Seed time capsule

The Joshua tree is one of the many species whose seeds are stored in the Project Baseline frozen seed bank.

IN a visionary project of the U.S. National Science Foundation (NSF), called “Project Baseline”, a time capsule containing more than five million seeds frozen in time has been created at a U.S. Department of Agriculture facility in Fort Collins, Colorado. The capsule will be maintained at –18 °C for the next 50 years after which the seeds will be made available so that scientists can study evolution in wild plant populations across time and space, using what is called the “resurrection approach”. With an NSF funding of $1.3 million, a team of scientists led by Julie Etterson of the University of Minnesota Duluth established this seed bank. Most seed banks aim at preserving biological diversity. Project Baseline is aimed at controlled studies of how plants evolve under the stresses of climate change and environmental degradation.

In a paper published earlier this year in American Journal of Botany, Julie Etterson and colleagues described the project. The seeds, representing about 60 species, were taken from around 250 locations in the U.S. The process of seed collection began in 2012, and samples were taken from diverse environments and a wide variety of species. The collection phase has now been completed.

Hitherto, when studying the impact of anthropogenic pressures, scientists looked at the differences in similar species growing at different sites or temporal changes at a single site. But with such studies, it can be difficult to distinguish changes caused by evolution from those due to adaptation of plant species to a changing environment, termed plasticity.

The “resurrection approach” is a powerful way to observe evolution in action in the wild and provides insights into how plant populations evolve in response to stressors. Dormant ancestors of a known age are reared in a common garden with the contemporary descendants collected from the same site to directly observe evolutionary change over time and examine how it differs across space. Such studies can tell scientists whether the early flowering observed in some plants in conjunction with global warming is attributable to evolution or plasticity or how fast adaptive evolution is occurring and whether it can keep up with climate change. The project has long timescales compared with the average evolution study, which is important if global change is to be studied, researchers said. The first call for proposals under the project to work with the specimens is planned for 2018.

Compiled by R. Ramachandran