Modelling the influence of biotic plant stress on atmospheric aerosol particles

text by Ülo Niinemets

Our paper on modelling of aerosol formation due to biological stresses has been just published in Atmospheric Chemistry and Physics. This paper convincingly shows that plants, when attacked by insects or pathogens, release a volatile burst high enough to make a difference in atmospheric characteristics. Aerosols determine how much solar radiation penetrates the atmosphere, and thus, alterations of aerosol abundance and characteristics can have major effects of climate. This is one of the ways of how plants can alter our climate. The study is based on plant stress studies in my lab, and on aerosol studies in Prof. Markku Kulmala​’s lab at the University of Helsinki. The study was initiated when Ditte Taipale​ was a postdoc in my lab in frames of my ERC grant SIP-VOL+. Ditte made a wonderful job in combing plant physiology and aerosol physics and modelling, and I believe that we all should be proud of the final result. In addition to Markku, Prof. Veli-Matti Kerminen and Dr Mikael Ehn from the Univ. Helsinki contributed to the study.  

Link to the articel

Taipale, D., Kerminen, V.-M., Ehn, M., Kulmala, M., and Niinemets, Ü.: Modelling the influence of biotic plant stress on atmospheric aerosol particle processes throughout a growing season, Atmos. Chem. Phys., 21, 17389–17431, Figure 1.
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The 3rd Lichen Photobiont Symposion, 27.-29.09.2021 in Czech Republic

Our researcher studying cryptogam ecology and physiology, Kristiina Mark, attended in the end of September the 3rd Lichen Photobiont Symposion in the beautiful (but “terrrrrible”) Giant Mountains National Park in Czech Republic. The conference talks and posters were focussed on the most recent research on lichen photobionts (both, chloro- and cyanobionts) but in addition held also a workshop on identification of aerophytical green algae and a field excursion to the national park mountains. In two days 21 oral presentations and 9 posters were presented by researchers from around the world. In this meeting, Kristiina had a talk on one of the most resent line of our research in cryptogams, about investigations on algal volatilomes.

Great acknowledgements and appreciation goes to Pavel Škaloud and all the co-organizers for planning and making it possible to attend such a nice meeting together with so many wonderful researchers!

Participants of the 3rd Lichen Photobiont Symposion in front of the hosting facility Patejdlova bouda (mountain cottage in the Giant Mountains National Park owned by the Charles University Faculty of Science; photo provided by the organizers).
View on the Giant Mountains National Park (photo by K. Mark).

A tasty way to know your organism – gingerbread biscuits with the logo of the meeting (a graphical visualization of Trebouxia sp; photos provided by the organizers).

Kristiina’s travel was funded by the Estonian Research Council grant PRG537 to Ülo Niinemets, “Increasing contribution of cryptogams to primary productivity of ecosystems in warmer and more humid climates”.

Text by Kristiina Mark.

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A new young member in our team

Text and photo by Jesamine Rikisahedew

My name is Jesamine Rikisahedew and as of September 2021, I am a first year PhD candidate in Environmental Sciences and Applied Biology at Eesti Maaülikool. My home country is South Africa, where I grew up along the coast with easy access to some of the best nature has to offer. We are renowned for having an unmatched diversity and abundance of plant life and are the proud home of 10% of the world’s flowering species, making SA a major contributor to the global ecological scene. It was natural then for me to gravitate towards plant biology in my academic career.

I graduated from the University of KwaZulu-Natal (UKZN) in South Africa with a BSc in Biological Sciences, in which my focuses were plant and animal ecophysiology and forensic genetics. My undergraduate thesis was based on the cultivation of microalgae for the development of enzyme inhibitors, which segued into my interest in microscopy. My Master’s thesis was entitled “Histo-phytochemical evaluation and characterization of the foliar structures of Tagetes minuta L. (Astereaceae)” in which electron microscopy was a large component, which compounded my interest in plant anatomy and microscopy techniques.  

To expand my horizons and hone my skills in plant ecophysiology, I have joined Professor Ülo Niinemets’ team under the primary supervision of Associate Professor Tiina Tosens where I will be working on the topic “Physiological and structural trade-offs underlying the global variation of mesophyll conductance” wherein I will be gathering anatomical and physiological data from higher and lower plant specimens collected from every major clade in the efforts of determining what factors affect mesophyll conductance, and thus, photosynthesis in photosynthetic organisms. I am hopeful that this project will give me the opportunity to contribute towards this field of knowledge, meet new and interesting people, and motivate me towards a career in academics.

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Estonian forest exploration: Lichens, nature and much more!!

Text and photos by Upasana Sharma

Hello everyone!

This Summer I was exploring Estonian forests for sampling lichens for my PhD project. My fieldwork took me to six different forests and parks nearby Tartu, most of which I visited for the first time. It was exciting and a bit challenging for me to visit different forest alone as Estonian landscapes and forests are so different to the natural areas in my home country and what I am used to but later on, I started enjoying to be in the forest and the ambiance out there. I was able to accomplish each task successfully.

This field work was a great opportunity for me to better understand the ecology of lichens and increased my knowledge about the most frequent lichen species in Estonian natural forest and urban parks. For example; Xanthoria parietina, a bright orange or yellow colored lichen (as shown in picture) having high amount of parietin pigment is mostly growing on highly sun exposed locations, i.e. common in urban parks but generally absent deep in natural dense forests where light availability is scarce. During these visits I also experienced the different forest types that are around Tartu and learned about the common tree species in these forests.

Lichen Xanthoria parietina (yellow patches)on tree bark.
Example of Estonian natural forest nearby Kambja, Tartumaa.

I am grateful to my supervisor Dr. Kristiina Mark for her immense encouragement during the work and also thankful to my colleague Tiia for her help. This field work made me more independent as it was something beyond my comfort zone.  I enjoyed thoroughly going to the forest. Now I am more close to the nature I can say. I would love to explore more forests again and can’t wait for the next summer.


Doing fieldwork in Vapramäe forest nearby Peedu, Tartumaa
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A new team member – João Paulo Silva Souza

Text and photo by João Paulo

I am João Paulo Silva Souza from North of Brazil and from September 2021 I started my PhD studies in the Institute of Agricultural and Environmental Sciences of the Estonian University of Life Sciences.

I am grateful for having the opportunity to integrate into the professor Ülo Niinemets work team, and for having the opportunity to continue my academic career as a PhD student at an institution of excellence.

I graduated with BSc Degree from the State University of Pará/Brazil (UEPA) in 2017, where I worked with botanical collections, plant taxonomy and ecology, focusing on the diversity and distribution of bryophytes. Right after graduation I started my Master’s Degree in Plant Biology at the Federal University of Pernambuco/Brazil (UFPE) where I had the opportunity to continue my research on bryophyte diversity and distribution. My MSc dissertation was entitled “Spatial distribution of bryophyte functional characteristics along environmental gradients in an Atlantic Forest remnant in Northeast Brazil”. Since then, I have enrolled in several English courses in Ireland.

Now with the possibility to continue working with the organisms I am interested in, I am very excited to continue my studies under the supervision of Prof. Dr. Ülo Niinemets and Dr. Kristiina Mark on the topic of “Cryptogam microbial communities diversity, distribution and dependence on climatic, ecological and biological factors” as a PhD student.

Over the next four years I will encounter many new and exciting challenges that will improve me as a scientist. I will work mainly with cryptogam species (bryophytes and lichens) and their associated microbiome (bacteria, fungi and algae) regarding taxonomic and functional diversity, using next-generation sequencing (NGS). My goal is to improve scientific knowledge and understanding of the ecological roles of these organisms in the ecosystems on the face of environmental changes.

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Sweet potatoes grew well in hot and dry weather conditions in the 2021 season!

Text and photos created by Eve Runno-Paurson

Sweet potato harvesting on 27 September 2021

Tuber quality grown with biodegradable black mulch were excellent

Cultivar Evangeline tubers

And Chinese beauties

Beds after tuber digging

Master student Siim and PhD student Helina in action

Supervisor Astrid and PhD student Ivar are happy due high quality harvest

Our harvesting team

In lab: Siim evaluates and measures the tuber yield

Season succeeded!

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News about carbon in plant leaves…

Text and graphs by Ülo Niinemets

Carbon, C, is the most frequent chemical element in plant leaves, but leaf carbon content is a surprisingly understudied plant trait. Modern elemental analyzers typically give estimates of nitrogen, N, and C contents, but often only N (that is present in proteins) is used and C is neglected. We have just shown that C in combination with Ca provides key insight into leaf structure and function both at local and global scales. Looking back at this work, publication of these two papers was a saga. Lots of rejections, invitations to resubmit, revisions and rejections again. Many good comments, but also comments in a style “I just do not believe it”. This was the frustrating part of it. Perhaps it reflected the feeling in the research community that C and Ca are that common elements that there is nothing to find. Yet, people had not looked at these two key elements together. Taken alone, C and Ca are non-informative. Taken together, a marvelous set of patterns with major functional implications emerges. The work builds upon an earlier study of Niinemets and Tamm (2005) that demonstrated a negative scaling between leaf structural carbon and leaf Ca content across woody species.

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Sweet potato season 2021 started in Eerika field of the University!

Text and photos created by Eve Runno-Paurson

On 4 June our research team at the Chair of Crop Science and Plant Biology planted sweet potato plants on the field at Eerika. This is our 4th season. Together six cultivars and breeding lines are tested under the two cultivation technologies (on furrows and under plastic mulch) and four fertilization treatments.

The sweet potato is a promising new crop in Estonia, considering climate change in the near future.

The plants were grown in cassettes, so they were nicely rooted

Growing on furrows

Beds covered with biodegradable black mulch

The weather was fantastic for planting and this is our team after hard job!

The planting job is done. Hopefully growing period lasts 4 months!

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The European Research Council (ERC) celebrates a new milestone – the 10 000th researcher awarded an ERC grant

On May 6 European Research Council (ERC) celebrated a new milestone – the 10 000th researcher awarded an ERC grant. Who are these grantees? What are they doing? The ERC cites 15 examples of researchers who have truly changed science. One of them is Professor Ülo Niinemets of the Estonian University of Life Sciences.

Look at the article and podcast on the occasion of ERC 10,000th grantee celebration. It will be part of a story package ‘How the ERC transformed science’. Only 15 stories (among 10,000 ERC grantees) have been chosen to feature in this series.

Among the 15 stories is the story of Professor Ülo Niinemets.

The work of ERC grantee Ülo Niinemets has shown that monitoring plant stress emissions could help us to better understand atmospheric processes. This has led to a rethink on global climate modelling and strengthened research into crop resilience. His project’s successful international collaboration has also demonstrated how ERC funding can boost scientific excellence in smaller countries like Estonia.

Embed podcast here: h ]

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PhD position on cryptogam-associated microbial interactions biology and ecology

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