Modelling facilitation or competition within a root system: importance of the overlap of root depletion and accumulation zones

Henri de Parseval, Sébastien Barot, Jacques Gignoux, Jean Christophe Lata, Xavier Raynaud

    Research output: Contribution to journalArticle

    6 Citations (Scopus)

    Abstract

    Aims: The concept of intra-plant, inter-root competition considers the overlap of nutrient depletion zones around roots, but neglects the spatial pattern of root exudates that can increase nutrient availability. We tested the hypothesis that interactions between nutrient accumulation zones due to exudation by different roots can lead to intra-plant inter-root facilitation. Methods: We used the PARIS model (Raynaud et al. 2008) to simulate phosphorus uptake by a population of roots that are able to increase phosphorus availability by exuding citrate. We carried out several simulations with the same parameters but with increasing root density in order to study out if changes in root densities would alter nutrient uptake per unit root. Results: Emerging relationships between root uptake efficiency and root length density indicated cases of inter-root competition or facilitation. The sizes of the accumulation and depletion zones were calculated to explain these results. Our simulations showed a continuum between cases of inter-root competition and facilitation. Facilitation occurred at low exudation rates, when phosphorus supply was not saturated within the phosphorus depletion zone surrounding roots. Low exudation systems led to a lower phosphorus uptake per unit root length, but minimized phosphorus losses in the process. Conclusions: Based on our model, we derived conditions that allowed predicting whether competition, facilitation or no interaction, is the dominant interaction between roots within a root system, based on the different distances to which an isolated root alters P concentration and supply.

    Original languageEnglish
    Pages (from-to)1-15
    Number of pages15
    JournalPlant and Soil
    Volume419
    Issue number1-2
    DOIs
    Publication statusAccepted/In press - 7 Jul 2017

    Keywords

    • Diffusion
    • Exudation
    • Modelling
    • Phosphorus
    • Rhizosphere
    • Spatial distribution

    ASJC Scopus subject areas

    • Soil Science
    • Plant Science

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