Kooperativer Bibliotheksverbund

In: New Phytologist, July 2013, Vol.199(2), pp.520-528

Description: The spatiotemporal dynamics of, and interspecific differences in, the acquisition of litter‐derived nitrogen (N) by natural assemblages of ectomycorrhizal root tips are poorly understood. Small cylindrical mesh bags containing 15N‐labelled beech (Fagus sylvatica) leaf litter that permit hyphal but not root ingrowth were inserted vertically into the top soil layer of an old‐growth beech forest. The lateral transfer of 15N into the circumjacent soil, roots, microbes and ectomycorrhizas was measured during an 18‐month exposure period. Ectomycorrhial fungi (EMF) showed large interspecific variation in the temporal pattern and extent of 15N accumulation. Initially, when N was mainly available from the leachate, microbes were more efficient at N immobilization than the majority of EMF, but distinct fungal species also showed significant 15N accumulation. During later phases, the enrichment of 15N in Tomentella badia was higher than in microbes and other EMF species. Roots and soil accumulated 15N with a large delay compared with microbes and EMF. Because approximately half of the studied fungal species had direct access to N from leaf litter and the remainder to N from leached compounds, we suggest that EMF diversity facilitates the N utilization of the host by capturing N originating from early‐released solutes and late degradation products from a recalcitrant source.

Keywords: ‐Labelled Leaf Litter ; Deciduous Forest ; Ectomycorrhiza ; Microbes ; Nitrogen Uptake ; Roots ; Soil ; Stable Isotopes

ISSN: 0028-646X

E-ISSN: 1469-8137

DOI: 10.1111/nph.12272

Language: English

In: Environmental and Experimental Botany, March, 2013, Vol.87, p.207(11)

Description: To link to full-text access for this article, visit this link: http://dx.doi.org/10.1016/j.envexpbot.2012.11.005 Byline: Rodica Pena (a), Judy Simon (b), Heinz Rennenberg (b)(c), Andrea Polle (a) Keywords: Cost-benefit; Drought; Mycorrhiza; Shade;.sup.15N; Nitrogen partitioning Abstract: Display Omitted Author Affiliation: (a) Busgen-Institut, Abteilung: Forstbotanik und Baumphysiologie, Georg-August Universitat Gottingen, Busgenweg 2, 37077 Gottingen, Germany (b) Institut fur Forstbotanik und Baumphysiologie Professur fur Baumphysiologie, Georges-Kohler Allee, Geb. 53/54, 79085 Freiburg, Germany (c) College of Science, King Saud University, Riyadh 11451, Saudi Arabia Article History: Received 9 June 2012; Revised 11 November 2012; Accepted 12 November 2012

Keywords: Architecture ; Droughts ; Cost Benefit Analysis

ISSN: 0098-8472

Source: Cengage Learning, Inc.

Language: English

In: Plant and Soil, 2013, Vol.369(1), pp.657-668

Description: Aims: Our aims were to characterize the fate of leaf-litter-derived nitrogen in the plant-soil-microbe system of a temperate beech forest of Southern Germany and to identify its importance for N nutrition of beech seedlings. Methods: super(15)N-labelled leaf litter was traced in situ into abiotic and biotic N pools in mineral soil as well as into beech seedlings and mycorrhizal root tips over three growing seasons. Results: There was a rapid transfer of super(15)N into the mineral soil already 21 days after tracer application with soil microbial biomass initially representing the dominant litter-N sink. However, super(15)N recovery in non-extractable soil N pools strongly increased over time and subsequently became the dominant super(15)N sink. Recovery in plant biomass accounted for only 0.025 % of super(15)N excess after 876 days. After three growing seasons, super(15)N excess recovery was characterized by the following sequence: non-extractable soil N〉〉extractable soil N including microbial biomass〉〉plant biomass〉ectomycorrhizal root tips. Conclusions: After quick vertical dislocation and cycling through microbial N pools, there was a rapid stabilization of leaf-litter-derived N in non-extractable N pools of the mineral soil. Very low super(15)N recovery in beech seedlings suggests a high importance of other N sources such as root litter for N nutrition of beech understorey.

Keywords: Nitrogen cycling ; Beech ; 15N-labelled leaf litter ; 15N tracing ; Microbial biomass ; Ectomycorrhiza

ISSN: 0032-079X

E-ISSN: 1573-5036

DOI: 10.1007/s11104-013-1603-6

URL: View full text in Springer (Subscribers only)

In: The ISME Journal, 2013, Vol.8(2), p.321

Description: Mycorrhizal fungi have a key role in nitrogen (N) cycling, particularly in boreal and temperate ecosystems. However, the significance of ectomycorrhizal fungal (EMF) diversity for this important ecosystem function is unknown. Here, EMF taxon-specific N uptake was analyzed via super(15)N isotope enrichment in complex root-associated assemblages and non-mycorrhizal root tips in controlled experiments. Specific super(15)N enrichment in ectomycorrhizas, which represents the N influx and export, as well as the exchange of super(15)N with the N pool of the root tip, was dependent on the fungal identity. Light or water deprivation revealed interspecific response diversity for N uptake. Partial taxon-specific N fluxes for ectomycorrhizas were assessed, and the benefits of EMF assemblages for plant N nutrition were estimated. We demonstrated that ectomycorrhizal assemblages provide advantages for inorganic N uptake compared with non-mycorrhizal roots under environmental constraints but not for unstressed plants. These benefits were realized via stress activation of distinct EMF taxa, which suggests significant functional diversity within EMF assemblages. We developed and validated a model that predicts net N flux into the plant based on taxon-specific super(15)N enrichment in ectomycorrhizal root tips. These results open a new avenue to characterize the functional traits of EMF taxa in complex communities.

Keywords: Isotopes ; Ectomycorrhizas ; Fungi ; Stress ; Roots ; Nutrition ; Electromagnetic Fields ; Light Effects ; Nitrogen ; Cell Biology;

ISSN: 1751-7362

E-ISSN: 1751-7370

DOI: 10.1038/ismej.2013.158

URL: View this record in Nature

Language: English

In: Soil Biology and Biochemistry, July 2016, Vol.98, pp.127-137

Description: Phosphorus (P) is an important nutrient, whose concentrations are declining in many European forest ecosystems. Here, we selected five old-aged temperate beech ( ) forests that represented a sequence of decreasing soil P resources. We addressed the following hypotheses: (i) root P concentrations correspond to soil P concentrations, when P availability is suboptimal for tree nutrition, (ii) decreasing soil P concentrations, and increasing host P demand foster increasing ectomycorrhizal fungal (EMF) species richness and lead to a shift in the EMF community structure towards increasing soil exploration. We found that the decrease in P concentrations along the geosequence was less steep in the organic layer than that in the mineral topsoil. P concentrations in roots showed a positive relationship with P concentrations in soil, with a stronger correlation in coarse than in fine roots. This finding indicates that low P availability mainly affected P storage of the host. The root tips were completely colonized with EMF. In the organic layer EMF biomass was higher than that of saprophytic fungi, and correlated with inorganic P (P ). In the mineral topsoil EMF biomass was about 10-fold lower than in the organic layer and biomass of saprophytes and microbial P, but not that of EMF, was correlated with P and phosphatase activities. Based on these results, we propose that beech P nutrition was mainly achieved by EMF in the organic layer. Variation in EMF species richness was unrelated to P in soil and decreased with increasing N in the organic layer. The EMF community structures were taxonomically divergent and filtered by habitat soil chemistry in the mineral layer and P in the organic layer between the P-rich forest and the P-poor forest. Changes in the taxonomic structures of the EMF did not result in corresponding changes in soil exploration. In conclusion, our results support a relationship between soil P concentrations and P storage in roots, but do not support mono-causal relationships between soil P and EMF species richness or hyphal soil exploration. Our results suggest that the taxonomic dissimilarities of the EMF along the P gradient were mainly driven by P concentrations in the organic layer and by the nutrient resources in the mineral layer.

Keywords: Organic P ; Inorganic P ; Exploration Types ; Mycorrhizal Diversity ; Functional Traits ; P Recycling ; Agriculture ; Chemistry

ISSN: 0038-0717

E-ISSN: 1879-3428

DOI: 10.1016/j.soilbio.2016.04.006

URL: View record in ScienceDirect (Access to full text may be restricted)

Language: English

In: Mycorrhiza, 2017, Vol.27(3), pp.233-245

Description: Ectomycorrhizal (EM) fungal taxonomic, phylogenetic, and trait diversity (exploration types) were analyzed in beech and conifer forests along a north-to-south gradient in three biogeographic regions in Germany. The taxonomic community structures of the ectomycorrhizal assemblages in top soil were influenced by stand density and forest type, by biogeographic environmental factors (soil physical properties, temperature, and precipitation), and by nitrogen forms (amino acids, ammonium, and nitrate). While α-diversity did not differ between forest types, β-diversity increased, leading to higher γ-diversity on the landscape level when both forest types were present. The highest taxonomic diversity of EM was found in forests in cool, moist climate on clay and silty soils and the lowest in the forests in warm, dry climate on sandy soils. In the region with higher taxonomic diversity, phylogenetic clustering was found, but not trait clustering. In the warm region, trait clustering occurred despite neutral phylogenetic effects. These results suggest that different forest types and favorable environmental conditions in forests promote high EM species richness in top soil presumably with both high functional diversity and phylogenetic redundancy, while stressful environmental conditions lead to lower species richness and functional redundancy.

Keywords: Beech () ; Exploration type ; Ectomycorrhiza ; Drought ; Nitrogen ; Spruce () ; Pine ()

ISSN: 0940-6360

E-ISSN: 1432-1890

DOI: 10.1007/s00572-016-0742-z

URL: View full text in Springer (Subscribers only)

In: Applied and Environmental Microbiology, 2010, Vol. 76(6), p.1831

Description: The relationships between plant carbon resources, soil carbon and nitrogen content, and ectomycorrhizal fungal (EMF) diversity in a monospecific, old-growth beech (Fagus sylvatica) forest were investigated by manipulating carbon flux by girdling. We hypothesized that disruption of the carbon supply would not affect diversity and EMF species numbers if EM fungi can be supplied by plant internal carbohydrate resources or would result in selective disappearance of EMF taxa because of differences in carbon demand of different fungi. Tree carbohydrate status, root demography, EMF colonization, and EMF taxon abundance were measured repeatedly during 1 year after girdling. Girdling did not affect root colonization but decreased EMF species richness of an estimated 79 to 90 taxa to about 40 taxa. Cenococcum geophilum, Lactarius blennius, and Tomentella lapida were dominant, colonizing about 70% of the root tips, and remained unaffected by girdling. Mainly cryptic EMF species disappeared. Therefore, the Shannon-Wiener index (H') decreased but evenness was unaffected. H' was positively correlated with glucose, fructose, and starch concentrations of fine roots and also with the ratio of dissolved organic carbon to dissolved organic nitrogen (DOC/DON), suggesting that both H' and DOC/DON were governed by changes in belowground carbon allocation. Our results suggest that beech maintains numerous rare EMF species by recent photosynthate. These EM fungi may constitute biological insurance for adaptation to changing environmental conditions. The preservation of taxa previously not known to colonize beech may, thus, form an important reservoir for future forest development.

Keywords: Engineering ; Biology ; Economics;

ISSN: 0099-2240

ISSN: 00992240

E-ISSN: 10985336

DOI: 10.1128/AEM.01703-09

URL: View this record in ASM

URL: View full text in ASM (subscribers only)

Language: English

In: Environmental and Experimental Botany, March 2013, Vol.87, pp.207-217

Description: ► Beech benefits from EMF colonization under mild drought stress. ► The responses diverge depending on light climate. ► Shade grown EM plants responded to drought stress more slowly than NM plants. ► Light grown EM plants increased N acquisition under drought compared to NM plants. The aim of this study was to investigate the influence of ectomycorrhizal fungi (EMF) on the architecture of and nitrogen (N) partitioning in young beech ( ) plants in response to different light regimes and water deprivation. We hypothesized that EMF modify biomass partitioning and architecture of young beech plants by increased N uptake in comparison with non-mycorrhizal (NM) plants and that therefore, the drought responses of EM and NM plants diverge. We anticipated that full light-exposed plants were more drought tolerant due to improved water status and nutrition, whereas shade-acclimated EM plants were more drought susceptible because of decreased mycorrhizal colonization. To test these hypotheses seedlings were grown in native or sterilized forest soil. To avoid effects of soil pretreatment NM and EM plants were transplanted into sand-peat culture systems and exposed to shade, drought or the combination of both factors. Shade resulted in reduced root biomass production decreasing the root-to-shoot ratio. Mild drought stress (pre-dawn water potential [ ] = −1.3 MPa) did not affect biomass partitioning. EMF colonization did not increase plant biomass, but had strong effects on root architecture: the numbers of root tips as well as the absolute and specific root lengths were increased because of formation of thin roots, especially in the diameter classes from 0.2 to 0.8 mm. In contrast to our expectation N uptake of well irrigated EM plants was not increased despite their larger potential for soil exploitation. Overall, EM plants exhibited higher amounts of carbon fixed per unit of N taken up than NM plants and shifted N partitioning towards the roots. Beneficial effects of EMFs were apparent under mild drought but the responses differed depending on the light availability: shaded EM plants showed a delay in the decrease of ; light exposed EM plants showed increased N uptake compared with NM beeches. These results indicate that EMFs are involved in mediating divergent responses of beech to drought depending on the light availability.

Keywords: Cost-Benefit ; Drought ; Mycorrhiza ; Shade ; 15n ; Nitrogen Partitioning ; Environmental Sciences ; Botany

ISSN: 0098-8472

E-ISSN: 1873-7307

DOI: 10.1016/j.envexpbot.2012.11.005

URL: View record in ScienceDirect (Access to full text may be restricted)

Language: English

In: Frontiers in plant science, 2014, Vol.5, pp.229

Description: Roots of forest trees are associated with various ectomycorrhizal (ECM) fungal species that are involved in nutrient exchange between host plant and the soil compartment. The identification of ECM fungi in small environmental samples is difficult. The present study tested the feasibility of attenuated total reflection Fourier-transform infrared (ATR-FTIR) spectroscopy followed by hierarchical cluster analysis (HCA) to discriminate in situ collected ECM fungal species. Root tips colonized by distinct ECM fungal species, i.e., Amanita rubescens, Cenococcum geophilum, Lactarius subdulcis, Russula ochroleuca, and Xerocomus pruinatus were collected in mono-specific beech (Fagus sylvatica) and mixed deciduous forests in different geographic areas to investigate the environmental variability of the ECM FTIR signatures. A clear HCA discrimination was obtained for ECM fungal species independent of individual provenance. Environmental variability neither limited the discrimination between fungal species nor provided sufficient resolution to discern species sub-clusters for different sites. However, the de-convoluted FTIR spectra contained site-related spectral information for fungi with wide nutrient ranges, but not for Lactarius subdulcis, a fungus residing only in the litter layer. Specific markers for distinct ECM were identified in spectral regions associated with carbohydrates (i.e., mannans), lipids, and secondary protein structures. The present results support that FTIR spectroscopy coupled with multivariate analysis is a reliable and fast method to identify ECM fungal species in minute environmental samples. Moreover, our data suggest that the FTIR spectral signatures contain information on physiological and functional traits of ECM fungi.

Keywords: Cluster Analysis ; Deciduous Forests ; Field Samples ; Infrared Spectroscopy ; Mycorrhiza ; Soilborne Fungi

ISSN: 1664-462X

DOI: 10.3389/fpls.2014.00229

URL: View this record in MEDLINE/PubMed

Language: English

In: Trees, 2017, Vol.31(4), pp.1215-1225

Description: To access, purchase, authenticate, or subscribe to the full-text of this article, please visit this link: http://dx.doi.org/10.1007/s00468-017-1539-1 Byline: Quynh Ngoc Nguyen (1,2), Andrea Polle (1), Rodica Pena (1) Keywords: Drought resistance; Drought avoidance; Drought tolerance; Climate change; Temperate forests; Isohydric; Anisohydric Abstract: Key message European beech presents intraspecific variations in drought resistance strategies that are mediated by the amount of precipitation in the habitat. Abstract Climate change predictions forecast extended drought periods, which are expected to pose an enhanced risk to forest trees. Here, we investigated the drought response and fitness traits in European beech (Fagus sylvatica L.) in response to a severe progressive drought. The capability of three beech provenances from habitats differing in annual precipitation (544, 665, and 766 mm year.sup.-1) to cope with drought was compared in a common garden experiment using beech seedlings. Soil and plant water status, maximum quantum yield of PSII, growth and biomass partitioning, stomatal conductance, and transcript abundance pattern of the kinase, Open Stomata 1 (OST1), of control (well-watered) and drought-treated (water withheld) plants from each provenance were repeatedly measured during a 60-day drought experiment. The lowest precipitation provenance displayed a more isohydric phenotype with a prompt stomatal closure, increased OST1 levels, high water potential and leaf water content, and a decrement in the maximum quantum yield of PSII. The other two provenances showed a more anisohydric stomatal regulation with a slow and delayed stomatal closure and a decrease in the water status. These findings suggest that intraspecific variations in beech for diverging drought resistance strategies exist and might be mediated by differences in the abscisic acid signaling pathway. The higher precipitation provenance maintained high quantum yield of PSII, and water potentials above -2.0 MPa for a longer period of time than the other two provenances, and consequently, mortality was delayed in this provenance. We concluded that lower precipitation adapted plants employ a drought resistance strategy suitable for the moderate drought, whereas the higher precipitation habitat plants revealed mechanisms, which could be better suited to cope with more severe drought events. Author Affiliation: (1) Forest Botany and Tree Physiology, University of Goettingen, Buesgenweg 2, 37077, Goettingen, Germany (2) Hung Vuong University, Nong Trang, Viet Tri, Phu Tho, Vietnam Article History: Registration Date: 07/03/2017 Received Date: 23/07/2016 Accepted Date: 06/03/2017 Online Date: 20/03/2017 Article note: Communicated by M. Zwieniecki.

Keywords: Drought resistance ; Drought avoidance ; Drought tolerance ; Climate change ; Temperate forests ; Isohydric ; Anisohydric

ISSN: 0931-1890

E-ISSN: 1432-2285

DOI: 10.1007/s00468-017-1539-1

URL: View full text in Springer (Subscribers only)