Christine Scoffoni

Christine Scoffoni
California State University, Los Angeles | CSULA · Department of Biological Sciences

PhD

About

61
Publications
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4,450
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Publications

Publications (61)
Article
• Ecophysiologists have reported a range of relationships, including intrinsic trade-offs across and within species between plant relative growth rate in high resource conditions (RGR) versus adaptation to tolerate cold or arid climates, arising from trait-based mechanisms. Few studies considered ecotypes within a species, in which the lack of a tr...
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Understanding how environmental adaptations mediate plant and ecosystem responses becomes increasingly important under accelerating global environmental change. Multi-stemmed trees, for example, differ in form and function from single-stemmed trees and may possess physiological advantages that allow for persistence during stressful climatic events...
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One of the most notable ecological trends—described more than 2,300 years ago by Theophrastus—is the association of small leaves with dry and cold climates, which has recently been recognized for eudicotyledonous plants at a global scale1,2,3. For eudicotyledons, this pattern has been attributed to the fact that small leaves have a thinner boundary...
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Different microclimates can have significant impact on the physiology of succulents that inhabit arid environments such as the Mojave Desert (California). We investigated variation in leaf physiology, morphology and anatomy of two dominant Mojave Desert monocots, Yucca brevifolia (Joshua tree) and Hesperoyucca whipplei , growing along a soil water...
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• Increases in leaf mass per area (LMA) are commonly observed in response to environmental stresses and are achieved through increases in leaf thickness and/or leaf density. Here, we investigated how the two underlying components of LMA differ in relation to species native climates and phylogeny, across deciduous and evergreen species. • Using a ph...
Article
Drought decreases water transport capacity of leaves and limits gas exchange, which involves reduced leaf leaf hydraulic conductance (Kleaf) in both the xylem and outside-xylem pathways. Some literature suggests that grapevines are hyper-susceptible to drought-induced xylem embolism. We combined Kleaf and gas exchange measurements, micro-computed t...
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Increases in the frequency and severity of droughts across many regions worldwide necessitate an improved capacity to determine the water status of plants at organ, whole plant, canopy, and regional scales. Noninvasive methods have most potential for simultaneously improving basic water relations research and ground‐, flight‐, and space‐based sensi...
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Climate change is a worldwide threat to biodiversity and ecosystem structure, functioning, and services. To understand the underlying drivers and mechanisms, and to predict the consequences for nature and people, we urgently need better understanding of the direction and magnitude of climate‐change impacts across the soil–plant–atmosphere continuum...
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Stomata, the microvalves on leaf surfaces, exert major influences across scales, from plant growth and productivity to global carbon and water cycling. Stomatal opening enables leaf photosynthesis, and plant growth and water use, whereas plant survival of drought depends on stomatal closure. Here we report that stomatal function is constrained by a...
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Key message Leaf density links the resistance to mechanical and hydraulic stress in Mediterranean shrubs as it is associated with the water potential at turgor loss and the moduli of elasticity and strength. Abstract Understanding the patterns of hydraulic and mechanical trait variation in vascular plants is critical to predicting species’ stress...
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Given increasing water deficits across numerous ecosystems worldwide, it is urgent to understand the sequence of failure of leaf function during dehydration. We assessed dehydration‐induced losses of rehydration capacity and maximum quantum yield of the photosystem II (Fv/Fm) in the leaves of 10 diverse angiosperm species, and tested when these occ...
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The influence of the dynamics of leaf hydraulic conductance (Kleaf) diurnally and during dehydration on stomatal conductance and photosynthesis remains unclear. Using the model species Arabidopsis thaliana (ecotype Col-0)., we applied a multi-tiered approach including physiological measurements, high-resolution X-ray micro-computed tomography, and...
Article
Leaves are a nexus for the exchange of water, carbon, and energy between terrestrial plants and the atmosphere. Research in recent decades has highlighted the critical importance of the underlying biophysical and anatomical determinants of CO2 and H2O transport, but a quantitative understanding of how detailed 3D leaf anatomy mediates within-leaf t...
Article
1.The application of functional traits to predict and explain plant species’ distributions and vital rates has been a major direction in functional ecology for decades, yet numerous physiological traits have not yet been incorporated into the approach. 2.Using commonly measured traits such as leaf mass per area (LMA) and wood density (WD), and addi...
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Resolving the drivers of hydraulic decline during drought is crucial for understanding drought tolerance in crops and natural ecosystems. In the past 15 years, studies of the decline of leaf hydraulic conductance (Kleaf) have supported a major role in controlling plant drought responses. We analyzed the variation in Kleaf decline with dehydration i...
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p style="text-align: justify;"> It has been shown that replacing ultra-pure water solution with ion solution closer to the composition of natural xylem sap increases stem hydraulic conductance by up to 58%, likely due to changes in electroviscosity in the pit membrane pores. This effect has been proposed to contribute to the control of plant hydrau...
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The sites of evaporation within leaves are unknown, but have drawn attention for decades due to their perceived implications for many factors, including patterns of leaf isotopic enrichment, maintenance of mesophyll water status, stomatal regulation and interpretation of leaf hydraulic conductance and stomatal conductance. We used a spatially expli...
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Leaf dry mass per unit leaf area (LMA) is a central trait in ecology, but its anatomical and compositional basis has been unclear. An explicit mathematical and physical framework for quantifying the cell and tissue determinants of LMA will enable tests of their influence on species, communities and ecosystems. We present an approach to explaining L...
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Leaf hydraulic supply is crucial to maintaining open stomata for CO2 capture and plant growth. During drought-induced dehydration, the leaf hydraulic conductance (Kleaf) declines, which contributes to stomatal closure and eventually to leaf death. Previous studies have tended to attribute the decline of Kleaf to embolism in the leaf vein xylem. We...
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Ecosystems worldwide are facing increasingly severe and prolonged droughts during which hydraulic failure from drought-induced embolism can lead to organ or whole plant death. Understanding the determinants of xylem failure across species is especially critical in leaves, the engines of plant growth. If the vulnerability segmentation hypothesis hol...
Article
As plant tissues dehydrate, water transport efficiency declines, a process typically attributed to air obstruction (embolism) in the xylem. Trifiló et al. (pages 5029-5039) dissect leaf hydraulic vulnerability and show that both xylem and living tissues may be important. If confirmed and clarified, an important role for outsidexylem hydraulic decli...
Conference Paper
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Background/Question/Methods Changes in the environment can directly alter ecosystem composition and processes, and trait-based approaches can in principle improve predictions of forest responses. For over 150 years stomatal traits have been recognized as critical determinants of plant function, but rarely incorporated into prediction of community p...
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Deciphering how air enters the plant hydraulic transport tissues represents a major challenge to understanding plant drought responses. Using a non-invasive and cheap visualization technique applied to leaves, the spread of embolism is found to initiate in the midrib, increase with vein order, and is seemingly influenced by vein topology.
Article
Clarifying the evolution and mechanisms for photosynthetic productivity is a key to both improving crops and understanding plant evolution and habitat distributions. Current theory recognizes a role for the hydraulics of water transport as a potential determinant of photosynthetic productivity based on comparative data across disparate species. How...
Article
Water plays a central role in plant biology and the efficiency of water transport throughout the plant affects both photosynthetic rate and growth, an influence that scales up deterministically to the productivity of terrestrial ecosystems. Moreover, hydraulic traits mediate the ways in which plants interact with their abiotic and biotic environmen...
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• Premise of the study: The diverse early Eocene flora from Laguna del Hunco (LH) in Patagonia, Argentina has many nearest living relatives (NLRs) in Australasia but few in South America, indicating the differential survival of an ancient, trans-Antarctic rainforest biome. To better understand this significant biogeographic pattern, we used detaile...
Article
Note: this article is open-access. Please visit the journal website to download the pre-print version free of charge, at http://www.plantphysiol.org/content/early/2015/06/17/pp.15.00731.abstract Leaves are arguably the most complex and important physico-biological systems in the ecosphere. Yet water transport outside the leaf xylem remains poor...
Article
Leaf hydraulic conductance (Kleaf ) quantifies the capacity of a leaf to transport liquid water and is a major constraint on light-saturated stomatal conductance (gs ) and photosynthetic rate (Amax ). Few studies have tested the plasticity of Kleaf and anatomy across growth light environments. These provided conflicting results. The Hawaiian lobeli...
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Leaves are enormously diverse in size and shape, and especially in their internal anatomy, including their venation architecture. This variation across species in vein and lamina anatomy carries extensive information about the physiological function, development, evolution, ecology, and paleohistory of leaves. Much of the functional importance of t...
Conference Paper
Background/Question/Methods The decline in the leaf hydraulic conductance (Kleaf; the capacity for water flow through the leaf per pressure driving force) with dehydration has potential impacts on photosynthetic rate and whole plant growth for plants in moist soil and during drought. Previous studies have shown that Kleaf declines as leaf water p...
Conference Paper
Background/Question/Methods Grasses dominate ≈40% of the Earth’s land surface, accounting for > 25% of terrestrial primary productivity, largely due to the abundance of species using C4 photosynthesis. The C4 photosynthesis syndrome is defined by a CO2 concentrating mechanism and associated specialized leaf anatomy that drive high photosynthetic...
Conference Paper
Background/Question/Methods Across species and environments leaves vary enormously in their size and structure. To understand this huge variation in leaf traits, and their influence on plant productivity, a framework has emerged of correlated traits that make up a single, unified axis known as the “leaf economic spectrum” (LES). Leaf dry mass per...
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It has been recently proposed that leaf vein length per area (VLA) is the major determinant of leaf mass per area (LMA), and would thereby determine other traits of the leaf economic spectrum (LES), such as photosynthetic rate per mass (A mass), nitrogen concentration per mass (N mass) and leaf lifespan (LL). In a previous paper we argued that this...
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Leaf vein length per unit leaf area (VLA; also known as vein density) is an important determinant of water and sugar transport, photosynthetic function, and biomechanical support. A range of software methods are in use to visualize and measure vein systems in cleared leaf images; typically, users locate veins by digital tracing, but recent articles...
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A recent study found that cutting shoots under water while xylem was under tension (which has been the standard protocol for the past few decades) could produce artifactual embolisms inside the xylem, overestimating hydraulic vulnerability relative to shoots cut under water after relaxing xylem tension (Wheeler et al. 2013). That study also raised...
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Winter cold limits temperate plant performance, as does summer water stress in drought-prone ecosystems. The relative impact of seasonal extremes on plant performance has received considerable attention for individual systems. An integrated study compiling the existing literature was needed to identify overall trends. First, we conducted a meta-ana...
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Leaf shrinkage with dehydration has attracted attention for over 100 years, especially as it becomes visibly extreme during drought. However, little has been known of its correlation with physiology. Computer simulations of the leaf hydraulic system showed that a reduction of hydraulic conductance of the mesophyll pathways outside the xylem would c...
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Two highly contrasting variables summarizing the efficiency of transport of materials within the leaf are recognized as playing central roles in determining gas exchange and plant performance. This paper summarizes current approaches for the measurement of mesophyll conductance to CO2 (g m) and leaf hydraulic conductance (K leaf) and addresses the...
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Leaf vein traits are implicated in the determination of gas exchange rates and plant performance. These traits are increasingly considered as causal factors affecting the ‘leaf economic spectrum’ (LES), which includes the light-saturated rate of photosynthesis, dark respiration, foliar nitrogen concentration, leaf dry mass per area (LMA) and leaf l...
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Unlabelled: • Premise of the study: Allometric relationships among the dimensions of leaf cells, cell walls, and tissues, and whole-leaf thickness and area are likely to have key implications for leaf construction and function, but have remained virtually untested, despite the explosion of interest in allometric analysis of numerous plant proper...
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Leaf physiology determines the carbon acquisition of the whole plant, but there can be considerable variation in physiology and carbon acquisition within individual leaves. Alocasia macrorrhiza (L.) Schott is an herbaceous species that can develop very large leaves of up to 1 m in length. However, little is known about the hydraulic and photosynthe...
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The design and function of leaf venation are important to plant performance, with key implications for the distribution and productivity of ecosystems, and applications in paleobiology, agriculture and technology. We synthesize classical concepts and the recent literature on a wide range of aspects of leaf venation. We describe 10 major structural...
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The genus Ruscus (Asparagaceae) consists of evergreen, woody monocot shrubs with modified photosynthetic stems (phylloclades) that occur in dry, shaded woodland areas of the Mediterranean Basin and southern Europe. The combined drought and shade tolerance of Ruscus species challenges the 'trade-off model', which suggests that plants can be either d...
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Water is a key resource, and the plant water transport system sets limits on maximum growth and drought tolerance. When plants open their stomata to achieve a high stomatal conductance (gs) to capture CO2 for photosynthesis, water is lost by transpiration1,2. Water evaporating from the airspaces is replaced from cell walls, in turn drawing water fr...
Article
1. Across plant species, drought tolerance and distributions with respect to water availability are strongly correlated with two physiological traits, the leaf water potential at wilting, that is, turgor loss point (πtlp), and the cell solute potential at full hydration, that is, osmotic potential (πo). We present methods to determine these paramet...
Conference Paper
Full-text available
Background / Purpose: Leaf hydraulic conductance is a fundamental trait which measures the capacity of water to move through the leaf. Water moves through the vein xylem, exits through the bundle sheath, moves through the mesophyll where it evaporates and diffuses through stomata. Leaf shrinkage has been observed for over a century but no one has...
Conference Paper
Background/Question/Methods The greatest challenge to terrestrial plant life is overcoming the relative moisture deficit. The resulting struggle between maximization of photosynthesis and costs of water transport has produced great diversity in plant anatomical and physiological traits. Consequently, understanding of plant water use and response...
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Leaf size and venation show remarkable diversity across dicotyledons, and are key determinants of plant adaptation in ecosystems past and present. Here we present global scaling relationships of venation traits with leaf size. Across a new database for 485 globally distributed species, larger leaves had major veins of larger diameter, but lower len...
Conference Paper
Background/Question/Methods Leaf water transport affects the ability of leaves to maintain photosynthesis for well watered and droughted plants, and their growth. For over 100 years, leaf shrinkage with dehydration has drawn attention, especially as it can become extreme during drought, and potentially impact on the pathways of water transport, a...
Article
Ecology Letters (2012) 15: 393–405 Increasing drought is one of the most critical challenges facing species and ecosystems worldwide, and improved theory and practices are needed for quantification of species tolerances. Leaf water potential at turgor loss, or wilting (πtlp), is classically recognised as a major physiological determinant of plant w...
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Full-text available
Leaf hydraulic conductance (Kleaf) is a major determinant of photosynthetic rate in well-watered and drought-stressed plants. Previous work assessed the decline of Kleaf with decreasing leaf water potential (Ψleaf), most typically using rehydration kinetics methods, and found that species varied in the shape of their vulnerability curve, and that h...
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The leaf is a hydraulic bottleneck, accounting for a large part of plant resistance. Thus, the leaf hydraulic conductance (K(leaf) ) is of key importance in determining stomatal conductance (g(s) ) and rates of gas exchange. Previous studies showed that K(leaf) is dynamic with leaf water status and irradiance. For four species, we tested the combin...
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PROTOCOL http://prometheuswiki.publish.csiro.au/tiki-index.php?page=Quantifying+leaf+vein+traits
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Full-text available
Across plant species, leaves vary enormously in their size and their venation architecture, of which one major function is to replace water lost to transpiration. The leaf hydraulic conductance (K(leaf)) represents the capacity of the transport system to deliver water, allowing stomata to remain open for photosynthesis. Previous studies showed that...
Conference Paper
Background/Question/Methods Leaf hydraulic conductance (Kleaf) is a measure of how efficiently water is transported through a leaf. In theory, Kleaf should decrease with increasing water stress and should be higher for post-fire resprouts than pre-fire adults. These predictions were tested for a fire-prone member of the chaparral shrub community of...
Article
Previous studies have shown a rapid enhancement in leaf hydraulic conductance (K(leaf)) from low to high irradiance (from <10 to >1000 micromol photons m(-2) s(-1)), using the high-pressure flow meter (HPFM), for 7 of 14 tested woody species. However, theoretical suggestions have been made that this response might arise as an artifact of the HPFM....

Projects

Project (1)
Project
The goals of this project are to identify mechanisms and hydraulic functions for positive xylem pressure in plants.