Dormancy and Storage 267 



with dormancy in a manner very much Hke their disappearance at 

 the end of natural dormancy. Glutathione has been demonstrated ir 

 many instances to break dormancy (potatoes, pears, peaches, and oat 

 seeds). These observations linked with the finding that the glutathione 

 content increases as potato tubers emerge from dormancy (Emilsson, 

 1949), suggest that this compound or related compounds may play 

 a key role in the breaking of dormancy in general. 



Judging from all of the information available at present, it ap- 

 pears that dormancy is a result of the presence of acidic inhibitors in 

 the buds or seeds. In the presence of these inhibitors the endogenous 

 auxin is ineffective. As dormancy is lost, glutathione may be formed 

 and an associated disappearance of the inhibitors occurs; the auxin 

 content becomes effective and growth commences. 



Recent evidence of Elliott and Leopold (1953) indicates that 

 dormancy in oats may be due to inhibitors which antagonize or form 

 complexes with sulfhydryl-containing enzymes such as the amylases. 

 Apparently by protecting the sulfhydryl enzymes from these inhibitors 

 such substances as glutathione and British Anti-Lewisite (1,2-di- 



O 100 



< 

 or 



h- 



X 



UJ 90h 



UJ 

 CC 



=> 

 I- 



% 



O 



< 

 UJ 



SO- 



TO 



60- 



1 



Ethylene Chloro. 

 Treated 



Controls © 





6 DAYS 



TIME AFTER TREATMENT 



Fig. 111. The inhibition of growth in the Avena test by extracts of peelings of 

 dormant potato tubers, and the regression of that inhibition following treatment 

 with ethylene chlorohydrin to break dormancy. Extracts of 80 mg. of peeling were 

 used in each instance and tested with a constant, unspecified quantity of indole 

 acetic acid. Curvature expressed as a percentage of auxin control (Hemberg, 

 1949). 



