Plant roots have greatly diversified in form and function since the emergence of the first land plants1,2, but the global organization of functional traits in roots remains poorly understood3,4. Here we analyse a global dataset of 10 functionally important root traits in metabolically active first-order roots, collected from 369 species distributed across the natural plant communities of 7 biomes. Our results identify a high degree of organization of root traits across species and biomes, and reveal a pattern that differs from expectations based on previous studies5,6 of leaf traits. Root diameter exerts the strongest influence on root trait variation across plant species, growth forms and biomes. Our analysis suggests that plants have evolved thinner roots since they first emerged in land ecosystems, which has enabled them to markedly improve their efficiency of soil exploration per unit of carbon invested and to reduce their dependence on symbiotic mycorrhizal fungi. We also found that diversity in root morphological traits is greatest in the tropics, where plant diversity is highest and many ancestral phylogenetic groups are preserved. Diversity in root morphology declines sharply across the sequence of tropical, temperate and desert biomes, presumably owing to changes in resource supply caused by seasonally inhospitable abiotic conditions. Our results suggest that root traits have evolved along a spectrum bounded by two contrasting strategies of root life: an ancestral ‘conservative’ strategy in which plants with thick roots depend on symbiosis with mycorrhizal fungi for soil resources and a more-derived ‘opportunistic’ strategy in which thin roots enable plants to more efficiently leverage photosynthetic carbon for soil exploration. These findings imply that innovations of belowground traits have had an important role in preparing plants to colonize new habitats, and in generating biodiversity within and across biomes.
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Kenrick, P. & Crane, P. R. The origin and early evolution of plants on land. Nature 389, 33–39 (1997)
Field, K. J., Pressel, S., Duckett, J. G., Rimington, W. R. & Bidartondo, M. I. Symbiotic options for the conquest of land. Trends Ecol. Evol. 30, 477–486 (2015)
Bardgett, R. D., Mommer, L. & De Vries, F. T. Going underground: root traits as drivers of ecosystem processes. Trends Ecol. Evol. 29, 692–699 (2014)
Weemstra, M. et al. Towards a multidimensional root trait framework: a tree root review. New Phytol. 211, 1159–1169 (2016)
Díaz, S. et al. The global spectrum of plant form and function. Nature 529, 167–171 (2016)
Wright, I. J. et al. The worldwide leaf economics spectrum. Nature 428, 821–827 (2004)
Roumet, C. et al. Root structure–function relationships in 74 species: evidence of a root economics spectrum related to carbon economy. New Phytol. 210, 815–826 (2016)
Pregitzer, K. S. et al. Fine root architecture of nine North American trees. Ecol. Monogr. 72, 293–309 (2002)
McCormack, M. L. et al. Redefining fine roots improves understanding of below-ground contributions to terrestrial biosphere processes. New Phytol. 207, 505–518 (2015)
Chen, W. et al. Root morphology and mycorrhizal symbioses together shape nutrient foraging strategies of temperate trees. Proc. Natl Acad. Sci. USA 113, 8741–8746 (2016)
Norby, R. J., Ledford, J., Reilly, C. D., Miller, N. E. & O’Neill, E. G. Fine-root production dominates response of a deciduous forest to atmospheric CO2 enrichment. Proc. Natl Acad. Sci. USA 101, 9689–9693 (2004)
Jackson, R. B., Mooney, H. A. & Schulze, E. D. A global budget for fine root biomass, surface area, and nutrient contents. Proc. Natl Acad. Sci. USA 94, 7362–7366 (1997)
McCormack, M. L. et al. Building a better foundation: improving root-trait measurements to understand and model plant and ecosystem processes. New Phytol. 215, 27–37 (2017)
Chen, W. L., Zeng, H., Eissenstat, D. M. & Guo, D. Variation of first-order root traits across climatic gradients and evolutionary trends in geological time. Glob. Ecol. Biogeogr. 22, 846–856 (2013)
Guo, D. et al. Anatomical traits associated with absorption and mycorrhizal colonization are linked to root branch order in twenty-three Chinese temperate tree species. New Phytol. 180, 673–683 (2008)
Reich, P. B. et al. Scaling of respiration to nitrogen in leaves, stems and roots of higher land plants. Ecol. Lett. 11, 793–801 (2008)
Valverde-Barrantes, O. J., Freschet, G. T., Roumet, C. & Blackwood, C. B. A worldview of root traits: the influence of ancestry, growth form, climate and mycorrhizal association on the functional trait variation of fine-root tissues in seed plants. New Phytol. 215, 1562–1573 (2017)
Iversen, C. M. et al. A global fine-root ecology database to address below-ground challenges in plant ecology. New Phytol. 215, 15–26 (2017)
Kong, D. et al. Leading dimensions in absorptive root trait variation across 96 subtropical forest species. New Phytol. 203, 863–872 (2014)
Feild, T. S. & Arens, N. C. Form, function and environments of the early angiosperms: merging extant phylogeny and ecophysiology with fossils. New Phytol. 166, 383–408 (2005)
Comas, L. H. et al. Evolutionary patterns and biogeochemical significance of angiosperm root traits. Int. J. Plant Sci. 173, 584–595 (2012)
Ackerly, D. D. & Reich, P. B. Convergence and correlations among leaf size and function in seed plants: a comparative test using independent contrasts. Am. J. Bot. 86, 1272–1281 (1999)
Wing, S. L. et al. Late Paleocene fossils from the Cerrejon Formation, Colombia, are the earliest record of Neotropical rainforest. Proc. Natl Acad. Sci. USA 106, 18627–18632 (2009)
Woodward, F. I., Lomas, M. R. & Kelly, C. K. Global climate and the distribution of plant biomes. Philos. Trans. Roy. Soc. Lond. B. 359, 1465–1476 (2004)
Eissenstat, D. M., Kucharski, J. M., Zadworny, M., Adams, T. S. & Koide, R. T. Linking root traits to nutrient foraging in arbuscular mycorrhizal trees in a temperate forest. New Phytol. 208, 114–124 (2015)
Li, H., Liu, B., McCormack, M. L., Ma, Z. & Guo, D. Diverse belowground resource strategies underlie plant species coexistence and spatial distribution in three grasslands along a precipitation gradient. New Phytol. 216, 1140–1150 (2017)
Hummel, I. et al. Relating root structure and anatomy to whole-plant functioning in 14 herbaceous Mediterranean species. New Phytol. 173, 313–321 (2007)
Ostonen, I. et al. Fine root foraging strategies in Norway spruce forests across a European climate gradient. Glob. Chang. Biol. 17, 3620–3632 (2011)
Leppälammi-Kujansuu, J. et al. Fine root longevity and carbon input into soil from below- and aboveground litter in climatically contrasting forests. For. Ecol. Manage. 326, 79–90 (2014)
Withington, J. M., Reich, P. B., Oleksyn, J. & Eissenstat, D. M. Comparisons of structure and life span in roots and leaves among temperate trees. Ecol. Monogr. 76, 381–397 (2006)
Sun, K., McCormack, M. L., Li, L., Ma, Z. & Guo, D. Fast-cycling unit of root turnover in perennial herbaceous plants in a cold temperate ecosystem. Sci. Rep. 6, 19698 (2016)
Xia, M., Guo, D. & Pregitzer, K. S. Ephemeral root modules in Fraxinus mandshurica. New Phytol. 188, 1065–1074 (2010)
McCormack, M. L., Adams, T. S., Smithwick, E. A. H. & Eissenstat, D. M. Predicting fine root lifespan from plant functional traits in temperate trees. New Phytol. 195, 823–831 (2012)
Valenzuela-Estrada, L. R., Vera-Caraballo, V., Ruth, L. E. & Eissenstat, D. M. Root anatomy, morphology, and longevity among root orders in Vaccinium corymbosum (Ericaceae). Am. J. Bot. 95, 1506–1514 (2008)
Liu, B., He, J., Zeng, F., Lei, J. & Arndt, S. K. Life span and structure of ephemeral root modules of different functional groups from a desert system. New Phytol. 211, 103–112 (2016)
Hansson, K., Helmisaari, H.-S., Sah, S. P. & Lange, H. Fine root production and turnover of tree and understorey vegetation in Scots pine, silver birch and Norway spruce stands in SW Sweden. For. Ecol. Manage. 309, 58–65 (2013)
Huang, J. X. et al. Fine root longevity and controlling factors in subtropical Altingia grlilipes and Castanopsis carlesii forests. Acta Ecol. Sin. 32, 1932–1942 (2012)
Yavitt, J. B., Harms, K. E., Garcia, M. N., Mirabello, M. J. & Wright, S. J. Soil fertility and fine root dynamics in response to 4 years of nutrient (N, P, K) fertilization in a lowland tropical moist forest, Panama. Austral. Ecol. 36, 433–445 (2011)
Ling, H. et al. Influencing factors of fine root lifespans in two Chinese fir plantations in subtropical China. Acta Ecol. Sin. 31, 1130–1138 (2011)
Stover, D. B., Day, F. P., Drake, B. G. & Hinkle, C. R. The long-term effects of CO2 enrichment on fine root productivity, mortality, and survivorship in a scrub-oak ecosystem at Kennedy Space Center, Florida, USA. Environ. Exp. Bot. 69, 214–222 (2010)
Krasowski, M. J., Lavigne, M. B., Olesinski, J. & Bernier, P. Y. Advantages of long-term measurement of fine root demographics with a minirhizotron at two balsam fir sites. Can. J. For. Res. 40, 1128–1135 (2010)
Huang, G., Zhao, X., Zhao, H., Huang, Y. & Zuo, X. Linking root morphology, longevity and function to root branch order: a case study in three shrubs. Plant Soil 336, 197–208 (2010)
Girardin, C. A. J. et al. Net primary productivity allocation and cycling of carbon along a tropical forest elevational transect in the Peruvian Andes. Glob. Chang. Biol. 16, 3176–3192 (2010)
Espeleta, J. F., West, J. B. & Donovan, L. A. Tree species fine-root demography parallels habitat specialization across a sandhill soil resource gradient. Ecology 90, 1773–1787 (2009)
Vargas, R. & Allen, M. F. Dynamics of fine root, fungal rhizomorphs, and soil respiration in a mixed temperate forest: integrating sensors and observations. Vadose Zone J. 7, 1055–1064 (2008)
Graefe, S., Hertel, D. & Leuschner, C. Fine root dynamics along a 2,000-m elevation transect in South Ecuadorian mountain rainforests. Plant Soil 313, 155–166 (2008)
Green, J. J., Dawson, L. A., Proctor, J., Duff, E. I. & Elston, D. A. Fine root dynamics in a tropical rain forest is influenced by rainfall. Plant Soil 276, 23–32 (2005)
Baddeley, J. A. & Watson, C. A. Influences of root diameter, tree age, soil depth and season on fine root survivorship in Prunus avium. Plant Soil 276, 15–22 (2005)
Kern, C. C., Friend, A. L., Johnson, J. M. F. & Coleman, M. D. Fine root dynamics in a developing Populus deltoides plantation. Tree Physiol. 24, 651–660 (2004)
Wells, C. E., Glenn, D. M. & Eissenstat, D. M. Changes in the risk of fine-root mortality with age: a case study in peach, Prunus persica (Rosaceae). Am. J. Bot. 89, 79–87 (2002)
King, J. S. et al. Below-ground carbon input to soil is controlled by nutrient availability and fine root dynamics in loblolly pine. New Phytol. 154, 389–398 (2002)
Gill, R. A., Burke, I. C., Lauenroth, W. K. & Milchunas, D. G. Longevity and turnover of roots in the shortgrass steppe: influence of diameter and depth. Plant Ecol. 159, 241–251 (2002)
Wells, C. E. & Eissenstat, D. M. Marked differences in survivorship among apple roots of different diameters. Ecology 82, 882–892 (2001)
Tierney, G. L. & Fahey, T. J. Evaluating minirhizotron estimates of fine root longevity and production in the forest floor of a temperate broadleaf forest. Plant Soil 229, 167–176 (2001)
Majdi, H., Damm, E. & Nylund, J.-E. Longevity of mycorrhizal roots depends on branching order and nutrient availability. New Phytol. 150, 195–202 (2001)
Coleman, M. D., Dickson, R. E. & Isebrands, J. G. Contrasting fine-root production, survival and soil CO2 efflux in pine and poplar plantations. Plant Soil 225, 129–139 (2000)
Chapin, F. S. III, Moilanen, L. & Kielland, K. Preferential use of organic nitrogen for growth by a nonmycorrhizal Arctic sedge. Nature 361, 150–153 (1993)
McKane, R. B. et al. Resource-based niches provide a basis for plant species diversity and dominance in arctic tundra. Nature 415, 68–71 (2002)
Aanderud, Z. T. & Bledsoe, C. S. Preferences for 15N-ammonium, 15N-nitrate, and 15N-glycine differ among dominant exotic and subordinate native grasses from a California oak woodland. Environ. Exp. Bot. 65, 205–209 (2009)
Andersen, K. M. & Turner, B. L. Preferences or plasticity in nitrogen acquisition by understorey palms in a tropical montane forest. J. Ecol. 101, 819–825 (2013)
Andresen, L. C., Michelsen, A., Jonasson, S. & Ström, L. Seasonal changes in nitrogen availability, and root and microbial uptake of 15N13C9-phenylalanine and 15N-ammonium in situ at a temperate heath. Appl. Soil Ecol. 51, 94–101 (2011)
Averill, C. & Finzi, A. Increasing plant use of organic nitrogen with elevation is reflected in nitrogen uptake rates and ecosystem δ15N. Ecology 92, 883–891 (2011)
Bardgett, R. D., Streeter, T. C. & Bol, R. Soil microbes compete effectively with plants for organic-nitrogen inputs to temperate grasslands. Ecology 84, 1277–1287 (2003)
Boczulak, S. A., Hawkins, B. J. & Roy, R. Temperature effects on nitrogen form uptake by seedling roots of three contrasting conifers. Tree Physiol. 34, 513–523 (2014)
Cheng, X. & Bledsoe, C. S. Competition for inorganic and organic N by blue oak (Quercus douglasii) seedlings, an annual grass, and soil microorganisms in a pot study. Soil Biol. Biochem. 36, 135–144 (2004)
Dunn, R. M., Mikola, J., Bol, R. & Bardgett, R. D. Influence of microbial activity on plant–microbial competition for organic and inorganic nitrogen. Plant Soil 289, 321–334 (2006)
Finzi, A. C. & Berthrong, S. T. The uptake of amino acids by microbes and trees in three cold-temperate forests. Ecology 86, 3345–3353 (2005)
Gallet-Budynek, A . et al. Intact amino acid uptake by northern hardwood and conifer trees. Oecologia 160, 129–138 (2009)
Harrison, K. A., Bol, R. & Bardgett, R. D. Preferences for different nitrogen forms by coexisting plant species and soil microbes. Ecology 88, 989–999 (2007)
Henry, H. A. L. & Jefferies, R. L. Interactions in the uptake of amino acids, ammonium and nitrate ions in the Arctic salt-marsh grass,Puccinellia phryganodes. Plant Cell Environ. 26, 419–428 (2003)
Jin, V. L. & Evans, R. D. Microbial 13C utilization patterns via stable isotope probing of phospholipid biomarkers in Mojave Desert soils exposed to ambient and elevated atmospheric CO2 . Glob. Chang. Biol. 16, 2334–2344 (2010)
Jin, V. L., Romanek, C. S., Donovan, L. A. & Sharitz, R. R. Soil nitrogen availability and in situ nitrogen uptake by Acer rubrum L. and Pinus palustris Mill. in the southeastern U. S. Coastal Plain. J. Torrey Bot. Soc. 137, 339–347 (2010)
Kahmen, A., Livesley, S. J. & Arndt, S. K. High potential, but low actual, glycine uptake of dominant plant species in three Australian land-use types with intermediate N availability. Plant Soil 325, 109–121 (2009)
Kaštovská, E. & Šantrůčková, H. Comparison of uptake of different N forms by soil microorganisms and two wet-grassland plants: a pot study. Soil Biol. Biochem. 43, 1285–1291 (2011)
Li, C. et al. Inorganic and organic nitrogen uptake by nine dominant subtropical tree species. iForest (Viterbo) 9, 253–258 (2015)
McFarland, J. W. et al. Cross-ecosystem comparisons of in situ plant uptake of amino acid-N and NH4+. Ecosystems 13, 177–193 (2010)
Metcalfe, R. J., Nault, J. & Hawkins, B. J. Adaptations to nitrogen form: comparing inorganic nitrogen and amino acid availability and uptake by four temperate forest plants. Can. J. For. Res. 41, 1626–1637 (2011)
Mozdzer, T. J., Zieman, J. C. & McGlathery, K. J. Nitrogen uptake by native and invasive temperate coastal macrophytes: importance of dissolved organic nitrogen. Estuaries Coast. 33, 784–797 (2010)
Nie, M. et al. Plants’ use of different nitrogen forms in response to crude oil contamination. Environ. Pollut. 159, 157–163 (2011)
Nordin, A., Högberg, P. & Näsholm, T. Soil nitrogen form and plant nitrogen uptake along a boreal forest productivity gradient. Oecologia 129, 125–132 (2001)
Öhlund, J. & Näsholm, T. Growth of conifer seedlings on organic and inorganic nitrogen sources. Tree Physiol. 21, 1319–1326 (2001)
Ouyang, S. et al. Nitrogen competition between three dominant plant species and microbes in a temperate grassland. Plant Soil 408, 121–132 (2016)
Paulding, E. M., Baker, A. J. M. & Warren, C. R. Competition for nitrogen by three sympatric species of Eucalyptus. Ann. For. Sci. 67, 406 (2010)
Persson, J. et al. Nitrogen acquisition from inorganic and organic sources by boreal forest plants in the field. Oecologia 137, 252–257 (2003)
Persson, J. & Näsholm, T. Regulation of amino acid uptake in conifers by exogenous and endogenous nitrogen. Planta 215, 639–644 (2002)
Pfautsch, S., Rennenberg, H., Bell, T. L. & Adams, M. A. Nitrogen uptake by Eucalyptus regnans and Acacia spp. – preferences, resource overlap and energetic costs. Tree Physiol. 29, 389–399 (2009)
Rains, K. C. & Bledsoe, C. S. Rapid uptake of 15N-ammonium and glycine-13C, 15N by arbuscular and ericoid mycorrhizal plants native to a Northern California coastal pygmy forest. Soil Biol. Biochem. 39, 1078–1086 (2007)
Schmidt, S. & Stewart, G. R. Waterlogging and fire impacts on nitrogen availability and utilization in a subtropical wet heathland (wallum). Plant Cell Environ. 20, 1231–1241 (1997)
Schmidt, S. & Stewart, G. R. Glycine metabolism by plant roots and its occurrence in Australian plant communities. Aust. J. Plant Physiol. 26, 253–264 (1999)
Scott, E. E. & Rothstein, D. E. Amino acid uptake by temperate tree species characteristic of low- and high-fertility habitats. Oecologia 167, 547–557 (2011)
Simon, J. et al. Competition for nitrogen between adult European beech and its offspring is reduced by avoidance strategy. For. Ecol. Manage. 262, 105–114 (2011)
Simon, J., Waldhecker, P., Brüggemann, N. & Rennenberg, H. Competition for nitrogen sources between European beech (Fagus sylvatica) and sycamore maple (Acer pseudoplatanus) seedlings. Plant Biol. 12, 453–458 (2010)
Stoelken, G., Simon, J., Ehlting, B. & Rennenberg, H. The presence of amino acids affects inorganic N uptake in non-mycorrhizal seedlings of European beech (Fagus sylvatica). Tree Physiol. 30, 1118–1128 (2010)
Wallander, H., Arnebrant, K., Östrand, F. & Kårén, O. Uptake of N15-labelled alanine, ammonium and nitrate in Pinus sylvestris L. ectomycorrhiza growing in forest soil treated with nitrogen, sulphur or lime. Plant Soil 195, 329–338 (1997)
Wanek, W., Arndt, S. K., Huber, W. & Popp, M. Nitrogen nutrition during ontogeny of hemiepiphytic Clusia species. Funct. Plant Biol. 29, 733–740 (2002)
Warren, C. R. Potential organic and inorganic N uptake by six Eucalyptus species. Funct. Plant Biol. 33, 653–660 (2006)
Warren, C. R. Does nitrogen concentration affect relative uptake rates of nitrate, ammonium, and glycine? J. Plant Nutr. Soil Sci. 172, 224–229 (2009)
Warren, C. R. & Adams, P. R. Uptake of nitrate, ammonium and glycine by plants of Tasmanian wet eucalypt forests. Tree Physiol. 27, 413–419 (2007)
Wei, L., Chen, C. & Yu, S. Uptake of organic nitrogen and preference for inorganic nitrogen by two Australian native Araucariaceae species. Plant Ecol. Divers. 8, 259–264 (2015)
Weigelt, A., Bol, R. & Bardgett, R. D. Preferential uptake of soil nitrogen forms by grassland plant species. Oecologia 142, 627–635 (2005)
Wu, J. et al. Mycorrhizas alter nitrogen acquisition by the terrestrial orchid Cymbidium goeringii. Ann. Bot. 111, 1181–1187 (2013)
The Angiosperm Phylogeny Group. An update of the Angiosperm Phylogeny Group classification for the orders and families of flowering plants: APG III. Bot. J. Linn. Soc. 161, 105–121 (2009)
Webb, C. O., Ackerly, D. D. & Kembel, S. W. Phylocom: software for the analysis of phylogenetic community structure and trait evolution. Bioinformatics 24, 2098–2100 (2008)
Wikström, N ., Savolainen, V. & Chase, M. W. Evolution of the angiosperms: calibrating the family tree. Proc. R. Soc. B 268, 2211–2220 (2001)
Blomberg, S. P., Garland, T., Jr & Ives, A. R. Testing for phylogenetic signal in comparative data: behavioral traits are more labile. Evolution 57, 717–745 (2003)
We thank C. Ma, L. Li, Y. Yue, M. Liu, F. Ma, H. Li, D. Kong, B. Liu and K. Sun for collecting data; X. Liu and X. Deng for their assistance in field sampling; and all members of field research stations of the Chinese Academy of Sciences for their support. This study was funded by the Natural Science Foundation of China (NSFC Grants 31325006, 31530011, and 41571130041).
The authors declare no competing financial interests.
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Extended data figures and tables
Trait loading on the plane defined by principal components 1 and 2 (PC1 and PC2). Brown arrows indicate four morphological traits; diameter, length, SRL and root tissue density (RTD). Green arrows indicate two physiological–chemical traits; root carbon (RootC) and root nitrogen (RootN). The yellow arrow shows mycorrhizal colonization. Three different analyses confirm the results shown here (detailed in Extended Data Table 2): (i) all data excluding the mycorrhizal colonization trait (n = 217 species); (ii) gaps in mycorrhizal colonization data interpolated using the regression from Fig. 1c (n = 217 species); and (iii) gaps in any trait value interpolated (n = 369) using the regressions in Fig. 1a, c or the multiple imputation method in the MICE R package).
a, There is no correlation between root nitrogen and SRL (r2 = 0.002, P = 0.81, n = 269). b, There is no correlation between root nitrogen and diameter (r2 = 0.02, P = 0.01, n = 274). Each point represents one species: brown, woody plants; green, herbaceous plants (a, b). c, Across plant growth forms, nitrogen uptake rates per root biomass did not vary significantly (P > 0.05) based on hydroponic measurements (brown). For in situ experiments (green) we observed a growth-form effect (P < 0.01), which was caused solely by higher root uptake in graminoid species compared to trees. All other growth forms were statistically indistinguishable. The letters ‘a’ and ‘b’ indicate significant difference based on an ANOVA across growth forms. d, Summary table of nitrogen uptake rates across different biomes by two approaches. This dataset included previously unpublished data from 22 species. A detailed description of these two approaches can be found in the Methods. Additional data were collected from refs 59, 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71, 72, 73, 74, 75, 76, 77, 78, 79, 80, 81, 82, 83, 84, 85, 86, 87, 88, 89, 90, 91, 92, 93, 94, 95, 96, 97, 98, 99, 100, 101.
Extended Data Figure 3 First-order-root nitrogen concentration across biomes and plant functional groups.
a, We did not detect a distinct pattern in first-order-root nitrogen concentration across biomes (a) (ANOVA; P > 0.14, n = 284 species). b, We detected a slight difference in first-order-root nitrogen concentration among plant functional groups (b) (ANOVA; P < 0.01, n = 284 species), which was mostly driven by the higher root nitrogen concentrations found in legumes. Each point represents one species; brown, woody plants; green, herbaceous plants. The letters ‘a’, ‘b’ and ‘ab’ indicate significant differences between categories.
a, c, Root median lifespan is significantly correlated with root diameter (a, r2 = 0.14, P < 0.01, linear regression) and SRL (c, r2 = 0.17, P < 0.01, linear regression). b, d, Root nitrogen uptake rate is not correlated with root diameter (b, r2 = 0.07, P > 0.05, linear regression) or with SRL (d, r2 = 0.07, P = 0.29, linear regression) in woody plants. Data are presented on a logarithmic scale (log10), with each point representing one species.
Extended Data Figure 5 Distribution of first-order-root diameter for woody and herbaceous plants across biomes.
a, Woody plant root diameter deceases from tropical to desert biomes, with the most frequent occurrence of coarse-root ancestral woody species in tropical and subtropical biomes. b, Herbaceous plant root diameters do not display a clear trend across biomes. In both panels, the letters ‘a’, ‘b’ and ‘c’ denote significant differences (P < 0.05) between biomes based on a linear mixed effects model (generated using the lmer function in R) with species included as a random effect. Diameter was first log10-transformed to correct for non-normality. Each point represents a species-specific observation at one site. The background violin plot characterizes the distribution of points in each biome. c, Pairwise comparisons for equal variance in first-order-root diameter using Levene’s test. Levene’s test is used for testing the homogeneity of variance, and is used here to explain biome differences in variance of root diameter.
a–c, Cyan bars identify the distribution of herbaceous plants, yellow bars identify woody plants, and green colour is where two distributions overlap. n, total number of species; s, skewness of all data.
The oldest taxonomic groups are highlighted in orange (gymnosperms), yellow (monocotyledons) and green (for example, Magnoliales, Lauraceae). The youngest taxonomic groups are highlighted in purple (for example, Betulaceae, Fagaceae).
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Ma, Z., Guo, D., Xu, X. et al. Evolutionary history resolves global organization of root functional traits. Nature 555, 94–97 (2018). https://doi.org/10.1038/nature25783
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