434 EXPERIMENT STATION RECORD. [Vol, 35 



somewhat gi-eater assimilation of the calcium On the other hand, the anions 

 of the nitrates and the phosphates were absorbed in considerably larger 

 amounts than the calcium ions. The difference in the amount of absorbed 

 anions and cations in these cases was so large that in no way could it be 

 accounted for as a possible experimental error. 



Effect of osmotic pressure in nutrient solutions on plant growth, A. A. 

 Stol'gane (Iz Rezul't. Yeget. Oi)ytov Lab. Ruhot (Rec. Trav. Lab. Agr07i.), 

 9 {1913), pp. 51Jf-550, pi. i).— The object of the author's experiments was to 

 determine the effect of the osmotic pressure in nutrient solutions on the gen- 

 eral development of plants and on their absorption of nitrogen. Flax and bar- 

 ley were grown in sand and water cultures to which various combinations of 

 nutrient solutions were added containing ammonium nitrate as well as sodium 

 chlorid, potassium chlorid, magnesium sulphate, potassium sulphate, and sodium 

 sulphate. 



It was found that the plants can resist only a comparatively low osmotic 

 pressure, which, however, when not exceeding two atmospheres, as was the case 

 with sodium chlorid, has even a stimulating effect upon the growth. Growth 

 was retarded by increased osmotic pressure and all the vegetative processes 

 may be checked entirely if the pressure becomes much higher than two atmos- 

 pheres. The percentage of nitrogen increased with increase of pressure, but its 

 total amount as shown in the yield was diminished except in those cases where 

 the osmotic pressure was comparatively low. 



Stimulants of plant growth, F. V. Chibikov (T. Tschieikow) (Iz ResuVt. 

 Yeget. Opytov Lab. Rabot (Rec. Trav. Lab. Agron.), 9 {WIS), pp. 431--i35).— 

 This work is a continuation of experiments of the previous year, potassium per- 

 manganate, manganese chlorid, molybdic acid, sodium tungstate, uranium 

 nitrate, and iron sulphate being tested as stimulants of plant growth with 

 Persian wheat, Swedish wheat, buckwheat, and peas grown in sand cultures. 



With wheat it was found that all the stimulants gave more or less positive 

 results, while with the other plants the results were variable. When two 

 stimulants were present together in the same culture, their combined effect 

 represented very closely the aggregate action of the two chemicals taken sepa- 

 rately. Uranium nitrate and sodium tungstate increased the quantity of seeds 

 in peas. The largest general increase of yield for wheat was obtained with 

 manganese chlorid, and for peas with uranium nitrate. 



The metabolism of nitrogenous substances in etiolated shoots of barley 

 nourished on ammonium salts, A. I. Smienov [Iz Rezul't. Yeget. Opytov Lab. 

 Rabot (Rec. Trav. Lab. Agro7i.), 9 {1913), pp. 470-50^ ) .—Experiments carried 

 out with carbamid, ammonium nitrate, and ammonium chlorid, the ammonium 

 nitrate and chlorid being used with and without the addition of calcium car- 

 bonate and calcium sulphate, demonstrated that seedlings of barley absorb the 

 nitrogen of the ammonium salts very energetically during the first days of 

 growth, showing also an increased activity in the formation of asparagin. 

 Later on the rate of absorption gradually decreased, but this was not found 

 to be due to the lessening of osmotic pressure in the solutions. 



Calcium salts influenced the assimilation of nitrogen from ammonium salts 

 and stimulated the formation of asparagin, as well as the splitting of proteins. 

 The nitrogen of the nitrates was absorbed with equal energy. 



Assimilation of nitrogen from ammonium salts and accumulation of am- 

 monium salts in the tissues were in reverse proportion. This fact is connected 

 with the consumption of carbohydrates and is analogous to the behavior of 

 etiolated seedlings of lupines, plants poor in carbohydrates. 



Absorption of nefrntivp inns by seedlings of barley was found to take place 

 only during the first few days of the experiment. 



