Evolutionary Patterns and Biogeochemical Significance of Angiosperm Root Traits

Comas, Louise H.; Mueller, Kevin E.; Taylor, Lyla L.; Midford, Peter E.; Callahan, Hilary S.; Beerling, David J.

doi:10.1086/665823

Cited by 157 publications

(198 citation statements)

References 100 publications

(137 reference statements)

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“…We found a general overall pattern of root diameter becoming thinner as species diversified, similar to the pattern found in a data set of tropical and subtropical species (Comas et al. 2012). No phylogenetic signal was found in tissue density, which other studies of temperate woody species have suggested may vary more in response to soil microsite properties rather than in association with differences among species (e.g., Comas and Eissenstat 2009).…”

Section: Discussionmentioning

confidence: 99%

“…2009; Comas et al. 2012). Clear evolutionary patterns are found of fine roots becoming thinner as angiosperms radiated, as compared to remaining relatively coarser in more basal and less diverse angiosperm and nonangiosoperm lineages (e.g., cycads, gnetophytes, and gingko) (Comas et al.…”

Section: Discussionmentioning

confidence: 99%

“…2009; Comas et al. 2012). Mycorrhizal associations formed by plants have also been found to be concurrent with plant effects on carbon and nutrient cycling (Cornelissen et al.…”

Section: Introductionmentioning

confidence: 99%

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Patterns in root traits of woody species hosting arbuscular and ectomycorrhizas: implications for the evolution of belowground strategies

Comas

Callahan

Midford

2014

Ecology and Evolution

147

149

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Root traits vary enormously among plant species but we have little understanding of how this variation affects their functioning. Of central interest is how root traits are related to plant resource acquisition strategies from soil. We examined root traits of 33 woody species from northeastern US forests that form two of the most common types of mutualisms with fungi, arbuscular mycorrhizas (AM) and ectomycorrhizas (EM). We examined root trait distribution with respect to plant phylogeny, quantifying the phylogenetic signal (K statistic) in fine root morphology and architecture, and used phylogenetically independent contrasts (PICs) to test whether taxa forming different mycorrhizal associations had different root traits. We found a pattern of species forming roots with thinner diameters as species diversified across time. Given moderate phylogenetic signals (K = 0.44–0.68), we used PICs to examine traits variation among taxa forming AM or EM, revealing that hosts of AM were associated with lower branching intensity (rPIC = −0.77) and thicker root diameter (rPIC = −0.41). Because EM evolved relatively more recently and intermittently across plant phylogenies, significant differences in root traits and colonization between plants forming AM and EM imply linkages between the evolution of these biotic interactions and root traits and suggest a history of selection pressures, with trade-offs for supporting different types of associations. Finally, across plant hosts of both EM and AM, species with thinner root diameters and longer specific root length (SRL) had less colonization (rPIC = 0.85, −0.87), suggesting constraints on colonization linked to the evolution of root morphology.

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Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

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Patterns in root traits of woody species hosting arbuscular and ectomycorrhizas: implications for the evolution of belowground strategies

Comas

Callahan

Midford

2014

Ecology and Evolution

147

149

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“…For woody plants, root diameter predominately controls differences in SRL and SSA among species, with root tissue density affecting plasticity within species due to plant responses to edaphic factors such as soil water (Comas et al, 2002; Comas and Eissenstat, 2009). Small diameter roots with greater SRL enable plants to efficiently increase hydraulic conductance by increasing surface area in contact with soil water, increasing the volume of soil that can be explored for water, and, also, increasing root hydraulic conductivity by decreasing the apoplastic barrier of water entering the xylem (Eissenstat and Achor, 1999; Rieger and Litvin, 1999; Huang and Eissenstat, 2000; Solari et al, 2006; Hernández et al, 2010; Comas et al, 2012). Accordingly, decrease in root diameter has been proposed as a trait for increasing plant acquisition of water and productivity under drought (Wasson et al, 2012).…”

Section: Root Systems Traits and Functioning In Water Uptakementioning

confidence: 99%

Root traits contributing to plant productivity under drought

Comas¹,

Becker²,

Cruz³

et al. 2013

Front. Plant Sci.

1,096

819

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Geneticists and breeders are positioned to breed plants with root traits that improve productivity under drought. However, a better understanding of root functional traits and how traits are related to whole plant strategies to increase crop productivity under different drought conditions is needed. Root traits associated with maintaining plant productivity under drought include small fine root diameters, long specific root length, and considerable root length density, especially at depths in soil with available water. In environments with late season water deficits, small xylem diameters in targeted seminal roots save soil water deep in the soil profile for use during crop maturation and result in improved yields. Capacity for deep root growth and large xylem diameters in deep roots may also improve root acquisition of water when ample water at depth is available. Xylem pit anatomy that makes xylem less “leaky” and prone to cavitation warrants further exploration holding promise that such traits may improve plant productivity in water-limited environments without negatively impacting yield under adequate water conditions. Rapid resumption of root growth following soil rewetting may improve plant productivity under episodic drought. Genetic control of many of these traits through breeding appears feasible. Several recent reviews have covered methods for screening root traits but an appreciation for the complexity of root systems (e.g., functional differences between fine and coarse roots) needs to be paired with these methods to successfully identify relevant traits for crop improvement. Screening of root traits at early stages in plant development can proxy traits at mature stages but verification is needed on a case by case basis that traits are linked to increased crop productivity under drought. Examples in lesquerella (Physaria) and rice (Oryza) show approaches to phenotyping of root traits and current understanding of root trait genetics for breeding.

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“…Similarly, differences in fine‐root traits among species are thought to represent their evolutionary history and adaptations to a wide range of biotic and abiotic factors (Kembel & Cahill ; Comas et al . ).…”

Section: Introductionmentioning

confidence: 97%

Climate, soil and plant functional types as drivers of global fine‐root trait variation

et al. 2017

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International audience* Ecosystem functioning relies heavily on below-ground processes, which are largely regulated by plant fine-roots and their functional traits. However, our knowledge of fine-root trait distribution relies to date on local- and regional-scale studies with limited numbers of species, growth forms and environmental variation. * We compiled a world-wide fine-root trait dataset, featuring 1115 species from contrasting climatic areas, phylogeny and growth forms to test a series of hypotheses pertaining to the influence of plant functional types, soil and climate variables, and the degree of manipulation of plant growing conditions on species fine-root trait variation. Most particularly, we tested the competing hypotheses that fine-root traits typical of faster return on investment would be most strongly associated with conditions of limiting versus favourable soil resource availability. We accounted for both data source and species phylogenetic relatedness. * We demonstrate that: (i) Climate conditions promoting soil fertility relate negatively to fine-root traits favouring fast soil resource acquisition, with a particularly strong positive effect of temperature on fine-root diameter and negative effect on specific root length (SRL), and a negative effect of rainfall on root nitrogen concentration; (ii) Soil bulk density strongly influences species fine-root morphology, by favouring thicker, denser fine-roots; (iii) Fine-roots from herbaceous species are on average finer and have higher SRL than those of woody species, and N2-fixing capacity positively relates to root nitrogen; and (iv) Plants growing in pots have higher SRL than those grown in the field. * Synthesis. This study reveals both the large variation in fine-root traits encountered globally and the relevance of several key plant functional types and soil and climate variables for explaining a substantial part of this variation. Climate, particularly temperature, and plant functional types were the two strongest predictors of fine-root trait variation. High trait variation occurred at local scales, suggesting that wide-ranging below-ground resource economics strategies are viable within most climatic areas and soil conditions

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Evolutionary Patterns and Biogeochemical Significance of Angiosperm Root Traits

Cited by 157 publications

References 100 publications

Patterns in root traits of woody species hosting arbuscular and ectomycorrhizas: implications for the evolution of belowground strategies

Patterns in root traits of woody species hosting arbuscular and ectomycorrhizas: implications for the evolution of belowground strategies

Root traits contributing to plant productivity under drought

Climate, soil and plant functional types as drivers of global fine‐root trait variation

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