Duckweed: The low-down on a tiny plant

Duckweeds - for many aquatic animals like ducks and snails, a treat, but for pond owners, sometimes a thorn in the side. The tiny and fast-growing plants are of great interest to researchers, and not at least because of their industrial applications - for example, to purify wastewater or generate energy. An international research team from Münster, Jena (both Germany), Zurich (Switzerland) and Kerala (India) have recently studied the genomics of the giant duckweed. They discovered that genetic diversity, i.e. the total number of genetic characteristics that are different among individuals, is very low. "This is remarkable given that their population size is very large - there can, for example, be millions of individuals in a single pond", says Shuqing Xu, professor for plant evolutionary ecology at the University of Münster and lead author of the study. To understand the reason behind this mystery, a team of plant researchers headed by Dr. Meret Huber from the Max Planck Institute for Chemical Ecology in Jena and the University of Münster measured the mutation rate of this duckweed under outdoor conditions, i.e. how many mutations accumulate per generation. The result: low genetic diversity in this plant was accompanied by an extremely low mutation rate.