Abstract
Functional trait variation in plants of the same species or genotype are
a critical determinant of ecosystem processes, especially in
agroecosystems where single crop species or genotypes exist in very high
abundances. Yet to date only a small number of studies have evaluated
if, how, or why traits forming the Leaf Economics Spectrum (LES) vary
within crops, despite such studies informing our understanding of: 1)
the environmental factors that drive crop LES trait variation; and 2)
how domestication has altered LES traits in crops vs. wild plants. We
assess intragenotype variation in LES traits in wine grape variety
‘Chardonnay’ (Vitis vinifera)—among the world’s most commercially
important crops, across a soil compaction gradient: one of the most
prominent characteristics of agricultural soils that may drive crop
trait variation. ‘Chardonnay’ traits covary along an intragenotype LES
in patterns that were qualitatively similar to, though statistically
distinguishable from, those observed among wild plants: resource
acquiring vines expressed a combination of high mass-based
photosynthesis (Amass), mass-based dark respiration (Rmass), leaf
nitrogen concentrations (N), coupled with low leaf mass per area (LMA);
the opposite set of trait values defined the resource conserving end of
the ‘Chardonnay’ LES. Traits related to resource acquisition (Amass,
Rmass, and leaf N) declined with greater bulk density, while traits
related to investment in leaf construction costs (LMA) increased with
greater bulk density. Compared to wild plants, ‘Chardonnay’ expressed
lower Rmass for a given rate of Amass, and an unexpected positive
covariation between leaf carbon (C) concentrations and Rmass, Amass, and
leaf N. Our findings uncover a deeper understanding of both the
domestication syndromes in grapevines, and expand our understanding of
trait-based crop responses to environmental change and gradients.