Clothing the Emperor

Dynamic Root–Shoot Allocation Trajectories in Relation to Whole-Plant Growth Rate and in Response to Temperature

David Robinson (Corresponding Author), John Henry Peterkin

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Abstract

We quantified how root–shoot biomass allocation and whole-plant growth rate co-varied ontogenetically in contrasting species in response to cooling. Seven grass and four forb species were grown for 56 days in hydroponics. Growth was measured repeatedly before and after day/night temperatures were reduced at 28 days from 20 °C/15 °C to 10 °C/5 °C; controls remained unchanged. Sigmoid trajectories of root and shoot growth were reconstructed from the experimental data to derive continuous whole-plant relative growth rates (RGRs) and root mass fractions (RMFs). Root mass fractions in cooled plants generally increased, but this originated from unexpected and previously uncharacterised differences in response among species. Root mass fraction and RGR co-trajectories were idiosyncratic in controls and cooled plants. The RGR–RMF co-trajectories responded to cooling in grasses, but not forbs. The RMF responses of stress-tolerant grasses were predictably weak but projected to eventually out-respond faster-growing species. Sigmoid growth constrains biomass allocation. Only when neither root nor shoot biomass is near-maximal can biomass allocation respond to environmental drivers. Near maximum size, plants cannot adjust RMF, which then reflects net above- and belowground productivities. Ontogenetic biomass allocations are not equivalent to those based on interspecific surveys, especially in mature vegetation. This reinforces the importance of measuring temporal growth dynamics, and not relying on “snapshot” comparisons to infer the functional significance of root–shoot allocation.
Original languageEnglish
Article number212
JournalPlants
Volume8
Issue number7
DOIs
Publication statusPublished - 10 Jul 2019

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clothing
trajectories
plant growth
dry matter partitioning
temperature
grasses
cooling
shoots
night temperature
forbs
hydroponics
stress response
vegetation
biomass

Keywords

  • allocation
  • biomass
  • forb
  • grass
  • relative
  • growth rate
  • root mass fraction
  • root-shoot
  • temperature
  • CO2
  • ALLOMETRY
  • BIOMASS ALLOCATION
  • MODELS
  • AVAILABILITY
  • NITROGEN
  • REGROWTH KINETICS
  • relative growth rate
  • TRANSIENT
  • PLASTICITY

Cite this

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title = "Clothing the Emperor: Dynamic Root–Shoot Allocation Trajectories in Relation to Whole-Plant Growth Rate and in Response to Temperature",
abstract = "We quantified how root–shoot biomass allocation and whole-plant growth rate co-varied ontogenetically in contrasting species in response to cooling. Seven grass and four forb species were grown for 56 days in hydroponics. Growth was measured repeatedly before and after day/night temperatures were reduced at 28 days from 20 °C/15 °C to 10 °C/5 °C; controls remained unchanged. Sigmoid trajectories of root and shoot growth were reconstructed from the experimental data to derive continuous whole-plant relative growth rates (RGRs) and root mass fractions (RMFs). Root mass fractions in cooled plants generally increased, but this originated from unexpected and previously uncharacterised differences in response among species. Root mass fraction and RGR co-trajectories were idiosyncratic in controls and cooled plants. The RGR–RMF co-trajectories responded to cooling in grasses, but not forbs. The RMF responses of stress-tolerant grasses were predictably weak but projected to eventually out-respond faster-growing species. Sigmoid growth constrains biomass allocation. Only when neither root nor shoot biomass is near-maximal can biomass allocation respond to environmental drivers. Near maximum size, plants cannot adjust RMF, which then reflects net above- and belowground productivities. Ontogenetic biomass allocations are not equivalent to those based on interspecific surveys, especially in mature vegetation. This reinforces the importance of measuring temporal growth dynamics, and not relying on “snapshot” comparisons to infer the functional significance of root–shoot allocation.",
keywords = "allocation, biomass, forb, grass, relative, growth rate, root mass fraction, root-shoot, temperature, CO2, ALLOMETRY, BIOMASS ALLOCATION, MODELS, AVAILABILITY, NITROGEN, REGROWTH KINETICS, relative growth rate, TRANSIENT, PLASTICITY",
author = "David Robinson and Peterkin, {John Henry}",
note = "The experimental work was part of John Peterkin’s PhD research at the former Unit of Comparative Plant Ecology, University of Sheffield, UK, funded by the Natural Environment Research Council.",
year = "2019",
month = "7",
day = "10",
doi = "10.3390/plants8070212",
language = "English",
volume = "8",
journal = "Plants",
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TY - JOUR

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T2 - Dynamic Root–Shoot Allocation Trajectories in Relation to Whole-Plant Growth Rate and in Response to Temperature

AU - Robinson, David

AU - Peterkin, John Henry

N1 - The experimental work was part of John Peterkin’s PhD research at the former Unit of Comparative Plant Ecology, University of Sheffield, UK, funded by the Natural Environment Research Council.

PY - 2019/7/10

Y1 - 2019/7/10

N2 - We quantified how root–shoot biomass allocation and whole-plant growth rate co-varied ontogenetically in contrasting species in response to cooling. Seven grass and four forb species were grown for 56 days in hydroponics. Growth was measured repeatedly before and after day/night temperatures were reduced at 28 days from 20 °C/15 °C to 10 °C/5 °C; controls remained unchanged. Sigmoid trajectories of root and shoot growth were reconstructed from the experimental data to derive continuous whole-plant relative growth rates (RGRs) and root mass fractions (RMFs). Root mass fractions in cooled plants generally increased, but this originated from unexpected and previously uncharacterised differences in response among species. Root mass fraction and RGR co-trajectories were idiosyncratic in controls and cooled plants. The RGR–RMF co-trajectories responded to cooling in grasses, but not forbs. The RMF responses of stress-tolerant grasses were predictably weak but projected to eventually out-respond faster-growing species. Sigmoid growth constrains biomass allocation. Only when neither root nor shoot biomass is near-maximal can biomass allocation respond to environmental drivers. Near maximum size, plants cannot adjust RMF, which then reflects net above- and belowground productivities. Ontogenetic biomass allocations are not equivalent to those based on interspecific surveys, especially in mature vegetation. This reinforces the importance of measuring temporal growth dynamics, and not relying on “snapshot” comparisons to infer the functional significance of root–shoot allocation.

AB - We quantified how root–shoot biomass allocation and whole-plant growth rate co-varied ontogenetically in contrasting species in response to cooling. Seven grass and four forb species were grown for 56 days in hydroponics. Growth was measured repeatedly before and after day/night temperatures were reduced at 28 days from 20 °C/15 °C to 10 °C/5 °C; controls remained unchanged. Sigmoid trajectories of root and shoot growth were reconstructed from the experimental data to derive continuous whole-plant relative growth rates (RGRs) and root mass fractions (RMFs). Root mass fractions in cooled plants generally increased, but this originated from unexpected and previously uncharacterised differences in response among species. Root mass fraction and RGR co-trajectories were idiosyncratic in controls and cooled plants. The RGR–RMF co-trajectories responded to cooling in grasses, but not forbs. The RMF responses of stress-tolerant grasses were predictably weak but projected to eventually out-respond faster-growing species. Sigmoid growth constrains biomass allocation. Only when neither root nor shoot biomass is near-maximal can biomass allocation respond to environmental drivers. Near maximum size, plants cannot adjust RMF, which then reflects net above- and belowground productivities. Ontogenetic biomass allocations are not equivalent to those based on interspecific surveys, especially in mature vegetation. This reinforces the importance of measuring temporal growth dynamics, and not relying on “snapshot” comparisons to infer the functional significance of root–shoot allocation.

KW - allocation

KW - biomass

KW - forb

KW - grass

KW - relative

KW - growth rate

KW - root mass fraction

KW - root-shoot

KW - temperature

KW - CO2

KW - ALLOMETRY

KW - BIOMASS ALLOCATION

KW - MODELS

KW - AVAILABILITY

KW - NITROGEN

KW - REGROWTH KINETICS

KW - relative growth rate

KW - TRANSIENT

KW - PLASTICITY

UR - http://www.mendeley.com/research/clothing-emperor-dynamic-rootshoot-allocation-trajectories-relation-wholeplant-growth-rate-response

U2 - 10.3390/plants8070212

DO - 10.3390/plants8070212

M3 - Article

VL - 8

JO - Plants

JF - Plants

SN - 2223-7747

IS - 7

M1 - 212

ER -