Plant Biomass Allocation: Understanding the Variability within Size Constraints

Persistent Link:
http://hdl.handle.net/10150/194007
Title:
Plant Biomass Allocation: Understanding the Variability within Size Constraints
Author:
McCarthy, Megan Campbell
Issue Date:
2007
Publisher:
The University of Arizona.
Rights:
Copyright © is held by the author. Digital access to this material is made possible by the University Libraries, University of Arizona. Further transmission, reproduction or presentation (such as public display or performance) of protected items is prohibited except with permission of the author.
Abstract:
The majority of studies on plant biomass partitioning have focused on the effects of environment. Optimal Partitioning Theory (OPT) suggests that plants should allocate biomass to the organ that acquires the most limiting resource. Though, it has recently been disputed as to how much of this variation is due to variation in size and not environment. Additionally, while a few studies have examined differences between growth forms, the effects of evolutionary history have been largely ignored. Leaf morphology and physiology may also contribute to patterns of biomass partitioning.The role of plant size has been shown to be considerable to plant biomass allocation. Allometric biomass Partitioning Theory (APT) has recently been proposed to predict how plants should partition metabolic production based on the constraints of body size. Here, I assess the relative contribution of environment, growth form, leaf traits and phylogeny on variation in biomass allocation, after accounting for changes in size, using both an empirical and experimental approach. I use a global dataset of seed plants in addition to growing plants with differing evolutionary histories and growth forms hydroponically in two nutrient levels to examine patterns of organ partitioning while accounting for allometrically driven biomass allocation. Both the empirical and experimental interspecific analyses indicate that phylogeny accounts for the majority of the variation in biomass partitioning. Leaf biomass partitioning is partially related to growth form, however this appears to be due to differences in leaf morphology and physiology. While a strong phylogenetic signal exists, about half of the variation was not explained by any of the factors interspecifically, suggesting room for plasticity in partitioning. Intraspecifically, biomass allocation and partitioning was related to environmental factors in the directions predicted by OPT. However, the species-specific allocation response to environmental differences was not uniform, therefore obscuring interspecific patterns. These results have important implications for ecological studies; such that partitioning studies must first assess the role of plant size and evolutionary history in order to fully understand variability in biomass partitioning. Additionally, differences from environment can be incorporated with allometric changes to help understand how plants should allocate biomass.
Type:
text; Electronic Dissertation
Keywords:
Ecology & Evolutionary Biology
Degree Name:
PhD
Degree Level:
doctoral
Degree Program:
Ecology & Evolutionary Biology; Graduate College
Degree Grantor:
University of Arizona
Advisor:
Enquist, Brian J.
Committee Chair:
Enquist, Brian J.

Full metadata record

DC FieldValue Language
dc.language.isoENen_US
dc.titlePlant Biomass Allocation: Understanding the Variability within Size Constraintsen_US
dc.creatorMcCarthy, Megan Campbellen_US
dc.contributor.authorMcCarthy, Megan Campbellen_US
dc.date.issued2007en_US
dc.publisherThe University of Arizona.en_US
dc.rightsCopyright © is held by the author. Digital access to this material is made possible by the University Libraries, University of Arizona. Further transmission, reproduction or presentation (such as public display or performance) of protected items is prohibited except with permission of the author.en_US
dc.description.abstractThe majority of studies on plant biomass partitioning have focused on the effects of environment. Optimal Partitioning Theory (OPT) suggests that plants should allocate biomass to the organ that acquires the most limiting resource. Though, it has recently been disputed as to how much of this variation is due to variation in size and not environment. Additionally, while a few studies have examined differences between growth forms, the effects of evolutionary history have been largely ignored. Leaf morphology and physiology may also contribute to patterns of biomass partitioning.The role of plant size has been shown to be considerable to plant biomass allocation. Allometric biomass Partitioning Theory (APT) has recently been proposed to predict how plants should partition metabolic production based on the constraints of body size. Here, I assess the relative contribution of environment, growth form, leaf traits and phylogeny on variation in biomass allocation, after accounting for changes in size, using both an empirical and experimental approach. I use a global dataset of seed plants in addition to growing plants with differing evolutionary histories and growth forms hydroponically in two nutrient levels to examine patterns of organ partitioning while accounting for allometrically driven biomass allocation. Both the empirical and experimental interspecific analyses indicate that phylogeny accounts for the majority of the variation in biomass partitioning. Leaf biomass partitioning is partially related to growth form, however this appears to be due to differences in leaf morphology and physiology. While a strong phylogenetic signal exists, about half of the variation was not explained by any of the factors interspecifically, suggesting room for plasticity in partitioning. Intraspecifically, biomass allocation and partitioning was related to environmental factors in the directions predicted by OPT. However, the species-specific allocation response to environmental differences was not uniform, therefore obscuring interspecific patterns. These results have important implications for ecological studies; such that partitioning studies must first assess the role of plant size and evolutionary history in order to fully understand variability in biomass partitioning. Additionally, differences from environment can be incorporated with allometric changes to help understand how plants should allocate biomass.en_US
dc.typetexten_US
dc.typeElectronic Dissertationen_US
dc.subjectEcology & Evolutionary Biologyen_US
thesis.degree.namePhDen_US
thesis.degree.leveldoctoralen_US
thesis.degree.disciplineEcology & Evolutionary Biologyen_US
thesis.degree.disciplineGraduate Collegeen_US
thesis.degree.grantorUniversity of Arizonaen_US
dc.contributor.advisorEnquist, Brian J.en_US
dc.contributor.chairEnquist, Brian J.en_US
dc.contributor.committeememberHuxman, Travisen_US
dc.contributor.committeememberRobichaux, Roben_US
dc.contributor.committeememberVenable, Larryen_US
dc.contributor.committeememberConway, Courtneyen_US
dc.identifier.proquest2116en_US
dc.identifier.oclc659747230en_US
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