THE EFFECT OF SALT PROPORTIONS AND CONCENTRATION 
ON THE GROWTH OF ASPERGILLUS NIGER^ 
C. M. Haenseler 
(Received for publication September 21, 1920) 
Introduction 
A great deal of work has been done in recent years on the various prob- 
lems of plant nutrition, and especially on the physiological balance of 
nutrient solutions and on the salt requirements of plants. Although these 
questions have received some attention ever since the introduction of water 
cultures by Sachs and Knop, they had never been carried to such logical 
completeness as was done by Tottingham (9) in his work on the study 
of the effect upon plant growth of varying the total concentration and 
salt proportions in Knop's solution. In 1915 Shive (6), using Tottingham's 
systematic methods, made similar exhaustive studies of a nutrient solution 
containing only three salts and a trace of iron. This three-salt solution, 
when properly balanced, gave a better yield than Tottingham's best four- 
salt solution and has the further advantage of being the simplest satis- 
factory water culture that had been used up to that time. 
Since the introduction of Shive's three-salt solution, which, on account 
of its relative simplicity, is especially suitable for studies in plant nutrition, 
it has been used extensively by Shive (6), McCall (4), Hibbard (3), and 
others for various physiological studies with green plants. 
Fundamental problems of nutrition have also been studied extensively 
in certain fungi and especially in Aspergillus niger. The greater number of 
these studies have dealt with carbon or nitrogen assimilation and with the 
toxic or stimulative action of various substances. The role played by total 
salt concentration and by the salt proportions of the nutrient medium has 
apparently received very little attention. There has been no systematic 
study made upon any fungus which corresponds to the nutrition studies 
made with green plants by Tottingham, Shive, and others. The results 
of these authors have proven of such fundamental importance in nutrition 
studies in higher plants that it was thought advisable to test the adapta- 
bility of their methods in similar studies upon fungi. 
In order to make this test, a series of experiments were planned to study 
the effect upon Aspergillus niger of varying the total salt concentration and 
salt proportions in a simple nutrient solution. 
1 Paper No. 21 of the Technical Series, New Jersey Agricultural Experiment Stations, 
Department of Plant Physiology. 
147 
