Fig. 2.

The proportion of Arabidopsis thaliana seeds germinating after different durations of seed burial at the Italian (A, C) and Swedish site (B, D; mean ± s.e.). Germination of seeds of the Italian and Swedish genotype produced in the glasshouse and at the site of burial was quantified after 1 week (A, B) and 4 weeks (C, D) in a growth room under standard conditions. For the seeds tested at the moment of seed burial and the seeds from the first excavation, the germination assays were conducted for only 1 week. The seed maturation and germination period of the natural populations at the two burial sites in Italy and Sweden are indicated on the x-axis together with the moments of seed burial (downward-pointing arrow) and the six sampling occasions (upward-pointing arrows).