Root traits as drivers of plant and ecosystem functioning : current understanding, pitfalls and future research needs

Freschet, Grégoire T. and Roumet, Catherine and Comas, Louise H. and Weemstra, Monique and Bengough, A. Glyn and Rewald, Boris and Bardgett, Richard D. and De Deyn, Gerlinde B. and Johnson, David and Klimešová, Jitka and Lukac, Martin and McCormack, M. Luke and Meier, Ina C. and Pagès, Loïc and Poorter, Hendrik and Prieto, Iván and Wurzburger, Nina and Zadworny, Marcin and Bagniewska-Zadworna, Agnieszka and Blancaflor, Elison B. and Brunner, Ivano and Gessler, Arthur and Hobbie, Sarah E. and Iversen, Colleen M. and Mommer, Liesje and Picon-Cochard, Catherine and Postma, Johannes A. and Rose, Laura and Ryser, Peter and Scherer-Lorenzen, Michael and Soudzilovskaia, Nadejda A. and Sun, Tao and Valverde-Barrantes, Oscar J. and Weigelt, Alexandra and York, Larry M. and Stokes, Alexia (2021) Root traits as drivers of plant and ecosystem functioning : current understanding, pitfalls and future research needs. New Phytologist, 232 (3). pp. 1123-1158. ISSN 1469-8137

Abstract

The effects of plants on the biosphere, atmosphere and geosphere are key determinants of terrestrial ecosystem functioning. However, despite substantial progress made regarding plant belowground components, we are still only beginning to explore the complex relationships between root traits and functions. Drawing on the literature in plant physiology, ecophysiology, ecology, agronomy and soil science, we reviewed 24 aspects of plant and ecosystem functioning and their relationships with a number of root system traits, including aspects of architecture, physiology, morphology, anatomy, chemistry, biomechanics and biotic interactions. Based on this assessment, we critically evaluated the current strengths and gaps in our knowledge, and identify future research challenges in the field of root ecology. Most importantly, we found that belowground traits with the broadest importance in plant and ecosystem functioning are not those most commonly measured. Also, the estimation of trait relative importance for functioning requires us to consider a more comprehensive range of functionally relevant traits from a diverse range of species, across environments and over time series. We also advocate that establishing causal hierarchical links among root traits will provide a hypothesis-based framework to identify the most parsimonious sets of traits with the strongest links on functions, and to link genotypes to plant and ecosystem functioning.