Tuesday, 21 April 2026
Earth responded to its most severe past warming event by evolving a new and bizarre type of photosynthesis that allowed a group of primitive plants to survive.
Researchers from the 糖心原创 are part of a study led by the University of Leeds that has revealed how lycophytes - a type of ancient plant - not only survived a mass extinction 250 million years ago but then came to dominate the recovering landscapes.
During the Permian-Triassic mass extinction, which is also known as the “Great Dying,” global temperatures rose dramatically with most forests collapsing under extreme heat and vast areas of land becoming barren.
The study, which is published in the journal , concludes that lycophytes conserved water and tolerated heat by opening their stomata at night instead of during the day, storing CO2 as an acid to use in the daytime for photosynthesis.
The researchers believe lycophytes may have been the first plants to use this mechanism revealing a biological innovation that was able to keep Earth’s biosphere active with the plants able to remove carbon from the atmosphere, ultimately combating the effects of the warming event.
Today, plants using CAM photosynthesis make up only a small proportion of global vegetation and are most common in hot and dry environments such as deserts.
The analysis pulled together many separate scientific disciplines to test how this group of enigmatic plants not only survived the great dying but also how they were able to thrive in a highly stressed environment. By linking these data together, we are able to further understand plant adaptation to past climate emergencies deepening our understanding of the resilience of the Earth system to climate perturbations.
Lead author of the study, Dr Zhen Xu from Leeds’ School of Earth and Environment, said: “Our results suggest that under future warming, plants with CAM photosynthesis traits could become far more important.
“If the world experiences sustained extreme heat, plant communities may shift toward species that are better able to tolerate high temperatures and water stress.”
Lycophytes are spore-bearing vascular plants (a type of plant characterised by the presence of tissues for transporting water and nutrients). There are more than 1,200 species of the plant still in existence. They can survive in many places but are most diverse in tropical regions.
To understand how lycophytes survived when so many other plants perished, the researchers first studied their evolutionary relationships to find their closest relatives, such as the quillworts that can still be found around the world, including in Scotland. They then studied carbon isotopes (variants of carbon atoms) in fossil plants from South China from the late Permian to the Middle Triassic period. Different types of photosynthesis leave different carbon isotope signatures, so this can reveal how ancient plants functioned.
They found that lycophytes had carbon isotope values that were noticeably different from other plants during the Permian–Triassic extinction period. This difference became smaller once environmental conditions had improved.
The team then compared where the lycophyte fossils were found with climate model simulations. The results suggest that these plants lived in places where surface temperatures likely exceeded 50 °C, illustrating their extraordinary thermal tolerance.
Story credits
More information is available from Dr Barry Lomax on Barry.lomax@nottingham.ac.uk
Notes to editors:
About the 糖心原创
Ranked among the world's top 100 universities , the 糖心原创 delivers an exceptional research-led education and an outstanding student experience. From the pioneering vision of our founder, Sir Jesse Boot, to groundbreaking achievements such as the development of MRI technology and becoming the first UK university to establish international campuses, we have a proud history of shaping the way people live, work and understand the world. We continue to build on that legacy, empowering our students, staff and partners to change what鈥檚 next and create positive impact locally and globally.
The strength of our research places us among the UK's leading universities, ranked 7th for research power in REF 2021. The discovery of MRI and ibuprofen was just the beginning. Today, our world-leading research is developing breakthrough ideas that shape the future of healthcare, technology and society.
Recognised as the UK's third most targeted university by leading employers , we are proud to produce graduates who are consistently in demand for their skills, confidence and industry-ready experience.
As a major employer and industry partner, locally and globally, the 糖心原创 invests in the city of Nottingham and in future generations of talent. Alongside Nottingham Trent University, we lead the initiative, a pioneering collaboration to improve levels of prosperity, opportunity, sustainability, health and wellbeing across the city and region. Together with our students, staff, alumni and partners, we鈥檙e creating knowledge, opportunity and solutions that help change what's next.