AbstractFor over 10,000 years humans have shaped plant traits through domestication. Studies of domestication have focused on changes to trait averages; however, plants also have characteristic levels of trait variability among their repeated parts, which can be heritable and mediate critical ecological interactions. Here, we ask how domestication selection has altered among-leaf trait variability using alfalfa (Medicago sativa), the oldest forage crop in the world. We found that domestication changed variability more than averages for multiple traits. Relative to wild progenitors, domesticates had elevated variability in specific leaf area, trichomes, C:N, and phytochemical concentrations and reduced variability in phytochemical composition among their leaves. Our work shows that within-plant trait variability is a novel facet of the domesticated plant phenotype, constituting a novel frontier of trait diversity within crop fields. As many critical biotic interactions occur at the scale of individual plants, our findings suggest that trait variability and diversity among leaves could act to magnify or counter the depauperate trait diversity often found at higher scales in agroecosystems.
Monitoring salt stress in grapevines: are measures of plant trait variability useful?