Induction of secondary dormancy in sunflower seeds by high temperature. Possible involvement of ethylene biosynthesis |
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Authors: | F. Corbineau,R. M. Rudnicki,D. Cô me |
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Affiliation: | Lab. de Physiologie des Organes Végétaux après Récolte, 4ter, route des Gardes, F-92190 Meudon, France;;Research Institute of Pomology and Floriculture, Pomologiczan 18, PL-96–100 Skierniewice, Poland. |
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Abstract: | High temperature (45°C) inhibits seed germinition and seedling sunflower ( Helianthus annuus L. cv. Mirasol). Treatment of imbibed seeds at 45°C for more than 48 h induces a secondary dormancy, which is associated with progressive decrease of germination ability at optimal temperature (25°C) as well as with abnormal seedling growth. Ethylene (55μl l−1) and 2-chloroethylphosphonic acid (ethephon) (2.5 m M ) improve germination of thermodormant seeds at 25°C. but the abnormal growth of the seedlings remains. O2-enriched atmosphere and dry storage improve germination and normal seedling growth. The induction of thermodormancy in sunflower seeds seems associated with loss of their ability to convert 1-aminocyclopropane-1-carboxylic acid (ACC) to ethylene. Possible effects of high temperature on membranes and ethylene forming enzyme (EFE) are discussed. |
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Keywords: | 1-Aminocyelopropane-l-carboxylic acid ethylene Helianthus anuus oxygen secondary dormancy sunflower seeds temperature |
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