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.
Siobhán McDonald captures landscapes at tipping points - The Boglands Are Breathing exhibition
'Siobhan McDonald communicate complex science in a visual way — reaching out to people with their heartstrings’
Siobhán’s latest exhibition – ‘The Boglands Are Breathing’ blends scientific and creative processes to make sculptures, videos, works on paper, paintings and sound pieces. The exhibition gathered numerous collaborators, bringing together scientists, conservators, musicians, philosophers, perfumers and celestial phenomena, all of whom collectively take part in the evolution of the work. Our shared boglands are positioned as the protagonists of an unseen drama, and this work makes visible the collective memory that is held in the rich repository that exists within the thin layer between the soil and the rocks. An installation entitled ‘A library of lost smells,’ consisting of plant species, gathered from numerous bog sites across Ireland acts as a slow distillation of deep time created from plants and mineral-rich bog waters, that explores links between smell & memory. The installation holds an assortment of hand-blown glass bottles containing scents from eight of the most important notes. Some of the vessels contain scent-infused remnants that were buried deep in a bog for over 20 years alluding to the low oxygen levels and unusual smells derived from the preservation conditions.
Find out more about Siobhán’s exhibition, which took place at Model Arts Centre in Sligo, from the Irish Times article.
Click below to see the short documentary on the exhibition.
