Divergence in wilt tolerance across the range of Mimulus guttatus in the absence of stomatal regulation
- 1Connecticut College
Abstract
Whether phenotypes and environments predict performance under stress is central to ecology and evolution and can reveal species' vulnerability to global change. We sampled Mimulus guttatus range-wide to test whether reproductive, morphological, and physiological traits predict drought responses. Surprisingly, we find that stomatal response, a key mediator of water balance, did not change as drought intensified. Climate, however, predicted survival after turgor loss: plants from regions with large daily relative to seasonal temperature ranges survived wilting longer. Stress responses also depended on life history: where summers are dry, perennials withstood lower water potentials, whereas annuals increased leaf cooling as they wilted. Known trait associations were not fixed: although many baseline traits tracked climate, none predicted drought responses. Drought performance therefore cannot be inferred from traits measured under well-watered conditions. Lacking stomatal regulation, riparian drought escapers like M. guttatus may be vulnerable if shorter growing seasons bring drought before reproduction.
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BibTeX
@misc{branch2026divergence,
title = {{Divergence in wilt tolerance across the range of Mimulus guttatus in the absence of stomatal regulation}},
author = {H. A. Branch and P. Raimondeau and V. Tonet and H. Arenas Castro and A. Fairclough and L. Hyde and D. Lakes and A. Singletary and B. K. Blackman and K. Toll and M. Vallejo-Marin and C. R. Brodersen and E. Edwards and J. M. Coughlan},
howpublished = {bioRxiv},
year = {2026},
month = sep,
doi = {10.64898/2026.09.30.755782},
url = {https://www.biorxiv.org/content/10.64898/2026.09.30.755782v1},
note = {CC BY-NC},
}
RIS
TY - UNPB
TI - Divergence in wilt tolerance across the range of Mimulus guttatus in the absence of stomatal regulation
AU - H. A. Branch
AU - P. Raimondeau
AU - V. Tonet
AU - H. Arenas Castro
AU - A. Fairclough
AU - L. Hyde
AU - D. Lakes
AU - A. Singletary
AU - B. K. Blackman
AU - K. Toll
AU - M. Vallejo-Marin
AU - C. R. Brodersen
AU - E. Edwards
AU - J. M. Coughlan
PY - 2026
DA - 2026/09/30
PB - bioRxiv
DO - 10.64898/2026.09.30.755782
UR - https://www.biorxiv.org/content/10.64898/2026.09.30.755782v1
AB - Whether phenotypes and environments predict performance under stress is central to ecology and evolution and can reveal species' vulnerability to global change. We sampled Mimulus guttatus range-wide to test whether reproductive, morphological, and physiological traits predict drought responses. Surprisingly, we find that stomatal response, a key mediator of water balance, did not change as drought intensified. Climate, however, predicted survival after turgor loss: plants from regions with large daily relative to seasonal temperature ranges survived wilting longer. Stress responses also depended on life history: where summers are dry, perennials withstood lower water potentials, whereas annuals increased leaf cooling as they wilted. Known trait associations were not fixed: although many baseline traits tracked climate, none predicted drought responses. Drought performance therefore cannot be inferred from traits measured under well-watered conditions. Lacking stomatal regulation, riparian drought escapers like M. guttatus may be vulnerable if shorter growing seasons bring drought before reproduction.
ER -