Adam B Roddy

Adam B Roddy
Florida International University | FIU · Department of Biological Sciences

PhD

About

71
Publications
11,659
Reads
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894
Citations
Additional affiliations
March 2015 - present
Yale University
Position
  • PostDoc Position
August 2008 - February 2015
University of California, Berkeley
Position
  • PhD Student
August 2008 - March 2015
University of California, Berkeley
Position
  • PhD Student

Publications

Publications (71)
Article
Full-text available
Flowers face desiccating conditions, yet little is known about their ability to transport water. We quantified variability in floral hydraulic conductance (Kflower ) for 20 species from 10 families and related it to traits hypothesized to be associated with liquid and vapor phase water transport. Basal angiosperm flowers had trait values associated...
Article
Full-text available
Early angiosperm evolution, beginning approximately 140 million years ago, saw many innovations that enabled flowering plants to alter ecosystems globally. These included the development of novel, flower-based pollinator attraction mechanisms and the development of increased water transport capacity in stems and leaves. Vein length per area (VLA) o...
Preprint
Full-text available
Background and Aims While genome size limits the minimum sizes and maximum numbers of cells that can be packed into a given leaf volume, mature cell sizes can be substantially larger than their meristematic precursors and vary in response to abiotic conditions. Mangroves are iconic examples of how abiotic conditions can influence the evolution of p...
Preprint
Full-text available
The spongy mesophyll is a complex, porous tissue found in plant leaves that enables carbon capture and provides mechanical stability. Unlike many other biological tissues, which remain confluent throughout development, the spongy mesophyll must develop from an initially confluent tissue into a tortuous network of cells with a large proportion of in...
Article
Full-text available
Mangroves are frequently inundated with saline water and have evolved different anatomical and physiological mechanisms to filter and, in some species, excrete excess salt from the water they take up. Because salts impose osmotic stress, interspecific differences in salt tolerance and salt management strategy may influence physiological responses t...
Article
Full-text available
ABSTRACT As educators, we should not assume that students are progressing toward intended STEM careers simply because they have persisted and received a STEM degree. In addition to learning biology content and scientific skills, students need guidance in making optimal career choices. In this study, we present seven career development modules desig...
Article
Full-text available
Many plant leaves have two layers of photosynthetic tissue, the palisade and spongy mesophyll. While palisade mesophyll consists of tightly packed columnar cells, the structure of spongy mesophyll is not well characterized and often treated as a random assemblage of irregularly shaped cells. Using micro-computed tomography imaging, topological anal...
Article
Full-text available
The physiological mechanisms underlying drought responses are poorly documented in mangroves, which experience nearly constant exposure to saline water. We measured gas exchange, foliar abscisic acid (ABA) concentration, and vulnerability to embolism in a soil water-withholding experiment of two co-occurring mangroves, Avicennia marina (Forsskål) V...
Article
Full-text available
Coastal zones, which connect terrestrial and aquatic ecosystems, are among the most resource‐rich regions globally and home to nearly 40% of the global human population. Because human land‐based activities can alter natural processes in ways that affect adjacent aquatic ecosystems, land‐sea interactions are increasingly recognized as critical to co...
Article
Full-text available
Genome size in cellular organisms varies by six orders of magnitude, yet the cause of this large variation remains unexplained. The influential Drift-Barrier Hypothesis proposes that large genomes tend to evolve in small populations due to inefficient selection. However, to our knowledge no explicit tests of the Drift-Barrier Hypothesis have been r...
Article
Full-text available
OPEN ACCESS Maintaining high rates of photosynthesis in leaves requires efficient movement of CO 2 from the atmosphere to the mesophyll cells inside the leaf where CO 2 is converted into sugar. CO 2 diffusion inside the leaf depends directly on the structure of the mesophyll cells and their surrounding airspace, which have been difficult to charact...
Article
Full-text available
OPEN ACCESS Maintaining high rates of photosynthesis in leaves requires efficient movement of CO 2 from the atmosphere to the mesophyll cells inside the leaf where CO 2 is converted into sugar. CO 2 diffusion inside the leaf depends directly on the structure of the mesophyll cells and their surrounding airspace, which have been difficult to charact...
Article
Full-text available
There are multiple hypotheses for the spectacular plant diversity found in deserts. We explore how different factors, including the roles of ecological opportunity and selection, promote diversification and disparification in Encelia, a lineage of woody plants in the deserts of the Americas. Using a nearly complete species‐level ddRAD‐based phyloge...
Article
Full-text available
Understanding how floral traits affect reproduction is key for understanding genetic diversity, speciation, and trait evolution in the face of global changes and pollinator decline. However, there has not yet been a unified framework to characterize the major trade-offs and axes of floral trait variation. Here, we propose the development of a flora...
Article
Significance In Baja California, the deserts meet the coastal dunes in a narrow transition visible even from satellite images. We study two species pairs of desert shrubs ( Encelia ) that occur across this transition. Although these species can interbreed, they remain distinct. Using a combination of genetics, field experiments, three-dimensional i...
Article
Premise: The young seedling life stage is critical for reforestation after disturbance and for species migration under climate change, yet little is known regarding their basic hydraulic function or vulnerability to drought. Here, we sought to characterize responses to desiccation including hydraulic vulnerability, xylem anatomical traits, and imp...
Preprint
Full-text available
There are multiple hypotheses for the spectacular plant diversity found in deserts. We explore how different factors, including the roles of ecological opportunity and selection, promote diversification and disparification in Encelia , a lineage of woody plants in the deserts of the Americas. Using a nearly complete species-level phylogeny along wi...
Preprint
Full-text available
Natural selection is an important driver of genetic and phenotypic differentiation between species. A powerful way to test the role of natural selection in the formation and maintenance of species is to study species complexes in which potential gene flow is high but realized gene flow is low. For a recent radiation of New World desert shrubs ( Enc...
Preprint
Full-text available
Maintaining high rates of photosynthesis in leaves requires efficient movement of CO 2 from the atmosphere to the chloroplasts inside the leaf where it is converted into sugar. Throughout the evolution of vascular plants, CO 2 diffusion across the leaf surface was maximized by reducing the sizes of the guard cells that form stomatal pores in the le...
Preprint
Full-text available
The spongy mesophyll layer in leaves is ubiquitous among vascular plants, yet its structure is relatively unknown and typically described as a disordered assemblage of isodiametric cells. We characterized spongy mesophyll structure among diverse taxa using X-ray microCT imaging and found that leaves with small cell sizes, high cell packing densitie...
Article
Full-text available
A central challenge in plant ecology is to define the major axes of plant functional variation with direct consequences for fitness. Central to the three main components of plant fitness (growth, survival, and reproduction) is the rate of metabolic conversion of CO2 into carbon that can be allocated to various structures and functions. Here we (1)...
Article
Full-text available
Premise: Because of its broad range in the neotropical rainforest and within tree canopies, the tank bromeliad Guzmania monostachia was investigated as a model of how varying leaf hydraulic conductance (Kleaf ) could help plants resist and recover from episodic drought. The two pathways of Kleaf , inside and outside the xylem, were also examined t...
Article
Full-text available
Despite the diversity of branching architectures in plants, the impact of this morphological variation on hydraulic efficiency has been poorly studied. Branch junctions are commonly thought to be points of high hydraulic resistance, but adjustments in leaf area or xylem conduit abundance or dimensions could compensate for the additional hydraulic r...
Article
Water transport in vascular plants represents a critical component of terrestrial water cycles and supplies the water needed for the exchange of CO 2 in the atmosphere for photosynthesis. Yet, many fundamental principles of water transport are difficult to assess given the scale and location of plant xylem. Here we review the mechanistic principles...
Preprint
Full-text available
A central challenge in plant ecology is to define the major axes of plant functional variation with direct consequences for fitness. Central to the three main components of plant fitness (growth, survival, and reproduction) is the rate of metabolic conversion of CO2 into carbon that can be allocated to various structures and functions. Here we (1)...
Preprint
Full-text available
For most angiosperms, flowers are critical to reproduction because they increase rates of outcrossing. Flowers are highly variable in numerous traits, including size, shape, and color. Most of this variation is thought to have arisen due to selection by pollinators. Yet, non-pollinator selection is increasingly being recognized as contributing to f...
Article
Full-text available
Maintaining water balance has been a critical constraint shaping the evolution of leaf form and function. However, flowers, which are heterotrophic and relatively short‐lived, may not be constrained by the same physiological and developmental factors. We measured physiological parameters derived from pressure‐volume curves for leaves and flowers of...
Article
Full-text available
Synopsis Information, energy, and matter are fundamental properties of all levels of biological organization, and life emerges from the continuous flux of matter, energy, and information. This perspective piece defines and explains each of the three pillars of this nexus. We propose that a quantitative characterization of the complex interconversio...
Preprint
Full-text available
The need to maintain water balance has been a critical constraints shaping the evolution of leaf form and function. Vein and stomatal traits have undergone coordinated evolution to maintain water supply and prevent water loss. However, flowers, which are heterotrophic and relatively short-lived, may not be constrained by the same physiological and...
Article
Full-text available
FREE FULL TEXT : http://www.plantphysiol.org/content/early/2018/07/24/pp.18.00550 The leaf intercellular airspace (IAS) is generally considered to have high conductance to CO2 diffusion relative to the liquid phase. While previous studies accounted for leaf-level variation in porosity and mesophyll thickness, they omitted 3D IAS traits that potent...
Article
Full-text available
For most angiosperms, producing and maintaining flowers is critical to sexual reproduction, yet little is known about the physiological processes involved in maintaining flowers throughout anthesis. Among extant species, flowers of the genus Calycanthus have the highest hydraulic conductance and vein densities of species measured to date, yet they...
Preprint
Full-text available
Angiosperm flowers are remarkably diverse anatomically and morphologically, yet they all must satisfy the physiological constraints of supplying sufficient amounts of water and carbon effectively promote pollination. Flowers often occur in the hottest, driest parts of the plant canopy and can face harsh abiotic conditions. Prior evidence suggests t...
Article
Full-text available
The abrupt origin and rapid diversification of the flowering plants during the Cretaceous has long been considered an “abominable mystery.” While the cause of their high diversity has been attributed largely to coevolution with pollinators and herbivores, their ability to outcompete the previously dominant ferns and gymnosperms has been the subject...
Article
Full-text available
During the Cretaceous (145-66 Ma), early angiosperms rapidly diversified, eventually outcompeting the ferns and gymnosperms previously dominating most ecosystems. While the cause of their high diversity has been attributed largely to coevolution with pollinators and herbivores, their ability to outcompete the previously dominant ferns and gymnosper...
Data
Fossil data of anatomical traits plotted with limits of trait values reconstructed from extant species (curves from Fig 4). Data can be found in S1 Data. (TIF)
Data
Bootstrapping analyses of the lower limit of genome size modeled from ancestral state reconstructions based on 35%, 52%, and 78% of angiosperm species in our entire dataset. Heavy black lines are the modeled limit from the entire dataset, and the light grey, red, and blue lines are the modeled limits from each of 100 replicate runs at each level of...
Data
Trait and PGLS regressions for all species and for only the angiosperms. Trait regressions are in the upper triangle and PGLS regressions are in the lower triangle. Values are regression slopes. Asterisks indicate significance level: *p < 0.05; **p < 0.01; ***p < 0.001. PGLS, phylogenetic generalized least squares. (DOCX)
Data
The distributions of genome size among angiosperms in the Kew plant DNA C-values database, which includes over 7,000 species, and of species sampled in the present study are not significantly different (t = 1.69, p = 0.1). (a) Untransformed distributions and (b) Log-transformed distributions. In both figures, the number of species for the Kew datab...
Data
lg, Ds, and Dv for species used in the analysis. Ds, stomatal density; Dv, vein density; lg, guard cell length. (DOCX)
Data
lg, Ds, and Dv for species used in the analysis. Ds, stomatal density; Dv, vein density; lg, guard cell length. (XLSX)
Data
The number of currently accepted species for 20 named clades in our phylogeny is strongly correlated with the number of species representing those clades in our dataset (r = 0.69, p < 0.001). (TIFF)
Preprint
Full-text available
Because of the importance of reproduction in plant life history, the physiological costs of reproduction often influence vegetative structure and function. In dioecious species, these effects can be quite obvious, as different costs of male and female reproductive functions are entirely separated among different individuals in a population. In fire...
Article
Full-text available
Anthropogenic threats to natural systems can be exacerbated due to connectivity between marine, freshwater, and terrestrial ecosystems, complicating the already daunting task of governance across the land-sea interface. Globalization, including new access to markets, can change social-ecological, land-sea linkages via livelihood responses and adapt...
Data
Public domain image of white shrimp in Fig 5. The image of Litopenaeus setiferus (white shrimp) in Fig 5 is in the public domain of the United States. (PDF)
Data
Public domain image of shrimp in Fig 5. The image of Farfantepenaeus duorarum (shrimp) in Fig 5 is in the public domain of the United States. (PDF)
Data
Permissions for fish images in Fig 5. Permission granted from Diane Peebles for Cynoscion spp. (weakfish), Centropomus undecimalis (snook), Micropogonias spp. (croaker), Eugerres plumieri (mojarra), Caranx hippos (jack), and Bagre marinus (catfish) in Fig 5. (PDF)
Preprint
Full-text available
Flowers are critical for successful reproduction, yet we know little about how they remain turgid and showy throughout anthesis to attract pollinators. Recent evidence suggests that early in angiosperm evolution there was a major shift in the hydraulic structure-function relationships of flowers, with early-divergent ANA grade and magnoliid flowers...
Article
Full-text available
Tropical forest conversion to pasture, which drives greenhouse gas emissions, soil degradation, and biodiversity loss, remains a pressing socio-ecological challenge. This problem has spurred increased interest in the potential of small-scale agroforestry systems to couple sustainable agriculture with biodiversity conservation, particularly in rapid...
Data
Plant species or morphotypes found in each land use type. (XLSX)
Data
Proportion of species that have 1 or more functions in each land use studied. Proportion of species that have 1 (a), 2 (b), or 3(c) functions in each land use type. Non-overlapping letters signify significant difference at ? ? 0.05. (DOCX)
Data
Sample location and raw soil and plant data. (XLSX)
Preprint
Full-text available
Flowers face desiccating conditions, yet little is known about their ability to transport water. We quantified variability in floral hydraulic conductance ( K flower ) for 20 species from 10 families and related it to traits hypothesized to be associated with liquid and vapor phase water transport. Basal angiosperm flowers had trait values associat...
Article
Full-text available
Continuous measurements of sap flow have been widely used to estimate water flux through tree stems and branches. However, stem-level measurements lack the resolution necessary for accurately determining fine-scale, leaf-level responses to environmental variables. We used the heat ratio method to measure sap flow rates through leaf petioles and lea...
Article
Full-text available
Continuous measurements of sap flow have been widely used to estimate water flux through tree stems and branches. However, stem-level measurements lack the resolution necessary for accurately determining fine-scale, leaf-level responses to environmental variables. We used the heat ratio method to measure sap flow rates through leaf petioles and lea...
Conference Paper
Background/Question/Methods Since the early work of Kölreuter (1761) and Sprengel (1793) over 200 years ago, animal pollinators have long been thought to be the primary agents of selection responsible for variation in floral traits. Case studies of narrowly defined clades (populations or congeneric species) have been showcased as exemplars of the...
Article
Two rising challenges in ecology are understanding the linkages between above- and belowground components of terrestrial ecosystems and connecting genes to their ecological consequences. Here, we blend these emerging perspectives using a long-term common-garden experiment in a coastal dune ecosystem, whose dominant shrub species, Baccharis pilulari...
Preprint
Full-text available
Continuous measurements of sap flow have been widely used to measure water flux through tree stems and branches. However, these measurements lack the resolution necessary for determining fine-scale, leaf-level responses to environmental variables. We used the heat ratio method to measure sap flow rates through leaf petioles and leaflet petiolules o...
Article
Full-text available
During daylight hours the isotope composition of leaf water generally approximates steady-state leaf water isotope enrichment model predictions. However, until very recently there was little direct confirmation that isotopic steady-state (ISS) transpiration in fact exists. Using isotope ratio infrared spectroscopy (IRIS) and leaf gas exchange syste...
Article
Full-text available
Recent methodological advances toward measuring sap flow on smalldiameter stems allow for near continuous monitoring of leaf-level water flux in response to naturally varying environmental conditions. Elucidating the response functions of sap flow to environmental variables is necessary for accurately understanding and modeling the processes underl...
Article
1. Understanding the factors that limit species distributions along environmental gradients is a central question of ecology. Here, we evaluate the hypothesis that the traits that result in performance trade-offs between habitats contribute to the turnover of woody species along a rainfall gradient in the Isthmus of Panama. 2. We studied 24 plant s...
Conference Paper
Background/Question/Methods Extreme weather events related to climate change, such as heatwaves, are predicted to increase in California. The impact of an increased frequency of heatwaves on native shrub species in the Mediterranean-type climate of California has not been evaluated. To evaluate whether populations of the widespread California nat...
Article
Full-text available
Angiosperms dominate almost every ecosystem globally, and for the vast majority, flowering is vital to successful reproduction, yet little work has characterized the dynamics of water use during flowering and its impacts on the reproductive biology of wild plants. Here we demonstrate a new implementation of the heat ratio method to measure sap flow...
Article
Full-text available
In tropical forests, regional differences in annual rainfall correlate with differences in plant species composition. Although water availability is clearly one factor determining species distribution, other environmental variables that covary with rainfall may contribute to distributions. One such variable is light availability in the understory,...