Papers by Catharina Meinen
Biomass and morphology of Wne roots in temperate broad-leaved forests diVering in tree species diversity: is there evidence of below-ground overyielding?
Oecologia, 2009
Root discrimination of closely related crop and weed species using FT MIR-ATR spectroscopy
Frontiers in Plant Science, 2015
Root discrimination of species is a pre-condition for studying belowground competition processes ... more Root discrimination of species is a pre-condition for studying belowground competition processes between crop and weed species. In this experiment, we tested Fourier transform mid-infrared (FT MIR)-attenuated total reflection (ATR) spectroscopy to discriminate roots of closely related crop and weed species grown in the greenhouse: maize/barnyard grass, barley/wild oat, wheat/blackgrass (Poaceae), and sugar beet/common lambsquarters (Chenopodiaceae). Fresh (moist) and dried root segments as well as ground roots were analyzed by FT MIR-ATR spectroscopy. Root absorption spectra showed species specific peak distribution and peak height. A clear separation according to species was not possible with fresh root segments. Dried root segments (including root basis, middle section, and root tip) of maize/barnyard grass and sugar beet/common lambsquarters formed completely separated species clusters. Wheat and blackgrass separated in species specific clusters when root tips were removed from cluster analysis. A clear separation of dried root segments according to species was not possible in the case of barley and wild oat. Cluster analyses of ground roots revealed a 100% separation of all tested crop and weed species combinations. Spectra grouped in Poaceae and Chenopodiaceae clusters. Within the Poaceae cluster, C3 and C4 species differed significantly in heterogeneity. Thus, root spectra reflected the degree of kinship. To quantify species proportion in root mixtures, a two- and a three-species model for species quantification in root mixtures of maize, barnyard grass, and wild oat was calculated. The models showed low standard errors of prediction (RMSEP) and high residual predictive deviation values in an external test set validation. Hence, FT MIR-ATR spectroscopy seems to be a promising tool for root research even between closely related plant species.
www.frontiersin.org Citation: Rewald B and Meinen C(2013) Plant roots and spectroscopic methods-a... more www.frontiersin.org Citation: Rewald B and Meinen C(2013) Plant roots and spectroscopic methods-analysing species, biomass and vitality. 4:393. Abstract 31 In order to understand plant functioning, plant community composition and terrestrial 32 biogeochemistry it is decisive to study standing root biomass, (fine) root dynamics and 33 interactions below ground. While most plant taxa can be identified by visual criteria above 34 ground, roots show less distinctive features. Furthermore, root systems of neighbouring plants 35 are rarely spatially segregated; thus, most soil horizons and samples hold roots of more than 36 one species necessitating root sorting according to taxa. 37 In the last decades, various approaches, ranging from anatomical and morphological analyses 38 to differences in chemical composition and DNA sequencing were applied to discern species' 39 identity and biomass below ground. Among those methods, a variety of spectroscopic 40 methods was used to detect differences in the chemical composition of roots. 41 In this review, spectroscopic methods used to study root systems of herbaceous and woody 42 species in excised samples or in situ will be discussed. In detail, techniques will be reviewed 43 according to their usability to discern root taxa, to determine root vitality, and to quantify root 44 biomass non-destructively or in soil cores holding mixtures of plant roots. In addition, 45 spectroscopic methods which may be able to play an increasing role in future studies on root 46 biomass and related traits are highlighted. 47 48 Keywords 49 Electrochemical Impedance Spectroscopy; Fine root; IR spectrometry; Root biomass; Root 50 taxa; Root vitality 51 52
Trees, 2009
Differences in spatial rooting patterns among coexisting species have been recognized as an impor... more Differences in spatial rooting patterns among coexisting species have been recognized as an important mechanism for generating biodiversity effects on ecosystem functioning. However, it is not yet clear whether complementarity in root space exploration is a universal characteristic of multi-species woody communities. In a temperate broad-leaved forest with a mosaic of speciespoor and species-rich stands, we tested two hypotheses related to putative below-ground 'overyielding' in more diverse forests, (1) that species mixture results in a partial spatial segregation of the fine root systems of different species, and (2) that stand fine root biomass increases with tree species diversity. We investigated 12 stands either with one, three, or five dominant tree species (4 replicate stands each) under similar soil and climate conditions for stand fine root biomass and spatial root segregation in vertical and horizontal direction in the soil. Fine roots of different tree species were identified using a morphological key based on differences in colour, periderm surface structure, and branching patterns. In species-poor and species-rich stands, and in all tree species present, fine root density (biomass per soil volume) decreased exponentially with soil depth at very similar rates. Stand fine root biomass in the densely rooted upper soil (0-40 cm depth) was not significantly different between stands with 1, 3 or 5 dominant tree species. We conclude that 'below-ground overyielding' in terms of higher fine root biomasses in species-rich stands as compared to monospecific ones does not occur in these broad-leaved forests which most likely results from a missing complementarity in vertical rooting patterns of the present tree species.
Plant and Soil, 2012
Background Studying root biomass, root system distribution and belowground interactions is essent... more Background Studying root biomass, root system distribution and belowground interactions is essential for understanding the composition of plant communities, the impact of global change, and terrestrial biogeochemistry. Most soil samples and minirhizotron pictures hold roots of more than one species or plant individual. The identification of taxa by their roots would allow species-specific questions to be posed; information about root affiliation to plant individuals could be used to determine intra-specific competition. Scope Researchers need to be able to discern plant taxa by roots as well as to quantify abundances in mixed root samples. However, roots show less distinctive features that permit identification than aboveground organs. This review discusses the primary use of available methods, outlining applications, shortcomings and future developments. Conclusion Methods are either non-destructive, e.g. visual examination of root morphological criteria in situ, or require excavated and excised root samples. Among the destructive methods are anatomical keys, chemotaxonomic approaches and molecular markers. While some methods allow for discerning the root systems of individual plants, others can distinguish roots on the functional group or plant taxa level; methods such as IR spectroscopy and qPCR allow for quantifying the root biomass proportion of species without manual sorting.
Oecologia, 2009
Biodiversity eVects on ecosystem functioning in forests have only recently attracted increasing a... more Biodiversity eVects on ecosystem functioning in forests have only recently attracted increasing attention. The vast majority of studies in forests have focused on above-ground responses to diVerences in tree species diversity, while systematic analyses of the eVects of biodiversity on root systems are virtually non-existent. By investigating the Wne root systems in 12 temperate deciduous forest stands in Central Europe, we tested the hypotheses that (1) stand Wne root biomass increases with tree diversity, and (2) 'below-ground overyielding' of species-rich stands in terms of Wne root biomass is the consequence of spatial niche segregation of the roots of diVerent species. The selected stands represent a gradient in tree species diversity on similar bedrock from almost pure beech forests to mediumdiverse forests built by beech, ash, and lime, and highlydiverse stands dominated by beech, ash, lime, maple, and hornbeam. We investigated Wne root biomass and necromass at 24 proWles per stand and analyzed species diVerences in Wne root morphology by microscopic analysis. Fine root biomass ranged from 440 to 480 g m ¡2 in the species-poor to species-rich stands, with 63-77% being concentrated in the upper 20 cm of the soil. In contradiction to our two hypotheses, the diVerences in tree species diversity aVected neither stand Wne root biomass nor vertical root distribution patterns. Fine root morphology showed marked distinctions between species, but these root morphological diVerences did not lead to signiWcant diVerences in Wne root surface area or root tip number on a stand area basis. Moreover, diVerences in species composition of the stands did not alter Wne root morphology of the species. We conclude that 'below-ground overyielding' in terms of Wne root biomass does not occur in the species-rich stands, which is most likely caused by the absence of signiWcant spatial segregation of the root systems of these late-successional species.
Ecosystems, 2009
In contrast to studies on aboveground processes, the effect of species diversity on belowground p... more In contrast to studies on aboveground processes, the effect of species diversity on belowground productivity and fine-root regrowth after disturbance is still poorly studied in forests. In 12 oldgrowth broad-leaved forest stands, we tested the hypotheses that (i) the productivity and recovery rate (regrowth per standing biomass) of the fineroot system (root diameter < 2 mm) increase with increasing tree species diversity, and that (ii) the seasonality of fine-root biomass and necromass is more pronounced in pure than in tree species-rich stands as a consequence of non-synchronous root biomass peaks of the different species. We investigated stands with 1, 3, and 5 dominant tree species growing under similar soil and climate conditions for changes in fine-root biomass and necromass during a 12-month period and estimated fine-root productivity with two independent approaches (ingrowth cores, sequential coring). According to the analysis of 360 ingrowth cores, fine-root growth into the root-free soil increased with tree species diversity from 72 g m -2 y -1 in the monospecific plots to 166 g m -2 y -1 in the 5-species plots, indicating an enhanced recovery rate of the root system after soil disturbance with increasing species diversity (0.26, 0.34, and 0.51 y -1 in 1-, 3-, and 5-species plots, respectively). Fine-root productivity as approximated by the sequential coring data also indicated a roughly threefold increase from the monospecific to the 5-species stand. We found no indication of a more pronounced seasonality of fine-root mass in species-poor as compared to species-rich stands. We conclude that species identification on the fine root level, as conducted here, may open new perspectives on tree species effects on root system dynamics. Our study produced first evidence in support of the hypothesis that the fine-root systems of more diverse forest stands are more productive and recover more rapidly after soil disturbance than that of species-poor forests.
Effects of tree diversity and environmental factors on the soil microbial community in three soil depth in a Central European beech forest
We investigated the link between aboveground and belowground diversity in forest ecosystems. Ther... more We investigated the link between aboveground and belowground diversity in forest ecosystems. Therefore, we determined the effect of tree composition on amount and composition of the soil microbial community using phospholipid fatty acid profiles in the Hainich National Park in Thuringia, a deciduous mixed forest on loess over limestone in Central Germany. On the one hand we investigated the composition of the microbial community in dependence of leave litter composition, hypothesizing that distinct leave litter compositions activated signature PLFA's. On the other hand we determined if environmental factor like clay content or nutrient status influence the microbial community in deeper soil horizons. Consequently soil was sampled from depth intervals of 0-5 cm, 5-10 cm and 10-20 cm. Plots with highest diversity of leave litter had highest total amounts of fatty acids in the upper 5 cm. Mainly PLFA 16:1?5 was activated in autumn, being a common marker for mycorrhizal fungi. In so...
Publications by Catharina Meinen
Plant and Soil, 2012
Background
Studying root biomass, root system distribution and belowground interactions is essen... more Background
Studying root biomass, root system distribution and belowground interactions is essential for understanding the composition of plant communities, the impact of global change, and terrestrial biogeochemistry. Most soil samples and minirhizotron pictures hold roots of more than one species or plant individual. The identification of taxa by their roots would allow species-specific questions to be posed; information about root affiliation to plant individuals could be used to determine intra-specific competition.
Scope
Researchers need to be able to discern plant taxa by roots as well as to quantify abundances in mixed root samples. However, roots show less distinctive features that permit identification than aboveground organs. This review discusses the primary use of available methods, outlining applications, shortcomings and future developments.
Conclusion
Methods are either non-destructive, e.g. visual examination of root morphological criteria in situ, or require excavated and excised root samples. Among the destructive methods are anatomical keys, chemotaxonomic approaches and molecular markers. While some methods allow for discerning the root systems of individual plants, others can distinguish roots on the functional group or plant taxa level; methods such as IR spectroscopy and qPCR allow for quantifying the root biomass proportion of species without manual sorting.
Uploads
Papers by Catharina Meinen
Publications by Catharina Meinen
Studying root biomass, root system distribution and belowground interactions is essential for understanding the composition of plant communities, the impact of global change, and terrestrial biogeochemistry. Most soil samples and minirhizotron pictures hold roots of more than one species or plant individual. The identification of taxa by their roots would allow species-specific questions to be posed; information about root affiliation to plant individuals could be used to determine intra-specific competition.
Scope
Researchers need to be able to discern plant taxa by roots as well as to quantify abundances in mixed root samples. However, roots show less distinctive features that permit identification than aboveground organs. This review discusses the primary use of available methods, outlining applications, shortcomings and future developments.
Conclusion
Methods are either non-destructive, e.g. visual examination of root morphological criteria in situ, or require excavated and excised root samples. Among the destructive methods are anatomical keys, chemotaxonomic approaches and molecular markers. While some methods allow for discerning the root systems of individual plants, others can distinguish roots on the functional group or plant taxa level; methods such as IR spectroscopy and qPCR allow for quantifying the root biomass proportion of species without manual sorting.