CHAPTER XV 



Dormancy and Storage 



Dormancy, storage, and ripening of plant materials are essentially 

 expressions of growth and respiratory phenomena. In view of the 

 powerful influence of auxins upon both growth and respiration, it is 

 not surprising that auxins should be able to exert considerable in- 

 fluence upon dormancy and storage characteristics of plant crops. The 

 first demonstration of the possibility of using auxins in controlling 

 dormancy was made by Guthrie (1939), who effectively prevented the 

 sprouting of potatoes in storage by application of naphthaleneacetic 

 acid. Making use of the same principle, Winkelpleck (1937) reported 

 some success in delaying bud growth in woody plants by auxin 

 treatment. The possibility of improving the storage quality of citrus 

 crops with auxin sprays was first demonstrated by Stewart (1949). 

 This last effect of auxins is essentially an indirect one, since the auxin 

 apparently acts more to limit the activity of pathogens on the fruit 

 than to alter the fruit per se. 



CONTROL OF DORMANCY 



For many decades empirical research has sought for chemicals and 

 types of treatments to break dormancy or induce dormancy in stored 

 agricultural products. A good many treatments have been found which 

 can alter dormancy, but only in the last few years has there begun 

 to evolve the semblance of a physiological understanding of dormancy 

 and how it can intelligently be controlled. 



The Physiological Basis for Dormancy 



In discussing the rather large question of the physiological basis 

 of dormancy, attention will here be focused only upon dormancy in 

 relation to the biochemical environment of meristems. In many in- 

 stances, particularly in seeds, dormancy may be caused by mechanical 

 factors, especially in the seed coat, but these are not to be considered 

 here. 



For many years it has been known that auxins can promote bud 

 growth, and that more generally they inhibit bud growth — particu- 

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