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Repeated Summer Drought and Re-watering during the First Growing Year of Oak (Quercus petraea) Delay Autumn Senescence and Bud Burst in the Following Spring.

Vander Mijnsbrugge K, Turcsán A, Maes J, Duchêne N, Meeus S, Steppe K, Steenackers M - Front Plant Sci (2016)

Bottom Line: Remarkably, survival was independent of the provenance, although relatively more plants had died off in two provenances compared to the third one with mean plant height being higher in one provenance and standard deviation of plant height being higher in the other.Timing of leaf senescence was clearly delayed after the severe drought treatment followed by re-watering, with two seedlings per pot showing a lesser retardation compared to single plants.In both phenological models significant differences among the three provenances were detected independent from the treatment.

View Article: PubMed Central - PubMed

Affiliation: Department of Forest Genetic Resources, Research Institute for Nature and Forest Geraardsbergen, Belgium.

ABSTRACT
Climate change predicts harsher summer droughts for mid-latitudes in Europe. To enhance our understanding of the putative impacts on forest regeneration, we studied the response of oak seedlings (Quercus petraea) to water deficit. Potted seedlings originating from three locally sourced provenances were subjected to two successive drought periods during the first growing season each followed by a plentiful re-watering. Here, we describe survival and phenological responses after the second drought treatment, applying general linear mixed modeling. From the 441 drought treated seedlings 189 subsisted with higher chances of survival among smaller plants and among single plants per pot compared to doubles. Remarkably, survival was independent of the provenance, although relatively more plants had died off in two provenances compared to the third one with mean plant height being higher in one provenance and standard deviation of plant height being higher in the other. Timing of leaf senescence was clearly delayed after the severe drought treatment followed by re-watering, with two seedlings per pot showing a lesser retardation compared to single plants. This delay can be interpreted as a compensation time in which plants recover before entering the subsequent developmental process of leaf senescence, although it renders seedlings more vulnerable to early autumn frosts because of the delayed hardening of the shoots. Onset of bud flush in the subsequent spring still showed a significant but small delay in the drought treated group, independent of the number of seedlings per pot, and can be considered as an after effect of the delayed senescence. In both phenological models significant differences among the three provenances were detected independent from the treatment. The only provenance that is believed to be local of origin, displayed the earliest leaf senescence and the latest flushing, suggesting an adaptation to the local maritime climate. This provenance also displayed the highest standard deviation of plant height, which can be interpreted as an adaptation to variable and unpredictable weather conditions, favoring smaller plants in drought-prone summers and higher plants in more normal growing seasons.

No MeSH data available.


Related in: MedlinePlus

Modeled probability of having reached at least leaf senescence score 4 (yellowing leaves) on the two observation days, depending on the provenance and on the number of seedlings per pot. The higher the relative weight loss, the higher the drought stress. doy: day of the year.
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Figure 5: Modeled probability of having reached at least leaf senescence score 4 (yellowing leaves) on the two observation days, depending on the provenance and on the number of seedlings per pot. The higher the relative weight loss, the higher the drought stress. doy: day of the year.

Mentions: Decolouration and finally shedding of the leaves was scored in the autumn of 2014, following a severe drought and re-watering period. In the phenological model, provenance (without interaction term) and the interaction between number of seedlings per pot and relative weight loss appeared significant (Table 4). With a more severe drought stress, as expressed by a high relative weight loss, decolouration of the leaves was clearly retarded (Figures 4 and 5). Both in the control group as in the drought treated group (thus independent of the drought treatment), leaf senescence appeared first in KLA, than in VOE and finally in BOR (Figures 4 and 5). The significant interaction term with seedling per pot was visualized by differing steepness of the modeled S curves between single and double plants per pot (Figure 5) indicating that among the double plants per pot in stressed conditions senescence of the leaves was less retarded compared to single plants. According to the fitted model, the control and stressed group of plants differed 18.8 days in timing of leaf senescence for single plants per pot. In the control group double plants per pot senesced 1.5 days later compared to the single plants, whereas they senesced 6.4 days earlier than the singles in the stressed condition. For the different provenances, a time lag was observed between KLA and VOE of 6.7 days and between KLA and BOR of 14.7 days (independent of the drought treatment).


Repeated Summer Drought and Re-watering during the First Growing Year of Oak (Quercus petraea) Delay Autumn Senescence and Bud Burst in the Following Spring.

Vander Mijnsbrugge K, Turcsán A, Maes J, Duchêne N, Meeus S, Steppe K, Steenackers M - Front Plant Sci (2016)

Modeled probability of having reached at least leaf senescence score 4 (yellowing leaves) on the two observation days, depending on the provenance and on the number of seedlings per pot. The higher the relative weight loss, the higher the drought stress. doy: day of the year.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4814502&req=5

Figure 5: Modeled probability of having reached at least leaf senescence score 4 (yellowing leaves) on the two observation days, depending on the provenance and on the number of seedlings per pot. The higher the relative weight loss, the higher the drought stress. doy: day of the year.
Mentions: Decolouration and finally shedding of the leaves was scored in the autumn of 2014, following a severe drought and re-watering period. In the phenological model, provenance (without interaction term) and the interaction between number of seedlings per pot and relative weight loss appeared significant (Table 4). With a more severe drought stress, as expressed by a high relative weight loss, decolouration of the leaves was clearly retarded (Figures 4 and 5). Both in the control group as in the drought treated group (thus independent of the drought treatment), leaf senescence appeared first in KLA, than in VOE and finally in BOR (Figures 4 and 5). The significant interaction term with seedling per pot was visualized by differing steepness of the modeled S curves between single and double plants per pot (Figure 5) indicating that among the double plants per pot in stressed conditions senescence of the leaves was less retarded compared to single plants. According to the fitted model, the control and stressed group of plants differed 18.8 days in timing of leaf senescence for single plants per pot. In the control group double plants per pot senesced 1.5 days later compared to the single plants, whereas they senesced 6.4 days earlier than the singles in the stressed condition. For the different provenances, a time lag was observed between KLA and VOE of 6.7 days and between KLA and BOR of 14.7 days (independent of the drought treatment).

Bottom Line: Remarkably, survival was independent of the provenance, although relatively more plants had died off in two provenances compared to the third one with mean plant height being higher in one provenance and standard deviation of plant height being higher in the other.Timing of leaf senescence was clearly delayed after the severe drought treatment followed by re-watering, with two seedlings per pot showing a lesser retardation compared to single plants.In both phenological models significant differences among the three provenances were detected independent from the treatment.

View Article: PubMed Central - PubMed

Affiliation: Department of Forest Genetic Resources, Research Institute for Nature and Forest Geraardsbergen, Belgium.

ABSTRACT
Climate change predicts harsher summer droughts for mid-latitudes in Europe. To enhance our understanding of the putative impacts on forest regeneration, we studied the response of oak seedlings (Quercus petraea) to water deficit. Potted seedlings originating from three locally sourced provenances were subjected to two successive drought periods during the first growing season each followed by a plentiful re-watering. Here, we describe survival and phenological responses after the second drought treatment, applying general linear mixed modeling. From the 441 drought treated seedlings 189 subsisted with higher chances of survival among smaller plants and among single plants per pot compared to doubles. Remarkably, survival was independent of the provenance, although relatively more plants had died off in two provenances compared to the third one with mean plant height being higher in one provenance and standard deviation of plant height being higher in the other. Timing of leaf senescence was clearly delayed after the severe drought treatment followed by re-watering, with two seedlings per pot showing a lesser retardation compared to single plants. This delay can be interpreted as a compensation time in which plants recover before entering the subsequent developmental process of leaf senescence, although it renders seedlings more vulnerable to early autumn frosts because of the delayed hardening of the shoots. Onset of bud flush in the subsequent spring still showed a significant but small delay in the drought treated group, independent of the number of seedlings per pot, and can be considered as an after effect of the delayed senescence. In both phenological models significant differences among the three provenances were detected independent from the treatment. The only provenance that is believed to be local of origin, displayed the earliest leaf senescence and the latest flushing, suggesting an adaptation to the local maritime climate. This provenance also displayed the highest standard deviation of plant height, which can be interpreted as an adaptation to variable and unpredictable weather conditions, favoring smaller plants in drought-prone summers and higher plants in more normal growing seasons.

No MeSH data available.


Related in: MedlinePlus