Water stress is a ubiquitous abiotic factor influencing plant populations. Plants have evolved different mechanisms to deal with drought stress, including dehydration avoidance and drought escape. Here, we examine whether Arabidopsis thaliana responds plastically (differentially) with respect to dehydration avoidance and drought escape traits when grown in different soil moisture conditions. Twenty-six European ecotypes of A. thaliana were grown under well-watered or drought conditions. We quantified the effect of watering regime for plant growth and reproduction (chlorophyll content, rosette diameter, and total reproduction), drought avoidance (leaf hair production), and drought escape (flowering time) traits.
Results/Conclusions
Drought stress reduced plant size and chlorophyll content but did not affect total fruit production. The ecotypes responded plastically to drought with respect to flowering time and leaf hair density; plants experiencing drought flowered earlier and produced leaves with greater leaf hair density. We found significant genetic variation among the ecotypes for plasticity in flowering time and leaf hair density, indicating the potential for plasticity in these traits to evolve via natural selection. To determine whether the induced plastic responses in leaf hair production and flowering time in the maternal generation were transmitted to the progeny and influenced progeny reproductive potential, we grew offspring under well-watered and drought conditions. We expect that offspring experiencing an environment similar to the mother’s will show higher fitness (flower and fruit production) than those individuals experiencing the water treatment opposite of their mother’s.