Evolution of Arabidopsis thaliana Flowering Time in Response to Water Availability Post-Introduction.

摘要

Flowering is one of the most influential events in the life history of a plant---its beginning and duration are two main determinants of reproductive investment and lifetime fitness. Understanding the selective pressures influencing time to flowering and being able to reliably predict how it will evolve in novel environments is an unsolved challenge for plant evolutionary geneticists. Using naturalized lines of Arabidopsis thaliana from across the eastern North American range, I examined the impact of simulated winter precipitation levels on flowering time and the fitness consequences of early versus late flowering. Flowering time was significantly genetically correlated across two environments---in common gardens outdoors and in environmental chambers set to mimic mid-range photoperiod and temperature conditions---suggesting that flowering time rank between lines remains consistent. The interaction between flowering time and water treatment for fitness indicates that water availability contributes to differential selection on flowering time in introduced populations.