VOLUME XXXVII ; NUMBER 4 
BOTANICAL GAZETTE 
APRIL, 1904 
ARE ROOTS AEROTROPIC??* 
MARY ELLA BENNETT. 
(WITH FIVE FIGURES) 
I. HISTORICAL REVIEW. 
AFTER noting the peculiar curvings and contortions that roots 
of Zea Mays exhibited when growing in water, especially when 
their tips were just touching the surface of the water or were 
slightly immersed, Molisch? formulated the hypothesis that these 
roots were affected by a poverty of oxygen in their immediate 
vicinity, and through their curvings were brought into a richer 
supply of that gas. In pursuance of that thought, he sought to 
determine whether roots of other seedlings would not also show 
definite responses to the influence of various gases. In deter- 
mining this point, Molisch employed only one form of apparatus, 
which is here described. 
The chamber containing the gas to be used was a wide-necked 
bettle, closed with a plate of hard rubber in which were cut one 
or two slits 2™ high by 1.5 to 2™™ wide. A strip of cork was 
fastened to the neck of the bottle in such a position that the seed- 
lings, when pinned to it, were supported in front of and very 
close to the slits. The bottle was laid, with the slits in a verti- 
cal position, on a glazed dish, and was covered with a large bell 
jar lined with moist filter paper. Light was excluded. 
*LXVIII Contribution from the Botanical Laboratory of the University of 
Michigan. 
? MOLISCH: Ueber die Ablenkung der Wurzeln von ihrer normalen Wachsthums- 
richtung durch Gase (Aerotropismus). Sitzungsber. Akad. Wiss. Wien go: 111. 1885. 
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