Dormancy Regulation in Subterranean Clover Seeds by Ethylene

Abstract

In the past there have been scattered reports of breaking of dormancy in seeds by ethylene (4, 11) or by ethylene chlorohydrin (5) which apparently acts on plants through a release of ethylene (12). The advent of gas chromatographic techniques has made it possible to show that many seeds produce ethylene naturally during the germination process (8,9, 10); these reports raise the interesting possibility that the production of ethylene by the imbibed seed may contribute to the breaking of dormancy. This possibility has been examined for peanuts by Toole et al. (10) and Ketring and Morgan (6), who concluded that the ethylene production may actually contribute to the breaking of dormancy. From studies with lettuce, Abeles and Lonski (1) reached the opposite conclusion since ethylene was produced mainly by those seeds which were going to germinate, and there were only small increases in percentage germination in the presence of added ethylene. We have been studying the role of ethylene in germination of seeds of several species, and our evidence indicates that in some seeds there is a substantial response to ethylene in breaking of dormancy, and further that the ethylene produced by the seed can have a regulatory role in determining whether or not germination will be achieved.