824 EXPERIMENT STATION RECORD. 



Recent studies on the formation of flower coloring materials, Elisabeth 

 ScHiEiiANN {Ztschr. Induktive Abstam. u. Yererhungslehre, 14 {1915), No. 2, 

 pp. 80-96). — This is a brief discussion of the results of studies reported during 

 1902 to 1914 by a number of authors listed with their contributions. The 

 material, which is regarded from the standpoint of Mendelian splitting, Is dis- 

 cussed under the main heads of the glucosid-splitting enzym, the oxidases, the 

 limiting factor, and the chromogens. 



The relation between veg'etative vigor and reproduction in some Sapro- 

 legniaceae, A. J. Pieters (Amer. Jour. Bot., 2 (1915), No. 10, pp. 520^76, figs. 

 2). — The author, reporting a study of S. fcrax, S. monoica, Achlya raccmosa, 

 and A. prolifera, states that there is no constant relation between vegetative 

 growth and sexual reproduction when the concentration of the food supply 

 exceeds the minimum requirement of the species therefor. This is not far 

 from 0.1 per cent of peptone for the production of both sporangia and oogonla. 



Tendencies developed by a mycelium while growing vegetatively may affect 

 the number and character of the reproductive organs produced later under 

 different conditions. Maltose and levulose are especially favorable among the 

 carbohydrates u.sed as regards vegetative growth, and the latter has an especial 

 value for the production of oogonia. Sucrose is probably not usetl by species 

 of Saprolegnia or of Achlya unless it is first inverted by some other agency. 

 Phosphates tend to increase the reproductive capacity of the fungus. 



The achievement of comparable results requires the use of a medium of 

 definite and known composition. 



A bibliography is given. 



On the influence of nutrition upon the development of sexual organs in 

 the fern prothallia, I. Nagai (.four. Col. A(jr. Imp. I'nii: Tokyo. 6 (1915), No. 

 2, pp. 121-l()Jf, pi. 1, figs. 7). — On account of recent investigations showing the 

 effect of nutrition on the development of sex in plants, the author made a study 

 of the inlUience of nutrition on the development of sexual organs in the game- 

 tophytes of Osmunda rcfjaU.^ jnponica and Asplcnium nidux. 



The prothallia were grown from .spores in Knop's solution, and it was found 

 that the development of antherldia and archegonia was dependent upon the 

 concentration of the solution in which they were grown. The prothallia of 

 O. rcffalis jnponica grown in solutions which lacked calcium and magnesium 

 salts wore almost completely sterile. Starch was found to accumulate abnor- 

 mally in the chlorophyll bodies of prothallia of Osmunda which were grown 

 under a nitrogen-hungry condition, but a normal condition was soon restore<l 

 if weak solutions of ammonium salts and nitrates were supplied. 



Relation of moisture to seed production in alfalfa, J. N. Martin (loxca 

 Sta. Research Bui. 23 (1915), pp. 302-324, figs. 2).—\ report Is given of in- 

 vestigations conducted to determine the cause of the frequent failure of alfalfa 

 to produce seed in Iowa. 



As a result of laboratory and other experiments, it was determined that 

 the proper functioning of alfalfa pollen is the limiting factor In seed produc- 

 tion. For the germination of the pollen, a proper supply of water Is required, 

 and a certain ratio between the moisture delivere<l by the stigma and the 

 moisture of the air was found necessary. When the optimum supply of soil 

 and atmospheric moisture Is present, an Increase In .soil moisture resulting 

 In an increased moisture delivery of the stigma, or a change in the atmospheric 

 moisture disturbs the supply for pollen germination and prevents fertilization. 

 The blasting of seed is said to be commonly due to arreste<l development, and 

 this may be brought about by inability on the part of the plant to furnish the 

 proper water and food supply, or It may be due to pathological conditions to 

 which the seed is susceptible under drought conditions. 



