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Evidence for inhibitor involvement in thermodormancy of Grand Rapids lettuce seeds

Published online by Cambridge University Press:  19 September 2008

J. G. Chris Small*
Affiliation:
Department of Botany and Genetics, University of the Orange Free State, PO Box 339, Bloemfontein 9300, South Africa
Yitzchak Gutterman
Affiliation:
The Jacob Blaustein Institute for Desert Research, Ben Gurion University of the Negev, Sede Boker Campus, Israel 84990
*
* Correspondence

Abstract

Prolonged imbibition and incubation of lettuce seeds at a supraoptimal temperature induces secondary dormancy. Such seeds no longer germinate when returned to conditions optimal for germination of non-dormant seeds. The possibility that inhibitors are involved in the induction of thermodormancy was investigated.

Washing of thermodormant seeds restored germination to a small extent. However, continuous leaching of seeds during high-temperature treatment with distilled water, largely prevented the induction of thermodormancy. Such seeds were qualitatively similar to nondormant seeds, i.e. they required only light to germinate at a lower temperature and germinated in the dark if given GA3. The germination water from thermodormant seeds inhibited the germination of non-dormant lettuce seeds. The inhibition was not an osmotic effect. Absorbance in the ultraviolet region was higher in germination water from thermodormant seeds than that of non-dormant seeds. It is concluded that inhibitors are involved in the induction of thermodormancy of lettuce seeds.

Type
Research Papers
Copyright
Copyright © Cambridge University Press 1991

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