Leaf metabolic traits reveal hidden dimensions of plant form and function

Abstract

The metabolome is the biochemical basis of plant form and function, but we know little about its macroecological variation across the plant kingdom. Here, we used the plant functional trait concept to interpret leaf metabolome variation among 457 tropical and 339 temperate plant species. Distilling metabolite chemistry into five metabolic functional traits reveals that plants vary on two major axes of leaf metabolic specialization—a leaf chemical defense spectrum and an expression of leaf longevity. Axes are similar for tropical and temperate species, with many trait combinations being viable. However, metabolic traits vary orthogonally to life-history strategies described by widely used functional traits. The metabolome thus expands the functional trait concept by providing additional axes of metabolic specialization for examining plant form and function.

Estimating essential phenotypic and molecular traits from integrative biodiversity data

“…As a result, classic phenotypic traits such as those involving plant sizes or discernible plant parts 2 are often difficult to assess. By contrast, molecular traits have recently been shown to explain additional axes of specialisation in tracheophytes 8 supporting the hypothesis that bryophytes interact with their biotic and abiotic environment predominantly at the molecular scale via small molecules 9,10 . In order to resolve this hypothesis, experimental data and methodological frameworks are needed to systematically assess traits in bryophytes 1 .…”

“…In addition, we performed ordination using distance-based redundancy analysis (dbRDA) to correlate molecular with phenotypic traits and molecular with “classic” traits obtained from TRY 4 . Taken together, these analyses allow assessments of trait quality and gaining deeper insights into functional mechanisms 8 . Exemplary code to perform integration of functional ecology data is available on GitHub (https://ipb-halle.github.io/iESTIMATE/doc/data_integration.html).…”

“…They also facilitate data integration by providing an intermediate abstraction layer between primary observations and ecological functions 27 . Distilling the phenotypic and molecular data into EMVs and integrating them into a coherent ecological context enhances the explanatory power of the functional trait concept and offers a new set of tools for the discovery of mechanisms in functional ecology, biodiversity and related disciplines 2,3,8 .…”

“…The idea of molecular plant traits representing ecological functions or patterns via the presence/absence or abundance of small molecules has been around since the beginning of the century 13 . But only recently, they have been proposed to be integrated as conceptual entities into functional ecology 8 mainly due to insufficient reference data and facilitated by recent computational breakthroughs in metabolomics such as in silico annotations 14,15 , in silico compound classification 16 utilizing chemical ontologies 17,18 , computational molecular structure representations leading to quantitative structure-activity (QSARs) and -property relationships (QSPRs) and other chemical modelling approaches enabling the calculation of molecular descriptors 19–22 , computer-assisted community-guided chemical knowledge extraction 23 , open-source cheminformatics libraries 24 , or public libraries that compile and provide these various information using the FAIR principles 25,26 . However, data on molecular traits are still scarce, fragmented and ambiguous as controlled vocabularies and standardised frameworks are largely incomplete defining and naming the individual components of molecular traits relevant in ecology.…”

Effects of Leaf Size and Defensive Traits on the Contribution of Soil Fauna to Litter Decomposition

“…Fujii et al [35] proposed a theory that litter traits (food-traits related to resource economics and stoichiometry, habitat traits related to particle size and shape) provide both food and habitats for soil fauna. Walker et al [36] conducted a comprehensive analysis of the leaf chemical defense spectrum across 457 tropical and 339 temperate plant species worldwide. These litter traits have an afterlife effect on soil fauna and litter decomposition [37]: (i) traits associated with the LES, including carbon, nitrogen, phosphorus, and other elements, which can affect the decomposition rate and soil organisms [32]; (ii) traits related to the SSS, including leaf length, leaf width, and leaf area, which moderate the litter layer's temperature, humidity, and oxygen content, thereby affecting the foraging behavior and nutrient cycling activities of soil fauna [1,27,34].…”