Abstract
Combining plant growth analysis with a simple model of local resource capture and biomass allocation applied to exemplary experimental data, showed that dynamic changes in allocation to roots when nutrients are scarce is caused by disparities in growth rates between roots and shoots. Whole-plant growth rates also change but are not caused by an adaptive allocation response. Allocation and whole-plant growth rate are interdependent, not independent, traits. Following a switch in nutrient availability or partial biomass removal, convergence of allocation and growth rate trajectories does not reflect goal-seeking behaviour, but the constraints imposed by finite resource availability. Optimal root−shoot allocations are unnecessary to maximise whole-plant growth rate. Similar growth rates are attainable with different allocations. Changes in allocation cannot maintain or restore a superior whole-plant growth rate. Roots and shoots do not have to be tightly coordinated but can operate semiautonomously, as their modular construction permits. These findings question the plausibility of the prevailing general explanation of plants' root-shoot allocation responses, ‘optimal partitioning theory’ (OPT). Local allocation models, not OPT, explain the origins of variability in root−shoot trade-offs in individuals, the allocation of biomass at global and ecosystem scales and inform selection for allocation plasticity in crop breeding.
Original language | English |
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Pages (from-to) | 3023-3039 |
Number of pages | 17 |
Journal | Plant, Cell Environment |
Volume | 46 |
Issue number | 10 |
Early online date | 7 Nov 2022 |
DOIs | |
Publication status | Published - 1 Oct 2023 |
Bibliographical note
ACKNOWLEDGEMENTSI thank Hendrik Poorter, Didier Reinhardt and their coauthors for their excellent data. Hendrik also provided valuable and insightful comments on an earlier version of this paper, as did Ian Bingham, Rob Brooker, John Peterkin and three anonymous reviewers, all of whom improved it significantly. Some of my ideas and text appeared originally in an online preprint: www.biorxiv.org/content/10.1101/2020.06.29.177824v1.
Data Availability Statement
Data sharing is not applicable to this article as no new data were created or analysed in this study.Keywords
- balanced growth
- Hordeum
- modularity
- Petunia
- phenotypic plasticity
- physiological coordination
- plant-environment interaction
- plant growth analysis
- temporal dynamics