THE ACTION OF CERTAIN NUTRIENT AND NON-NUTRIENT 

 BASES ON PLANT GROWTH — I 



THE ANTITOXIC ACTION OF CERTAIN NUTRIENT AND NON-NUTRIENT 

 BASES WITH RESPECT TO PLANTS * 



M. M. McCooL 



{Received for ^publication July 1, 1912) 



In determining whether any substance or ion may act injuriously on 

 plant growth, it is customary to compare the rate or amount of growi:h in 

 the presence of such a substance with that in its absence. The presence 

 of any chemical agents aside from the substance tested is a complica- 

 tion to be avoided, or at least controlled, if possible, since there may 

 be either a direct reaction between the different substances in the 

 substratum or an indirect influence exerted through changes induced in 

 the plant. In testing any injurious action — such as inhibition or retarda- 

 tion of gro\\i;h — of the mineral nutrients used singly in solution, it is 

 important in the first place to compare the growth-rate with that of plants 

 in pure distilled water. The distilled- water comparison is not ideal, but 

 it is necessary. Further comparisons may be made with plants grown in 

 full nutrient solutions. In the hands of various investigators this type 

 of controlled experiment has yielded results of much value, and such 

 results may be made useful in studying the more complex conditions exist- 

 ing in the soil. 



REVIEW OF GENERAL LITERATURE 



While making a study of the proper composition of nutrient solutions, 

 Von Raumer (1883) f reported the observation that a solution containing 

 magnesium without calcium is highly injurious to plants. Loew (1892a) 

 reported the first extensive study of the function of these two nutrients 

 and of a relation between them with respect to plants. In this valuable 

 paper, which has been overlooked by some of the later investigators, Loew 

 emphasizes two most important points: (1) In a nutrient solution lacking 

 calcium the organism Spirogyra is rapidly injured, the injury being more 

 rapid than when any other nutrient is omitted. (2) Although magnesium 



* Laboratory of Plant Physiology', Cornell University, Contribution No. 9. 

 tDatea in parenthesis refer to bibliography. 



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