﻿VOLUME LXI 



THE 



Botanical Gazette 



APRIL igi6 



BIOCHEMICAL AND PHYSIOLOGICAL STUDY OF THE 

 REST PERIOD IN THE TUBERS OF SOLANUM 

 TUBEROSUM 1 



Charles O. Appleman 

 (WITH TWO FIGURES) 



Introduction 



The cause and control of the rest period in plants have long been 

 the subject of study, not only on account of their scientific interest, 

 but also on account of the practical values which would accrue in 

 many cases if the rest period were subject to control. Although 

 many seeds have a rest period, this paper is concerned mainly with 

 the rest periods in stems. 



In spite of the immense amount of work that has been done on 

 this problem, there still exist today two schools of thought, which 

 stand directly opposed to each other on the first and most funda- 

 mental question involved, one school claiming that the rest period 

 is a direct response to changing external conditions, while the other 

 considers it to be the result of fixed, hereditary, internal causes. 

 A middle ground is taken by others who attribute the rest period to 

 a "cooperation of an hereditary tendency to rhythm, with the after 

 effect of periodic repetition of reactions induced by external con- 

 ditions." This diversity of opinion may be attributed largely to 

 the variety of material used for the study of the problem and to 

 the lack of exact and reliable experimental data. 



^ ■ Contribution from the Laboratory of Plant Physiology, Maryland Agricultural 



