An introduction on below-ground environment and resource acquisition, with special reference on trees. Simulation models should include plant structure and function

Abstract

-Resource acquisition within the soil is a complex process, which consists of several sub-processes involving both the soil and the plant. A brief analysis of the whole system is presented, first by focusing on the components of the system, and then on the successive events. This analysis stresses the diversity and specificity of the components involved, as well as their interactive roles, at several organisation levels, both in space and time. Therefore, a systemic approach using dynamic models is defended in order to gather available knowledge and gain new insight within the whole system. In comparison to many of the traditional modelling approaches, which tended to over-simplify the plant part of the system, some new and promising attempts are presented. These new models give a good illustration of what can be expected to be gained by associating structural and functional characteristics of the plant components. model / root system / soil -plant system / uptake Résumé -Introduction sur l'environnement souterrain et l'acquisition des ressources, avec références particulières aux arbres. Les modèles de simulation devraient inclure la structure et les fonctions de la plante. L'acquisition des ressources du sol est un processus complexe, que l'on peut subdiviser en plusieurs processus plus élémentaires faisant intervenir conjointement la plante et le sol. Nous faisons une brève analyse de ce système, en insistant d'abord sur ses composants, puis sur les événements successifs. Cette analyse révèle la diversité et la spécificité des composants impliqués, ainsi que leurs rôles interactifs, à plusieurs niveaux d'organisation dans le temps et dans l'espace. Aussi, nous défendons une approche systémique, utilisant la modélisation dynamique, pour synthétiser les connaissances disponibles, et obtenir ainsi un nouvel éclairage sur le système pris dans sa globalité. En comparaison avec les approches de modélisation traditionnelles, qui tendent à simplifier outrageusement la partie plante du système, nous pré-sentons quelque démarches nouvelles et prometteuses. Ces derniers modèles illustrent bien les progrès que l'on peut escompter en associant davantage les caractéristiques structurales et fonctionnelles des composants de la plante. absorption / modèle / système racinaire / système sol -plante Ann. For. Sci. 57 (2000) [513][514][515][516][517][518][519][520] 513

Influence of xylem development on axial hydraulic conductance within Prunus root systems

“…The axial conductance and its variation throughout the root system should be more thoroughly investigated to identify relationships linking structural and functional characteristics leading to an integrated approach for below-ground resource acquisition from the root segment level up to the entire root system (Pagès et al 2000).…”

Assessing and analyzing 3D architecture of woody root systems, a review of methods and applications in tree and soil stability, resource acquisition and allocation

“…The latter include e.g. structural-functional uptake and carbon allocation models (Pagès et al 2000b), models of slope stability (Kokutse et al 2006;Danjon et al 2007a, b), or biomechanical models (Dupuy et al 2003a(Dupuy et al , b, 2007.…”

Carbon-based models of individual tree growth: A critical appraisal

“…Thus, no topological links can be assigned between them, in contrast to the above-ground growth units. This inconsistency of tree architecture representation for above-and below-ground parts is often not deliberate because process-based models should emphasise the interaction between architecture and function in determining the response to environmental variables for both shoots and roots [20,32,90]. Actually, this inconsistency reflects the fact that roots have partly escaped due attention by soil scientists, plant physiologists and ecologists because they are more difficult to study than shoots.…”

“…This is particularly true for models simulating competition between tree individuals, because both shoot and root development and competition play a significant part in determining the growth of coexisting individual plants [145]. This is readily feasible because some models are now available to link the 3D root architecture dynamics and carbon allocation [19,90].…”