title: Genotypic variation in traits linked to climate and aboveground productivity in a widespread C₄ grass: evidence for a functional trait syndrome.
abstract: Examining intraspecific variation in growth and function in relation to climate may provide insight into physiological evolution and adaptation, and is important for predicting species responses to climate change. Under common garden conditions, we grew nine genotypes of the C₄ species Panicum virgatum originating from different temperature and precipitation environments. We hypothesized that genotype productivity, morphology and physiological traits would be correlated with climate of origin, and a suite of adaptive traits would show high broad-sense heritability (H(2)). Genotype productivity and flowering time increased and decreased, respectively, with home-climate temperature, and home-climate temperature was correlated with genotypic differences in a syndrome of morphological and physiological traits. Genotype leaf and tiller size, leaf lamina thickness, leaf mass per area (LMA) and C : N ratios increased with home-climate temperature, whereas leaf nitrogen per unit mass (Nm ) and chlorophyll (Chl) decreased with home-climate temperature. Trait variation was largely explained by genotypic differences (H(2) = 0.33-0.85). Our results provide new insight into the role of climate in driving functional trait coordination, local adaptation and genetic divergence within species. These results emphasize the importance of considering intraspecific variation in future climate change scenarios.
authors.affiliation: Section of Integrative Biology, University of Texas at Austin, Austin, TX, 78712, USA.|Hawkesbury Institute for the Environment, University of Western Sydney, Richmond, NSW, 2753, Australia.
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Aspinwall
authors.affiliation: Section of Integrative Biology, University of Texas at Austin, Austin, TX, 78712, USA.
authors.forename: David B
authors.initials: DB
authors.lastname: Lowry
authors.affiliation: Section of Integrative Biology, University of Texas at Austin, Austin, TX, 78712, USA.|Biology Department, Bowdoin College, Brunswick, ME, 04011, USA.
authors.forename: Samuel H
authors.initials: SH
authors.lastname: Taylor
authors.affiliation: Section of Integrative Biology, University of Texas at Austin, Austin, TX, 78712, USA.
authors.forename: Thomas E
authors.initials: TE
authors.lastname: Juenger
authors.affiliation: Section of Integrative Biology, University of Texas at Austin, Austin, TX, 78712, USA.
authors.forename: Christine V
authors.initials: CV
authors.lastname: Hawkes
authors.affiliation: USDA-NRCS Resources Assessment Division, Temple, TX, 76502, USA.
authors.forename: Mari-Vaughn V
authors.initials: MV
authors.lastname: Johnson
authors.affiliation: USDA-ARS Grassland Soil and Water Research Laboratory, Temple, TX, 76502, USA.
authors.forename: James R
authors.initials: JR
authors.lastname: Kiniry
authors.affiliation: USDA-ARS Grassland Soil and Water Research Laboratory, Temple, TX, 76502, USA.
authors.forename: Philip A
authors.initials: PA
authors.lastname: Fay
mesh_terms: D000704:Analysis of Variance; D002244:Carbon / Q000378:metabolism; D002980:Climate; D014644:Genetic Variation; D005838:Genotype; D005843:Geography; D040582:Inheritance Patterns / Q000235:genetics; D008897:Panicum / Q000033:anatomy & histology / Q000235:genetics* / Q000254:growth & development*; D018515:Plant Leaves / Q000033:anatomy & histology / Q000235:genetics / Q000254:growth & development; D011003:Ploidies; D025341:Principal Component Analysis; D019655:Quantitative Trait, Heritable; D012621:Seasons
chemical_list: D002244:Carbon
keywords: C4; Panicum virgatum (switchgrass); climate change; evolution; genecology; physiology; polyploidy