Five years of experimental summer drought – Anatomical and physiological acclimation of mature beech and spruce

2020 ◽  
Author(s):  
Thorsten Grams
Keyword(s):  
Norway Spruce ◽  
Soluble Sugars ◽  
Soil Microbial Communities ◽  
European Beech ◽  
Microbial Interactions ◽  
Rooting Depth ◽  
Summer Drought ◽  
Soil Microbial ◽  
Roof Experiment ◽  
Whole Tree

<p>This contribution summarizes the outcome of a five-year experiment on mature (60-80 years old) trees in a Central European forest. We studied roughly 100 trees of European beech and Norway spruce, two tree species of contrasting foliage (i.e. deciduous vs. evergreen) and stomatal sensitivity to drought (i.e. anisohydric vs. isohydric behavior). Trees were exposed to experimentally induced summer droughts from 2014 to 2018 with precipitation throughfall being completely excluded during the growing seasons. The throughfall-exclusion study was established on 12 plots with trees readily accessible by canopy crane (Kranzberg forest roof experiment, southern Germany). We aimed at bringing trees to the edge of survival to studying trees’ capability for acclimation under repeated, severe summer droughts as expected more frequently in future climate scenarios. Results come from a multidisciplinary approach focusing on mechanisms of acclimation, eventually reducing trees’ vulnerability to drought during the five-year study period. Presented data integrate responses from the level of soil/microbial interactions over tree organs and whole-tree morphology to responses at the stand level.</p><p>During the first two years, restrictions caused by drought were most prominent, exemplified by pre-dawn leaf water potentials of down to -2.5 MPa and reductions in photosynthesis and growth by up to 50 and 80 % in European beech and Norway spruce, respectively. Nevertheless, percentage loss of conductivity in branch xylem was hardly affected. Likewise, concentrations of non-structural carbohydrates (sum of soluble sugars and starch) in tree organs remained largely unaffected, but translated to significantly lower carbohydrate pool sizes in view of strongly reduced tree growth. Nevertheless, two spruce trees died from drought, in the absence of bark beetle or pathogen interactions. During the fourth and fifth year of summer drought, trees showed clear signs of drought acclimation with e.g. some recovery of stomatal conductance, reductions of whole-tree leaf area, changes in rooting depth and acclimation of associated soil microbial communities. Accordingly, stem diameter growth recovered during the last years of the stress treatment, indicating reduced vulnerability of trees towards the end of the five-year drought treatment.</p>

scholarly journals Fine Spatial Scale Variation of Soil Microbial Communities under European Beech and Norway Spruce

2016 ◽  
Vol 7 ◽  
Author(s):  
Heiko Nacke ◽  
Kezia Goldmann ◽  
Ingo Schöning ◽  
Birgit Pfeiffer ◽  
Kristin Kaiser ◽  
...  
Keyword(s):  
Microbial Communities ◽  
Spatial Scale ◽  
Norway Spruce ◽  
Soil Microbial Communities ◽  
European Beech ◽  
Fine Spatial Scale ◽  
Soil Microbial ◽  
Scale Variation

scholarly journals Need for Laboratory Ecosystems To Unravel the Structures and Functions of Soil Microbial Communities Mediated by Chemistry

mBio ◽  
2018 ◽  
Vol 9 (4) ◽  
Author(s):  
Kateryna Zhalnina ◽  
Karsten Zengler ◽  
Dianne Newman ◽  
Trent R. Northen
Keyword(s):  
Microbial Communities ◽  
Metabolic Networks ◽  
Soil Microbial Communities ◽  
Microbial Interactions ◽  
Microbial Consortia ◽  
Cellular Biology ◽  
Model Organisms ◽  
Soil Microbial ◽  
Integrative Framework ◽  
Genome Annotations

ABSTRACTThe chemistry underpinning microbial interactions provides an integrative framework for linking the activities of individual microbes, microbial communities, plants, and their environments. Currently, we know very little about the functions of genes and metabolites within these communities because genome annotations and functions are derived from the minority of microbes that have been propagated in the laboratory. Yet the diversity, complexity, inaccessibility, and irreproducibility of native microbial consortia limit our ability to interpret chemical signaling and map metabolic networks. In this perspective, we contend that standardized laboratory ecosystems are needed to dissect the chemistry of soil microbiomes. We argue that dissemination and application of standardized laboratory ecosystems will be transformative for the field, much like how model organisms have played critical roles in advancing biochemistry and molecular and cellular biology. Community consensus on fabricated ecosystems (“EcoFABs”) along with protocols and data standards will integrate efforts and enable rapid improvements in our understanding of the biochemical ecology of microbial communities.

scholarly journals Micro-aggregation of a pristine grassland soil selects for bacterial and fungal communities and changes in nitrogen cycling potentials

2021 ◽  
Author(s):  
Christoph Keuschnig ◽  
Jean Martins ◽  
Aline Navel ◽  
Pascal Simonet ◽  
Catherine Larose
Keyword(s):  
Particle Size ◽  
Nitrogen Cycling ◽  
Bacterial Communities ◽  
Soil Microbial Communities ◽  
Microbial Interactions ◽  
Fungal Communities ◽  
Supernatant Fraction ◽  
Soil Microbial ◽  
Microbial Analysis

Microbial analysis at the micro scale of soil is essential to the overall understanding of microbial organization and interactions, and necessary for a better understanding of soil ecosystem functioning. While bacterial communities have been extensively described, little is known about the organization of fungal communities as well as functional potentials at scales relevant to microbial interactions. Fungal and bacterial communities and changes in nitrogen cycling potentials in the pristine Rothamsted Park Grass soil (bulk soil) as well as in its particle size sub-fractions (PSFs; > 250 µm, 250-63 µm, 63-20 µm, 20-2 µm, < 2 µm and supernatant) were studied. The potential for nitrogen reduction was found elevated in bigger aggregates. The relative abundance of Basidiomycota deceased with decreasing particle size, Ascomycota showed an increase and Mucoromycota became more prominent in particles less than 20 µm. Bacterial community structures changed below 20 µm at the scale where microbes operate.Strikingly, only members of two bacterial and one fungal phyla (Proteobacteria, Bacteroidota and Ascomycota, respectively) were washed-off the soil during fractionation and accumulated in the supernatant fraction where most of the detected bacterial genera (e.g., Pseudomonas, Massilia, Mucilaginibacter, Edaphobaculum, Duganella, Janthinobacterium and Variovorax) were previously associated with exopolysaccharide production and biofilm formation.Overall, the applied method shows potential to study soil microbial communities at micro scales which might be useful in studies focusing on the role of specific fungal taxa in soil structure formation as well as research on how and by whom biofilm-like structures are distributed and organized in soil.

scholarly journals Specific impacts of beech and Norway spruce on the structure and diversity of the rhizosphere and soil microbial communities

2016 ◽  
Vol 6 (1) ◽  
Author(s):  
S. Uroz ◽  
P. Oger ◽  
E. Tisserand ◽  
A. Cébron ◽  
M.-P. Turpault ◽  
...  
Keyword(s):  
Microbial Communities ◽  
Norway Spruce ◽  
Soil Microbial Communities ◽  
Soil Microbial

scholarly journals Long-Term Drought and Warming Alter Soil Bacterial and Fungal Communities in an Upland Heathland

Ecosystems ◽  
2021 ◽  
Author(s):  
Fiona M. Seaton ◽  
Sabine Reinsch ◽  
Tim Goodall ◽  
Nicola White ◽  
Davey L. Jones ◽  
...  
Keyword(s):  
Climate Change ◽  
Microbial Communities ◽  
Soil Microbial Communities ◽  
Fungal Communities ◽  
Its2 Region ◽  
Rrna Gene ◽  
Summer Drought ◽  
Soil Microbial ◽  
Soil Bacterial

AbstractThe response of soil microbial communities to a changing climate will impact global biogeochemical cycles, potentially leading to positive and negative feedbacks. However, our understanding of how soil microbial communities respond to climate change and the implications of these changes for future soil function is limited. Here, we assess the response of soil bacterial and fungal communities to long-term experimental climate change in a heathland organo-mineral soil. We analysed microbial communities using Illumina sequencing of the 16S rRNA gene and ITS2 region at two depths, from plots undergoing 4 and 18 years of in situ summer drought or warming. We also assessed the colonisation of Calluna vulgaris roots by ericoid and dark septate endophytic (DSE) fungi using microscopy after 16 years of climate treatment. We found significant changes in both the bacterial and fungal communities in response to drought and warming, likely mediated by changes in soil pH and electrical conductivity. Changes in the microbial communities were more pronounced after a longer period of climate manipulation. Additionally, the subsoil communities of the long-term warmed plots became similar to the topsoil. Ericoid mycorrhizal colonisation decreased with depth while DSEs increased; however, these trends with depth were removed by warming. We largely ascribe the observed changes in microbial communities to shifts in plant cover and subsequent feedback on soil physicochemical properties, especially pH. Our results demonstrate the importance of considering changes in soil microbial responses to climate change across different soil depths and after extended periods of time.

scholarly journals Enriched root bacterial microbiome in invaded vs native ranges of the model grass allotetraploid Brachypodium hybridum

2021 ◽  
Author(s):  
Brooke Pickett ◽  
Chelsea J. Carey ◽  
Keshav Arogyaswamy ◽  
Jon Botthoff ◽  
Mia Maltz ◽  
...  
Keyword(s):  
Brachypodium Distachyon ◽  
Bacterial Community Composition ◽  
Soil Microbial Communities ◽  
Biotic Interactions ◽  
Plant Invasions ◽  
Amplicon Sequencing ◽  
Microbial Interactions ◽  
Bioenergy Crops ◽  
Native Range ◽  
Soil Microbial

AbstractInvasive species can shift the composition of key soil microbial groups, thus creating novel soil microbial communities. To better understand the biological drivers of invasion, we studied plant-microbial interactions in species of the Brachypodium distachyon complex, a model system for functional genomic studies of temperate grasses and bioenergy crops. While Brachypodium hybridum invasion in California is in an incipient stage, threatening natural and agricultural systems, its diploid progenitor species B. distachyon is not invasive in California. We investigated the root, soil, and rhizosphere bacterial composition of Brachypodium hybridum in both its native and invaded range, and of B. distachyon in the native range. We used high-throughput, amplicon sequencing to evaluate if the bacteria associated with these plants differ, and whether biotic controls may be driving B. hybridum invasion. Bacterial community composition of B. hybridum differed based on provenance (native or invaded range) for root, rhizosphere, and bulk soils, as did the abundance of dominant bacterial taxa. Bacteroidetes, Cyanobacteria and Bacillus spp. (species) were significantly more abundant in B. hybridum roots from the invaded range, whereas Proteobacteria, Firmicutes, Erwinia and Pseudomonas were more abundant in the native range roots. Brachypodium hybridum forms novel biotic interactions with a diverse suite of rhizosphere microbes from the invaded range, which may not exert a similar influence within its native range, ostensibly contributing to B. hybridum’s invasiveness. These associated plant microbiomes could inform future management approaches for B. hybridum in its invaded range and could be key to understanding, predicting, and preventing future plant invasions.

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