New publication – Anatomical constraints to nonstomatal diffusion conductance and photosynthesis in lycophytes and bryophytes

Text by Kristiina Mark

Bryophytes – polyphyletic group consisting liverworts, hornworts and mosses – and lycophytes (also known as ‘fern allies’) are considered the earliest living relatives to ancient land plants that first migrated from aquatic environment to land. Both, bryophytes and lycophytes, are known for their simple structure, reproduction by spores, and tendency to prefer moist and shady environment. Being the second largest group of land plants (topped only by angiosperms), bryophytes contribute substantially to primary productivity in high latitude ecosystems where conditions for vascular plants are unsuitable.

Photosynthesis is the key process in primary metabolism and is often limited by CO2 concentration at carboxylation sites in chloroplast, which is determined by CO2 diffusion through plant tissues. Bryophytes and lycophytes show low photosynthetic capacity compared to vascular plants, however, contribution of specific constraining factors remained unexamined. Global collaborative study between seven research institutes from six countries (Spain, Australia, Chile, Estonia, USA, Indonesia) hypothesized that bryophyte and lycophyte lower rate of photosynthesis is largely due to constrained CO2 diffusion through photosynthetic tissues, specifically, limited by nonstomatal diffusion conductance (gnsd).

Research concluded that low photosynthesis rate in bryophytes and lycophytes is indeed related to their specific anatomical characteristics, especially their very thick cell walls and low chloroplast exposure to intercellular air spaces. Photosynthesis in mosses was mostly limited by gnsd and in lycophytes co-limited by gnsd and leaf photochemistry. These results support the suggested phylogenetic trend towards increasing photosynthesis and link to increasing stomatal and mesophyll/nonstomatal conductance.

kristiina samblad kaart

Study sites of the species included in this study (Fig 1 from the study)

Citation: Carriquí, M., Roig-Oliver, M., Brodribb, T. J., Coopman, R., Gill, W., Mark, K., Niinemets, Ü., Perera-Castro, A. V., Ribas-Carbó, M., Sack, L., Tosens, T., Waite, M., & Flexas, J. (2019). Anatomical constraints to non-stomatal diffusion conductance and photosynthesis in lycophytes and bryophytes. New Phytologist, https://doi.org/10.1111/nph.15675. (link to full text)

 

Abstract:

Photosynthesis in bryophytes and lycophytes has received less attention than terrestrial plant groups. In particular, few studies have addressed the non-stomatal diffusion conductance to CO2 (gnsd) of these plant groups. Their lower photosynthetic rate per leaf mass area at any given nitrogen concentration as compared to vascular plants suggested a stronger limitation by CO2 diffusion. We hypothesized that bryophyte and lycophyte photosynthesis is largely limited by low gnsd. Here we studied CO2 diffusion inside the photosynthetic tissues and its relationships with photosynthesis and anatomical parameters in bryophyte and lycophyte species in Antarctica, Australia, Estonia, Hawaii and Spain. On average, lycophytes and, specially, bryophytes had the lowest photosynthetic rates and non-stomatal diffusion conductance reported for terrestrial plants. These low values are related to their very thick cell walls and their low exposure of chloroplasts to cell perimeter. We conclude that the reason why bryophytes lie at the lower end of the leaf economics spectrum is their strong non-stomatal diffusion conductance limitation to photosynthesis, which is driven by their specific anatomical characteristics.

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EcolChange seminar – Kairi Kreegipuu about windows into the brain

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

Speaker: Associate Professor Kairi Kreegipuu works in the field of experimental psychology at the Institute of Psychology and is the Vice Dean of Research and Development at the of University of Tartu.

Title of the talk: Mismatch negativity – a window to the brain

Time: Thursday, 21. February 2018 at 15.15

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

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

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Brain window (pic from here)

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EcolChange seminar – Elin Org about mice and men and microbiota

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

Speaker: Dr. Elin Org is senior researcher in genomics and microbiomics at the Institute of Genomics of University of Tartu.

Title of the talk: Host-gut microbiota interactions and metabolic traits in mice and human

Time: Thursday, 14. February 2018 at 15.15

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

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

Insert a colonial joke here. Or colonal… (pic from here)

 

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Blogyear summary 2018

Text Lauri Laanisto

It is already February. Nearly a month too late. But as the years go by, more and more reports are required every January, which is why the summaries of voluntary nature tend to get delayed or even fail to appear completely.

Our second year of blogging resulted in 55 blog posts by 26 different authors (last years numbers were 69 and 21, respectively). Blog was reached by 2200 unique visitors with 3390 clicks, from 75 countries and territories (Estonia, USA, HongKong, Germany and UK had the most visitors from). The blog has 250 followers, mostly through accompaniying Twitter account.

The most popular post from last year was written by Ivika Ostonen about root-foraging strategies in forests, a paper that was published in New Phytologist.

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Not one, but again two seminars: Marc-André Selosse & Benoît Perez-Lamarque about mycorrhiza

Holiday season is thankfully over, and time to get back to science!

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

Speaker1Prof. Selosse is based at the National Museum of Natural History (Muséum National d’Histoire Naturelle) in Paris, France.

Title of the talk: A case study of plant-fungal cointroduction: a pantropically introduced tree was followed by pseudovertically transmitted mycorrhizal fungi

Speaker2MSc Perez-Lamarque is his PhD student at Ecole Normale Supérieure in Paris. They are visiting plant ecology work group of Department of Botany.

Title of the talk: Constraints on the emergence of cheating mycoheterotrophic plants in the arbuscular mycorrhizal symbiosis

Time: Thursday, 10. January 2019 at 15.15

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

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

'Mom, Dad -  this is Jeremy.'

Introducing fungi (pic from here)

Calendar of the department’s events: https://botany.ut.ee

Add directly to Google calendar: http://bit.ly/botany_AddToGoogleCalendar

iCal format: http://bit.ly/botany_iCal

Additional information: Maarja Öpik, maarja.opik@ut.ee

 

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Ilkka Hanski´s “Messages from Islands” now in Estonian

Text by Lauri Laanisto

In a tiny country like Estonia scientists are probably more concious about progeny than in more populated places where the flow of potential students is much more steady. So, most of Estonian scientists are involved in various activities promoting science in general and their specific discipline more narrowly.

My niche in this field, in addition to blogging, is translating. I´m trying to make science more accessible for young people like I was when growing up, or people who do not speak English.

And just today my latest translation hit the already overloaded shelves of bookstores. It´s Ilkka Hanski´s posthumously published “scientific testament” called “Messages from Islands” (University of Chicago Press 2016). In Estonian (which is the second language after Finnish – naturally – it has been translated into) it is called “Sõnumeid saartelt”. Here is the cover:

Ilkka Hanski collaborated with members of EcolChange, and the concept of extinction debt (link to Helm, Hanski and Pärtel 2005 in EcolLetters) is quite thouroughly discussed also in this book.

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Soil biodiversity training school

/Here´s an announcment about slightly EcolChange-related soil biodiversity training school that will take place in Tartu in January. But it´s important to stress out that the registration deadline is already on 15th of December!/

 

COST Action “KEYSOM” – 3rd Training School

Soil fauna – Key to Soil Organic Matter Dynamics and Modelling. Interactions with other components of soils – Mycorrhizal fungi

Tartu, Estonia, 22-24 January 2019

http://www.keysom.eu/

'Just think...our pies feed the soil,the soil feeds the grass,the grass feeds us...'

Once you start thinking about the interactions… (pic from here)

Linking Soil Biodiversity with Soil Organic Matter Dynamics

Framed within the objectives of the COST ACTION KEYSOM (Soil fauna – Key to Soil Organic Matter Dynamics and Modelling – see http://keysom.eu/) this third Training School aims at linking the role of the soil biodiversity with the soil organic matter dynamics. This school will provide a comprehensive overview of the tools available to assess the soil biodiversity (including macrofauna, mesofauna, microfauna and microorganisms), such as classical taxonomic approaches and novel soil DNA metabarcoding. The originality of this training school lies in the interdisciplinarity of its subjects, from molecular biology to soil science, and its trainers, getting together soil ecologists, biogeochemists and modellers.

Dr. Maarja Öpik and Prof. Alar Astover will be hosting this third KEYSOM Training School. A selection of relevant speakers (see below) are invited to provide their knowledge and experience in themes ranging from soil biodiversity, soil function, and SOM interaction. Targeted mainly at PhD students and young post-doctoral fellows (ECIs), this training school also aims at stimulating collaborative research among participants and with the guest lecturers.

 

PARTICIPATION & REGISTRATION (30 participants max.):

The participation in this Training School has no registration fees. Participants will be selected based on their CV and motivation letter. Applications (one single pdf), including a CV and a motivation letter, should be sent by e-mail to Maarja Öpik (maarja.opik@ut.ee) until December 15, 2018.

Selected participants will receive a “trainee grant” as a contribution to their expenses regarding travelling, accommodation and meals, according to COST regulations. Trainees eligible for reimbursement are those from all COST countries, approved Near Neighbour Countries’ institutions and approved European RTD Organisations (see COST rules in the vademecum at: https://www.cost.eu/wp-content/uploads/2018/08/COSTVademecum.pdf).

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New publication – Fungal diversity regulates plant-soil feedbacks in temperate grassland

Text and pic by John Davison and Marina Semchenko

Ecologists have long suspected that one key to explaining plant diversity lies with their enemies, including pathogenic soil microbes. Plant–soil feedback describes a process whereby plants shape the microbial communities living alongside them in the soil; and the microbes then have a ‘feedback’ effect on the performance of subsequent generations of plants. Feedback effects can be negative if driven by pathogenic microbes or positive if driven by beneficial microbes, such as mycorrhizal fungi. However, we remain largely in the dark about the mechanism involved, especially concerning the identity and diversity of microbes that could drive plant-soil feedbacks.

An international collaboration involving Dr John Davison (Ecolchange, University of Tartu) and led by Dr Marina Semchenko (University of Manchester, UK; formerly University of Tartu) has shed light on the drivers of plant-soil feedbacks in a study published in Science Advances. The team identified the microbes responsible for feedback effects and discovered why some plants live fast and die young whilst others have long and healthy lives. Their experiment consisted of a ‘conditioning phase’ where 14 different grassland plant species were grown for 3 years in field-based mesocosms containing natural grassland soil. The microbial communities in the soil were then described using high-throughput sequencing, and a ‘feedback’ experiment was conducted where plant species were grown on soil conditioned by the same or different species.

They found that the fungal communities present in conditioned soil varied considerably, with some plant species promoting different plant pathogenic fungi, and others favouring more beneficial fungi. The balance between pathogenic and beneficial fungi was dependent on plant functional traits and soil characteristics. Plants with more nutrient-acquisitive traits attracted more diverse communities of pathogenic fungi and associated with fewer mycorrhizal fungi. Soil microbial communities inhabiting fertile soils were more conducive to antagonistic interactions with plants, and plants were more susceptible to pathogens when grown on fertile soils. In the feedback stage, plant performance was negatively related to the diversity of harmful fungi rather than to the abundance of any particular specialist pathogens. It was also positively related to the diversity of mycorrhizal fungi. Lead author, Dr. Semchenko said: “We found that plant growth is strongly controlled by how many different harmful and beneficial fungi are attracted to plant roots. Some plants are slow to grow but enjoy a long life by cooperating with beneficial fungi; others grow fast and are initially successful, but then they are brought down by diseases caused by harmful fungi.”

The results could pave the way for new approaches in agriculture to achieve the right microbial balance for the production of healthy crops. The study also helps us understand how plant diversity is maintained. This, in turn, could help improve nature conservation and natural habitat restoration. Richard Bardgett, Professor of Ecology at The University of Manchester, said: “While these results come from grasslands in northern England, it is likely that the same mechanisms occur in other ecosystems around the world.” Dr. Semchenko added: “Soil microbes are known to be sensitive to human interference, such as intensive agriculture, and our findings suggest that negative impacts on soil microbes may have knock-on effects on the conservation of plant diversity.”

The study involved a collaboration between nine institutions including the Universities of Berlin, Colorado, Edinburgh, Lancaster, Manchester and Tartu.

Citation: Semchenko, M., Leff, J. W., Lozano, Y. M., Saar, S., Davison, J., Wilkinson, A., … & Mason, K. E. (2018). Fungal diversity regulates plant-soil feedbacks in temperate grassland. Science Advances, 4(11), eaau4578. (link to full paper)

marina ja john seened

Fungal diversity may be key to the maintenance of plant diversity in grasslands

Abstract:

Feedbacks between plants and soil microbial communities play an important role in vegetation dynamics, but the underlying mechanisms remain unresolved. Here, we show that the diversity of putative pathogenic, mycorrhizal, and saprotrophic fungi is a primary regulator of plant-soil feedbacks across a broad range of temperate grassland plant species. We show that plant species with resource-acquisitive traits, such as high shoot nitrogen concentrations and thin roots, attract diverse communities of putative fungal pathogens and specialist saprotrophs, and a lower diversity of mycorrhizal fungi, resulting in strong plant growth suppression on soil occupied by the same species. Moreover, soil properties modulate feedbacks with fertile soils, promoting antagonistic relationships between soil fungi and plants. This study advances our capacity to predict plant-soil feedbacks and vegetation dynamics by revealing fundamental links between soil properties, plant resource acquisition strategies, and the diversity of fungal guilds in soil.

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Not one, but two seminars: Björn Lindahl about symbiotic composition in boreal soils & Paul Ashton about genes and grasses in meadow

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

Speaker1: Prof. Björn Lindahl is based at Swedish University of Agricultural Sciences, Uppsala, Sweden. He is visiting the Department of Botany to act as opponent at the PhD defence of Petr Kohout on December 10th, at 9:15 AM in Vaga auditorium, Lai 40-218, Tartu.

Title of the talk: Symbiotic decomposition in boreal forest soils

Time: Tuesday, 11. December 2018 at 10.15

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

Speaker2: Prof. Paul Ashton is based at Edge Hill University, United Kingdom. He is visiting the Department of Botany to act as opponent at the PhD defence of Lisanna Schmidt on December 12th, at 9:15 AM in Vaga auditorium, Lai 40-218, Tartu.

Title of the talk: Let the grass grow and the genes flow! Lessons learned from research into hay meadow vegetation

Time: Tuesday, 11. December 2018 at 15.15

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

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

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Instead of a joke, a little addition to the commandments: let the grass grow, the genes flow, and keep the aspidistra flying! (pic from here

Calendar of the department’s events: https://botany.ut.ee

Add directly to Google calendar: http://bit.ly/botany_AddToGoogleCalendar

iCal format: http://bit.ly/botany_iCal

Additional information: Maarja Öpik, maarja.opik@ut.ee

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Annual update on our share of most influencal scientist

Text by Lauri Laanisto

Last year, when Clarivate Analytics published the list of most influential scientists in the world, we in EcolChange were rather happy about it, because: “From those 7 most influential Estonian researchers 4 (!!!) are members of our centre of excellence: Ülo Niinemets, Martin Zobel, Urmas Kõljalg and Leho Tedersoo. So one can say that EcolChange really is the dominant force in Estonian science.” (link to last year´s blogpost).

Well – new list was published about a week ago (link to the list). And this year we have even more influencers! Among the 6,000 most cited researchers of the world are the following EcolChange (associated) scientists: Ülo Niinemets from Estonian University of Life Sciences; Urmas Kõljalg, Leho Tedersoo, Martin Zobel (in two fields: plant and animal sciences and environment and ecology), Meelis Pärtel, Mari Moora, Kessy Aberenkov and Mohammad Bahram from Tartu Ülikool.

Thus, we have doubled our influence! Considering that EcolChange will run for five more years, we could expect about 256 people in that list by the end of 2023…

social-media-impact

Although, we are pretty far away from the impact of “actual” influencers… (pic from here)

 

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