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Moringa oleifera is widely grown throughout the tropics and increasingly used for its therapeutic and nutraceutical properties. These properties are attributed to potent antioxidant and metabolism regulators, including glucosinolates/isothiocyanates as well as flavonoids, polyphenols, and phenolic acids. Research to date largely consists of geographically limited studies that only examine material available locally. These practices make it unclear as to whether moringa samples from one area are superior to another, which would require identifying superior variants and distributing them globally. Alternatively, the finding that globally cultivated moringa material is essentially functionally equivalent means that users can easily sample material available locally. We brought together accessions of Moringa oleifera from four continents and nine countries and grew them together in a common garden. We performed a metabolomic analysis of leaf extracts (MOLE) using an LC-MSMS ZenoTOF 7600 mass spectrometry system. The antioxidant capacity of leaf samples evaluated using the Total Antioxidant Capacity assay did not show any significant difference between extracts. MOLE samples were then tested for their antioxidant activity on C2C12 myotubes challenged with an oxidative insult. Hydrogen peroxide (H2O2) was added to the myotubes after pretreatment with different extracts. H2O2 exposure caused an increase in cell death that was diminished in all samples pretreated with moringa extracts. Our results show that Moringa oleifera leaf extract is effective in reducing the damaging effect of H2O2 in C2C12 myotubes irrespective of geographical origin. These results are encouraging because they suggest that the use of moringa for its therapeutic benefits can proceed without the need for the lengthy and complex global exchange of materials between regions.
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Antioxidantes , Metabolómica , Moringa oleifera , Fibras Musculares Esqueléticas , Extractos Vegetales , Hojas de la Planta , Moringa oleifera/química , Moringa oleifera/metabolismo , Hojas de la Planta/química , Hojas de la Planta/metabolismo , Antioxidantes/farmacología , Antioxidantes/metabolismo , Extractos Vegetales/farmacología , Extractos Vegetales/química , Metabolómica/métodos , Animales , Ratones , Fibras Musculares Esqueléticas/metabolismo , Fibras Musculares Esqueléticas/efectos de los fármacos , Línea Celular , Peróxido de Hidrógeno/metabolismo , Estrés Oxidativo/efectos de los fármacos , Metaboloma/efectos de los fármacosRESUMEN
Hypoallometric (slope<1) scaling between metabolic rate and body mass is often regarded as near-universal across organisms. However, there are compelling reasons to question hypoallometric scaling in woody plants, where metabolic rate is directly proportional to leaf area. This leaf area must provide carbon to the volume of the metabolically active sapwood (VMASW). Within populations of a species, variants in which VMASW increases per unit leaf area with height growth (e.g. â or ¾ scaling) would have proportionally less carbon for growth and reproduction as they grow taller. Therefore, selection should favor individuals in which, as they grow taller, leaf area scales isometrically with shoot VMASW (slope=1). Using tetrazolium staining, we measured total VMASW and total leaf area (LAtot) across 22 individuals of Ricinus communis and confirmed that leaf area scales isometrically with VMASW, and that VMASW is much smaller than total sapwood volume. With the potential of the LAtot-VMASW relationship to shape factors as diverse as the crown area-stem diameter relationship, conduit diameter scaling, reproductive output, and drought-induced mortality, our work indicates that the notion that sapwood increases per unit leaf area with height growth requires revision.
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Biomasa , Hojas de la Planta , Árboles , Hojas de la Planta/crecimiento & desarrollo , Hojas de la Planta/metabolismo , Hojas de la Planta/anatomía & histología , Árboles/crecimiento & desarrollo , Árboles/metabolismo , Ricinus/crecimiento & desarrollo , Ricinus/metabolismo , Madera/crecimiento & desarrollo , Madera/metabolismoRESUMEN
BACKGROUND: The mechanisms leading to dieback and death of trees under drought remain unclear. To gain an understanding of these mechanisms, addressing major empirical gaps regarding tree structure-function relations remains essential. SCOPE: We give reasons to think that a central factor shaping plant form and function is selection simultaneously favouring constant leaf-specific conductance with height growth and isometric (1:1) scaling between leaf area and the volume of metabolically active sink tissues ('sapwood'). Sapwood volume-leaf area isometry implies that per-leaf area sapwood volumes become transversely narrower with height growth; we call this 'stretching'. Stretching means that selection must favour increases in permeability above and beyond that afforded by tip-to-base conduit widening ("ultra-widening permeability"), via fewer and wider vessels or tracheids with larger pits or larger margo openings. Leaf area-metabolically active sink tissue isometry would mean that it is unlikely that larger trees die during drought because of carbon starvation due to greater sink-source relationships as compared to shorter plants. Instead, an increase in permeability is most plausibly associated with greater risk of embolism, and this seems a more probable explanation of the preferential vulnerability of larger trees to climate change-induced drought. Other implications of selection favouring constant per-leaf area sapwood construction and maintenance costs are departure from the da Vinci rule expectation of similar sapwood areas across branching orders, and that extensive conduit furcation in the stem seems unlikely. CONCLUSIONS: Because all these considerations impact the likelihood of vulnerability to hydraulic failure versus carbon starvation, both implicated as key suspects in forest mortality, we suggest that these predictions represent essential priorities for empirical testing.
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Árboles , Árboles/fisiología , Árboles/crecimiento & desarrollo , Árboles/anatomía & histología , Hojas de la Planta/fisiología , Hojas de la Planta/anatomía & histología , Hojas de la Planta/crecimiento & desarrollo , Permeabilidad , Sequías , Modelos Biológicos , Madera/fisiología , Madera/anatomía & histología , Agua/fisiología , Agua/metabolismoRESUMEN
Greater diversity in functional morphology should be associated with the evolution of greater ontogenetic diversity, an expectation difficult to test in most long-lived wild organisms. In the cells derived from the wood meristem (vascular cambium), plants provide extraordinary systems for reconstructing ontogenies in often long-lived organisms. The vascular cambium produces files of cells from the stem center to the periphery, with each cambial derivative "deciding" which of four cell types it differentiates into. Wood cell files remain in place, allowing tracing of the ontogenetic "decisions" taken throughout the life of a stem. We compared cell files from the Pedilanthus clade (genus Euphorbia), which span a range of growth forms from small trees and shrubs of tropical habitats to desert succulents. Using language theory, we represented wood cell types as "letters" and combinations of cell types in cell files as "words," allowing us to measure the diversity of decisions based on word frequency matrices. We also used information content metrics to compare levels of predictability in "decision-making." Our analyses identified a wider array of developmental decisions in woody trees as compared to succulent shrubs, illustrating ways that woody plants provide unparalleled systems for studying the evolution of ontogeny in long-lived, non-model species.
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Plantas , Madera , Cámbium/anatomía & histología , Árboles/anatomía & histología , EcosistemaRESUMEN
Knowing how species and communities respond to environmental change is fundamental in the context of climate change. The search for patterns of abundance and phenotypic variation along altitudinal gradients can provide evidence on adaptive limits. We evaluated the species abundance and the variation in morphometric and stomatal characters in five tree ferns species (Cyathea fulva, C. divergens, C. myosuroides, Alsophila firma and Gymnosphaera salvinii) distributed along an elevation gradient in a well-preserved Mexican cloud forest. Variation at the community and species level was assessed using exploratory and multivariate data analysis methods. We wanted to explore if the species abundance is environmentally determined, to determine the degree of variation along the elevation gradient, to test for differences between zones and associations with elevation, humidity and soil nutrients, and to assess contribution of the intra- and interspecific variation to the community response to elevation and soil nutrients. The studied fern community showed strong species turnover along the elevation gradient, with some influence of soil nutrient concentration, supporting environmental determinism. All measured characters displayed variation along the gradient. Stomatal characters (size and density) had significantly less variation than morphometric characters (trunk diameter, stipe length and blade length), but stomatal density also shows interesting intraspecific patterns. In general, patterns within the fern community suggest a strong influence of species identity, especially of species inhabiting the lower edge of the cloud forest, which showed the clearest morphometric and stomatal patterns, associated to contrasting environments rather than to changes in elevation. The coincidence between morphometric and stomatal patterns in this area suggest hydraulic adjustments in response to contrasting environments. Our results provide evidence that tree ferns species respond to environmental changes through adjustments of morphometric plasticity and stomatal density, which is relevant to predict possible responses to variation in environmental conditions resulting from climate change.
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Trees and other woody plants are immensely ecologically important, making it essential to understand the causes of relationships between tree structure and function. To help these efforts, we highlight persistent traditions in plant biology of appealing to environmental factors "limiting" or "controlling" woody plant features. Examples include the idea that inevitable drops in cell turgor with plant height limit cell expansion and thus leaf size and tree height; that low temperatures prohibit lignification of cells and thus the growth of woody plants at high elevation; and notions from dendrochronology and related fields that climate factors such as rainfall and temperature "control" growth ring features. We show that notions of "control," "limitation," and the like imply that selection would favor a given trait value, but that these would-be favored values are developmentally impossible to produce. Such "limitation" scenarios predict trait frequency distributions that are very narrow and are abruptly curtailed at the upper limit of developmental possibility (the right-hand side of the distribution). Such distributions have, to our knowledge, never been observed, so we see little empirical support for "limitation" hypotheses. We suggest that, as a more productive starting point, plant biologists should examine adaptation hypotheses, in which developmental possibility is wide (congruent with the wide ranges of trait variation that really are observed), but only some of the possible variants are favored. We suggest that (1) the traditional the proximate/ultimate causation distinction, (2) purging scenarios of teleology/anthropomorphism, and (3) stating hypotheses in terms of developmental potential and natural selection are three simple ways of making "limitation" hypotheses clearer with regard to biological process and thus empirically testable.
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Hojas de la Planta , Xilema , Animales , Temperatura , Plantas , BiologíaRESUMEN
Evo-devo is often thought of as being the study of which genes underlie which phenotypes. However, evo-devo is much more than this, especially in plant science. In leaf scars along stems, cell changes across wood growth rings, or flowers along inflorescences, plants trace a record of their own development. Plant morpho evo-devo provides data that genes could never furnish on themes such as heterochrony, the evolution of temporal phenotypes, modularity, and phenotype-first evolution. As plant science surges into increasingly -omic realms, it is essential to keep plant morpho evo-devo in full view as an honored member of the evo-devo canon, ensuring that plant scientists can, wherever they are, generate fundamental insights at the appropriate level of biological organization.
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Nutrient allocation is central to understanding plant ecological strategies and forest roles in biogeochemical cycles. Thought to be mainly driven by environmental conditions, nutrient allocation to woody organs, especially to living tissues, is poorly understood. To examine the role of differences in living tissues (sapwood, SW, vs inner bark, IB), organs, ecological strategies, and environmental conditions in driving nutrient allocation and scaling in woody plants, we quantified nitrogen and phosphorus in main stems and coarse roots of 45 species from three tropical ecosystems with contrasting precipitation, fire regime, and soil nutrients. Nutrient concentration variation was mostly explained by differences between IB and SW, followed by differences between species and, in the case of phosphorus, soil nutrient availability. IB nutrient concentrations were four times those of SW, with root tissues having slightly higher concentrations than stem tissues. Scaling between IB and SW, and between stems and roots, was generally isometric. In cross-sections, IB contributed half of total nutrients in roots and a third in stems. Our results highlight the important role of IB and SW for nutrient storage, the coordination in nutrient allocation across tissues and organs, and the need to differentiate between IB and SW to understand plant nutrient allocation.
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Ecosistema , Nitrógeno , Fósforo , Corteza de la Planta , Hojas de la Planta , Árboles , Suelo , Raíces de Plantas , Tallos de la PlantaRESUMEN
Replicated radiations, in which sets of similar forms evolve repeatedly within different regions, can provide powerful insights into parallel evolution and the assembly of functional diversity within communities. Several cases have been described in animals, but in plants we lack well-documented cases of replicated radiation that combine comprehensive phylogenetic and biogeographic analyses, the delimitation of geographic areas within which a set of 'ecomorphs' evolved independently and the identification of potential underlying mechanisms. Here we document the repeated evolution of a set of leaf ecomorphs in a group of neotropical plants. The Oreinotinus lineage within the angiosperm clade Viburnum spread from Mexico to Argentina through disjunct cloud forest environments. In 9 of 11 areas of endemism, species with similar sets of leaf forms evolved in parallel. We reject gene-flow-mediated evolution of similar leaves and show, instead, that species with disparate leaf forms differ in their climatic niches, supporting ecological adaptation as the driver of parallelism. Our identification of a case of replicated radiation in plants sets the stage for comparative analyses of such phenomena across the tree of life.
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Bosques , Flujo Génico , Adaptación Fisiológica , Animales , México , FilogeniaRESUMEN
The imbalance between reactive oxygen species (ROS) production and antioxidant defense systems leads to macromolecule and tissue damage as a result of cellular oxidative stress. This phenomenon is considered a key factor in fatigue and muscle damage following chronic or high-intensity physical exercise. In the present study, the antioxidant effect of Moringa oleifera leaf extract (MOLE) was evaluated in C2C12 myotubes exposed to an elevated hydrogen peroxide (H2O2) insult. The capacity of the extract to influence the myotube redox status was evaluated through an analysis of the total antioxidant capacity (TAC), glutathione homeostasis (GSH and GSSG), total free thiols (TFT), and thioredoxin (Trx) activity, as well as the enzyme activities of superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GPx) and transferase (GST). Moreover, the ability of MOLE to mitigate the stress-induced peroxidation of lipids and oxidative damage (TBARS and protein carbonyls) was also evaluated. Our data demonstrate that MOLE pre-treatment mitigates the highly stressful effects of H2O2 in myotubes (1 mM) by restoring the redox status (TFT, Trx, and GSH/GSSG ratio) and increasing the antioxidant enzymatic system (CAT, SOD, GPx, GST), thereby significantly reducing the TBARs and PrCAR levels. Our study provides evidence that MOLE supplementation has antioxidant potential, allowing myotubes better able to cope with an oxidative insult and, therefore, could represent a useful nutritional strategy for the preservation of muscle well-being.
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Plant life-history variation reflects different outcomes of natural selection given the strictures of resource allocation trade-offs. However, there is limited theory of selection predicting how leaves, stems, roots, and reproductive organs should evolve in concert across environments. Here, we synthesize two optimality theories to offer a general theory of plant carbon economics, named as Gmax theory, that shows how life-history variation is limited to phenotypes that have an approximately similar lifetime net carbon gain per body mass. In consequence, fast-slow economics spectra are the result of trait combinations obtaining similar lifetime net carbon gains from leaves and similar net carbon investment costs in stems, roots, and reproductive organs. Gmax theory also helps explain ecosystem and crop productivity and even helps guide carbon conservation strategies.
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Carbono , Rasgos de la Historia de Vida , Ecosistema , Hojas de la Planta , PlantasRESUMEN
Viviparity, an innovation enhancing maternal control over developing embryos, has evolved >150 times in vertebrates, and has been proposed as an adaptation to inhabit cold habitats. Yet, the behavioral, physiological, morphological, and life history features associated with live-bearing remain unclear. Here, we capitalize on repeated origins of viviparity in phrynosomatid lizards to tease apart the phenotypic patterns associated with this innovation. Using data from 125 species and phylogenetic approaches, we find that viviparous phrynosomatids repeatedly evolved a more cool-adjusted thermal physiology than their oviparous relatives. Through precise thermoregulatory behavior viviparous phrynosomatids are cool-adjusted even in warm environments, and oviparous phrynosomatids warm-adjusted even in cool environments. Convergent behavioral shifts in viviparous species reduce energetic demand during activity, which may help offset the costs of protracted gestation. Whereas dam and offspring body size are similar among both parity modes, annual fecundity repeatedly decreases in viviparous lineages. Thus, viviparity is associated with a lower energetic allocation into production. Together, our results indicate that oviparity and viviparity are on opposing ends of the fast-slow life history continuum in both warm and cool environments. In this sense, the 'cold climate hypothesis' fits into a broader range of energetic/life history trade-offs that influence transitions to viviparity.
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Lagartos , Animales , Evolución Biológica , Femenino , Nacimiento Vivo , Lagartos/fisiología , Oviparidad/fisiología , Filogenia , Embarazo , Viviparidad de Animales no Mamíferos/fisiologíaRESUMEN
PREMISE: Comparative anatomy is necessary to identify the extremes of combinations of functionally relevant structural traits, to ensure that physiological data cover xylem anatomical diversity adequately, and thus achieve a global understanding of xylem structure-function relations. A key trait relationship is that between xylem vessel diameter and wall thickness of both the single vessel and the double vessel+adjacent imperforate tracheary element (ITE). METHODS: We compiled a comparative data set with 1093 samples, 858 species, 350 genera, 86 families, and 33 orders. We used broken linear regression and an algorithm to explore changes in parameter values from linear regressions using subsets of the data set to identify a threshold, at 90-µm vessel diameter, in the wall thickness-diameter relationship. RESULTS: Below 90 µm diameter for vessels, virtually any wall thickness could be associated with virtually any diameter. Below this threshold, selection is free to favor a very wide array of combinations, such as very thick walls and narrow vessels in ITE-free herbs, or very thin-walled, wide vessels in evergreen dryland pioneers. Above 90 µm, there was a moderate positive relationship. CONCLUSIONS: Our analysis shows that the space of vessel wall thickness-diameter combinations is very wide, with selection apparently eliminating individuals with vessel walls "too thin" for their diameter. Most importantly, our survey revealed poorly studied plant hydraulic syndromes (functionally significant trait combinations). These data suggest that the full span of trait combinations, and thus the minimal set of hydraulic syndromes requiring study to span woody plant functional diversity adequately, remains to be documented.
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Magnoliopsida , Ambiente , Magnoliopsida/fisiología , Síndrome , Agua , Madera/anatomía & histología , Xilema/fisiologíaRESUMEN
Shaping global water and carbon cycles, plants lift water from roots to leaves through xylem conduits. The importance of xylem water conduction makes it crucial to understand how natural selection deploys conduit diameters within and across plants. Wider conduits transport more water but are likely more vulnerable to conduction-blocking gas embolisms and cost more for a plant to build, a tension necessarily shaping xylem conduit diameters along plant stems. We build on this expectation to present the Widened Pipe Model (WPM) of plant hydraulic evolution, testing it against a global dataset. The WPM predicts that xylem conduits should be narrowest at the stem tips, widening quickly before plateauing toward the stem base. This universal profile emerges from Pareto modeling of a trade-off between just two competing vectors of natural selection: one favoring rapid widening of conduits tip to base, minimizing hydraulic resistance, and another favoring slow widening of conduits, minimizing carbon cost and embolism risk. Our data spanning terrestrial plant orders, life forms, habitats, and sizes conform closely to WPM predictions. The WPM highlights carbon economy as a powerful vector of natural selection shaping plant function. It further implies that factors that cause resistance in plant conductive systems, such as conduit pit membrane resistance, should scale in exact harmony with tip-to-base conduit widening. Furthermore, the WPM implies that alterations in the environments of individual plants should lead to changes in plant height, for example, shedding terminal branches and resprouting at lower height under drier climates, thus achieving narrower and potentially more embolism-resistant conduits.
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Evolución Biológica , Modelos Biológicos , Fenómenos Fisiológicos de las Plantas , Agua/fisiología , Xilema/anatomía & histologíaRESUMEN
It is common for studies that employ the comparative method for the study of adaptation, that is, documentation of potentially adaptive across-species patterns of trait-environment or trait-trait correlation, to be designated as "macroevolutionary." Authors are justified in using "macroevolution" in this way by appeal to definitions such as "evolution above the species level." I argue that regarding the comparative method as "macroevolutionary" is harmful because it hides in serious ways the true causal content of hypotheses tested with the comparative method. The comparative method is a means of testing hypotheses of adaptation and their alternatives. Adaptation is a population-level phenomenon, involving heritable interindividual variation that is associated with fitness differences. For example, given heritable intrapopulational variation, more streamlined individuals in populations of fast-moving aquatic animals have higher locomotory efficiency and thus better survivorship and more resources directed to reproduction than less streamlined ones. Direct evidence consistent with this population-level scenario includes the observation that many unrelated species of fast-moving aquatic animals have similar streamlined shapes, an example of the comparative method. Crucial to note in this example is that although the data are observed across species, the comparative method for studying adaptation tests hypotheses regarding standard population-level natural selection with no content that can be construed as "macro." Even less "macro," individual-level developmental dynamics can limit or bias the range of variants available for selection. Calling any of these studies "macroevolutionary" implies that some additional process is at work, shrouding the need to test adaptation hypotheses and study the range of variants that can be produced in development. [Adaptation; comparative method; constraint; macroevolution; optimality models; population biology.].
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Adaptación Fisiológica , Evolución Biológica , Adaptación Fisiológica/genética , Animales , Humanos , Fenotipo , Filogenia , Selección GenéticaRESUMEN
Non-structural carbohydrates (NSC) are crucial for forest resilience, but little is known regarding the role of bark in NSC storage. However, bark's abundance in woody stems and its large living fraction make it potentially key for NSC storage. We quantified total NSC, soluble sugar (SS) and starch concentrations in the most living region of bark (inner bark, IB), and sapwood of twigs, trunks and roots of 45 woody species from three contrasting tropical climates spanning global extremes of bark diversity and wide phylogenetic diversity. NSC concentrations were similar (total NSC, starch) or higher (SS) in IB than wood, with concentrations co-varying strongly. NSC concentrations varied widely across organs and species within communities and were not significantly affected by climate, leaf habit or the presence of photosynthetic bark. Starch concentration tended to increase with density, but only in wood. IB contributed substantially to NSC storage, accounting for 17-36% of total NSC, 23-47% of SS and 15-33% of starch pools. Further examination of the drivers of variation in IB NSC concentration, and taking into account the substantial contribution of IB to NSC pools, will be crucial to understand the role of storage in plant environmental adaptation.