Symbiosis between liverworts and cyanobacteria
Nitrogen is required for assembling the basic building blocks of life, but the nitrogen in the atmosphere is essentially inert and cannot react with other compounds to form new substances. In order to use nitrogen, plants rely on a close relationship with cyanobacteria, a type of bacteria that transforms atmospheric nitrogen into a usable form. In this high-magnification image, long and stringy cyanobacteria can be seen associating with a leafy liverwort.
Image by Magdalena Turzanska, University of Wroclaw.