TY - JOUR
T1 - Local control of resource allocation is sufficient to model optimal dynamics in syntrophic systems
AU - Ledder, Glenn
AU - Russo, Sabrina E.
AU - Muller, Erik B.
AU - Peace, Angela
AU - Nisbet, Roger M.
N1 - Funding Information:
This work was developed during working group meetings at the National Institute for Mathematical and Biological Synthesis (NIMBioS) (DEB Model for Trees) sponsored by the National Science Foundation through NSF Award #DBI-1300426, with additional support from The University of Tennessee, Knoxville and the University of Nebraska-Lincoln (UNL). GL was partly supported as a Sabbatical Fellow at NIMBioS. Part of this work was conducted while SER and GL were on Faculty Development Leave from UNL.
Publisher Copyright:
© 2020, Springer Nature B.V.
PY - 2020/12
Y1 - 2020/12
N2 - Syntrophic systems are common in nature and include forms of obligate mutualisms in which each participating organism or component of an organism obtains from the other an essential nutrient or metabolic product that it cannot provide for itself. Models of how these complementary resources are allocated between partners often assume optimal behavior, but whether mechanisms enabling global control exist in syntrophic systems, and what form they might take, is unknown. Recognizing that growth of plant organs that supply complementary resources, like roots and shoots, can occur autonomously, we present a theory of plant growth in which root-shoot allocation is determined by purely local rules. Each organ uses as much as it can of its locally produced or acquired resource (inorganic nitrogen or photosynthate) and shares only the surplus. Subject to stoichiometric conditions that likely hold for most plants, purely local rules produce the same optimal allocation as would global control across a wide range of environmental scenarios, with sharing the surplus being the specific mechanism stabilizing syntrophic dynamics. Our local control model contributes a novel approach to plant growth modeling because it assumes a simple mechanism of root:shoot allocation that can be considered a higher-level physiological rule, from which the optimal growth outcome emerges from the system’s dynamics, rather than being built into the model. Moreover, our model is general, in that the mechanism of sharing the surplus can readily be adapted to many obligate syntrophic relationships.
AB - Syntrophic systems are common in nature and include forms of obligate mutualisms in which each participating organism or component of an organism obtains from the other an essential nutrient or metabolic product that it cannot provide for itself. Models of how these complementary resources are allocated between partners often assume optimal behavior, but whether mechanisms enabling global control exist in syntrophic systems, and what form they might take, is unknown. Recognizing that growth of plant organs that supply complementary resources, like roots and shoots, can occur autonomously, we present a theory of plant growth in which root-shoot allocation is determined by purely local rules. Each organ uses as much as it can of its locally produced or acquired resource (inorganic nitrogen or photosynthate) and shares only the surplus. Subject to stoichiometric conditions that likely hold for most plants, purely local rules produce the same optimal allocation as would global control across a wide range of environmental scenarios, with sharing the surplus being the specific mechanism stabilizing syntrophic dynamics. Our local control model contributes a novel approach to plant growth modeling because it assumes a simple mechanism of root:shoot allocation that can be considered a higher-level physiological rule, from which the optimal growth outcome emerges from the system’s dynamics, rather than being built into the model. Moreover, our model is general, in that the mechanism of sharing the surplus can readily be adapted to many obligate syntrophic relationships.
KW - Dynamic energy budgets
KW - Obligate syntrophy
KW - Optimal growth
KW - Plant growth
KW - Resource partitioning
KW - Root:shoot allocation
UR - http://www.scopus.com/inward/record.url?scp=85088651926&partnerID=8YFLogxK
U2 - 10.1007/s12080-020-00464-9
DO - 10.1007/s12080-020-00464-9
M3 - Article
AN - SCOPUS:85088651926
VL - 13
SP - 481
EP - 501
JO - Theoretical Ecology
JF - Theoretical Ecology
SN - 1874-1738
IS - 4
ER -