XVI International Botanical Congess

We used a phylogenetic and quantitative genetic approach to investigate the evolution of phenotypic plasticity in Scandinavian accessions of A. thaliana and closely related species. Plants were exposed to long and short photoperiods. Variation for plasticity was found for 5 of 8 traits. Phylogenetically independent contrasts showed the coevolution of 2 (of 10) plasticities and 6 (of 15) across-treatment means. One (of 3) across-treatment means coevolved with their respective plasticities. Phylogenetically informed ANOVA contrasts revealed that character means evolved faster than character plasticities (as judged by the number of significant contrasts for the two classes of traits). Results are currently being compared with the response of the same accessions to light quality (shade avoidance) to determine if the two types of plasticity constrain each other's evolution.