganese nitrate and other salts which indicate the presence of the sepa- 

 rated ions by tissue coloration. 



The results, while varying in details, showed agreement as to the main facts 

 observed. The cations were found mainly in the roots (particularly in the 

 meristems of the secondary roots), but occasionally in the aerial portions, in 

 this case in close relation to the protein storage cells, as in the case of the bean 

 plant. It is thought that these circumstances reveal the regions in which 

 occurs the utilization of nitrates, sulphates, etc., with synthesis of proteins, 

 such regions always being those of newly formed or actively dividing cefts. 



In some cases it was noted that the endodermis limited the movement or 

 localization of the cations. This layer is thought to exhibit here' the char- 



6724°— 13 3 



