Abstract
More severe summer droughts are predicted for mid-latitudes in Europe. To evaluate the impact on forest ecosystems and more specifically on forest regeneration, we studied the response to summer drought in oak seedlings (Quercus petraea). Acorns were collected from different mother trees in three stands in Belgium, sown in pots and grown in non-heated greenhouse conditions. We imposed drought on the seedlings in early summer by first watering the pots to saturation and then stopping any watering. Weight of the pots and stomatal conductance were regularly measured. Re-watering followed this drought period of 5 weeks. Height of the seedlings and apical bud development were observed. Stomatal resistance increased toward the end of the experiment in the drought-treated group and was restored after re-watering. The seedlings from the drought treatment displayed a higher probability to produce additional shoot growth after re-watering (p ≤ 0.05). A higher competition for water (two plants per pot) increased this chance. Although this chance was also higher for smaller seedlings, the actual length of the extra growth after re-watering was higher for larger seedlings (p ≤ 0.01). Both in the drought-treated and in the control group the autochthonous provenance growing on a xeric site produced less extra shoots compared to the two other provenances. Finally, stressed plants showed less developed apical buds compared to the control group after re-watering, suggesting a phenological effect on the growth cycle of oaks (p ≤ 0.0001). The higher chance for an extra shoot growth after the drought period can be considered as a compensation for the induced growth arrest during the drought period.
Highlights
Several periods of dry, wet, cold, or warm climate were recorded during the past centuries in Europe (Masson-Delmotte et al, 2005)
Oak seedlings respond efficiently to drought stress by closing stomata, allowing the leaf water potential to remain above a critical threshold value at which cavitation damage occurs (Vivin et al, 1993; Cochard et al, 1996)
We studied the effect of a late spring/early summer drought stress on sessile oak (Q. petraea) seedlings originating from Belgium during the first growing year
Summary
Wet, cold, or warm climate were recorded during the past centuries in Europe (Masson-Delmotte et al, 2005). The number of precipitation anomalies increased during the past century (Zhang et al, 2007). The predicted climate change indicates even more extreme weather events such as longer dry periods, swifts in precipitation and rain intensity. Forest vitality will be challenged by such changes and forests will become more vulnerable in Europe (Lindner et al, 2010), but all over the globe (Choat et al, 2012). For Europe, climate projections predict increasing temperatures and irregular precipitation patterns in summer, augmenting the number and the intensity of drought events (IPCC, 2013). For Belgium, drier conditions due to climate change are predicted for the end of the century especially in summer periods (Baguis et al, 2010)
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
