224 EXPERIMENT STATION RECORD. 



Alkali studies, VI, H. G. Knight and R. B. Moudy (Wypming l^ta. Rpt. 

 1906, PI). 45-51). — In continuation of previous alkali studies, the investigations 

 here reported were begun to determine what effect the presence of ions of 

 different velocity had upon the absorption of salts by seeds and incidentally to 

 determine whether ionic velocities had any marked effect upon salt absorption. 



The authors, summarizing their report, conclude that in pure water seeds 

 lose a portion of the salt. The absorption of salts by seeds is in direct ratio to 

 the relative mobility of the ions. The addition of a more rapid ion, whether 

 positive or negative, in small quantities to solutions of slower ions retai'ds 

 absorption of the slower ion. The experiments in which a slow positive cal- 

 cium ion was added to rapidly moving ions were not very satisfactory, but the 

 results indicate tliat the slow-moving calcium tends slightly to increase 

 absorption. 



The influence of magnesium sulphate on the growth of seedlings, Ger- 

 trude S. BuELiXGHAM {Jouv. Amer. Chem. Soc, 29 (1907), No. 7, pp. 1095-1112. 

 figs. 6). — The investigations reported are the outgrowth of a comprehensive 

 study of the nutrition of plants, the aim being to learn the effect of different 

 mineral nutrients on the growth of a test plant and to note the variations pro- 

 duced by modifying the composition of the solutions. The test plant used was 

 the common velvet weed, and the seedlings were transferred to water cultures 

 in l^eakers containing various strengths of solutions based on the molecular 

 weight of magnesium sulphate. In addition to the velvet weed, similar e;speri- 

 ments were conducted with pea and maize seedlings. 



The author gives the following summary of conclusions : 



" Magnesium sulphate in solutions of greater concentrations than 7»/8192 has 

 a toxic action on most seedlings, the degree of toxicity varying with the type of 

 seedling and with the conditions. An j«/8192 solution is toxic to pea seedlings, 

 slightly stimulating to velvet weed, while it has a marked stimulating effect on 

 corn seedlings. Maximum stimulation in magnesium sulphate results in solu- 

 tions from »»/32768 to )»/1310T2, the point again varying according to tlie kind 

 of seedlings grown. When magnesium sulphate is used in proper dilutions there 

 may be produced a total growth nearly double that in the control ; or in the case 

 of velvet weed seedlings, a gi'owth of the primary root 15 times that in the 

 control. Not only is the growth of the primary root increased, but the lateral 

 roots develop sooner, are more numerous, and attain a greater growth. Further- 

 more, the stimulation is lot limited to the root system, but the magnesium forces 

 a more rapid and a greater growth of the hypocotyl and plumule. In these 

 same concentrations, calcium nitrate causes very little stimulation. 



" In addition to the mai-ked stimulation which magnesium sulphate causes 

 when it is used in dilutions from }»/16.384 to j?i/524288. it increases the vitality 

 of the seedlings. The seedlings grown in the magnesium sulphate outlived 

 those in the control by two or three weeks, and in some cases by a greater 

 period. 



" From the foregoing results and conclusions, it is then evident that magne- 

 sium sulphate, in the absence of other salts, is not necessarily injurious in its 

 effects, but on the other hand may be highly beneficial ; while any inhibitory 

 action is due to the presence of a relatively large proportion of magnesium in 

 the solution." 



The presence of organic silica in plants, T. Takeuchi (Bnl. Col. Afjr. Tokyo 

 Imp. Univ., 7 (1907), Xo. S. pp. .>i29-.'i31). — The author made a study of a num- 

 ber of species of plants to determine whether in plants or their products silica 

 occurs in an organic form. The leaves of various species of grasses were sub- 

 jected to analysis, and it was found tliat silica occurred in an organic form 



