Abstract
(1) Background: Prunus species have the ability to suspend (induce dormancy) and restart growth, in an intricate process in which environmental and physiological factors interact. (2) Methods: In this work, we studied the evolution of sugars, antioxidant metabolism, and abscisic acid (ABA) and gibberellins (GAs) levels during bud dormancy evolution in a high-chill peach variety, grown for two seasons in two different geographical areas with different annual media temperature, a cold (CA) and a temperate area (TA). (3) Results: In both areas, starch content reached a peak at ecodormancy, and then decreased at dormancy release (DR). Sorbitol and sucrose declined at DR, mainly in the CA. In contrast, glucose and fructose levels progressively rose until DR. A decline in ascorbate peroxidase, dehydroascorbate reductase, superoxide dismutase and catalase activities occurred in both seasons at DR. Moreover, the H2O2-sensitive SOD isoenzymes, Fe-SOD and Cu,Zn-SOD, and two novel peroxidase isoenzymes, were detected. Overall, these results suggest the occurrence of a controlled oxidative stress during DR. GA7 was the major bioactive GA in both areas, the evolution of its levels being different between seasons and areas. In contrast, ABA content decreased during the dormancy period in both areas, resulting in a reduction in the ABA/total GAs ratio, being more evident in the CA. (4) Conclusion: A possible interaction sugars-hormones-ROS could take place in high-chill peach buds, favoring the DR process, suggesting that, in addition to sugar metabolism, redox interactions can govern bud DR, regardless of chilling requirements.
Highlights
Introduction iationsDeciduous woody plants, as stone fruit trees, are characterized by their capacity to interrupt and restart growth regularly in response to environmental and seasonal challenges [1]
A correlation among fructose and glucose accumulation, decreased starch content, and reduced abscisic acid (ABA) content and ABA/GAs ratio was observed at dormancy release (DR)
Sucrose and sorbitol were the major sugars in peach buds from the GEM020 variety
Summary
As stone fruit trees, are characterized by their capacity to interrupt and restart growth regularly in response to environmental and seasonal challenges [1]. Dormancy has been defined as the absence of visible growth in any plant structure containing a meristem. Other authors proposed a definition of dormancy similar to that proposed for seed dormancy as “the incapability to achieve any growth from meristems under favorable conditions” [1]. A differential characteristic of bud dormancy is its quantitative nature, in relation to the chilling requirements for bud dormancy breaking [1]. This is the case of stone fruit trees.
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