Physical and Biochemical Studies of Dormancy in Apple Buds

Abstract

<jats:p>Membrane lipids and cellular water states were studied in endodormant and paradormant apple buds. Paradormancy was overcome by thidiazuron while endodormant buds were forced to break after a certain period of chilling. Nuclear magnetic resonance imaging was used to determine water states in buds of different stages of dormancy. In endodormant buds, the changes in water states from a more tightly-bound to a more free form were correlated with changes in membrane fatty acid composition. The ratio of saturated/unsaturated fatty acids decreased with chilling, especially in C18:l/C18:3 molecular species of phosphatidylcholine and phosphatidylethanolamine. Bud lipase activity, which was assayed by <jats:underline>in</jats:underline> <jats:underline>vitro</jats:underline> hydrolysis of triglycerides, showed an abrupt increase after chilling treatments.</jats:p>

New contribution to the survey of the acrotony theory on the branch of one year grapevine: III - Role of buds and leaves in development, application in the vineyard of results obtained in laboratory and greenhouse

“…L'acrotonie est donc un phénomène complexe : il peut mettre en jeu plusieurs facteurs d'origine biologique : la balance hormonale que nous avons tenté d'étudier ici. Selon FAUST et al (1998), FAUST et al (1991), LIU (1992), ROWLAND et al (1992, interviennent dans ce phénomène : l'état hydrique des bourgeons, l'évolution de la structure de leurs membranes cellulaires : WANG et FAUST (1988FAUST ( , 1989aFAUST ( et b, 1990, RANJAN et LEWAK (1995), LIU (1992), FAUST et al (1998) et leur potentiel anabolique (CHAMPAGNAT, cité par FAUST et al, 1998).…”