Submitted to: American Journal of Potato Research
Publication Type: Peer reviewed journal
Publication Acceptance Date: 2/6/2004
Publication Date: 9/1/2004
Citation: Suttle, J.C. 2004. Physiological regulation of potato tuber dormancy. American Journal of Potato Research. 81:253-262. Interpretive Summary: For an indeterminate period of time following harvest, potatoes will not sprout and are physiologically dormant. Dormancy is gradually lost during postharvest storage and the resultant sprouting is detrimental to the nutritional and processing qualities of potatoes. Because of this, sprouting results in severe financial loss to producers. Currently sprouting is controlled through the use of synthetic sprout inhibitors. The research being conducted in this lab is directed towards 1.) identifying key physiological processes that naturally regulate tuber dormancy and, ultimately, 2.) modifying these processes genetically thereby eliminating the need for artificial sprout suppression. Much of our current research concerns the roles of plant hormones in the regulation of tuber dormancy. In this invited review, the roles of endogenous hormones in the regulation of tuber dormancy are critically assessed. To date, only two classes of naturally occurring hormones (abscisic acid and ethylene) have been proven to play a role in dormancy regulation in tubers. Recent research has implicated a third class (the cytokinins) as possible natural dormancy terminating agents. In contrast, auxins and gibberellins appear to play no direct role in dormancy control but do regulate subsequent sprout growth. A more complete understanding of the roles of the naturally occurring plant hormones in tuber dormancy regulation and the internal mechanisms controlling their synthesis and action will greatly speed the processes of improving the activity of current sprout control agents and identifying new sprout control agents/technologies.
Technical Abstract: At harvest, potato (Solanum tuberosum L.) tubers are dormant and will not sprout. As the period of postharvest storage is extended, tuber dormancy is broken and sprout growth commences. The loss of tuber dormancy and onset of sprout growth is accompanied by numerous biochemical changes, many of which are detrimental to the nutritional and processing qualities of potatoes. Endogenous hormones have been posited to play a significant role in tuber dormancy regulation. The involvement of all major classes of endogenous hormones in tuber dormancy is reviewed. Based on available evidence, it is concluded that both ABA and ethylene are required for dormancy induction but only ABA is needed to maintain bud dormancy. An increase in cytokinin sensitivity and content appear to be the principal factors leading to dormancy exit. Changes in endogenous IAA and GA content appear to be more closely related to the regulation of subsequent sprout growth.