Bud burst timing in Picea abies seedlings as affected by temperature during dormancy induction and mild spells during chilling

Abstract

In trees adapted to cold climates, conditions during autumn and winter may influence the subsequent timing of bud burst and hence tree survival during early spring frosts. We tested the effects of two temperatures during dormancy induction and mild spells (MS) during chilling on the timing of bud burst in three Picea abies (L.) Karst. provenances (58-66 degrees N). One-year-old seedlings were induced to become dormant at temperatures of 12 or 21 degrees C applied during 9 weeks of short days (12-h photoperiod). The seedlings were then moved to cold storage and given either continuous chilling at 0.7 degrees C (control), or chilling interrupted by one 14-day MS at either 8 or 12 degrees C. Interruptions with MS were staggered throughout the 175-day chilling period, resulting in 10 MS differing in date of onset. Subsets of seedlings were moved to forcing conditions (12-h photoperiod, 12 degrees C) throughout the chilling period, to assess dormancy status at different timings of the MS treatment. Finally, after 175 days of chilling, timing of bud burst was assessed in a 24-h photoperiod at 12 degrees C (control and MS-treated seedlings). The MS treatment did not significantly affect days to bud burst when given early (after 7-35 chilling days). When MS was given after 49 chilling days or later, the seedlings burst bud earlier than the controls, and the difference increased with increasing length of the chilling period given before the MS. The 12 degrees C MS treatment was more effective than the 8 degrees C MS treatment, and the difference remained constant after the seedlings had received 66 or more chilling days before the MS treatment was applied. In all provenances, a constant temperature of 21 degrees C during dormancy induction resulted in more dormant seedlings (delayed bud burst) than a constant temperature of 12 degrees C, but this did not delay the response to the MS treatment.

Predicting the Timing of Cherry Blossoms in Washington, DC and Mid-Atlantic States in Response to Climate Change

“…It should be noted that an extended growing season and autumn warming in the previous year could delay the onset of autumn syndrome stages (e.g., growth cessation, leaf fall, dormancy induction) and subsequently affect the phenology of the following spring in temperate and boreal trees [10], [38], [39]. In the current model, we assumed that the onset of dormancy takes place on Oct 1 of the previous year without explicitly accounting for the effects of autumn climate on dormancy induction.…”

The dynamic nature of bud dormancy in trees: environmental control and molecular mechanisms

“…2003; Søgaard et al . 2008; Granhus, Fløistad & Søgaard 2009). In Rosaceae species, dormancy is induced by the same temperature conditions, which also release the dormancy (Heide & Prestrud 2005; Heide 2008); in this instance, the response of the meristem to temperature changes during the endogenous development.…”

The Annual Phenological Cycle

“…However, it has also been found that intermittent high temperature exposure may enhance the effects of chilling (Erez and Lavee 1971;Erez et al 1979a) and that the effect of intermittent high temperature exposure may depend on its timing (Hänninen and Pelkonen 1989;Young 1992;Granhus et al 2009) A review of studies addressing these complicated dynamics is outside the scope of the present volume, but the chilling negation observed in some of these experimental studies shows that unlike ontogenetic development, rest break is at least partially reversible. This has important implications for the modelling of rest break, as is shown in the next section.…”