Science on Sundays – July 2025

Sun 20 July

Cambridge Botanic Garden

Dr Katharina Schiessl, Sainsbury Laboratory, University of Cambridge
Legumes, such as peas and beans, have evolved a remarkable way to access nitrogen, an essential nutrient often in short supply in the soil. They form specialised root nodules—structures that house nitrogen-fixing bacteria, which convert atmospheric nitrogen into a form the plant can use.

This symbiotic relationship begins when the plant’s root hairs recognise and respond to specific bacterial signals, allowing the bacteria to enter. The resulting nodules develop deep within the root, but intriguingly, they share their origins with lateral roots—the branching roots that extend outward. This raises an important question: how do nodules take on such a distinct structure and function compared to lateral roots, despite arising from the same root tissue?

In this talk, Katharina will share her research into the developmental pathways that shape these unique root structures and what they reveal about plant-bacteria interactions.


20-day-old root nodules of Medicago truncatula. Credit: Katharina Schiessl
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Science on Sundays
A programme of free, informal, monthly science talks bringing the latest discoveries in plant science, as well as research linked to the plant collection at CUBG to our visitors in a 30 minute nutshell.

We will be running these talks live from the Botanic Garden Classroom for those visiting the Garden on the day.
Free with normal Garden admission.
Please check the website and social media for updates.
Suitable for adults and children aged 12+.
Talks run monthly March to July.

Cost: Normal Garden Admission