4,933 results match your criteria American journal of botany[Journal]


Rarity does not limit genetic variation or preclude subpopulation structure in the geographically restricted desert forb Astragalus lentiginosus var. piscinensis.

Am J Bot 2019 Feb 14. Epub 2019 Feb 14.

Department of Biology, University of Nevada, Reno, NV, USA.

Premise Of The Study: Characteristics of rare taxa include small population sizes and limited geographical ranges. The genetic consequences of rarity are poorly understood for most taxa. A small geographical range could result in reduced opportunity for isolation by distance or environment, thereby limiting genetic structure and variation, but few studies explore genetic structure at small spatial scales with sufficient resolution to test this hypothesis. Read More

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http://dx.doi.org/10.1002/ajb2.1235DOI Listing
February 2019

Biomechanical control of beech pole verticality (Fagus sylvatica) before and after thinning: theoretical modelling and ground-truth data using terrestrial LiDAR.

Am J Bot 2019 Feb 11. Epub 2019 Feb 11.

Université de Lorraine, AgroParisTech, INRA, UMR Silva, F-54000, Nancy, France.

Premise Of The Study: Thinning is a frequent disturbance in managed forests, especially to increase radial growth. Due to buckling and bending risk associated with height and mass growth, tree verticality is strongly constrained in slender trees growing in dense forests and poor light conditions. Tree verticality is controlled by uprighting movements implemented from local curvatures induced by wood maturation stresses and/or eccentric radial growth. Read More

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http://dx.doi.org/10.1002/ajb2.1228DOI Listing
February 2019

Testing the hypothesis of loss of defenses on islands across a wide latitudinal gradient of Periploca laevigata populations.

Am J Bot 2019 Feb 11. Epub 2019 Feb 11.

Departamento de Biodiversidad Molecular y Banco de ADN, Jardín Botánico Canario 'Viera y Clavijo' - Unidad Asociada CSIC, Cabildo de Gran Canaria, Camino del Palmeral 15 de Tafira Alta, 35017, Las Palmas de Gran Canaria, Spain.

Premise Of The Study: We tested a hypothesis that predicts loss of chemical defenses on island plant populations (LCDIH) as an evolutionary response to limited herbivore pressures.

Methods: Using a common garden approach, we grew 16 populations (N = 286 seedlings) of Periploca laevigata, a Mediterranean shrub for which previous studies suggested that animal browsing elicits defensive responses mediated by tannins. Our experimental setting represented a wide latitudinal gradient (37-15°N) encompassing three island systems, virtually free of large herbivores, and three mainland areas. Read More

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http://dx.doi.org/10.1002/ajb2.1232DOI Listing
February 2019

Within-crown plasticity in leaf traits among the tallest conifers.

Am J Bot 2019 Feb 6. Epub 2019 Feb 6.

Department of Forestry and Wildland Resources, Humboldt State University, 1 Harpst Street, Arcata, CA, 95521, USA.

Premise Of The Study: Leaves are the sites of greatest water stress in trees and a key means of acclimation to the environment. We considered phenotypic plasticity of Pseudotsuga menziesii leaves in their ecological context, exploring responsiveness to natural gradients in water stress (indicated by sample height) and light availability (measured from hemispherical photos) to understand how leaf structure is controlled by abiotic factors in tall tree crowns.

Methods: After measuring anatomy, morphology, and carbon isotope composition (δ C) of leaves throughout crowns of P. Read More

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http://dx.doi.org/10.1002/ajb2.1230DOI Listing
February 2019
1 Read

Decrypting the phyllosphere microbiota: progress and challenges.

Am J Bot 2019 Feb 6. Epub 2019 Feb 6.

Plant and Microbial Biology, North Carolina State University, Raleigh, NC, USA.

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http://dx.doi.org/10.1002/ajb2.1229DOI Listing
February 2019
1 Read

Holantarctic diversity varies widely among genetic loci within the gametophytically allotriploid peat moss Sphagnum × falcatulum.

Am J Bot 2019 Jan 15;106(1):137-144. Epub 2019 Jan 15.

Department of Ecology, Evolution and Natural Resources, School of Environmental and Biological Sciences, Rutgers University, New Brunswick, New Jersey, 08901-8551, USA.

Premise Of The Study: The traditional approach used in analyses of population genetic data for historical inference is to average across multiple marker loci, but averaging conflates the different evolutionary signals provided by stable vs. labile markers.

Methods: We used a battery of microsatellites with a wide range of mutation/substitution rates, grouping them into two sets (stable and hypervariable) to provide a more nuanced reconstruction of the population genetics and evolutionary history of the allotriploid peat moss Sphagnum × falcatulum across three disjunct regions. Read More

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http://dx.doi.org/10.1002/ajb2.1220DOI Listing
January 2019
1 Read

Variation in the transcriptome of different ecotypes of Arabidopsis thaliana reveals signatures of oxidative stress in plant responses to spaceflight.

Am J Bot 2019 Jan 15;106(1):123-136. Epub 2019 Jan 15.

Department of Botany, University of Wisconsin-Madison, Birge Hall, 430 Lincoln Drive, Madison, WI, 53706, USA.

Premise Of The Study: Spaceflight provides a unique environment in which to dissect plant stress response behaviors and to reveal potentially novel pathways triggered in space. We therefore analyzed the transcriptomes of Arabidopsis thaliana plants grown on board the International Space Station to find the molecular fingerprints of these space-related response networks.

Methods: Four ecotypes (Col-0, Ws-2, Ler-0 and Cvi-0) were grown on orbit and then their patterns of transcript abundance compared to ground-based controls using RNA sequencing. Read More

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http://dx.doi.org/10.1002/ajb2.1223DOI Listing
January 2019
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Revisiting the relative growth rate hypothesis for gymnosperm and angiosperm species co-occurrence.

Am J Bot 2019 Jan 15;106(1):101-112. Epub 2019 Jan 15.

Centro de Investigación en Ecosistemas de la Patagonia (CIEP), Moraleda 16, Coyhaique, 5951601, Chile.

Premise Of The Study: It is unclear to what extent the co-occurrence of angiosperm and gymnosperm species in some marginal ecosystems is explained by reduced growth in angiosperms due to carbon (C) limitation and by high stress tolerance in gymnosperms associated with lack of vessels and resource conservation.

Methods: We examined growth patterns and traits associated with C balance in four evergreen angiosperm species (including one vesselless species, Drimys winteri) and three gymnosperm tree species of a cold-temperate rainforest in southern Chile. We measured the mean basal area increment for the first 50 (BAI ) and the last 10 years (BAI ), wood density, leaf lifespan, and nonstructural carbohydrate (NSC) concentrations in different organs. Read More

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http://doi.wiley.com/10.1002/ajb2.1221
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http://dx.doi.org/10.1002/ajb2.1221DOI Listing
January 2019
5 Reads

Asynchrony between ant seed dispersal activity and fruit dehiscence of myrmecochorous plants.

Am J Bot 2019 Jan 15;106(1):71-80. Epub 2019 Jan 15.

Department of Ecology and Evolutionary Biology, University of Toronto, 25 Willcocks Street, Toronto, Ontario, M5S 3B2, Canada.

Premise Of The Study: Phenological mismatch has received attention in plant-pollinator interactions, but less so in seed dispersal mutualisms. We investigated whether the seasonal availability of myrmecochorous seeds is well matched to the seasonal activity patterns of seed-dispersing ants.

Methods: We compared seasonal timing of seed removal by a keystone seed-dispersing ant, Aphaenogaster rudis, and fruit dehiscence of several species of plants whose seeds it disperses in a deciduous forest in southern Ontario, Canada. Read More

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http://dx.doi.org/10.1002/ajb2.1214DOI Listing
January 2019
1 Read

Inter- and intraspecific competition and shade avoidance in the carnivorous pale pitcher plant in a nutrient-poor savanna.

Authors:
J Stephen Brewer

Am J Bot 2019 Jan 14;106(1):81-89. Epub 2019 Jan 14.

Department of Biology, University of Mississippi, University, Mississippi, 38677-1848, USA.

Premise Of The Study: Ecologists generally agree that weak interspecific competition for light contributes to high plant species diversity in ecosystems with nutrient-poor soils. However, the role of competition for light in such ecosystems that are also maintained by fire is poorly understood. I quantified intra- and interspecific competition for light in a fire-maintained nutrient-poor pine savanna by contrasting the effects of conspecific and heterospecific neighbors of the pale pitcher plant, Sarracenia alata. Read More

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http://dx.doi.org/10.1002/ajb2.1219DOI Listing
January 2019
1 Read

What makes a weed a weed? A large-scale evaluation of arable weeds through a functional lens.

Am J Bot 2019 Jan 11;106(1):90-100. Epub 2019 Jan 11.

Centre d'Ecologie Fonctionnelle et Evolutive, UMR 5175 CNRS - Université de Montpellier - Université Paul Valéry - EPHE, 34293, Montpellier, France.

Premise Of The Study: Despite long-term research efforts, a comprehensive perspective on the ecological and functional properties determining plant weediness is still lacking. We investigated here key functional attributes of arable weeds compared to non-weed plants, at large spatial scale.

Methods: We used an intensive survey of plant communities in cultivated and non-cultivated habitats to define a pool of plants occurring in arable fields (weeds) and one of plants occurring only in open non-arable habitats (non-weeds) in France. Read More

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http://doi.wiley.com/10.1002/ajb2.1213
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http://dx.doi.org/10.1002/ajb2.1213DOI Listing
January 2019
5 Reads

Weather cues associated with masting behavior dampen the negative autocorrelation between past and current reproduction in oaks.

Am J Bot 2019 Jan 11;106(1):51-60. Epub 2019 Jan 11.

Department of Ecology and Evolutionary Biology, University of California, Irvine, California, USA, 92697.

Premise Of The Study: The influence of weather conditions on masting and the ecological advantages of this reproductive behavior have been the subject of much interest. Weather conditions act as cues influencing reproduction of individual plants, and similar responses expressed across many individuals lead to population-level synchrony in reproductive output. In turn, synchrony leads to benefits from economies of scale such as enhanced pollination success and seed predator satiation. Read More

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http://doi.wiley.com/10.1002/ajb2.1210
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http://dx.doi.org/10.1002/ajb2.1210DOI Listing
January 2019
3 Reads

Does hybrid Phragmites australis differ from native and introduced lineages in reproductive, genetic, and morphological traits?

Am J Bot 2019 Jan 11;106(1):29-41. Epub 2019 Jan 11.

Smithsonian Tropical Research Institute, Apartado, 0843-03092, Balboa, Ancon, Republic of Panama.

Premise Of The Study: Hybridization between previously isolated species or lineages can stimulate invasiveness because of increased genetic diversity and inherited traits facilitating competitive and reproductive potential. We evaluated differences in stand characteristics and sexual and vegetative reproduction among native, introduced, and hybrid Phragmites australis lineages in the southwestern United States. We also assessed the degree of hybridization among lineages and backcrossing of hybrids with parental lineages. Read More

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http://dx.doi.org/10.1002/ajb2.1217DOI Listing
January 2019
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A quick glance at noteworthy articles for January 2019.

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Am J Bot 2019 Jan 11;106(1):1-2. Epub 2019 Jan 11.

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http://dx.doi.org/10.1002/ajb2.1225DOI Listing
January 2019
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Allometry of the pyrophytic Aristida in fire-maintained longleaf pine-wiregrass ecosystems.

Am J Bot 2019 Jan 10;106(1):18-28. Epub 2019 Jan 10.

Tall Timbers Research Station, Tallahassee, FL, 32312, USA.

Premise Of The Study: Aboveground biomass (AGB) of herbaceous vegetation is a primary source of fuel in frequent surface fires that maintain grasslands, savannas, and woodlands. Methods for nondestructively estimating AGB are required to understand the mechanisms by which fuels affect fire behavior and the effects of time since the last burn. We developed allometric equations to estimate AGB in wiregrass (Aristida beyrichiana/A. Read More

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http://dx.doi.org/10.1002/ajb2.1215DOI Listing
January 2019
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The renaissance of comparative biochemistry.

Am J Bot 2019 Jan 10;106(1):3-13. Epub 2019 Jan 10.

Department of Biochemistry and Center for Plant Biology, Purdue University, West Lafayette, IN, USA.

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http://doi.wiley.com/10.1002/ajb2.1216
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http://dx.doi.org/10.1002/ajb2.1216DOI Listing
January 2019
3 Reads

A temporal shift in resource allocation facilitates flowering before leaf out and spring vessel maturation in precocious species.

Authors:
Jessica A Savage

Am J Bot 2019 Jan 10;106(1):113-122. Epub 2019 Jan 10.

Department of Biology, University of Minnesota, Duluth, MN, USA.

Premise Of The Study: New growth in the spring requires resource mobilization in the vascular system at a time when xylem and phloem function are often reduced in seasonally cold climates. As a result, the timing of leaf out and/or flowering could depend on when the vascular system resumes normal function in the spring. This study investigated whether flowering time is influenced by vascular phenology in plants that flower precociously before they have leaves. Read More

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http://dx.doi.org/10.1002/ajb2.1222DOI Listing
January 2019
1 Read

Sex-specific plasticity of reproductive allocation in response to water depth in a clonal, dioecious macrophyte.

Am J Bot 2019 Jan 10;106(1):42-50. Epub 2019 Jan 10.

Jiangxi Province Key Laboratory of Watershed Ecosystem Change and Biodiversity, Center for Watershed Ecology, Institute of Life Science and School of Life Sciences, Nanchang University, Nanchang, 330031, China.

Premise Of The Study: Sex-specific differences in reproductive investment contribute to sexual dimorphism in dioecious plants. Along environmental gradients, males and females may plastically adjust reproductive allocation differently because of contrasting reproductive costs. In dioecious macrophytes, variation in water depth is likely to influence reproductive allocation but has not been investigated in detail. Read More

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http://dx.doi.org/10.1002/ajb2.1218DOI Listing
January 2019
1 Read
2.603 Impact Factor

Phylogenetic inference in section Archerythroxylum informs taxonomy, biogeography, and the domestication of coca (Erythroxylum species).

Am J Bot 2019 Jan 10;106(1):154-165. Epub 2019 Jan 10.

Department of Biological Sciences, University of Illinois at Chicago, 845 West Taylor Street Room 3256 (M/C 066), Chicago, IL, 60612, USA.

Premise Of The Study: This investigation establishes the first DNA-sequence-based phylogenetic hypothesis of species relationships in the coca family (Erythroxylaceae) and presents its implications for the intrageneric taxonomy and neotropical biogeography of Erythroxylum. We also identify the closest wild relatives and evolutionary relationships of the cultivated coca taxa.

Methods: We focused our phylogenomic inference on the largest taxonomic section in the genus Erythroxylum (Archerythroxylum O. Read More

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http://dx.doi.org/10.1002/ajb2.1224DOI Listing
January 2019
1 Read

No evidence that seed predators constrain pollinator-mediated trait evolution in a tropical vine.

Am J Bot 2019 Jan 9;106(1):145-153. Epub 2019 Jan 9.

Centre for Biodiversity Dynamics, Department of Biology, Norwegian University of Science and Technology, NTNU, 7491, Trondheim, Norway.

Premise Of The Study: Turnover in biotic communities across heterogeneous landscapes is expected to lead to variation in interactions among plants, their mutualists, and their antagonists. Across a fragmented landscape in northern Costa Rica, populations of the euphorb vine Dalechampia scandens vary widely in mating systems and associated blossom traits. Previous work suggested that populations are well adapted to the local reliability of pollination by apid and megachilid bees. Read More

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http://dx.doi.org/10.1002/ajb2.1209DOI Listing
January 2019
2 Reads

Autopolyploid lineage shows climatic niche expansion but not divergence in Arabidopsis arenosa.

Am J Bot 2019 Jan 4;106(1):61-70. Epub 2019 Jan 4.

Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, MA, 02138, USA.

Premise Of The Study: Successful establishment of neopolyploids, and therefore polyploid speciation, is thought to be contingent on environmental niche shifts from their progenitors. We explore this niche shift hypothesis in the obligate outcrosser Arabidopsis arenosa complex, which includes diploid and recently formed autotetraploid populations.

Methods: To characterize the climatic niches for both cytotypes in Arabidopsis arenosa, we first gathered climatic data from localities with known ploidy types. Read More

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http://dx.doi.org/10.1002/ajb2.1212DOI Listing
January 2019
1 Read

The nonrandom evolution of gene families.

Am J Bot 2019 Jan 31;106(1):14-17. Epub 2018 Dec 31.

Department of Ecosystem Science and Management, College of Agriculture and Life Sciences, Texas A&M University, College Station, TX, 77843, USA.

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http://dx.doi.org/10.1002/ajb2.1211DOI Listing
January 2019
1 Read

Sympatric diploid and tetraploid cytotypes of Centaurea stoebe s.l. do not differ in arbuscular mycorrhizal communities and mycorrhizal growth response.

Am J Bot 2018 Dec 14;105(12):1995-2007. Epub 2018 Dec 14.

Department of Botany, Faculty of Science, Charles University, Benátská 2, CZ-128 01, Prague, Czech Republic.

Premise Of The Study: Genome duplication is associated with multiple changes at different levels, including interactions with pollinators and herbivores. Yet little is known whether polyploidy may also shape belowground interactions.

Methods: To elucidate potential ploidy-specific interactions with arbuscular mycorrhizal fungi (AMF), we compared mycorrhizal colonization and assembly of AMF communities in roots of diploid and tetraploid Centaurea stoebe s. Read More

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https://onlinelibrary.wiley.com/doi/abs/10.1002/ajb2.1206
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http://dx.doi.org/10.1002/ajb2.1206DOI Listing
December 2018
5 Reads

Synchrotron X-ray imaging of a dichasium cupule of Castanopsis from Eocene Baltic amber.

Am J Bot 2018 Dec 13;105(12):2025-2036. Epub 2018 Dec 13.

Department of Palaeobiology, Swedish Museum of Natural History, Box 50007, 10405, Stockholm, Sweden.

Premise Of The Study: The Eocene Baltic amber deposit represents the largest accumulation of fossil resin worldwide, and hundreds of thousands of entrapped arthropods have been recovered. Although Baltic amber preserves delicate plant structures in high fidelity, angiosperms of the "Baltic amber forest" remain poorly studied. We describe a pistillate partial inflorescence of Castanopsis (Fagaceae), expanding the knowledge of Fagaceae diversity from Baltic amber. Read More

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http://dx.doi.org/10.1002/ajb2.1202DOI Listing
December 2018
2 Reads

Ecological differentiation facilitates fine-scale coexistence of sexual and asexual Boechera.

Am J Bot 2018 Dec 13;105(12):2051-2064. Epub 2018 Dec 13.

Department of Biology, Duke University, Box 90338, Durham, North Carolina, 27708, USA.

Premise Of The Study: Ecological differentiation (ED) between sexual and asexual organisms may permit the maintenance of reproductive polymorphism. Several studies of sexual/asexual ED in plants have shown that the geographic ranges of asexuals extend beyond those of sexuals, often in areas of higher latitude or elevation. But very little is known about ED at fine scales, wherein coexistence of sexuals and asexuals may be permitted by differential niche occupation. Read More

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http://dx.doi.org/10.1002/ajb2.1201DOI Listing
December 2018
2 Reads

Reproductive consequences of variation in flowering phenology in the dry forest tree Enterolobium cyclocarpum in Guanacaste, Costa Rica.

Am J Bot 2018 Dec 13;105(12):2037-2050. Epub 2018 Dec 13.

Centro de Investigación en Biología Celular y Molecular, Universidad de Costa Rica, Ciudad Universitaria "Rodrigo Facio", San Pedro de Montes de Oca, San José, Costa Rica.

Premise Of The Study: Flowering initiation, duration and magnitude, and degree of flowering synchrony within a population can affect the reproductive fitness of individuals. We examined the flowering phenology within a population of the tropical dry forest Guanacaste tree (Enterolobium cyclocarpum) to gauge the impact of phenological variation among trees on fruit production and progeny vigor.

Methods: We monitored the flowering phenology of 93 trees weekly during 2005, 2006, and 2007, using a scale based on the percentage of the crown with open flowers. Read More

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https://onlinelibrary.wiley.com/doi/abs/10.1002/ajb2.1205
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http://dx.doi.org/10.1002/ajb2.1205DOI Listing
December 2018
7 Reads

Chiral events in developing gametophores of Physcomitrella patens and other moss species are driven by an unknown, universal direction-sensing mechanism.

Am J Bot 2018 Dec 11;105(12):1986-1994. Epub 2018 Dec 11.

University of Wrocław, Institute of Experimental Biology, Department of Plant Developmental Biology, Kanonia 6/8, 50-328, Wrocław, Poland.

Premise Of The Study: We used the model species Physcomitrella patens to examine chirality in moss gametophores. Chirality is manifested in the direction of consecutive apical cell divisions, cell plate configurations, and deviations of leaf connecting lines from the vertical course. However, the frequencies of chiral configurations of all these processes as well as their mutual dependence-especially in the case of gametophore branching-are not known. Read More

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http://dx.doi.org/10.1002/ajb2.1200DOI Listing
December 2018
2 Reads

A quick glance at noteworthy articles in this month's issue.

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Am J Bot 2018 Dec 10;105(12):1951-1952. Epub 2018 Dec 10.

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http://dx.doi.org/10.1002/ajb2.1204DOI Listing
December 2018
1 Read

The link between selfing and greater dispersibility in a heterocarpic Asteraceae.

Am J Bot 2018 Dec 11;105(12):2065-2074. Epub 2018 Dec 11.

Departamento de Biología Vegetal y Ecología, Universidad de Sevilla, Apdo. 1095, 41080, Sevilla, Spain.

Premise Of The Study: Although an evolutionary link between breeding system and dispersibility has been proposed, to date empirical data and theoretical models of plants show contrasting trends.

Methods: We tested two competing hypotheses for the association between breeding systems and dispersibility in the heterocarpic Hypochaeris salzmanniana (Asteraceae) by using both an experimental approach and surveys over 2 years of five natural populations along an environmental cline with a gradient of pollinator availability.

Key Results: Hypochaeris salzmanniana produced two types of fruits, beaked (BF) and nonbeaked (NBF), which differ in their dispersal ability. Read More

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http://dx.doi.org/10.1002/ajb2.1207DOI Listing
December 2018
2 Reads

Extreme cold consistently reduces seedling growth but has species-specific effects on browse tolerance in summer.

Am J Bot 2018 Dec 6;105(12):2075-2080. Epub 2018 Dec 6.

Department of Integrative Biology, University of Wisconsin-Madison, 250 N. Mills Street, Madison, WI, 53706, USA.

Premise Of The Study: Extreme weather events can injure plants, causing decreased survival. However, we may underestimate the ecological importance of extreme events if they have strong sublethal effects that manifest after several months. We tested the hypothesis that late-winter extreme-cold events decrease the ability of woody plants to grow and tolerate stem removal in summer. Read More

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http://dx.doi.org/10.1002/ajb2.1203DOI Listing
December 2018
2 Reads

Reproductive heat tolerance in a Mojave Desert annual plant, Trianthema portulacastrum.

Am J Bot 2018 Dec 3;105(12):2018-2024. Epub 2018 Dec 3.

Department of Ecology and Evolutionary Biology, University of Toronto, 25 Willcocks Street, Toronto, ON, M5S 3B2, Canada.

Premise Of The Study: Reproduction in many crop species is impaired above 30° to 35°C; however, the sensitivity of reproduction in the natural flora remains uncertain. Studies focusing on the effect of high temperature on plant reproduction in wild species are necessary to improve our understanding of how rising global temperatures will impact global plant reproductive success and may ultimately inform models of plant distribution in the future. Additionally, these studies may highlight candidates for thermotolerance that could be further explored for crop improvement. Read More

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http://dx.doi.org/10.1002/ajb2.1199DOI Listing
December 2018
3 Reads

Belowground annual ring growth coordinates with aboveground phenology and timing of carbon storage in two tallgrass prairie forb species.

Am J Bot 2018 Dec 4;105(12):1975-1985. Epub 2018 Dec 4.

Department of Plant Biology, Ecology, and Evolution, Oklahoma State University, 301 Physical Sciences, Stillwater, Oklahoma, 74078, USA.

Premise Of The Study: Herb chronology, the study of belowground annual growth rings in perennial forbs, has much potential as a tool for monitoring plant growth as a function of environment. To harness this potential, understanding of the coordination between ring ontogeny, aboveground phenology, and the temporal allocation of carbon products belowground in herbaceous forbs must be improved.

Methods: We investigated these relationships in two southern United States tallgrass prairie perennial forb species, Asclepias viridis and Lespedeza stuevei, making monthly excavations for a year. Read More

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http://dx.doi.org/10.1002/ajb2.1198DOI Listing
December 2018
2 Reads

Long- and short-term responses of Asclepias species differ in respect to fire, grazing, and nutrient addition.

Am J Bot 2018 Dec 28;105(12):2008-2017. Epub 2018 Nov 28.

Department of Biology, College of William and Mary, Williamsburg, Virginia, 23185, USA.

Premise Of The Study: The tallgrass prairie ecosystem has experienced a dramatic reduction over the past 150 yr. This reduction has impacted the abundance of native grassland species, including milkweeds (Asclepias).

Methods: We used two long-term (27 yr) data sets to examine how fire, grazing, and nutrient addition shape milkweed abundance in tallgrass prairie. Read More

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http://dx.doi.org/10.1002/ajb2.1197DOI Listing
December 2018
2 Reads

Extended differentiation of veins and stomata is essential for the expansion of large leaves in Rheum rhabarbarum.

Am J Bot 2018 Dec 26;105(12):1967-1974. Epub 2018 Nov 26.

Purdue Center for Plant Biology, Department of Botany and Plant Pathology, Purdue University, West Lafayette, IN, 47907, USA.

Premise Of The Study: The densities of veins and stomata govern leaf water supply and gas exchange. They are coordinated to avoid overproduction of either veins or stomata. In many species, where leaf area is greater at low light, this coordination is primarily achieved through differential cell expansion, resulting in lower stomatal and vein density in larger leaves. Read More

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http://dx.doi.org/10.1002/ajb2.1196DOI Listing
December 2018
1 Read

The magic of flowers or: speciation genes and where to find them.

Am J Bot 2018 Dec 21;105(12):1957-1961. Epub 2018 Nov 21.

Institute of Botany, University of Hohenheim, Garbenstraße 30, D-70599, Stuttgart, Germany.

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http://dx.doi.org/10.1002/ajb2.1193DOI Listing
December 2018
1 Read

Skimming the surface: duckweed as a model system in ecology and evolution.

Am J Bot 2018 Dec 19;105(12):1962-1966. Epub 2018 Nov 19.

Department of Biology, University of Southern Denmark, 5230, Odense M, Denmark.

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http://dx.doi.org/10.1002/ajb2.1194DOI Listing
December 2018
1 Read

The growing importance of data literacy in life science education.

Am J Bot 2018 Dec 19;105(12):1953-1956. Epub 2018 Nov 19.

Director of Education and Diversity Programs, Ecological Society of America, Washington, D.C., USA.

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http://dx.doi.org/10.1002/ajb2.1195DOI Listing
December 2018
1 Read

Linking leaf hydraulic properties, photosynthetic rates, and leaf lifespan in xerophytic species: a test of global hypotheses.

Am J Bot 2018 Nov;105(11):1858-1868

Key Laboratory of Mountain Ecological Restoration and Bioresource Utilization, Chengdu Institute of Biology, Chinese Academy of Sciences, Chengdu, China, 610041.

Premise Of The Study: Leaf venation and its hierarchal traits are crucial to the hydraulic and mechanical properties of leaves, reflecting plant life-history strategies. However, there is an extremely limited understanding of how variation in leaf hydraulics affects the leaf economic spectrum (LES) or whether venation correlates more strongly with hydraulic conductance or biomechanical support among hierarchal orders.

Methods: We examined correlations of leaf hydraulics, indicated by vein density, conduit diameter, and stomatal density with light-saturated photosynthetic rates, leaf lifespan (LLS), and leaf morpho-anatomical traits of 39 xerophytic species grown in a common garden. Read More

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http://dx.doi.org/10.1002/ajb2.1185DOI Listing
November 2018
1 Read

A quick glance at noteworthy articles in this month's issue.

Authors:

Am J Bot 2018 Nov 15;105(11):1781-1782. Epub 2018 Nov 15.

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http://dx.doi.org/10.1002/ajb2.1190DOI Listing
November 2018
1 Read

Patterns and predictors of fleshy fruit phenology at five international botanical gardens.

Am J Bot 2018 Nov 12;105(11):1824-1834. Epub 2018 Nov 12.

Department of Geography, University of British Columbia, Vancouver, British Columbia, V6T 1Z2, Canada.

Premise Of The Study: To improve our understanding of the patterns and drivers of fleshy fruit phenology, we examined the sequence, patterns across years and locations, and drivers of fruiting times at five botanical gardens on three continents.

Methods: We monitored four stages of fruit phenology for 406 temperate, fleshy-fruited, woody plant species in 2014 and 2015.

Key Results: Across all gardens, ripe fruits were present from May to March of the following year, with peak fruiting durations ranging from under 1 week to over 150 days. Read More

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http://dx.doi.org/10.1002/ajb2.1189DOI Listing
November 2018
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Early Miocene CO estimates from a Neotropical fossil leaf assemblage exceed 400 ppm.

Am J Bot 2018 Nov 12;105(11):1929-1937. Epub 2018 Nov 12.

Department of Geological & Atmospheric Sciences, Iowa State University, Ames, Iowa, USA.

Premise Of The Study: The global climate during the early Miocene was warmer than the present and preceded the even warmer middle Miocene climatic optimum. The paleo-CO records for this interval suggest paradoxically low concentrations (<450 ppm) that are difficult to reconcile with a warmer-than-present global climate.

Methods: In this study, we use a leaf gas-exchange model to estimate CO concentrations using stomatal characteristics of fossil leaves from a late early Miocene Neotropical assemblage from Panama that we date to 18. Read More

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http://doi.wiley.com/10.1002/ajb2.1187
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http://dx.doi.org/10.1002/ajb2.1187DOI Listing
November 2018
2 Reads

Spatial phylogenetics reveals evolutionary constraints on the assembly of a large regional flora.

Am J Bot 2018 Nov 8;105(11):1938-1950. Epub 2018 Nov 8.

Department of Botany, University of Wisconsin, 430 Lincoln Drive, Madison, Wisconsin, 53704, USA.

Premise Of The Study: We used spatial phylogenetics to analyze the assembly of the Wisconsin flora, linking processes of dispersal and niche evolution to spatial patterns of floristic and phylogenetic diversity and testing whether phylogenetic niche conservatism can account for these patterns.

Methods: We used digitized records and a new molecular phylogeny for 93% of vascular plants in Wisconsin to estimate spatial variation in species richness and phylogenetic α and β diversity in a native flora shaped mainly by postglacial dispersal and response to environmental gradients. We developed distribution models for all species and used these to infer fine-scale variation in potential diversity, phylogenetic distance, and interspecific range overlaps. Read More

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http://doi.wiley.com/10.1002/ajb2.1191
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http://dx.doi.org/10.1002/ajb2.1191DOI Listing
November 2018
27 Reads

Variations in ramet performance and the dynamics of an alpine evergreen herb, Gentiana nipponica, in different snowmelt conditions.

Am J Bot 2018 Nov 2;105(11):1813-1823. Epub 2018 Nov 2.

Faculty of Environmental Earth Science, Hokkaido University, Sapporo, 060-0810, Japan.

Premise Of The Study: Variation in demographic parameters reflects the life-history strategies of plants in response to specific environments. We aimed to investigate the intraspecific variation in life-history traits of a clonal alpine herb, Gentiana nipponica, in various snowmelt conditions.

Methods: Individual ramets within genets accumulate leaves for 7-9 yr without shedding, and die after reproduction. Read More

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http://doi.wiley.com/10.1002/ajb2.1186
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http://dx.doi.org/10.1002/ajb2.1186DOI Listing
November 2018
6 Reads

Overall seed dispersal effectiveness is lower in endemic Trillium species than in their widespread congeners.

Am J Bot 2018 Nov 1;105(11):1847-1857. Epub 2018 Nov 1.

Department of Ecology and Evolutionary Biology, University of Tennessee, Knoxville, TN, 37996, USA.

Premise Of The Study: Comparing ecological attributes of endemic species with related, widespread species can reveal differences accounting for rarity. Forests of the southeastern United States are home to many range-restricted endemic and widespread species of Trillium, a genus of ant-dispersed herbs. Evidence suggests that aspects of seed-related life history stages are often correlated with plant rarity, but few studies have tested whether the process of seed dispersal differs for endemic and widespread species. Read More

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http://doi.wiley.com/10.1002/ajb2.1188
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http://dx.doi.org/10.1002/ajb2.1188DOI Listing
November 2018
10 Reads

Consequences of multiple flower-insect interactions for subsequent plant-insect interactions and plant reproduction.

Am J Bot 2018 Nov 30;105(11):1835-1846. Epub 2018 Oct 30.

Department of Biology, University of Massachusetts, 611 North Pleasant Street, Amherst, MA, 01003, USA.

Premise Of The Study: Plants often interact simultaneously with multiple antagonists and mutualists that can alter plant traits at the phenotypic or genetic level, subsequent plant-insect interactions, and reproduction. Although many studies have examined the effects of single floral antagonisms on subsequent pollination and plant reproduction, we know very little about the combined, potentially non-additive effects of multiple flower-insect interactions.

Methods: We simulated increased florivory, nectar robbing, and pollination on field-grown Impatiens capensis, which allowed us to determine interactive effects on five subsequent plant-insect interactions and 16 plant traits, including traits related to plant growth, floral attractiveness, floral defenses, and plant reproduction. Read More

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http://doi.wiley.com/10.1002/ajb2.1182
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http://dx.doi.org/10.1002/ajb2.1182DOI Listing
November 2018
11 Reads

Are fungal networks key to dryland primary production?

Am J Bot 2018 Nov 30;105(11):1783-1787. Epub 2018 Oct 30.

Department of Biological Sciences, University of Texas at El Paso, El Paso, TX, 79902, USA.

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http://dx.doi.org/10.1002/ajb2.1184DOI Listing
November 2018
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Evolution of leaf structure and drought tolerance in species of Californian Ceanothus.

Am J Bot 2018 Oct 12;105(10):1672-1687. Epub 2018 Oct 12.

Department of Ecology and Evolutionary Biology, University of California, Los Angeles, CA, 90095, USA.

Premise Of The Study: Studies across diverse species have established theory for the contribution of leaf traits to plant drought tolerance. For example, species in more arid climates tend to have smaller leaves of higher vein density, higher leaf mass per area, and more negative osmotic potential at turgor loss point (π ). However, few studies have tested these associations for species within a given lineage that have diversified across an aridity gradient. Read More

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http://doi.wiley.com/10.1002/ajb2.1164
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http://dx.doi.org/10.1002/ajb2.1164DOI Listing
October 2018
3 Reads

A quick glance at noteworthy articles in this month's issue.

Authors:

Am J Bot 2018 Oct;105(10):1611-1612

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http://dx.doi.org/10.1002/ajb2.1177DOI Listing
October 2018
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Stable isotope analyses reveal previously unknown trophic mode diversity in the Hymenochaetales.

Am J Bot 2018 Nov 26;105(11):1869-1887. Epub 2018 Oct 26.

Department of Ecology and Evolutionary Biology, University of Tennessee, 1416 Circle Drive, Knoxville, Tennessee, 37996, USA.

Premise Of The Study: The Hymenochaetales are dominated by lignicolous saprotrophic fungi involved in wood decay. However, the group also includes bryophilous and terricolous taxa, but their modes of nutrition are not clear. Here, we investigate patterns of carbon and nitrogen utilization in numerous non-lignicolous Hymenochaetales and provide a phylogenetic context in which these non-canonical ecological guilds arose. Read More

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http://doi.wiley.com/10.1002/ajb2.1183
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http://dx.doi.org/10.1002/ajb2.1183DOI Listing
November 2018
16 Reads

Monocot plastid phylogenomics, timeline, net rates of species diversification, the power of multi-gene analyses, and a functional model for the origin of monocots.

Am J Bot 2018 Nov 24;105(11):1888-1910. Epub 2018 Oct 24.

Department of Botany, University of Wisconsin-Madison, Madison, Wisconsin, 53706, USA.

Premise Of The Study: We present the first plastome phylogeny encompassing all 77 monocot families, estimate branch support, and infer monocot-wide divergence times and rates of species diversification.

Methods: We conducted maximum likelihood analyses of phylogeny and BAMM studies of diversification rates based on 77 plastid genes across 545 monocots and 22 outgroups. We quantified how branch support and ascertainment vary with gene number, branch length, and branch depth. Read More

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http://dx.doi.org/10.1002/ajb2.1178DOI Listing
November 2018
2 Reads