Final Year Thesis Spotlight: Do Cycads display CAM photosynthesis?

Plants are famous for their ability to photosynthesize. They produce sugars that are essential for life, using CO2 coupled with light energy from the sun. We know that photosynthesis occurs during daylight but what if we told you that in some plants, part of this process takes place in the dark of night? This unique process is known as Crassulacean Acid Metabolism or CAM photosynthesis and is a remarkable adaptation of some plants to hot and dry environments.   

As part of his thesis project, Hugh McGrath, a final year student at Trinity College Dublin set out to explore whether or not Cycadales, exhibit CAM photosynthesis, using an array of species available at Trinity College Botanic Garden.  

But why Cycads? Cycads peaked in diversity about 145 million years ago, during the Jurassic-Cretaceous period which is often termed ‘the age of cycads’. The Earth’s climate was hotter back then, with CO2 being as much as 4 times higher.  

Cycad diversity has dwindled since their Jurassic reign. Today, 300 species exist, limited to pockets of suitable tropical and sub-tropical climate, many threatened with extinction. But could it be that CAM photosynthesis aided the success of this ancient group of plants during ‘the age of cycads’?  

CAM plants have adapted to close their stomata during daylight. Stomata are tiny pores on plant leaves through which atmospheric CO2 enters the leaves and water is released, a process known as transpiration. Closing these pores during the day enables plants growing in areas of water scarcity to conserve this precious resource 

However, CO2 still remains essential for photosynthesis. CAM plants uniquely assimilate CO2 by opening their stomata at night. 

Hugh investigated the possible occurrence of CAM photosynthesis in the Cycads growing at TCBG. Overall, it was observed that 4 cycad species are potential exhibitors of CAM photosynthesis, supporting the case for further exploration of CAM in this ancient group of plants.  

Can we reverse climate change? By-product use for a sustainable future

An exciting collaboration is taking place between Trinity College Dublin’s TERRAFORM group and a research team at University College Dublin working on the “Crushed returned concrete as a soil amendment for carbon capture” project. Co-funded by iCRAG and Silicate, the project aims to investigate the potential of concrete application on agricultural soils as a negative emissions technology. A team of botanists and geologists from two leading Irish universities have joined forces to provide a holistic understanding of the potential of enhanced weathering to capture carbon, as well as any possible benefits for crops.
The project draws on silicate weathering, an ancient process that plays an important role in the Earth’s long-term carbon cycle, capturing CO2 from the atmosphere and helping regulate the Earth’s climate over millions of years. Cations produced during rock weathering react with CO2 from the atmosphere and the reaction products are eventually stored deep in the ocean as carbonates.
The ancient silicate weathering process inspired the exploration of enhanced weathering as a negative emissions technology. The practice aims to accelerate weathering reactions in order to remove CO2 from the atmosphere and reduce the effects of global warming. It commonly involves crushing silicate rocks followed by application onto agricultural soils, where it has the added benefit of weathered rock acting as a fertilizer by providing nutrients to crops. This project is unique in that it aims to investigate the possibility of using an otherwise waste industrial product, concrete, as the reactant in this process, further streamlining the sustainability of enhanced weathering as a practice.
Pilot studies are in full swing on fields of barley and oat located in Co. Wexford. Dr Ruadhán MaGee and Leo Hickey, based at UCD, study the CO2 removal potential under field conditions. Terraform members, Dr Christos Chondrogiannis and Katie O’Dea investigate the impact of concrete application on crop physiology and yields.
Possible positive results yield multiple benefits including; 1) Enhanced weathering as a carbon negative emission technique, 2) Alternate use of crushed concrete, a waste by-product of construction industry, 3) use of rocks as a crop soil fertilizer.

Cycads Bring us Together

Facilitating an exciting investigation into photosynthesis.

An exciting collaboration is underway between the Variable Light and Atmosphere (VAL) lab, Trinity College Botanic Gardens and the National Botanic Gardens of Ireland. The VAL lab has borrowed a variety of Cycads from both botanic gardens. The plants hail from all three extant Cycad families including Cycadaceae, Stangeriaceae, and Zamiaceae, capturing current diversity across the group.

Evolving around 280 million years ago, Cycads are an ancient group of gymnosperms. Often termed ‘living fossils’, these plants have existed since before the appearance of dinosaurs. Once dominating ancient ecosystems, todays Cycad species are limited to tropical and subtropical regions.

Borrowed Cycads have been acclimated to pre-set conditions within the state-of-the-art CONVIRON climate control chambers available at the VAL lab. Temperature, humidity and light spectra and intensity have been set to simulate the tropical environments in which today’s cycads reside.

Dr. Christos Chondrogiannis and Katie O’Dea from the ERC funded TERRAFORM project are studying photosynthetic characteristics of this unique group. The study aims to deeper understand the evolution of this iconic biological process which enables plants to synthesize energy from light.

The VAL lab would like to thank Trinity College Botanic Gardens and the National Botanic Gardens of Ireland for facilitating this research.

'Carbon Dioxide Assimilation in Plants: from Genome to Biome' - Gordon's Research Conference 2023

Two of our lab members Prof. Jennifer McElwain and Dr. Christos Chondrogiannis had the privilege of attending a Gordons Research Conference (GRC) on the topic of photosynthesis from 7th – 12th of May 2023. The conference took place at Renaissance Tuscany Il Ciocco Resort & Spa, a tranquil estate nestled in the lush hilltops of Tuscany, Italy.

The conference, titled “CO2 Assimilation in Plants from Genome to Biome”, brought together researchers from leading labs, from PhDs making the first steps in their career to famous, well-established researchers of photosynthetic studies. The aim of the conference was to advance frontiers in the field of photosynthesis by showcasing cutting edge and unpublished research on a wide suite of plants, from rare species to widely cultivated crops. The rigorous discussions that happened between researchers informally were a highlight of the event. Fruitful discussions that stretched over lunch and well into the evening led to the genesis of new ideas and future collaborations.

Prof. Jennifer McElwain presented the final talk of the conference, titled ‘Reconstructing Terrestrial Ecosystem Function in Deep Time using Paleo-Plant Traits and Paleo-Ecosystem Modelling’. McElwain discussed the importance of accurate estimates and reconstructions of atmospheric CO2 through deep time. She also presented her idea of paleo-traits, the application of modern plant functional trait ecology within palaeobotany, which will enable reconstruction of plant activity in paleo-environments.

Dr. Christos Chondrogiannis presented a poster titled ‘Photosynthetic rate as a focal trait to assess plant weathering rate across evolutionary groups’, detailing how his chamber experiments aim to establish a correlation between photosynthesis and weathering rates and uncover information on how these processes interact. Chondrogiannis also had the pleasure of attending a workshop on the 6th of May, titled “Photosynthetic efficiency in a changing environment.”

EGU23 General Assembly - Vienna 2023

The EGU23 General Assembly was held in Vienna from 14-19 April 2023. Located on an island in the magical Danube, the warm and welcoming Austria Center Vienna welcomed the 15,453 attendees from 107 countries around the world. The conference was a great success, as 16,357 presentations were given in 938 different sessions.

TERRAFORM was represented by Christos Chondrogiannis, William Matthaeus and Richard Nair.

Christos Chondrogiannis gave an oral presentation in the session “Co-evolution of life and the Earth, and major transitions in Earth’s biosphere and environment” titled “TERRAFORM: Trait ecology and Biogeochemical cycles in deep time”. He presented the goals of TERRAFORM project, how plants affect the biogeochemical cycles, and how modern trait ecology can be implemented in the fossil record to inform us about plant activity in the deep time.

William Matthaeus had a poster titled “Moisture seasonality as a differential driver of modelled forest distribution during the Pennsylvanian” presenting part of his recent work. Specifically, by using the Paleo-BGC ecosystem process model, he showed simulation evidence supporting the long-held inference that moisture seasonality explains the spatial distribution of the major plant types of the late Paleozoic ice age.

Finally, Richard Nair, presented a poster titled “Day-night root dynamics change through the growing season”, where he showed shifts in the diurnal pattern of root growth during the growing season. Richard, was also a co-convener at the session titled “Vegetation functional responses to global change across multiple methods and scales” and presented during the townhall meeting for the CLEANFOREST EU COST action.

Many participants were interested in the work of the attending TERRAFORM members, with a high level of engagement around the presentations. In addition, the members of the group had the opportunity to attend presentations related to their research interests. At the same time, fruitful discussions and acquaintances with emerging and distinguished scientists took place.

EPA 5YAR Synthesis Report meeting

The Synthesis Report meeting for the EPA Five Year Assessment Report was held on 7th and 8th of November at FSTEM TCD. Authors from all four volumes on Ireland’s first climate assessment review were able to meet in-person and online. The aim of this meeting was to decide on the scope and outline of this important stage of the process, which follows a similar format to the IPCC.  


The Synthesis Report will provide an integrated overview of the key messages from all four volumes of 5YAR, and aims to provide information for the policy guidance needed as a long term assessment strategy for Ireland and climate change. It was a great meeting and great progress was made collectively on this task.  


More information on the 5YAR and the volumes provided within