No. 2, September, 1921] PHYSIOLOGY 155 



998. KoLKWiTZ, R. Die kiinstliche Zelle. [An artificial cell.] Ber. Deutsch. Bot. 

 Ges. 38: 13G-140. Fig. 1. 1920. — The author describes the construction of a new device by 

 which water absorption by osmosis, artificial turgor pressure, and secretion of water as the 

 result of high turgescence may be easily demonstrated. The apparatus consists of (a) a por- 

 tion which is similar in form to the expanded part of a thistle tube and of about 100 cc. capac- 

 ity, (b) a glass stopcock, and (c) an approximately cylindrical portion of about 5 cc. capacity 

 into which a tube with an internal diameter of several mm. may be fixed by means of a 

 stopper. The 3 parts of the apparatus are of glass and made in 1 piece. The stopcock con- 

 nects the narrower end of member "a" with "c," and is so bored that by proper adjustment 

 the chamber of "a" may be made to communicate with the chamber of "c." Either "a" 

 or "c" may be placed in communication with the atmosphere, or the entrance to both chambers 

 may be closed. An animal membrane is stretched across the large open end of "a," and 

 in the demonstration of water secretion the open end of "c" is closed with parchment 

 paper or some vegetable membrane. Directions for the use of the apparatus are given. — 

 R. M. Holman. 



999. Rudolfs, W. Effect of salt solutions having definite osmotic concentration upon 

 absorption by seeds. Soil Sci. 11:277-293. 2 fig. 1921. — The influence of single salt solutions, 

 varying from 0.001 to 7.0 atmospheres, of calcium nitrate, potassium carbonate, magnesium 

 sulphate, potassium dihydrogen phosphate, sodium chloride, potassium chloride, and sodium 

 nitrate upon water absorption by seeds was determined. Seeds of wheat, corn, watermelon, 

 buckwheat, Canada field pea, white lupine, soybeans, rape, and alfalfa were used. There 

 is a marked difference in the absorbing power of seeds of different species. The highest 

 rates were found in alfalfa, the lowest in corn. Average absorption rates show a linear rela- 

 tion to the osmotic concentration of the solutions, decreasing with increase in concentration 

 except in dilute solutions. The retardation of absorption is accomplished by osmotic action. 

 Low concentrations have a stimulating effect upon the absorption of some seeds but not upon 

 that of others. — W . J . Robbins. 



MINERAL NUTRIENTS 



1000. Haenseler, C. M. The effect of salt proportions and concentration on the growth 

 of Aspergillus niger. Amer. Jour. Bot. 8: 147-163. Fig. 6. 1921. — Aspergillus niger was 

 grown on 3-salt solutions of 3 different total concentrations (0.5, 2.1, and 4.2 atmospheres) 

 and in the presence of sugar. For each total concentration, al! possible combinations ob- 

 tainable by varying the partial concentration of each salt by increments of yo of the total 

 concentration were made. In certain cases the salts were kept constant and the concentra- 

 tion of the sugar was changed. When the salt proportions were the same, an increase in total 

 concentration gave an increase in the yield of the fungus (dry weight). The partial concen- 

 trations of KH2PO4 and MgS04 were varied within wide limits without in any way affecting 

 the yields. Yield is approximately proportional to the amount of NO3 present, whether this 

 amount is the result of changes in total or partial concentration. Beyond a certain point, 

 the concentration of sugar is the limiting factor in growth. When salt concentrations and 

 proportions are constant, yield is nearly proportional to the sugar concentration of the nutri- 

 ent solution. — E. W.Sinnott. 



1001. Mitchell, J, H. Report on inorganic plant constituents. Jour. Assoc. Official 

 Agric. Chem. 4: 391-394. 1921. — Methods are reported for determining calcium, magnesium, 

 and manganese in the presence of large amounts of phosphorus. The method is adapted for 

 use with certain seeds, cereals, and legumes. — F. M. Schertz. 



1002. True, Rodney H. The function of calcium in the nutrition of seedlings. Jour. 

 Amer. Soc. Agron. 13: 91-107. 1921. — The results were obtained by growing seedlings in lab- 

 oratory cultures. Pure water represents a partial ionic vacuum to roots of plants and tends 

 to establish an equilibrium with the cell contents by the withdrawal of ions from the plant. 

 Injurious action results and is not fully overcome by any pair of ions (salt) tested, but is very 



BOTANICAL ABSTRACTS, VOL. IX, NO. 2 



