224 EXPERIMENT STATION RECORD. 



and evening. It was found tliat instead of the evening tests showing a gi-eater 

 amount of nitrogen, they showed less than similar leaves tested in the morning. 

 The conclusion is drawn, therefore, that the leaves of nonleguminous plants do 

 not fix free nitrogen. 



Comparative absorption of salts of barium, strontium, and calcium by 

 living plants, H. Colin and J. de Rufz de Lavison (Rev. G6n. Bot., 22 {1910), 

 No. 261, pv, 537-3////).— In a previous publication (E. S. R., 3, p. 328) the 

 authors reported upon the localization of barium salts in the roots of peas 

 grown in cultures which contained small quantities of barium. Subsequent 

 studies have been made of strontium and calcium salts. 



While almost no trace of barium was to be found in the stems, strontium 

 occurred in small quantities and calcium abundantly, showing that the salts 

 of the latter two alkaline metals can penetrate the roots of peas and be trans- 

 ferred to the stems and other organs, but not the salts of barium. The results 

 were confirmed with other plants, as beans, lentils, lupines, maize, wheat, 

 hyacinth, etc. 



The excretion of mineral and org'anic substances by roots and water pores 

 of plants, P. Maz£ {Compt. Rend. Acad. Sci. [Paris], 152 (1911), No. 8, pp. 

 Ji52-Ifo6; abs. in Rev. Sci. [Paris], 49 (1911), I, No. 9, pp. 282, 283).— The 

 author shows by his experiments that roots return not only mineral matter but 

 also organic substances to the soil. In a like manner inorganic substances are 

 eliminated through the water pores of the leaves. 



The water collected from the leaves was found to contain chlorids, sulphates 

 of lime and magnesia, nitric acid, and ammonia. The elimination of the unused 

 mineral matter by roots and leaves, it is said, determines the composition of 

 the ash of plants, the absolute weight of which will be increased or diminished 

 according to the absorption. 



Reduction by roots, O. Schreiner and M. X. Sullivan (Bat. Gaz., 51 (1911), 

 No. 2, pp. 121-130). — A report is given of experiments on the reducing power of 

 seedlings grown in soil or solutions. The experiments were made to determine 

 the power of uninjured growing roots, especially of wheat, to reduce substances, 

 with the purpose of seeing if, like the oxidative power, the reducing power 

 would be found to play a significant part in soil fertility. 



Studies were made with wheat seedlings grown in various solutions, show- 

 ing that they were quickly decolorized, after which (jxperiments were carried 

 on with seedlings placed in starch iodid solution, sulphur, nitrates, sodium 

 selenite, and sodium tellurite to test their reducing power. 



The experiments showed conclusively that uninjured roots possess a reducing 

 power which is stronger in young seedlings and diminishes as the seedlings 

 become older. As judged by the quickness with which the deposit of selenium is 

 made on the roots and the intensity of the deposit, the reducing power increases 

 from the time of germination to the sixth or eighth day and then decreases. On 

 the other hand, the oxidizing power of wheat seedlings is said to be less in the 

 young seedlings, increasing with age. 



A bibliography is appended. 



Some investigations on the action of wind on plant growth, F. Cavara 

 (Bui. Orto Bot. R. Univ. NapoU, 2 (1910), No. 4, pp. 505-512, pi. i ) .—The results 

 are given of experiments on the effect of wind on the growth of Iresine 

 herbstii, Coleus hybridus. Aster chinensis. Zinnia violacea, and Sempervivum 

 clusiamim. 



It was found that in most instances the main axis of the stem was shortened 

 and thickened, resulting in a closer leaf formation approaching to a rosette 

 type of growth. This was especially noticeable in C. hybridus and A. chinensis. 



