Weak coordination between leaf structure and function among closely related tomato species

Abstract

Theory predicts that natural selection should favor coordination between leaf physiology, biochemistry and anatomical structure along a functional trait spectrum from fast, resource-acquisitive syndromes to slow, resource-conservative syndromes. However, the coordination hypothesis has rarely been tested at a phylogenetic scale most relevant for understanding rapid adaptation in the recent past or for the prediction of evolutionary trajectories in response to climate change. We used a common garden to examine genetically based coordination between leaf traits across 19 wild and cultivated tomato taxa. We found weak integration between leaf structure (e.g. leaf mass per area) and physiological function (photosynthetic rate, biochemical capacity and CO diffusion), even though all were arrayed in the predicted direction along a 'fast-slow' spectrum. This suggests considerable scope for unique trait combinations to evolve in response to new environments or in crop breeding. In particular, we found that partially independent variation in stomatal and mesophyll conductance may allow a plant to improve water-use efficiency without necessarily sacrificing maximum photosynthetic rates. Our study does not imply that functional trait spectra, such as the leaf economics spectrum, are unimportant, but that many important axes of variation within a taxonomic group may be unique and not generalizable to other taxa.

Divergent trait and environment relationships among parallel radiations in Pelargonium (Geraniaceae): a role for evolutionary legacy?

“…We suggest that differences in patterns of TT and TE associations between Pelargonium subclades may have been established during the diversification of the genus, perhaps facilitated by the evolution of divergent growth forms in response to environmental variation. We are not the first to conclude that global studies may be poor predictors of patterns and processes for smaller taxonomic or geographic scales (Prunier et al, 2012;Funk & Cornwell, 2013;Mason & Donovan, 2015;Mitchell et al, 2015;Messier et al, 2016;Muir et al, 2017). The challenge ahead is to determine at what phylogenetic level, and under what conditions, key lineage-specific anchor traits are shaping more commonly measured functional traits and their TE and TT interactions.…”

“…However, extrapolating from large, global datasets to regional or limited taxonomic scales has conflicting empirical support (e.g. matching global patterns -Blonder et al, 2015; not matching global patterns - Edwards et al, 2014;Mason & Donovan, 2015;Muir et al, 2017). With respect to TE relationships, the extensive environmental gradients assessed in global-scale studies generally do not occur at regional scales (Messier et al, 2016).…”

Variable Mesophyll Conductance among Soybean Cultivars Sets a Tradeoff between Photosynthesis and Water-Use-Efficiency

“…Clearly, genetic variation for g m exists in the monocots, although in 2014, half of the world's 10 most planted (as total area) crops were eudicots (FAOSTAT 2016; http://faostat3.fao.org/ download/Q/QC/E). Tomato (Solanum lycopersicum) and grape (Vitis vinifera) are the only eudicot food crops for which g m has been studied at the intrageneric (Muir et al, 2014(Muir et al, , 2017 or intraspecific (Galmés et al, 2011;Tomás et al, 2014) level, and estimates of genetic variation for g m in these and other eudicot crops are lacking, revealing a substantial knowledge gap.…”

“…The contrast between our positive g m -LMA relationship and that found by Gu et al (2012) is harder to explain, since they saw a negative relationship between LMA and g m in rice regardless of plant water status. A recent study in tomato and tomato wild relatives, bridging the gap between these intraspecific studies and broad taxonomic surveys where the g m -LMA relationship is consistently negative, demonstrates that, at finer taxonomic scales, this relationship is more labile, resulting from low coordination between LMA and leaf physiological activity (Muir et al, 2017). In any event, if the observed scaling of g m with LMA holds, it suggests an appealing trait for preliminary selection of candidate soybean genotypes with fast photosynthetic physiologies.…”

Functional ecology of congeneric variation in the leaf economics spectrum

“…The relationships change across ecological scales (Messier et al, 2010(Messier et al, , 2016 and among particular taxonomic groups. Support for the LES erodes when the range of comparison is narrowed to congeners (Mason & Donovan, 2015;Muir et al, 2017;Bahar et al, 2018), species (Niinemets, 2015;Anderegg et al, 2018), species within a functional group (Li et al, 2015(Li et al, , 2017, or co-occurring species in a single locality (Messier et al, 2016(Messier et al, , 2018aKatabuchi et al, 2017). Countergradient responses are also well documented, that is, situations where relationships between LES traits are strong but contrary to global trends (Lusk et al, 2008;Russo & Kitajima, 2016;Anderegg et al, 2018).…”