130 EXPERIMENT STATION RECORD. 



with the concentration to an optimum, after which the growth was gradually 

 reduced. 



In a second series of exijeriments an attempt was made to determine the 

 assimilation of manganese by- the fungus. It was found that the increased 

 weight of the mold was due not only to the manganese assimilated but also to 

 the stimulating effect the chemical produced on the assimilation of other com- 

 pounds by the fungus. 



The amount of manganese fixed was found quite small in proportion to the 

 total amount at the disposal of the plant, and it did not appear to be of physio- 

 logical use within the cells. It either simply colored the cell wall or was 

 changed into insoluble forms. The greatest stimulation to growth appeared 

 when manganese was used in the proportions between 1 part to 10,000 and 1 

 part to 500. The manganese appeared to stimulate the production of conidla, 

 as shown by differences in color of the growth on the media. 



The stimulating action of manganese and copper sulphates on plants, 

 L. MoNTEMARTiNi (Staz. Spev. Agr. Ital., ^^ {1911), No. 7, pp. 564-571; abs. in 

 Internat. Inst. Agr. [Rome], Bid. Bur. Agr. Intel, and Plant Diseases, 2 {1911), 

 No. 11-12, pp. 2467, 246S).—A study has been made of the effect of very dilute 

 solutions of the sulphates of manganese and copper on the development, respira- 

 tion, and photosynthesis of graiDes, lupines, beans, and potatoes, and the flowers 

 of Leucanthemum and Ageratum. Comparisons were drawn between the car- 

 bon dioxid liberated and the proportion of the different substances absorbed by 

 the plants. The manganese solutions varied from 0.001 to 0.025 per cent and 

 the copper sulphate from 0.005 to 0.05 per cent. 



The results show that when these salts were absorbed by the plants in very 

 small quantities both exerted a stimulating effect on the growth of all the 

 plants. Marljed differences were noted in the sensitiveness of the different 

 plants, as shown by their respiration. Grapes were the most sensitive, followed 

 by beans and potatoes in the order enumerated. The flowers of plants were 

 found to exhibit more sensitiveness to the chemicals than the leaves. Unopened 

 flowers were more sensitive than open ones. Photosynthesis was stimulated 

 more than respiration, and it varied to some extent with the different plants. 



The growth, of wheat seedlings as affected by acid or alkaline conditions, 

 J. F. Breazeale and J. A. LeClerc {ZJ. S. Dcpt. Agr., Bur. Chem. Bui. 149, 

 pp. 18, pis. 8). — ^A report is given of a physiological study to determine the 

 effect of the reaction of the culture medium on the growth of wheat seedlings 

 and particularly on the development of the root. Seedlings were grown in 

 water cultures containing various amounts of sodium nitrate, potassium chlorid, 

 potassium sulphate, hydrochloric acid, and sulphuric acid, singly and in com- 

 bination with calcium carbonate. Two crops of seedlings were grown in the 

 solutions, and the effect on germination was noted. Another series of experi- 

 ments was conducted in which aluminum and ferric hydroxids were used to 

 reduce the acidity of the solution, and still another series in which clover and 

 timothy were grown in connection with wheat. 



The investigations show that the seedlings grown in culture solutions con- 

 taining potassium chlorid, potassium sulphate, or hydrochloric or sulphuric acid 

 solutions (10 parts per million) exert a selective action whereby the potash ion 

 is absorbed by the roots and the chlorid and sulphate ions are for the most 

 part left in solution. This causes the solution to become acid, which in turn 

 acts injuriously on the root development. The addition of iron or lime or 

 aluminum hydrate to the media containing the other compounds used tended to 

 keep the solutions alkaline so that they acted favorably on the root development. 



New studies on narcosis in plants, O. Richter {Mitt. Natiirw. Ver. Univ. 

 Wien, 9 {1911), No. 1, pp. 14, 15; abs. in Bot. CentU., 116 {1911), No. 24, 



