title: The ubiquity of phenotypic plasticity in plants: a synthesis.
abstract: Adaptation to heterogeneous environments can occur via phenotypic plasticity, but how often this occurs is unknown. Reciprocal transplant studies provide a rich dataset to address this issue in plant populations because they allow for a determination of the prevalence of plastic versus canalized responses. From 31 reciprocal transplant studies, we quantified the frequency of five possible evolutionary patterns: (1) canalized response-no differentiation: no plasticity, the mean phenotypes of the populations are not different; (2) canalized response-population differentiation: no plasticity, the mean phenotypes of the populations are different; (3) perfect adaptive plasticity: plastic responses with similar reaction norms between populations; (4) adaptive plasticity: plastic responses with parallel, but not congruent reaction norms between populations; and (5) nonadaptive plasticity: plastic responses with differences in the slope of the reaction norms. The analysis included 362 records: 50.8% life-history traits, 43.6% morphological traits, and 5.5% physiological traits. Across all traits, 52% of the trait records were not plastic, and either showed no difference in means across sites (17%) or differed among sites (83%). Among the 48% of trait records that showed some sort of plasticity, 49.4% showed perfect adaptive plasticity, 19.5% adaptive plasticity, and 31% nonadaptive plasticity. These results suggest that canalized responses are more common than adaptive plasticity as an evolutionary response to environmental heterogeneity.
authors.affiliation: Department of Plant Biology, University of Vermont Burlington, Vermont, 05405.
authors.forename: Kattia
authors.initials: K
authors.lastname: Palacio-López
authors.affiliation: Department of Plant Biology, University of Vermont Burlington, Vermont, 05405.
authors.forename: Brian
authors.initials: B
authors.lastname: Beckage
authors.affiliation: Division of Environmental Biology, National Science Foundation 4201 Wilson Blvd., Arlington, Virginia, 22230.
authors.forename: Samuel
authors.initials: S
authors.lastname: Scheiner
authors.affiliation: Department of Plant Biology, University of Vermont Burlington, Vermont, 05405.
authors.forename: Jane
authors.initials: J
authors.lastname: Molofsky
keywords: Adaptive plasticity; canalization; life-history traits; local adaptation; morphological traits; reciprocal transplant studies