Papers by Markku Keinänen
Antioxidants
RADICAL-INDUCED CELL DEATH1 (RCD1) is an Arabidopsis thaliana nuclear protein that is disrupted d... more RADICAL-INDUCED CELL DEATH1 (RCD1) is an Arabidopsis thaliana nuclear protein that is disrupted during oxidative stress. RCD1 is considered an important integrative node in development and stress responses, and the rcd1 plants have several phenotypes and altered resistance to a variety of abiotic and biotic stresses. One of the phenotypes of rcd1 is resistance to the herbicide paraquat, but the mechanisms behind it are unknown. Paraquat causes a rapid burst of reactive oxygen species (ROS) initially in the chloroplast. We performed multi-platform metabolomic analyses in wild type Col-0 and paraquat resistant rcd1 plants to identify pathways conveying resistance and the function of RCD1 in this respect. Wild type and rcd1 plants were clearly distinguished by their abundance of antioxidants and specialized metabolites and their responses to paraquat. The lack of response in rcd1 suggested constitutively active defense against ROS via elevated flavonoid, glutathione, β-carotene, and to...
Strategy by latitude? Higher photosynthetic capacity and root mass fraction in northern than southern silver birch (Betula pendula Roth) in uniform growing conditions
Tree Physiology, Jun 7, 2021
Fotoniikasta valoa Suomen hyvinvointiin. Selvitys alan vaikuttavuudesta ja kasvunäkymistä
Genotype and tropospheric ozone generated differences in phenolic profiles of Euramerican popla
Journal of the American Society for Mass Spectrometry, 2021
In this study, we show that infrared laser ablation atmospheric pressure photoionization mass spe... more In this study, we show that infrared laser ablation atmospheric pressure photoionization mass spectrometry (LAAPPI-MS) imaging with 70 μm lateral resolution allows for the analysis of Arabidopsis thaliana (A. thaliana) leaf substructures ranging from single-cell trichomes and the interveinal leaf lamina to primary, secondary, and tertiary veins. The method also showed its potential for depth profiling analysis for the first time by mapping analytes at the different depths of the leaf and spatially resolving the topmost trichomes and cuticular wax layer from the underlying tissues. Negative ion LAAPPI-MS detected many different flavonol glycosides, fatty acids, fatty acid esters, galactolipids, and glycosphingolipids, whose distributions varied significantly between the different substructures of A. thaliana leaves. The results show that LAAPPI-MS provides a highly promising new tool to study the role of metabolites in plants.
Tree Physiology, 2019
Due to its ubiquity across northern latitudes, silver birch (Betula pendula Roth) is an attractiv... more Due to its ubiquity across northern latitudes, silver birch (Betula pendula Roth) is an attractive model species for studying geographical trait variation and acclimation capacity. Six birch provenances from 60 to 67°N across Finland were grown in a common garden and studied for provenance and genotype variation. We looked for differences in height growth, photosynthetic gas exchange and chlorophyll content index (CCI) and compared the gas exchange of early and late leaves on short and long shoots, respectively. The provenances stratified into southern and northern groups. Northern provenances attained less height growth increment and had higher stomatal conductance (gs) and lower intrinsic water-use efficiency (WUE, Anet/gs) than southern provenances, whereas net photosynthesis (Anet) or CCI did not show clear grouping. Short shoot leaves had lower gs and higher WUE than long shoot leaves in all provenances, but there was no difference in Anet between shoot types. The separation of...
Applied Clay Science, 2017
Preparation of gold nanoparticle-decorated halloysite nanotubes (Au-Hal) by a deposition method a... more Preparation of gold nanoparticle-decorated halloysite nanotubes (Au-Hal) by a deposition method and evaluation of their catalytic activity in an oxidation of benzyl alcohol are reported. An electrostatic attraction between positively charged polyethylenimine (PEI)-capped gold nanoparticles and the negatively charged external surfaces of halloysite nanotubes (Hal nanotubes) was the key factor in fabrication of Au-Hal nanotubes. Au-Hal catalysts showed good conversions and surprisingly high benzaldehyde selectivities (above 90%) in the benzyl alcohol oxidation. Influence of the amount of PEI used as a capping agent, the gold content and calcination of Au-Hal catalysts on the conversion and selectivity was investigated. A notable increase in the benzaldehyde selectivity at higher PEI contents and a significant drop in the benzaldehyde selectivity on calcination clearly indicate the central role of PEI in the selective formation of benzaldehyde. The high benzaldehyde selectivity of uncalcined catalysts are probably due to PEI donor molecules coordinating to certain surface sites on Au nanoparticles and thus blocking the catalytic sites required for further oxidation of benzaldehyde to benzoic acid. The high combined selectivity of benzoic acid and benzyl benzoate obtained with the calcined catalysts indicates that naked gold nanoparticles have the catalytic sites available for the benzoic acid formation.
Journal of Experimental Botany, 2016
Air humidity indicated as vapour pressure deficit (VPD) is directly related to transpiration and ... more Air humidity indicated as vapour pressure deficit (VPD) is directly related to transpiration and stomatal function of plants. We studied the effects of VPD and nitrogen (N) supply on leaf metabolites, plant growth, and mineral nutrition with young micropropagated silver birches (Betula pendula Roth.) in a growth chamber experiment. Plants that were grown under low VPD for 26 d had higher biomass, larger stem diameter, more leaves, fewer fallen leaves, and larger total leaf area than plants that were grown under high VPD. Initially, low VPD increased height growth rate and stomatal conductance; however, the effect was transient and the differences between low and high VPD plants became smaller with time. Metabolic adjustment to low VPD reflected N deficiency. The concentrations of N, iron, chlorophyll, amino acids, and soluble carbohydrates were lower and the levels of starch, quercetin glycosides, and raffinose were higher in the leaves that had developed under low VPD compared with high VPD. Additional N supply did not fully overcome the negative effect of low VPD on nutrient status but it diminished the effects of low VPD on leaf metabolism. Thus, with high N supply, the glutamine to glutamate ratio and starch production under low VPD became comparable with the levels under high VPD. The present study demonstrates that low VPD affects carbon and nutrient homeostasis and modifies N allocation of plants.
Author response: Arabidopsis RCD1 coordinates chloroplast and mitochondrial functions through interaction with ANAC transcription factors
Data in Brief, 2021
This paper presents data for the assessment of a portable UV-Vis spectrophotometer's performa... more This paper presents data for the assessment of a portable UV-Vis spectrophotometer's performance on predicting stream water DOC and Fe content. The dataset contains DOC and Fe concentrations by laboratory methods, in-situ and ex-situ spectral absorbances, monitoring environmental indexes such as water depth, temperature, turbidity and voltage. The records in Yli-Nuortti river (Cold station, Finland) took place during the hydrological year 2018-2019 and in Krycklan (C4 and C5, Sweden) during the hydrological years 2016-2019. The data analyses were conducted with ‘pls’ and ‘caret’ package in R. The correlation coefficient (R), root-mean-square deviation (RMSD), standard deviation (STD) and bias were used to check the performance of the models. This dataset can be combined with datasets from other regions around the world to build more universal models. For discussion and more information of the dataset creation, please refer to the full-length article “Assessment of a portable UV–...
Bioethanol production from short rotation S. schwerinii E. Wolf is carbon neutral with utilization of waste-based organic fertilizer and process carbon dioxide capture
Journal of Cleaner Production
Abstract The sustainability of transportation biofuel production value chains is under discussion... more Abstract The sustainability of transportation biofuel production value chains is under discussion as a consequence of the implementation of the European Union Bioeconomy Strategy and renewable energy production. Greenhouse gas emissions from the biomass produced for biofuel, and the energy required during the production process are, in many cases, greater than the emission reductions from the biofuels that are produced and used to replace fossil fuels. In this study, the sustainability of bioethanol production from short rotation coppice Salix schwerinii was considered from cultivation and harvesting to biofuel production and distribution. The sustainability of the full value chain was evaluated according to the European Union Renewable Energy Directive and calculations of greenhouse gas emission savings (%) from biofuel production were compared to a reference fossil fuel (gasoline). For comparison, four bioethanol production scenarios were developed, and specific attention was focused on the utilization of waste-based organic fertilizers (for biomass production) and on carbon dioxide capture at the fermentation stage, and their effects on value chain greenhouse gas emissions. Based on our evaluation, Salix bioethanol production achieved 60% emission savings compared to the fossil reference (requirement for installations that will commence operations until end of December 2020). When waste based organic fertilizers were used in the Salix biomass production, 65% emission savings were achieved (requirement for the installations that will commence operations from 2021). Moreover, the value chain sustainability and greenhouse gas emissions balance were improved by the carbon dioxide captured during the bioethanol fermentation stage.
Frontiers in Plant Science
redox transfer between cellular compartments in rcd1 could be sufficient to avoid the negative ef... more redox transfer between cellular compartments in rcd1 could be sufficient to avoid the negative effects of MV-induced toxicity.
High-performance liquid chromatographic determination of flavonoids in Betula pendula and Betula pubescens leaves
Journal of Chromatography A, 1998
A high-performance liquid chromatography (HPLC) procedure based on a water–methanol gradient with... more A high-performance liquid chromatography (HPLC) procedure based on a water–methanol gradient with tetrahydrofuran for simultaneous analysis of flavonoids and other phenolics of differing polarities in birch leaves was developed. Mobile phases with and without tetrahydrofuran or orthophosphoric acid provided additional information for tentative identification of the compounds. Forty-five compounds were determined from Betula pendula and B. pubescens leaves. Five of the isolated flavonol glycosides have not been reported earlier from B. pendula. B. pendula leaves have a range of myricetin and quercetin glycosides with the same sugar moieties in roughly the same proportions. Flavonoid aglycones were deposited on leaf surfaces.
Gene expression responses of paper birch to elevated O3 and CO2 during leaf maturation and senescence
Forest trees are exposed to increasing concentrations of O3 and CO2 simultaneously. The rise of c... more Forest trees are exposed to increasing concentrations of O3 and CO2 simultaneously. The rise of concentration in these gases causes changes in the gene expression of trees, which can be small in acclimated trees, but yet pivotal for the metabolism of the trees. We have studied the response of paper birch (Betula papyrifera) leaf gene expression to elevated O3 and
Canadian Journal of Forest Research
Agricultural and Food Science
Plant phenomics refers to the systematic study of plant phenotypes. Together with closely monitor... more Plant phenomics refers to the systematic study of plant phenotypes. Together with closely monitored, controlled climates, it provides an essential component for the integrated analysis of genotype-phenotype-environment interactions. Currently, several plant growth and phenotyping facilities are under establishment globally, and numerous facilities are already in use. Alongside the development of the research infrastructures, several national and international networks have been established to support shared use of the new methodology. In this review, an overview is given of the Nordic plant phenotyping and climate control facilities. Since many areas of phenomics such as sensor-based phenotyping, image analysis and data standards are still developing, promotion of educational and networking activities is especially important. These facilities and networks will be instrumental in tackling plant breeding and plant protection challenges. They will also provide possibilities to study wi...
Retene, pyrene and phenanthrene cause distinct molecular-level changes in the cardiac tissue of rainbow trout (Oncorhynchus mykiss) larvae, part 2 – Proteomics and metabolomics
Science of The Total Environment
Remote Sensing
The goal of this study was to investigate the variation in the leaf spectral reflectance and its ... more The goal of this study was to investigate the variation in the leaf spectral reflectance and its association with other leaf traits from 12 genotypes among three provenances of origin (populations) in a common garden for Finnish silver birch trees in 2015 and 2016. The spectral reflectance was measured in the laboratory from the detached leaves in the wavelength range of visible and near-infrared (VNIR, 400–1000 nm) and shortwave infrared (SWIR, 1000–2500 nm). The variation among the provenance was initially visualized with principal component analysis (PCA) and a clear separation among the provenances was detected with the discriminant analysis of principal components (DAPC) and partial least squares discriminant analysis (PLS-DA) depicting a less strong variation among the genotypes within the provenances. Wavelengths contributing to the separation of the genotypes and provenances were identified from the contribution plot of DAPC and the red edge was strongly related to the diffe...
Application of hyperspectral imaging of peat profiles to the case of fen-bog transition in aapa mires
<p>Hyperspectral imaging (HSI) is a promising precision tool for analysing chronolo... more <p>Hyperspectral imaging (HSI) is a promising precision tool for analysing chronological peat strata from vegetation transitions in peatlands. We explored the potential of HSI in identifying transitions in peat-forming vegetation and degree of peat humification. The changes in aapa mire complexes during recent decades have been assessed by various remote sensing methods (aerial image time series, satellite data and high-resolution UAV multispectral imaging) and HSI methods have been developed to support the data from other sources. Rapid growth of Sphagnum mosses over string-patterned aapa mires in the north-boreal zone has immense significance, since it can alter ecosystem structure and functions such as carbon sequestration. HSI is well suited for analysis of recent ecosystem changes, since it can be applied for large sample sets with extremely fine spatial detail. Additionally, peat layers have complex 3D structures that can be overlooked by other sampling methods.</p> <p>The HSI data was collected in laboratory conditions with two spectral imaging cameras, covering the visible to near-infrared range (VNIR 400-1000 nm), short-wave infrared range (SWIR, 1000-2500 nm). We used various methods such as PCA, k-means clustering and support vector machines for both quantitative and qualitative analysis of peat.  Our analyses revealed detailed spectral changes that matched with transitions in peat quality and composition. Methodological issues unique to peat samples, such as the effect of oxidation and water content, were assessed for method development. We also used HSI to estimate quality changes that would easily be overlooked or only found by most laborious conventional techniques, like high-frequency microscopic counting of plant remains. Here, the spectral results can be used to guide sampling for microscopic routines, for example.</p> <p>Results with Carex and Sphagnum peat proved that efficient image-based classification methods for identifying peat transitions can be developed. Our SVM models in the VNIR and SWIR regions were able to distinguish Sphagnum and Carex peat with overall accuracy of validation 80 % and 81 %, respectively. We also developed simple NDI indices for the estimation of von Post humification index that worked with accuracy of 86 % and 59 % for VNIR and SWIR, respectively. In combination with data collected from other sources (remote sensing, ground-truthing, conventional laboratory analysis), peat spectral analyses give strong inference of changes. In our study system, results indicate high sensitivity of northern aapa mires to ecosystem-scale changes.</p>
Remote Sensing
The availability of light within the tree canopy affects various leaf traits and leaf reflectance... more The availability of light within the tree canopy affects various leaf traits and leaf reflectance. We determined the leaf reflectance variation from 400 nm to 2500 nm among three canopy layers and cardinal directions of three genetically identical cloned silver birches growing at the same common garden site. The variation in the canopy layer was evident in the principal component analysis (PCA), and the influential wavelengths responsible for variation were identified using the variable importance in projection (VIP) based on partial least squares discriminant analysis (PLS-DA). Leaf traits, such as chlorophyll, nitrogen, dry weight, and specific leaf area (SLA), also showed significant variation among the canopy layers. We found a shift in the red edge inflection point (REIP) for the canopy layers. The canopy layers contribute to the variability in the reflectance indices. We conclude that the largest variation was among the canopy layers, whereas the differences among individual t...
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Papers by Markku Keinänen