Institut for Plante- og Miljøvidenskab > Ansatte
Irina Alexandra Ionescu
1871 Frederiksberg C
My PhD project focuses on the possible role of cyanogenic glucosides in breaking dormancy and flowering in perennial plants, with the example of the sweet cherry tree (Prunus avium).
A unique ability of perennial plants is the suspension and subsequent re-activation of growth. This resting phase, which is called dormancy, has evolved as a protective state against unfavourable environmental conditions. It is well known what characterizes growth and resting phases on a physiological level, but what induces the transition between them on a cellular level is still a mystery. Dormancy is induced by short day lengths and decreasing temperatures. At the same time we know that every perennial plant requires a certain period of cold to be able to induce growth again. These so called chill requirements are cultivar and location dependent. Subsequently the plant requires a certain period of warmth. Only after these two requirements are fulfilled can flowering take place.
In southern Europe, where a huge division of agricultural fruit production is located, climate change is becoming a threatening factor. Because of increasing temperatures, chill requirements are only partly fulfilled, leading to insufficient and non-uniform flowering. Dormancy-breaking agents like Dormex (AlzChem, Germany) are known to compensate for these missing chill requirements and to advance flowering time.
Dormex’ mechanism of action is unknown, but it has been shown to release cyanide in a reaction catalyzed by Catalase. Other compounds releasing cyanide in plants are cyanogenic glucosides, e.g. amygdalin and prunasin in Prunus species. We propose a common mechanism with hydrogen cyanide as a key player for breaking dormancy and flowering.
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