328 EXPERIMENT STATION RECORD. [Vol. 36 



effects corresponding to various altitudes have been evaluated. The prelimi- 

 nary studies of the Mohave Desert region are considered to have made such 

 advances as to condition progress in the interpretation of the origination, 

 phylogeny, and successions of the present vegetation of this region. Studies 

 of the role of the several factors in a desert complex are thought to prove that 

 the more divergent part of a population is eliminated by environic agencies, 

 but that this eliminating action is subject to various modificatons. 



Artificial absorption of liquids by plants through their aerial parts, O. 

 AcQUA and Virginia Jacobacci {Ann. Bot. [Rome], 14 (1916), No. 1, pp. 33- 

 ^0). — Having extended the studies previously reported by Acqua (E, S. R., 35, 

 p. 331), the authors state that solutions of glucose were absorbed by aerial 

 portions of young white mulberry trees and produced in very small plants a 

 conspicuous increase in growth accompanied by morphological variations both 

 external and internal, somewhat older plants being less affected, and still more 

 developed ones showing very slight effects from this treatment. Lupines sup- 

 plied through their aerial parts with potassium nitrate or magnesium phos- 

 phate showed a retardation of growth, and those given potassium or calcium 

 nitrate began to show decay in about 11 days, the controls remaining normal. 

 It thus appears that some solutions of salts having nutritional value when 

 taken up through the roots are injurious when passing directly into the plant. 



A study of physiological balance in nutrient media, J. W. Shive {Physiol. 

 Researches, 1 {1915), No. 7, pp. 327-397, figs. i5).— Results are given of ex- 

 perimental study of the growth made by plantlets of winter wheat in water 

 cultures with respect to the physiological balance of salts and the total con- 

 centration of the medium. For each of the total concentrations employed 

 corresponding to pressures of 0.1, 1.75, and 4 atmospheres, there were tested 

 simultaneously 36 different proportions of the three nutrient salts calcium 

 nitrate, magnesium sulphate, and potassium dihydrogen phosphate, a small 

 amount of ferric phosphate being added to furnish iron. The criteria em- 

 ployed were total water loss by transpiration and guttation during growth, 

 dry yield, water requirement of tops and of roots, apparent condition of tops, 

 especially as to leaf injury, and condition of roots, especially as to lateral 

 branching. 



It is stated that within the first four weeks of growth these three salts form 

 a nutrient medium well suited to the development of wheat plants when the 

 total osmotic concentration is about 1.75 atniosj)heres and when the salts are 

 present in either one of two somewhat similar sets of proportions which are 

 given with discussion. These solutions are thought to be equal to any and 

 superior to most of those of equal total concentration previously described and 

 in general use. For a given total concentration the best physiological balance 

 of salt proportions for tops is not the same as that for roots. The values of 

 the cation atomic ratios magnesium : calcium, magnesium : potassium, and cal- 

 cium : potassium appear to determine the growth in many cases, but this rela- 

 tion is not always clear for any single ratio. 



Cases of injury to leaves are noted in connection with certain concentrations, 

 also cases of root injury in connection with severe leaf injury. 



Water loss during growth corresponds in a somewhat reliable way to top 

 yields. While there appears to be no general relation between water require- 

 ment per gram of roots and total concentration for the optimal or suboptimal 

 total concentrations, the water requirement per gram of dry tops varies in 

 inverse order as regards the total concentration of the medium. 



Influence of certain salts and nutrient solutions on the secretion of dia- 

 stase by Penicillium camenibertii, W. .1. Robbins {Amer. Jour. Hot., 3 {1916), 

 No. 5, pp. 234-260, figs. 3). — The author describes a method of determining 



