Cumulative growth and stress responses to the 2018-2019 drought in a European floodplain forest

Droughts increasingly threaten the worlds forests and their potential to mitigate climate change. In 2018-2019, Central European forests were hit by two consecutive hotter drought years, an unprecedented phenomenon that is likely to occur more frequently with climate change. Here, we examine trees growth resistance and physiological stress responses (increase in carbon isotope composition; Δδ13C) to this consecutive drought based on tree-rings of dominant tree species in a Central European floodplain forest. Tree growth was not reduced for most species in 2018, indicating that water supply in floodplain forests can partly buffer meteorological water deficits. Drought stress in 2018 was comparable to former single drought years, but the cumulative drought stress in 2019 induced drastic decreases in growth resistance and increases in Δδ13C across all species. Consecutive hotter droughts pose a novel threat to forests under climate change, even in forest ecosystems with high levels of water supply.

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A BiomeBGC-based Evaluation of Dryness Stress of Central European Forests

ISPRS - International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences ◽

10.5194/isprsarchives-xl-7-w3-345-2015 ◽

2015 ◽

Vol XL-7/W3 ◽

pp. 345-351 ◽

Cited By ~ 1

Author(s):

H. Buddenbaum ◽

J. Hientgen ◽

S. Dotzler ◽

W. Werner ◽

J. Hill

Keyword(s):

Climate Change ◽

Time Series ◽

Drought Stress ◽

Primary Production ◽

Net Primary Production ◽

Stomatal Closure ◽

Vapour Pressure Deficit ◽

Water Vapour Pressure ◽

Central European ◽

European Forests

Dryness stress is expected to become a more common problem in central European forests due to the predicted regional climate change. Forest management has to adapt to climate change in time and think ahead several decades in decisions on which tree species to plant at which locations. The summer of 2003 was the most severe dryness event in recent time, but more periods like this are expected. Since forests on different sites react quite differently to drought conditions, we used the process-based growth model BiomeBGC and climate time series from sites all over Germany to simulate the reaction of deciduous and coniferous tree stands in different characteristics of drought stress. Times with exceptionally high values of water vapour pressure deficit coincided with negative modelled values of net primary production (NPP). In addition, in these warmest periods the usually positive relationship between temperature and NPP was inversed, i.e., under stress conditions, more sunlight does not lead to more photosynthesis but to stomatal closure and reduced productivity. Thus we took negative NPP as an indicator for drought stress. In most regions, 2003 was the year with the most intense stress, but the results were quite variable regionally. We used the Modis MOD17 gross and net primary production product time series and MOD12 land cover classification to validate the spatial patterns observed in the model runs and found good agreement between modelled and observed behaviour. Thus, BiomeBGC simulations with realistic site parameterization and climate data in combination with species- and variety-specific ecophysiological constants can be used to assist in decisions on which trees to plant on a given site.

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Genetically Different Isolates of the Arbuscular Mycorrhizal Fungus Rhizophagus irregularis Induce Differential Responses to Stress in Cassava

Frontiers in Plant Science ◽

10.3389/fpls.2020.596929 ◽

2020 ◽

Vol 11 ◽

Author(s):

Ricardo Peña ◽

Chanz Robbins ◽

Joaquim Cruz Corella ◽

Moses Thuita ◽

Cargele Masso ◽

...

Keyword(s):

Water Stress ◽

Drought Stress ◽

Stress Responses ◽

Mycorrhizal Fungi ◽

Crop Yields ◽

Physiological Stress ◽

Physiological Responses ◽

Mycorrhizal Fungus ◽

Arbuscular Mycorrhizal ◽

Field Conditions

Water scarcity negatively impacts global crop yields and climate change is expected to greatly increase the severity of future droughts. The use of arbuscular mycorrhizal fungi (AMF) can potentially mitigate the effects of water stress in plants. Cassava is a crop that feeds approximately 800 million people daily. Genetically different isolates of the AMF R. irregularis as well as their clonal progeny have both been shown to greatly alter cassava growth in field conditions. Given that cassava experiences seasonal drought in many of the regions in which it is cultivated, we evaluated whether intraspecific variation in R. irregularis differentially alters physiological responses of cassava to water stress. In a first experiment, conducted in field conditions in Western Kenya, cassava was inoculated with two genetically different R. irregularis isolates and their clonal progeny. All cassava plants exhibited physiological signs of stress during the dry period, but the largest differences occurred among plants inoculated with clonal progeny of each of the two parental fungal isolates. Because drought had not been experimentally manipulated in the field, we conducted a second experiment in the greenhouse where cassava was inoculated with two genetically different R. irregularis isolates and subjected to drought, followed by re-watering, to allow recovery. Physiological stress responses of cassava to drought differed significantly between plants inoculated with the two different fungi. However, plants that experienced higher drought stress also recovered at a faster rate following re-watering. We conclude that intraspecific genetic variability in AMF significantly influences cassava physiological responses during water stress. This highlights the potential of using naturally existing variation in AMF to improve cassava tolerance undergoing water stress. However, the fact that clonal progeny of an AMF isolate can differentially affect how cassava copes with natural drought stress in field conditions, highlights the necessity to understand additional factors, beyond genetic variation, which can account for such large differences in cassava responses to drought.

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Candidate regulators and target genes of drought stress in needles and roots of Norway spruce

10.1101/517151 ◽

2019 ◽

Cited By ~ 1

Author(s):

Julia C. Haas ◽

Alexander Vergara ◽

Vaughan Hurry ◽

Nathaniel R. Street

Keyword(s):

Drought Stress ◽

Norway Spruce ◽

Stress Responses ◽

Large Scale ◽

Target Genes ◽

Forest Tree ◽

Drought Response ◽

Severe Drought ◽

Molecular Response ◽

Transcriptional Responses

AbstractDrought stress impacts on seedling establishment, survival and whole-plant productivity. Drought stress responses have been extensively studied at the physiological and molecular level in angiosperms, particularly in agricultural species and the model Arabidopsis thaliana, with the vast majority of work performed on aboveground tissues. Boreal forests are dominated by coniferous tree species and cover vast areas of the terrestrial surface. These areas are predicted to be particularly influenced by ongoing climate change and will be exposed to more frequent and acute drought. The associated impact at all stages of the forest tree life cycle is expected to have large-scale ecological and economic impacts. To provide a comprehensive understanding of the drought response mechanisms of Picea abies seedlings, we assayed the physiological response of needles and transcriptional responses of roots and needles after exposure to mild and severe drought. Shoots and needles showed extensive reversible plasticity for physiological measures indicative of drought response mechanisms, including stomatal conductance (gs) and shoot water potential. Root and needle transcriptional responses contrasted, with an extensive root-specific down-regulation of growth. When we compared the responses of P. abies with previously-characterised A. thaliana drought response genes, we found that the majority of the genes were conserved across lineages. However, in P. abies, transcription factors (TFs) previously identified as belonging to the ABA-dependent pathway had a more limited role and most differentially expressed genes were specific to the stress response of P. abies. These results highlight the importance of profiling both above- and below-ground tissues and provide a comprehensive framework to advance understanding of the drought response mechanism of P. abies.One sentence summaryAnalysis of the drought transcriptome of Norway spruce reveals divergent molecular response pathways in conifers.

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Emotions and health: The impact of emotions, emotions regulation, music, and acculturation on health

Zeitschrift für Gesundheitspsychologie ◽

10.1026/0943-8149.16.3.112 ◽

2008 ◽

Vol 16 (3) ◽

pp. 112-115 ◽

Cited By ~ 1

Author(s):

Stephan Bongard ◽

Volker Hodapp ◽

Sonja Rohrmann

Keyword(s):

Stress Responses ◽

Physiological Stress ◽

Anger Expression ◽

Domain Specific ◽

Cardiovascular Stress ◽

Expression Behavior ◽

Cardio Vascular ◽

And Coping ◽

Relationship Of ◽

The Impact

Abstract. Our unit investigates the relationship of emotional processes (experience, expression, and coping), their physiological correlates and possible health outcomes. We study domain specific anger expression behavior and associated cardio-vascular loads and found e.g. that particularly an open anger expression at work is associated with greater blood pressure. Furthermore, we demonstrated that women may be predisposed for the development of certain mental disorders because of their higher disgust sensitivity. We also pointed out that the suppression of negative emotions leads to increased physiological stress responses which results in a higher risk for cardiovascular diseases. We could show that relaxation as well as music activity like singing in a choir causes increases in the local immune parameter immunoglobuline A. Finally, we are investigating connections between migrants’ strategy of acculturation and health and found e.g. elevated cardiovascular stress responses in migrants when they where highly adapted to the German culture.

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