Seed plants vary tremendously in size and morphology. However, variation and covariation between plant traits may at least in part be governed by universal biophysical laws and biological constants. Metabolic Scaling Theory (MST) posits that whole-organismal metabolism and growth rate are under stabilizing selection that minimizes the scaling of hydrodynamic resistance and maximizes the scaling of resource uptake. This constrains variation in physiological traits and in the rate of biomass accumulation, so that they can be expressed as mathematical functions of plant size with near constant allometric scaling exponents across species. However, observed variation in scaling exponents questions the evolutionary drivers and the universality of allometric equations. We have measured growth scaling and fitness traits of 451 Arabidopsis thaliana accessions with sequenced genomes. Variation among accessions around the scaling exponent predicted by MST correlated with relative growth rate, seed production and stress resistance. Genomic analyses indicate that growth allometry is affected by many genes associated with local climate and abiotic stress response. The gene with the strongest effect, PUB4, has molecular signatures of balancing selection, suggesting that intraspecific variation in growth scaling is maintained by opposing selection on the trade-off between seed production and abiotic stress resistance. Our findings support a core MST prediction and suggest that variation in allometry contributes to local adaptation to contrasting environments. Our results help reconcile past debates on the origin of allometric scaling in biology, and begin to link adaptive variation in allometric scaling to specific genes.
The main file (‘Accessions_phenotypes’) contains average trait values per accession for plant lifespan (days), fruit number, final rosette dry mass (DM, mg), absolute growth rate (mg d-1), relative growth rate (RGR, mg d-1 g-1), and the scaling exponent.
Accessions are identified with their 1001-genomes project IDs (http://1001genomes.org/), as well as latitude and longitude of origin.
This file contains rosette area (cm2) and shape descriptors for all plants (451 accessions with 2 replicates) grown until the end of the life cycle. Data were extracted from image analysis (see related papers) during the 25 first days after vernalization to estimate rosette dry mass and growth dynamics with a modelling approach.
This file contains rosette area (cm2) data at the end of the life cycle, when plants have been destructively harvested (451 accessions of A. thaliana, n=2).
This file contains rosette dry mass (mg) data measured at the end of the life cycle, when the plants have been destructively harvested (451 accessions with two replicates).
This file file contains rosette area (cm2) and shape descriptors, as well as rosette dry mass (mg) and leaf dry mass per area (LMA, g m-2) measured on 817 individuals (n = 2 per accession) by image analysis, plant dissection and weighing. Plants have been harvested 16 days after the end of vernalization (see related papers for details).
This file contains the skeleton parameters extracted from image analysis of each plant inflorescence (see related papers). This file is used to automatically estimated fruit number from pictures of inflorescences.
This file contains the manual counting of the number of siliques (fruits) per plant (n=385).
National Science Foundation, Award: NSF ATB and Macrosystems award