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Treeline shift under global change - ectomycorrhizas as a limiting factor?
Vašutová, Martina ; Holub, Filip ; Čermák, Martin ; Cudlín, Pavel
It is assumed that global change will cause a treeline shift . Because competitive abilities and natural regeneration of trees are infl uenced by ectomycorrhizal (ECM) symbiosis and fi ne roots and ECM mycelia play a key role in belowground carbon turnover, we have studied the ECM associations of treeline ecosystems. We aim to fi nd out how resistant and resilient current ECM associations of these ecosystems are and whether the absence of appropriate ECM symbionts could be a limiting factor of an ecosystem shift . We have focused on natural mountain spruce forests and spruce forests on the treeline; dwarf pine stands with scattered spruce trees above the treeline will be studied in years to come. Ectomycorrhizas were described by morphological features and sequenced to identify fungal species. In the case of taxonomically complicated ECM fungal groups, sequences from microscopically identifi ed sporocarps were used for the identifi cation of ectomycorrhizas. A disproportion between ECM fungi diversity in spruce stands and dwarf pine stands revealed based on a literature review can indicate diff erent ectomycorrhiza patterns at the treeline. According to preliminary results from the Giant Mts. there is an adequate ECM fungal species diversity in mountain spruce forest and spruce forests on the treeline.
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Changes in the photosynthetic apparatus of european beech and Norway spruce under long-term exposure to elevated CO2
Holišová, Petra ; Šprtová, Miroslava ; Kubásek, Jiří ; Lhotáková, Z. ; Mašková, P. ; Lipavská, H. ; Kočová, M. ; Holá, D. ; Radochová, Barbora ; Albrechtová, J. ; Urban, Otmar
The changes of photosynthetic performance caused by increasing CO2 concentration are refl ected at diff erent hierarchical levels of photosynthetic apparatus from the effi ciency of individual photosynthetic processes to changes in leaf structure. Th e aim of this study was to elucidate the relationships between the ultrastructure and function of photosynthetic apparatus under elevated CO2 concentration. We studied two common tree species – the European beech and the Norway spruce – grown under ambient (AC) and elevated CO2 concentrations (EC). Photosynthetic parameters were obtained using the gas-exchange system LI-6400 (LI-COR, USA). Th e characteristics of chlorophyll a fl uorescence were obtained in vivo with FluorPen FP100max (PSI, CZE) and in vitro polarographically in a suspension of isolated chloroplasts. Non-structural soluble saccharides and starch accumulation was quantifi ed using HPLC. Th e chloroplast ultrastructure was quantifi ed by stereological methods (Ellipse 2.08, SK) on the images acquired on a JEOL JEM-1011 (JEOL, JPN). Th e light-saturated CO2 assimilation rate was stimulated by EC in both species. Th e assimilation capacity of EC plants slightly decreased and was accompanied by a slight decrease in the rate of electron transport and the rate of Rubisco carboxylation. Th e growth in EC induced higher energy dissipation by light-harvesting antennae, diminished PSII activity, resulted in greater PSI capacity and in higher accumulation of starch and soluble sugars in the leaves of both species.
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Response of epidermal blue-green fluorescence emission from Barley leaves to uv radiation stress
Karlický, Václav ; Nezval, J. ; Štroch, Michal ; Špunda, Vladimír
Blue-green fl uorescence (BGF) is emitted by plant tissue when excited by UV radiation. Th e emission spectrum of BGF varies with plant species and is aff ected by the physiological status of the plant. BGF has been attributed mainly to cell wall-bound ferulic acid, although a contribution from fl avonoids and other simple phenols has also been suggested. Th e BGF signal is of interest due to its potential application in the remote sensing of plant stress: such techniques use ratios of blue and green to chlorophyll red and far-red fl uorescence emission intensities to estimate plant stress. In this work we investigated the response of BGF to UV-radiation stress and characterized changes in the shape of BGF emission spectra. We found these changes to be more signifi cant during the acclimation to UV-B radiation in comparison with UV-A or high irradiance of PAR. Furthermore, the spectral changes in BGF emission were due to a decline of fl uorescence at a wavelength of 435 nm compared with bands around 455 nm and 520 nm. In view of this, we have tried to distinguish individual fl uorescent components using more detailed fl uorescence analysis and to explain the causes of these spectral changes.
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Segmentation of tree crowns from airborne hyperspectral and lidar data: method comparison
Novotný, Jan ; Zemek, František
Structural and spectral information on single trees is needed for diff erent purposes in forest research and its applications. It can help, e.g., to explain the physiological performance of trees, to improve a parameterization of radiative transfer models, to estimate more precisely tree biomass or tree health status. Th is technical note aims at informing about the basic steps in the use of two categories of airborne digital data for tree crown segmentation: 1) passive multispectral (MS) and hyperspectral (HS) data; 2) active laser scanning (LiDAR) data. Basic assumptions of data quality and their pre-processing chains are mentioned for both data categories, followed by an analytical description of the basic steps in crown segmentation: a) detection of individual trees; b) delineation of a projected tree crown. Methods related to each data category and their common use are compared. As a result, synergic application of HS and laser scanning data resulted in the highest precision of tree crown delineation.
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Effects of UV radiation and drouhgt on the accumulation of UV-screening compounds and photosynthetic parameters in selected herbs and grasses of the mountain grassland ecosystem
Klem, Karel ; Holub, Petr ; Urban, Otmar ; Rajsnerová, Petra ; Kubásek, Jiří
The main objective of the experiment conducted on a mountain grassland ecosystem was to investigate the interactive eff ects of UV treatment and drought on the changes in accumulation of UV-screening compounds and photosynthetic parameters in selected herb (Hypericum maculatum) and grass (Agrostis tenuis) species. Th e experimental plots were manipulated using roof constructions enabling exclusion or transmission of incident precipitation and UV radiation, respectively. Generally, UV and drought treatments had a similar eff ect on the accumulation of fl avonols. UV exclusion resulted in a slight reduction of UV-screening compounds, particularly under the conditions of ambient precipitation. Likewise, drought treatment caused an increase in the accumulation of fl avonols per area unit. Under UV exclusion, drought slightly reduced the light-saturated CO2 assimilation rate (Amax) in both the species studied. Th e presence of UV radiation, however, led to less of a diff erence in Amax between [wet] and [dry] treatments. In addition to the increased induction of fl avonols, UV radiation increased water use effi ciency and alleviated thus the negative impact of drought on photosynthesis.
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Preconditioning under high par of exposure to UV-A radiation both allow acclimation of the photosynthetic apparatus of barley transferred to UV-B radiation
Štroch, Michal ; Materová, Z. ; Vrábl, D. ; Šigut, Ladislav ; Špunda, Vladimír
The acclimation response of the barley photosynthetic apparatus was examined aft er transfer of plants grown under low and high PAR to common conditions both with the same PAR and acute dose of UV-A and/or UV-B radiation. The aim was to evaluate how PAR received during growth aff ects the induction of regulatory and protective mechanisms during UV exposure. Contrary to UV-B radiation, UV-A exposure of barley plants acclimated to low PAR had no negative impact on the function of photosynthetic apparatus. Th e UV-A spectral region we used (350–400 nm) can be eff ectively utilised in photosynthetic reactions, thus compensating low PAR. Th e presence of UV-A radiation during acclimation to simultaneous UVA and UVB treatment not only mitigated but completely eliminated any negative eff ect of UV-B radiation on the photosynthetic function. Th e eff ect of UV-A and UV-B exposure was similar in plants grown under high PAR – causing moderately enhanced photosystem II (PSII) photoinhibition. We proposed that the ability to accumulate a considerable amount of UVscreening compounds under high PAR itself contributes to the resistance of PSII to UV-B radiation.
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Influence of cultivation conditions relating to climatic change on the selected polyphenol content in grapevine plants
Tříska, Jan ; Balík, J. ; Vrchotová, Naděžda ; Mikeš, O.
Winegrowing is highly climate sensitive. Even small changes in temperature could have big impacts on the whole industry. Because of the relatively high crop value, many growers can aff ord to invest in adaptation resources that might not be feasible for less valuable crops. Th ere are two basic types of response to climate change: working to adapt to or manage the impacts experienced, and trying to prevent or minimize further change (mitigation). Th ese are not mutually exclusive, and in fact, both are increasingly regarded as necessary. In our contribution we will discuss the eff ects of drought, irrigation and cultivation in greenhouses in comparison to cultivation in vineyards on the content of trans-piceid and trans-resveratrol in white and blue varieties of Vitis vinifera plants.
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Long term investigation of resveratrol content in moravian red wines in relation to climate conditions
Vrchotová, Naděžda ; Tříska, Jan ; Totušek, J. ; Balík, J.
The considerable commercial importance of wine together with the necessary quality control and investigation of the biological quality of constituent compounds leads to the development of adequate and reliable methods for the determination of macro- and micro-components in wine. Although wine contains a large amount of known compounds e.g. volatile (fl avour compounds), semi-volatile (phenolic) and non-volatile components (pigments), new compounds from all the above mentioned classes are still found in wine and are under heavy investigation, especially regarding their biological activity and their relation to the vinifi cation processes. Th e most signifi cant and famous due to the so-called French paradox is resveratrol-3,4´,5-trihydroxystilbene. Resveratrol is a stress metabolite formed in the grapevine in response to abiotic (UV irradiation) and biotic stresses (Botrytis cinerea). UV irradiation transforms trans isomer to cis form. But according the recent literature cis resveratrol could be also a result of organic farming – natural means of defence in organic viticulture against fungal infections. In our study we have investigated resveratrol content in diff erent vineyards in relation to annual mean temperature, precipitation and sun irradiation.
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Co-registration of chlorophyll fluorescence emission and 3D models of plants
Ryba, Tomáš ; Železný, Miloš
Chlorophyll fl uorescence is a powerful optical reporter signal yielding information about modulation of light use effi ciency. In standard imaging applications, fl uorescence transients are captured in 2 spatial dimensions and in time. Here, we demonstrate that it is possible to combine the information obtained in the 2D-t format with the 3D reconstruction of the entire plant using a process called co-registration. Two diff erent approaches to co-registration are presented here. Th e fi rst one is based on an image registration method, where the precise transformation parameters are iteratively estimated. Th is approach assumes that the initial position of a scanner is known and thus makes the method less general. To remove this assumption, a second approach can be used, which is based on analysis of a known calibration object. Th ere is no need to re-calibrate the system between individual measurements.
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Comparison of eddy covariance and bowen ratio energy balance method. Energy balance cloruse versus bowen ratio similarity assumption
Fischer, Milan ; Trnka, Miroslav ; Pozníková, Gabriela ; Sedlák, Pavel ; Orság, Matěj ; Kučera, J. ; Žalud, Z.
The Bowen ratio and the Monin-Obukhov similarity principles are based on the assumption that the eddy diff usivities for temperature and humidity are equal to each other under all atmospheric stratifi cations within turbulent surface boundary layer. However, several authors reported that this equality was violated under advective inversion or during the non-stationary conditions due to clouds passing by and sudden change of wind speed and direction. Th e inequality of the eddy diff usivity can lead to errors in the energy partitioning estimates by gradient techniques like the Bowen ratio energy balance (BREB) and the aerodynamical method, or methods based on residual energy balance such as the Penman-Monteith or Priestley-Taylor models. Th is study investigates two seasons of simultaneous measurement by eddy covariance (EC) and BREB above a high density poplar plantation at the Domanínek locality. Th e direct measurement of eddy diff usivities by EC is reinvestigating the validity of the long term measurement (since 2008) by BREB. Results showed unequal exchange coeffi cients with their mean 0.31 to 0.35 m2 s-1 for 2011 and 2012, respectively, favouring the transport of latent heat. Th is might be explained by the diff erent footprints of the BREB and EC methods, an undeveloped internal boundary layer or instrumental errors.
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