Norway Spruce (Picea abies L.) Provenances Use Different Physiological Strategies to Cope with Water Deficit

Abstract

Research Highlights: In this study, we found different regulatory mechanisms in two contrasting provenances of Norway spruce responding to progressive drought stress. Background and Objectives: In the context of climate and environmental changes, the following question of high importance in scientific studies is: How will Norway spruce, which forms a dominant component in European mountain and boreal forests, be able to cope with the increasing frequencies and intensities of drought periods? The aim of the study was to investigate the physiological responses of eight-month-old seedlings, as a most vulnerable phase of forest tree life, for different spruce provenances, to find out variable strategies in relation to controlled drought stress. Materials and Methods: We performed an experiment under controlled conditions with spruce seedlings from a climatologically warmer stand of 410 m above sea level (a.s.l.), and a moderately cool stand of 931 m a.s.l. The soil water content, leaf predawn water potential, the osmotic potential of needles, the relative water content of needles, and the photosynthetic performance and the contents of primary metabolites (proline and abscisic acid) were investigated as indicators of the spruce seedlings’ responses to water stress. The status of the indicators was analyzed at different temporal intervals, using repeated measures analysis of variance (ANOVA), reflecting the seedlings´ water conditions (early drought, drought, or recovery). On a daily basis, the differences among the indicators were tested with one-way ANOVA. A principal component analysis (PCA) was used to identify the provenance-specific responses of tree drought indicators in a multi-dimensional data set. Results: The responses to drought stress differed between the provenances. Whereas seedlings of ´warm´ provenance from a low altitude performed a conservation strategy, with high amounts of accumulated abscisic acid and closing the stomata faster, the reactions of ´cool´ provenance seedlings from a higher altitude were not so sensitive and the plants’ water supply and photosynthetic performance remained significantly higher. These findings indicate that a higher drought resistance in ´cool´ provenance could be related to greater amounts of proline amino-acids, which are accumulated from the beginning of the drought simulation. Furthermore, proline accumulation resulting in increased stress tolerance is controlled through another mechanism than osmotic adjustment. Conclusions: The observed variations in the regulatory mechanisms used to develop adaptive strategies in different provenances are an important factor for seedling survival under a changing climate.

Special issue in honour of Prof. Reto J. Strasser - Origin rather than mild drought stress influenced chlorophyll a fluorescence in contrasting silver fir (Abies alba Mill.) provenances

“…The fir provenances originating from relatively high altitudes (from wetter and colder localities) achieved and maintained relatively high efficiency of PSII photochemistry, even more they enhanced their efficiency at PSII level after mild water stress. These findings concur with those from provenances of other species, i.e., Fagus sylvatica (Kučerová et al 2018, Quercus suber L. (Aranda et al 2005), Picea abies (Oleksyn et al 1998, Jamnická et al 2019, and also Abies alba (Peguero-Pina et al 2007, reflecting the variation in the adaptation and acclimation abilities of forest tree species under conditions of a changing climate with possible use for forestry purposes.…”

Evolvability of Drought Response in Four Native and Non-native Conifers: Opportunities for Forest and Genetic Resource Management in Europe

“…This region harbors high genetic diversity due to multiple refugial areas and postglacial migration history (Tollefsrud et al, 2008 ; Mihai et al, 2020 ). Besides testing for immediate effects of extreme drought on radial growth, further studies on Norway spruce found significant provenance variation of the long-term growth reactions to climate parameters (i.e., Suvanto et al, 2016 ; Klisz et al, 2019 ) or different physiological strategies of seedlings to cope with water limitations (Jamnická et al, 2019 ).…”

“…This region harbors high genetic diversity due to multiple refugial areas and postglacial migration history (Tollefsrud et al, 2008;Mihai et al, 2020). Besides testing for immediate effects of extreme drought on radial growth, further studies on Norway spruce found significant provenance variation of the long-term growth reactions to climate parameters (i.e., Suvanto et al, 2016;Klisz et al, 2019) or different physiological strategies of seedlings to cope with water limitations (Jamnická et al, 2019). Evidence for genetic variation of climate-growth response within silver fir comes from dendroecological analysis throughout the Carpathian Mountains, demonstrating that radial growth within populations originating from Apennine origin, is more strongly driven by summer temperatures, whereas the increment of Balkan populations is more driven by summer drought (Bosela et al, 2016).…”

Growth and organic solutes accumulation in seedlings of Caatinga tree species in response of water deficit and potassium

“…Despite the high biological importance for the Caatinga, little is known about the physiological responses of these species under water deficit, especially during the seedling phase the most vulnerable phase of the forest tree life (JAMNICKÁ et al, 2019). Due to its climatic and pedological characteristics, the semi-arid region where the Caatinga is inserted presents itself as extremely susceptible to the changes resulting from the climate changes expected as a result of global warming.…”