EcolChange seminar – Enn Lust about hydrogen infra and fuel cells

Seminars of Department of Botany and Centre of Excellence EcolChange

Speaker: Enn Lust is professor and head of chair of physical chemistry at the Institute of Chemistry, University of Tartu, member of Estonian Academy of Sciences and head of Centre of Excellence „Advanced materials and high-technology devices for energy recuperation systems“.

Title of the talk: Development of hydrogen infrastructure and fuel cells/electrolysers for sustainable energetics

Time: Thursday, 10. October 2019 at 14.15

Place: Tartu, Lai 40-218 (Vaga auditorium)

Summary: The talk will analyse recent progress in development of hydrogen infrastructure in the world-leading regions such as USA, Japan, European Union, Korea Republic, Canada. Examples of high-energy efficiency electrochemical power sources (supercapacitors, fuel cells, Na-ion batteries and solid oxide devices) for sustainable energy generation/storage complexes powered by wind and solar cells will be discussed.

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Enn Lust (left) with the former president of Estonia, Toomas H. Ilves (pic from Facebook)

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New publication – Are stomata in ferns and allies sluggish? Stomatal responses to CO2, humidity and light and their scaling with size and density

Text by Liisa Kübarsepp

Recently our lab published a new paper in New Phytologist on the stomatal reactions of ferns and allies. In this paper, we question the overall sluggishness that is assumed of evolutionarily older plants, and study thoroughly the reactions of many fern species both from physiological, morphological and evolutionary perspective.

Stomata – microscopic pores on the leaf surface – are highly significant in the functioning of a plant. Stomatal pores enable gas exchange between the leaf inner structures and the atmosphere, which is otherwise minimal. The epidermal cells covered by a cuticular layer protect the plant from desiccation, pathogens, pollutants etc. however, some gas exchange between the plant and outside environment is crucial. The gradient between water concentrations in the intercellular airspaces inside the leaf and the atmosphere is one of the important factors creating the water flow from the roots to the leaves. Closed stomatal pores also prohibit CO2 from reaching the mesophyll cells – thus inhibiting photosynthesis. The opening and closing of stomatal pores are controlled by stomatal guard cells, which respond to different environmental cues such as light, CO2 concentration, and humidity (both in soil and air). 

Stomatal reactions have been studied thoroughly, however, most studies focus on the model species Arabidopsis thaliana or other angiosperms. More recently other plant species have caught more attention, and it has been demonstrated these reactions can significantly differ even within one genus. Digging even deeper and comparing angiosperms to phylogenetically more distant species, like gymnosperms, ferns or lycophytes, the differences are even more drastic. Some studies have even found no or very slow stomatal responses to factors like CO2 concentration and light in these older plant groups. Therefore, it has long been thought that the stomata of evolutionarily older species, like ferns, are sort of sluggish when it comes to any other environmental factor apart from water deficiency. However, when giving a closer look some studies have shown that it might not be quite that simple. Stomatal reactions of evolutionarily older species are controlled by other mechanisms, not just lack of water, which causes water potential decrease in the plant and thus induces the stomatal closure. 

In our study, we focused on ferns and allies (altogether 29 species), and their stomatal reactions to environmental factors. We compared their reactions also to two angiosperm species, one woody and one herbaceous (Alnus subcordata and Phaseolus vulgaris). In our experiment, we used the same set of species to measure reactions to different environmental stimuli: changes in CO2 concentration, air humidity and light. Most studies only focus on one environmental factor at a time, making it difficult to make generalizations about the stomatal reactions. Indeed, we discovered that the stomatal reactions of ferns and allies are dependent on the environmental conditions, the reactions were fastest in response to low air humidity, and slower in response to CO2 concentration and light. What was also very interesting – in many cases, the stomata of ferns are not sluggish at all, in fact, they are often quite similar to angiosperms. 

One important part of this study is also looking for the explanations behind the stomatal reactions. Why are some stomata reacting faster than others? Mainly we looked at morphology – the size and density of stomata. It appears that in some cases, the reactions of smaller stomata are indeed faster like many studies have previously found. These include reactions to low CO2 concentration, high light intensity and low air humidity. However, this is not universal to all reactions leading to the conclusion that different mechanisms should control the stomatal reactions in ferns – not only passive regulation by water content in the plant as many other studies have stated.

To search for the reasons behind the differences in stomatal reactions we went even further and used the phylogenetic signal analysis to see if perhaps there is a relationship between the phylogenetic distance of species and the differences in stomatal reactions. However, we did not manage to find such relations in our species set for any of the environmental condition changes. This would not necessarily mean that such a correlation could not exist, however, a much broader set of species would be needed to perform such analysis in the future.

 

To read further see the paper: Kübarsepp, L., Laanisto, L., Niinemets, Ü., Talts, E., & Tosens, T. (2019). Are stomata in ferns and allies sluggish? Stomatal responses to CO2, humidity and light and their scaling with size and density. The New phytologist, https://doi.org/10.1111/nph.16159 (link to full text)

 

Stomata of Microsorum diversifolium (pics by Liisa Kübarsepp)

 

Abstract

Fast stomatal reactions enable plants to successfully cope with constantly changing environment yet there is an ongoing debate on the stomatal regulation mechanisms in basal plant groups.

We measured stomatal morphological parameters in 29 fern and allies species from temperate to tropical biomes and two outgroup angiosperm species. Out of these, stomatal dynamic responses to environmental drivers were measured in 16 ferns and the two angiosperms using gas‐exchange system. PCA analyses were used to further reveal the structure ‐function relationships in stomata.

We show more than 10‐fold variation for stomatal opening delays and 20‐fold variation for stomatal closing delays in ferns. Across species, stomatal responses to VPD were the fastest, while light and [CO2] responses were slower. In most cases the outgroup species’ reaction speeds to changes in environmental variables were similar to those of ferns.

Correlations between stomatal response rate and size were apparent for stomatal opening in light and low [CO2] while not evident for closing reactions and changes in VPD. No correlations between stomatal density and response speed were observed. Altogether, this study demonstrates different mechanisms controlling stomatal reactions in ferns at different environmental stimuli, which should be considered in future studies relating stomatal morphology and function.

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EcolChange seminar – Adam Frew about how arbuscular mycorrhizal fungi impact belowground herbivores

Seminars of Department of Botany and Centre of Excellence EcolChange

Autumn is here. Which means seminars are back as well. The apples in Tartu have became extra sweet from night frost. And together with majority of life, mycorrhiza is winterizing. We´ll talk about them while they sleep…

Speaker: Adam Frew is Post-doctoral researcher at Charles Sturt University, Wagga Wagga, Australia. He studies interactions between plants, herbivores and soil microbiota. He is visiting Department of Botany, Tartu University in order to collaborate with the Plant Ecology Laboratory.

Title of the talk: How do arbuscular mycorrhizal fungi impact belowground herbivores?

Time: Thursday, 03. October 2019 at 14.15

Place: Tartu, Lai 40-218 (Vaga auditorium)

Summary: Almost all terrestrial plants are attacked by one, if not many, species of invertebrate herbivore. Most of these plants associate with arbuscular mycorrhizal (AM) fungi. Despite our increasing understanding of these tripartite interactions involving aboveground herbivores, we know less about the impacts of AM fungi on root-feeders. Here I will present results from a combination of experiments investigating these belowground interactions.

Panel 1: Pirates of Hawaii – C. elegans lab variant, N2, was originally isolated in Bristol from a pineapple. This is a cartoon on how the polymorphic variant of N2, the Hawaiian strain, tries to conquer N2’s use as the common lab strain.
Panel 2: Game of worms: Tyrion Lannister is depicted by the fat and stout mutant in C. elegans called Dumpy. E. coli strain, OP50, is compared to Tryrion’s wine because C. elegans feeds on OP50 as much as Tyrion Lannister on his wine.
Panel 3: Mite wars: One major, eternal threat to C. elegans is posed by Mites! Here, mites are compared to dark forces/Sith army while worms are compared to the Jedi army. Fungi are also a source of contamination to C. elegans. Hence, fungi are shown as allies of the dark forces.
Panel 4: The usual suspects: The most common mutants used in C. elegans community – the wildtype (N2), the dumpy (dpy), the long (lon) and the uncoordinated (unc). (picture together with the legend from here)

After the seminar everyone is welcome to coffee/tea and snacks in the seminar room (coffee room, ground floor).
AT 2 PM THE MINIBUS (yellow MB) DEPARTS FROM CHEMICUM TO LAI 40 AND AFTER THE SEMINAR YOU CAN GET BACK TO THE CHEMICUM WITH THE SAME BUS.
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New publication – Arbuscular mycorrhizal fungal community composition determines the competitive response of two grassland forbs

Anyone can name at least a couple of factors affecting plant growth, be it climate (drought, flooding, hail) or the presence of organisms feeding on plants (birds, insects, mammals, or plant diseases). Some might even think of the nutrients found in soil without which plants cannot grow. But few are probably aware that in addition to nutrients, there are microscopic fungi living in soil that are essential for plants. Furthermore, these fungi may be highly significant in determining the structure of plant communities.

Scientists from the Department of Botany at the University of Tartu Institute of Ecology and Earth Sciences recently published a study in the international journal PLOS ONE that found the microscopic Glomeromycota to have an important role in the development of plant community diversity.

For years, plant ecologists have been interested in the mechanisms influencing plant coexistence and diversity, and the importance of microorganisms is becoming ever clearer. The roots of many plants form arbuscular mycorrhizas (AM) with the microscopic Glomeromycota living in soil.

Glomeromycota are considered to be the oldest organisms living in symbiosis with terrestrial plants. They are widespread in ecosystems and an estimated 74% of plant species are arbuscular mycorrhizal.

The fungus obtains organic carbon from the plant via AM, and in turn, the fungus helps the plant obtain minerals and water from the soil. By dividing nutrients between plant species, Glomeromycota can determine plant-plant interactions by benefiting some plants and inhibiting the life of others.

Even though the influence of Glomeromycota in the competition between plants has already been studied for decades, most of the experiments have been conducted in laboratories using easily culturable fungi, which unfortunately represent only a small portion of the natural diversity of Glomeromycota. However, it is important to know that the communities of Glomeromycota vary in time and space, and therefore, the communities from different ecosystems may have different effects on plant growth.

As it is difficult to conduct experimental studies in nature, scientists from the UT Department of Botany studied the influence of natural Glomeromycota communities on plant-plant competition in a greenhouse growing two plant species – narrowleaf plantain (Plantago lanceolata) and rough hawkbit (Leontodon hispidus) – alone and with a competitor, the red fescue (Festuca rubra).

To avoid the influence of other microscopic soil organisms on plant growth, the plants were grown in sterilised soil to which scientists added Glomeromycota communities gathered from a calcareous grassland and a 60-year-old pine forest. In addition, plants were also grown in a soil without any symbiotic Glomeromycota, therefore, these plants were unable to form a mycorrhiza with the Glomeromycota.

Microscopic study of plant roots confirmed the formation of mycorrhiza but also showed that, in competitive conditions, Glomeromycota have a positive effect on plant growth – plants that formed the mycorrhiza had better competitive responses than non-mycorrhizal plants.

Furthermore, grassland and pine forest Glomeromycota communities had a different effect on plant growth. A species-rich grassland fungal community enhanced the competitive response of plants more (plants grew larger) than the species-poorer pine forest fungal community. The positive influence of the grassland Glomeromycota community was clearest with the narrowleaf plantain, which prefers to grow on grasslands. However, the competitive response of the rough hawkbit growing in grasslands as well as forests was not significantly influenced by the origin of the fungi.

Therefore, the great diversity of Western Estonian calcareous grasslands may be attributed to the microscopic fungi in the soil, as these fungi unify the competitiveness of many plant species in conditions where plants are competing for the same nutrients so individual species cannot dominate.

The results show that the origin of Glomeromycota communities is an important influencer of plant growth and competitive interactions. Knowing the role of Glomeromycota in plant-plant interactions might enable more accurate predictions about the development of plant communities, their diversity, sensitivity, resistance to disturbances, and to apply this knowledge in nature conservation, for example.

 

Citation: Neuenkamp, L., Zobel, M., Lind, E., Gerz, M., & Moora, M. (2019). Arbuscular mycorrhizal fungal community composition determines the competitive response of two grassland forbs. PloS one, 14(7), e0219527. (link to full text)

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Lena Neuenkamp in lab (pic from Novaator)

Abstract

We performed a greenhouse experiment to assess how differences in AM fungal community composition affect competitive response of grassland plant species. We used a full factorial design to determine how inoculation with natural AM fungal communities from different habitats in Western Estonia affects the growth response of two grassland forbs (Leontodon hispidus L., Plantago lanceolata L.) to competition with a dominant grass (Festuca rubra L.). We used AM fungal inocula that were known to differ in AM fungal diversity and composition: more diverse AM fungal communities from open grasslands and less diverse AM fungal communities from former grassland densely overgrown by pines (young pine forest). The presence of AM fungi balanced competition between forb and grass species, by enhancing competitive response of the forbs. The magnitude of this effect was dependent on forb species identity and on the origin of the AM fungal inoculum in the soil. The grassland inoculum enhanced the competitive response of the forb species more effectively than the forest inoculum, but inoculum-specific competitive responses varied according to the habitat preference of the forb species. Our findings provide evidence that composition and diversity of natural AM fungal communities, as well as co-adaptation of plant hosts and AM-fungal communities to local habitat conditions, can determine plant-plant interactions and thus ultimately influence plant community structure in nature.

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EcolChange seminar – Chun-Neng Wang about how pollinatiors affect plant flower color

Seminars of Department of Botany, Doctoral School of Earth Sciences and Ecology and Centre of Excellence EcolChange

Speaker: Chun-Neng Wang is associate Professor at Institute of Ecology and Evolutionary Biology of National Taiwan University, Taiwan. He studies plant development from genetic and evolutionary aspects. He is visiting Tartu University under the framework of Erasmus+ program.

Title of the talk: Over-dispersion of flower colour assembly due to possible competitions for pollinators in alpine community of Taiwan

Time: Thursday, 6. June 2019 at 15.15

Place: Tartu, Lai 40-218 (Vaga auditorium)

Summary: Taiwan is a subtropical island yet mountains extending to 3900 m high with temperate origin species relic in alpine areas.  Alpine community species tend to be more divergent in floral color than expected by chance. Our analysis revealed that over-dispersion of floral color is probably driven by competitive exclusion for limited pollinators in alpine.

Current political climate changes (pic from here)

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EcolChange seminar – Jeanalle Eck about microbes that shape plant disease and diversity

Seminars of Department of Botany, Doctoral School of Earth Sciences and Ecology and Centre of Excellence EcolChange

Speaker: Jenalle Eck is post-doctoral researcher at the University of Zürich, Switzerland. She studies plant population and community ecology, with special emphasis on plant-microbial interactions. Jenalle is visiting Department of Botany for collaboration with Plant Ecology Laboratory.

Title of the talk: Genotype-specific microbes shape plant disease and diversity: from Panama to Plantago

Time: Thursday, 16. May 2019 at 15.15

Place: Tartu, Lai 40-218 (Vaga auditorium)

Summary: Genotype is important in mediating interactions between plants and microbes, and genotype-specific interactions can create complex eco-evolutionary dynamics in plant populations and communities. In this talk, I describe insights on this topic from research in two study systems, the tropical forests of Panama and the temperate grasslands of Finland.

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Diseases might shape bacteria too… (pic from here)

 

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New publication – How do arbuscular mycorrhizal fungi travel

Text by Guillermo Bueno

Two of the members of the department of Botany (C. Guillermo Bueno and Mari Moora) were invited to write a commentary on a recently published paper in New Phytologist (Correia et al 2019). The paper commented showed the first evidence of co-dispersal of AM fungi and AM plants by birds. The commentary highlights the need for more research on the dispersal mechanisms of this important group of fungi (associated with around 80 % of plant species) and pose interesting lines of future prospect.

Citation: Bueno, C. G., & Moora, M. (2019). How do arbuscular mycorrhizal fungi travel?. New Phytologist, 222(2), 645-647. (link to full text)

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About to disperse mycorrhiza. Though, not AM, but EcM… (pic from here)

 

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EcolChange seminar – Guillermo Bueno about plant mycorrhizal traits

Seminars of Department of Botany, Doctoral School of Earth Sciences and Ecology and Centre of Excellence EcolChange

Speaker: Guillermo Bueno is research fellow at the Plant Ecology Laboratory, Department of Botany, Tartu University. He explores how biotic interactions shape plant communities.

Title of the talk: Plant mycorrhizal traits: from concepts to applications

Time: Thursday, 25. April 2018 at 15.15

Place: Tartu, Lai 40-218 (Vaga auditorium)

Summary: Applying trait-based frameworks to fundamental biotic interactions has the potential to unveil their patterns and processes at multiple spatial scales, ultimately defining their relevance and dynamics. Among plant biotic interactions, mycorrhizal symbiosis is an association between plant roots and soil fungi, present in around 80 % of the plants, and expected to be essential for plant species survival and distribution. I will present work on plant mycorrhizal traits, from concepts to applications, highlighting the limitations and challenges to categorize and measure these relevant traits in mycorrhizal ecology and biogeography.

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The left one is the one with mycorrhiza, of course (pic from here)

After the seminar everyone is welcome to coffee/tea and snacks in the seminar room (coffee room, ground floor).

 

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New publication – Are biotic as relevant as abiotic factors to determine the functional and phylogenetic diversity of communities at a biome scale?

Text by Guillermo Bueno

Taking as a reference the distribution of herbivores in the Arctic, James Speed with the contribution of 22 researchers of the herbivory network (including Guillermo Bueno from the Botany department of the UT) have tried to answer this question. Similar to large-scale diversity patterns, functional and phylogenetic diversities are commonly assumed to be driven by abiotic factors (i.e. climate), while few efforts have attempted to analyze whether biotic factors (i.e. trophic interactions) can have a role in large (functional and/or phylogenetic) diversity patterns. Here we estimated the functional diversity, considering herbivore traits including diet, digestive system type, group and body size, wintering strategy, mobility, habitat, population dynamics and litter size, and phylogenetic diversity through building an Arctic herbivore phylogeny using nucleotide sequences accessed from GenBank. We tested whether the spatial pattern of both diversities is driven by abiotic: climate severity (f.e. winter temperatures) and landscape heterogeneity, or biotic (trophic; predator diversity or vegetation productivity). In addition, we calculated the functional convergence (which is the functional similarity among species after taking into account their relatedness). Functional convergence will happen if a large functional diversity occurs within a group of closely related species (low phylogenetic diversity) and functional divergence in the opposite situation, when low functional diversity is not much clustered in the phylogeny. Convergence can indicate that the trait evolution has had certain constrains. In fact, our results showed that the assemblages of herbivores were functionally convergent in some parts of the Arctic, like Victoria Island and Subarctic Quebec region (see bottom figure), possibly indicating some weak environmental limitations. Overall, we found a predominant role of biotic interactions, both predators (top-down) and vegetation productivity (bottom-up) to herbivore functional and phylogenetic diversity, which along with winter temperature are driving the spatial patterns of functional and phylogenetic diversity (see figure below). These results highlight the need to consider biotic interactions at larger scales and under current changes in winter climate.

guillermo april2019

Figure including at the top – Hypothetical pairings of Arctic herbivores demonstrating high and low levels of functional (browsers and grazers) and phylogenetic diversity (Aves and Artiodactyla) and functional divergence to convergence (ratio of functional diversity to phylogenetic diversity); and at the bottom, the standardised effect sizes of phylogenetic and functional diversity and functional convergence (full details can be found in the paper

Citation: Speed, J. D., Skjelbred, I. Å., Barrio, I. C., Martin, M. D., Berteaux, D., Bueno, C. G., … & Grytnes, J. A. (2019). Trophic interactions and abiotic factors drive functional and phylogenetic structure of vertebrate herbivore communities across the Arctic tundra biome. Ecography, https://doi.org/10.1111/ecog.04347 (link to full text)

Abstract:

Communities are assembled from species that evolve or colonise a given geographic region, and persist in the face of abiotic conditions and interactions with other species. The evolutionary and colonisation histories of communities are characterised by phylogenetic diversity, while functional diversity is indicative of abiotic and biotic conditions. The relationship between functional and phylogenetic diversity infers whether species functional traits are divergent (differing between related species) or convergent (similar among distantly related species). Biotic interactions and abiotic conditions are known to influence macroecological patterns in species richness, but how functional and phylogenetic diversity of guilds vary with biotic factors, and the relative importance of biotic drivers in relation to geographic and abiotic drivers is unknown. In this study, we test whether geographic, abiotic or biotic factors drive biome‐scale spatial patterns of functional and phylogenetic diversity and functional convergence in vertebrate herbivores across the Arctic tundra biome. We found that functional and phylogenetic diversity both peaked in the Western North American Arctic, and that spatial patterns in both were best predicted by trophic interactions, namely vegetation productivity and predator diversity, as well as climatic severity. Our results show that both bottom‐up and top‐down trophic interactions, as well as winter temperatures, drive functional and phylogenetic structure of Arctic vertebrate herbivore assemblages.. This has implications for changing Arctic ecosystems; under future warming and northward movement of predators potential increases in phylogenetic and functional diversity in vertebrate herbivores may occur. Our study thus demonstrates that trophic interactions can determine large‐scale functional and phylogenetic diversity just as strongly as abiotic conditions.

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EcolChange seminar – John Clarke about fish macroevolutionary dynamics

Seminars of Department of Botany, Doctoral School of Earth Sciences and Ecology and Centre of Excellence EcolChange

Speaker: John Clarke is research fellow at the chair of entomology, Department of Zoology, Tartu University. He explores evolution, including diversification, using fishes as model systems.

Title of the talk: Polyploidy, historical expectations and habitat shifts: revealing macroevolutionary dynamics underpinning half of vertebrate diversity

Time: Thursday, 11. April 2018 at 15.15

Place: Tartu, Lai 40-218 (Vaga auditorium)

Summary: Why are some groups extremely diverse in morphology, while other groups vary little in morphology? To address this fundamental question, I use actinopterygian fishes (~33000 species today) as a model system, testing classic expectations regarding their morphological evolution through time, ranging from genome duplication to the role of habitat type.

 

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