2/ Fine-scale root community structure in the field: species aggregations change with root density

Plants are easier to study than animals as they do not move, but a (larger) half of their bodies is inaccessible being hidden in the soil and bearing no clear clues for identification. Specifically, assignment of roots into species in the field, a necessary condition for understanding how species interact, has long been an enigma. Still, these roots search for nutrients in the soil and respond to their concentrations, something that has been known only in culture conditions, but the true role of it in the field has been essentially unknown.  We bypassed this obstacle by using quantitative Real-time PCR and identified them into species and determined their amounts. This permitted us to show a snapshot of root interactions in the field. Using it we showed that root interactions and physical aggregations change strongly with nutrient availability and overall root density: roots of all species are finely intertwined in the shallow soil which is nutrient-rich, but behave much more individualistically in deeper layers poor in nutrients.

• Herben T., Balšánková T., Hadincová V., Krahulec F., Pecháčková S., Skálová H., Krak K. (2020). Fine‐scale root community structure in the field: species aggregations change with root density.  Journal of Ecology 108: 1738-1749. doi: 10.1111/1365-2745.13372

3/ Nutrient-demanding species face less negative competition and plant-soil feedback effects in a nutrient-rich environment

Competition and plant-soil feedback (PSF) have negative effects on plant performance. These mechanisms control plant abundance and thus maintain the diversity of plant communities. Resource availability can modulate the strength of these mechanisms, but to a variable extent in different species. We showed that nutrient addition attenuated negative effects of competition and of PSF, but to a larger degree in species from nutrient-rich than nutrient-poor habitats, enhancing dominance of the former species.

• Klinerová T.& Dostál P. (2020). Nutrient‐demanding species face less negative competition and plant-soil feedback effects in a nutrient‐rich environment. New Phytologist 225:1343–1354. doi:10.1111/nph.16227

Results of this study were obtained using an extensive garden experiment including more than 40 grassland species.

4/ Evaluating the role of biotic and chemical components of plant-soil feedback of primary successional plants

The results of our pot experiment showed that early-successional species accumulate more pathogenic fungi in their soils than mid-successionals. The most frequent predictors of plant performance in these soils were the plant-induced changes in soil chemical properties, while soil fungal communities influenced plant germination.

• Kuťáková E., Meszárošová L., Baldrian P. & Münzbergová Z. (2020). Evaluating the role of biotic and chemical components of plant-soil feedback of primary successional plants. Biology and Fertility of Soils 56 (3): 345-358. doi: 10.1007/s00374-019-01425-z

Seedling of Sanguisorba minor in the primary successional soil

5/ In vivo pressure gradient heterogeneity increases flow contribution of small diameter vessels in grapevine.

This study is the first to combine a 3D microCT reconstruction of a plant stem with MRI of water flow rates therein. It found that pressure gradients in the living plant redirect about a quarter of the theoretically expected flow from the widest vessels to their narrow neighbours. The result casts doubt on previous understanding of long-distance water transport in plants, with implications for the construction and evolution of stems, and applications towards breeding drought-resistant plants.

• Bouda M., Windt C. W., McElrone A. J. & Brodersen C. R. (2019). In vivo pressure gradient heterogeneity increases flow contribution of small diameter vessels in grapevine. Nature Communications: 10 (1) 1-10. doi:10.1038/s41467-019-13673-6.

False colour image of flow rates (slow–blue to fast–red) projected onto 3D reconstruction of X-ray microcomputed tomography of grapevine (Vitis vitifera L.,var. Cabernet Sauvignon) xylem at 3.2μm resolution.

6/ DNA methylation as a possible mechanism affecting ability of natural populations to adapt to changing climate

We explored the importance of epigenetic variation studied as DNA methylation for species climatic adaptations. The results suggest that DNA methylation may modify the response of a clonal grass to moisture. DNA methylation may thus affect the ability of clonal plants to adapt to novel climatic conditions. Despite the significant interactions between population of origin and demethylation, our data do not provide clear evidence that DNA methylation enabled adaptation to different environments. In fact, we obtained stronger evidence of local adaptation in demethylated than in naturally-methylated plants. As changes in DNA methylation may be quite dynamic, it is thus possible that epigenetic variation can mask plant adaptations to conditions of their origin due to pre-cultivation of the plants under standardized conditions. This possibility should be considered in future experiments exploring plant adaptations.

• Münzbergová Z, Latzel V., Šurinová M., Hadincová V. (2019). DNA methylation as a possible mechanism affecting ability of natural populations to adapt to changing climate. Oikos, 128: 124-134. doi: 10.1111/oik.05591

7/ Linking species abundance and overyielding from experimental communities with niche and fitness characteristics

So far, the principal force shaping local plant abundance patterns remains unclear. Rarity can result not only from the poor competitive ability or from small vegetative or generative reproduction but also from strong self-limitation. The same mechanisms can drive species-specific overyielding, that is, increased species productivity at high community diversity. To test which of the mechanisms shapes local abundance and overyielding, we measured vegetative growth, competitive ability (competitive effect), and negative frequency dependence for 49 perennial grassland species from Central Europe. We then linked these characteristics with species abundance and with species-specific overyielding in the Jena Experiment. We found that species with smaller rates of vegetative growth (i.e. in species with smaller fitness) were also less abundant in the Jena Experiment. Larger species-specific overyielding was then associated with a stronger negative frequency dependence.

• Dostál P., Tasevová K. & Klinerová T. (2019). Linking species abundance and overyielding from experimental communities with niche and fitness characteristics. Journal of Ecology 107: 178-189. doi.org/10.1111/1365-2745.13005