Submitted to: American Journal of Potato Research
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 1/30/2009
Publication Date: 3/7/2009
Publication URL: http://hdl.handle.net/10113/35555
Citation: Suttle, J.C. 2009. Ethylene Is Not Involved in Hormone- and Bromoethane-Induced Dormancy Break in Russet Burbank Minitubers. American Journal of Potato Research. 86:278-285. doi:10.1007/s12230-009-9081-3. 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. Many diverse physical and chemical treatments can prematurely terminate tuber dormancy and initiate sprout growth. Understanding the mechanism(s) through which these treatments act may shed light on the endogenous processes controlling dormancy release. In this study, the role of ethylene in the dormancy breaking actions of a variety of external agents was determined. It was demonstrated that, although all treatments increased the rate of ethylene production to some extent, ethylene appeared to play no role in the dormancy terminating actions of any of the agents examined. In addition, exogenous ethylene was found to have no effect on minituber dormancy under the conditions used. This research clarifies and corrects a widely held misconception regarding the efficacy of ethylene tuber dormancy release.
Technical Abstract: The involvement of ethylene in the dormancy breaking actions of cytokinins, GA, and BE was investigated using Russet Burbank minitubers. Injection of 10µg tuber-1 BA, CP, GA, NG, or ZEA or 24 hour exposure to BE effectively broke dormancy and stimulated sprout growth over a two-week period. Although ethylene production was slightly enhanced by all treatments, a significant increase in ethylene production was observed in minitubers treated with BE, CP, or NG. Pretreatment with the ethylene antagonists STS or MCP did not affect the dormancy breaking actions of any of the agents tested. Application of the ethylene synthesis inhibitor AVG to NG-treated minitubers, completely suppressed ethylene production but had no effect on dormancy break. Application of exogenous ethylene or stimulation of endogenous ethylene production by ACC treatment did not break minituber dormancy or stimulate sprout growth. Collectively, these results indicate that endogenous ethylene does not play a role in the dormancy breaking actions of cytokinins, GA, or BE.