1919] 



AGRICULTURAL BOTANY. 27 



It is to the osmotic activity of tliese substances in tlie vacuoles tliat turgidity 

 is due, and it is upon tliis largely that the maintenance of the turgidity of or- 

 gans depends. The complete conception of the cell includes its expansion by the 

 osmotic action of electrolytes and by the swelling resulting from imbibition or 

 hydration of its colloids, as well as the effect of such increasing changes within 

 its mass. 



Nowhere is metabolism more active than in the embryonic growing cells. 

 Changes are mentioned which are thought to exemplify but by no means to 

 exhaust the possibilities of modifications of the colloidal action in growth. 



Temperature and the hydration and growth of colloids and of cell masses, 

 D. T. MacDougal (Carncyie Inst. Washington Year Book, 17 (191S), pp. 

 6S-70). — Recognition of the complex character of the groups of reactions which 

 enter into the more prominent life processes is said to have l)rought convic- 

 tion as to the futility of attempts to define physical constants, such as tempera- 

 ture coefficients. Results of series of experiments are tabulated. 



Comparison of salt requirements for young and for mature buckwheat 

 plants grown in sand cultures, J. W. Shive {New Jersey Stas. Rpt. 1917, pp. 

 409-413, fig. 1). — A brief account is given of investigations previously reported 

 (E. S. R., 39, p. 524; 40, p. 425). 



A comparative study of salt requirements in solution cultures for the 

 growth of buckwheat to the flowering stage and to maturity, W. H. Martin 

 {New Jersey Stas. Rpt. 1917, pp. 4^9-422). — This reports in condensed form the 

 results of experiments previously noted (E. S. R., 39, p. 524). 



Experiments to determine whether one form of phosphorus in a complete 

 nutrient plant solution is more available for the growth of buckwheat seed- 

 lings than are other forms, H. L. Bancroft {New Jersey Stas. Rpt. 1917, pp. 

 423, 424)- — A brief report is given of studies made to determine the relative 

 availability of different forms of phosphorus in a Tottingham nutrient solution. 

 The original solution contains monopotassium phosphate, potassium nitrate, 

 calcium nitrate, and magnesium sulphate. In place of the monopotassium 

 phosphate, monosodium phosphate, monocalcium phosphate, monomagnesium 

 phosphate, and monammonium phosphate were substituted in the different 

 series. Buckwheat was grown in the different solutions to the flowering stage, 

 and while the data have not been completely tabulated, it is stated that great 

 variations in height, general growth, toxic effect, and final weights for the 

 buckwheat plants were found. As a rule the original Tottingham solution, con- 

 taining phosphorus in the form of monopotassium phosphate, produced a larger 

 total dry weight of plant substance than did any of the other forms of phos- 

 phorus, while the series receiving monammonium phosphate produced the 

 smallest total growth of plants. 



The toxicity of phosphates toward soy bean seedlings, J. W. Shive {Neio 

 Jersey Stas. Rpt. 1917, pp. 405-408). — A condensed account is given of investi- 

 gations previously reported (B. S. R., 39, p. 827). 



Effect of ammonium sulphate in nutrient solution on the growth of soy 

 beans in sand cultures, IVI. I. Wolkoff {Ncio Jersey Stas. Rpt. 1917, pp. 

 416-419). — This is a summary of investigations previously reported (E. S. R., 

 40, p. 30). 



Absorption of sodium and calcium by wheat seedlings, H. S. Reed {Bot. 

 Gaz., 66 {1918), No. 4, pp. 374-380, fig. J).— The author has studied the effects 

 of sodium and calcium compounds applied to wheat seedlings in lower con- 

 centrations than those commonly used. He has found that antagonism is 

 present even under these conditions, and also that concentrations of sodiun 

 chlorid strongly toxic to wheat seedlings were rendered harmless by a 



