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True nectar or stigmatic secretion? Structural evidence elucidates an old controversy regarding nectaries in Anthurium Am. J. Bot. (IF 3.038) Pub Date : 2021-01-15 Élder Antônio Sousa Paiva; Igor Ballego‐Campos; Marc Gibernau
Floral rewards are essential in understanding floral function and evolution of the relationships between flowers and pollinators. Whether sugars are present in stigmatic exudates in Anthurium and whether it has floral nectaries have remained controversial because of the scarcity of structural studies. To solve these questions, we investigated the floral anatomy of A. andraeanum to elucidate whether
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Inbreeding in Solanum carolinense alters floral attractants and rewards and adversely affects pollinator visitation Am. J. Bot. (IF 3.038) Pub Date : 2021-01-15 Rupesh R. Kariyat; Thomas G. Bentley; Chad T. Nihranz; Andrew G. Stephenson; Consuelo M. De Moraes; Mark C. Mescher
Inbreeding depression is well documented in flowering plants and adversely affects a wide range of fitness‐related traits. Recent work has begun to explore the effects of inbreeding on ecological interactions among plants and other organisms, including insect herbivores and pathogens. However, the effects of inbreeding on floral traits, floral scents, and pollinator visitation are less well studied
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Root vascular traits differ systematically between African savanna tree and grass species, with implications for water use Am. J. Bot. (IF 3.038) Pub Date : 2021-01-15 Isabel K. Wargowsky; Julienne E. NeSmith; Ricardo M. Holdo
Belowground functional traits play a significant role in determining plant water‐use strategies and plant performance, but we lack data on root traits across communities, particularly in the tropical savanna biome, where vegetation dynamics are hypothesized to be strongly driven by tree–grass functional differences in water use.
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Effects of latitude and conspecific plant density on insect leaf herbivory in oak saplings and seedlings Am. J. Bot. (IF 3.038) Pub Date : 2021-01-14 Xoaquín Moreira; Luis Abdala‐Roberts; Pieter De Frenne; Andrea Galmán; Álvaro Gaytán; Raimo Jaatinen; Beatriz Lago‐Núñez; Camille Meeussen; Pertti Pulkkinen; Pil U. Rasmussen; Jan P.J.G. Ten Hoopen; Bart G.H. Timmermans; Carla Vázquez‐González; Nick Bos; Bastien Castagneyrol; Ayco J.M. Tack
Abiotic factors and plant species traits have been shown to drive latitudinal gradients in herbivory, and yet, population‐level factors have been largely overlooked within this context. One such factor is plant density, which may influence the strength of herbivory and may vary with latitude.
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Phylogenetic signatures of ecological divergence and leapfrog adaptive radiation in Espeletia Am. J. Bot. (IF 3.038) Pub Date : 2021-01-11 Charles Pouchon; Sébastien Lavergne; Ángel Fernández; Adriana Alberti; Serge Aubert; Jesús Mavárez
Events of accelerated species diversification represent one of Earth’s most celebrated evolutionary outcomes. Northern Andean high‐elevation ecosystems, or páramos, host some plant lineages that have experienced the fastest diversification rates, likely triggered by ecological opportunities created by mountain uplifts, local climate shifts, and key trait innovations. However, the mechanisms behind
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Fine‐scale environmental heterogeneity and spatial niche partitioning among spring‐flowering forest herbs Am. J. Bot. (IF 3.038) Pub Date : 2021-01-11 Jared J. Beck; Thomas J. Givnish
Environmental heterogeneity influences plant distributions and diversity at several spatial scales. In temperate forests, fine‐scale environmental variation may promote local coexistence among herbaceous species by allowing plants to spatially partition microsites within forest stands. Here we argue that shallow soils, low soil water‐holding capacity and fertility, and reduced light near tree boles
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Unexplored dimensions of variability in vegetative desiccation tolerance Am. J. Bot. (IF 3.038) Pub Date : 2021-01-09 Rose A. Marks; Jill M. Farrant; D. Nicholas McLetchie; Robert VanBuren
Desiccation tolerance has evolved recurrently across diverse land plant lineages as an adaptation for survival in regions where seasonal rainfall drives periodic drying of vegetative tissues. Growing interest in this phenomenon has fueled recent physiological, biochemical, and genomic insights into the mechanistic basis of desiccation tolerance. Although, desiccation tolerance is often viewed as binary
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Parasites on parasites: hyper‐, epi‐, and autoparasitism among flowering plants Am. J. Bot. (IF 3.038) Pub Date : 2021-01-05 Yuliya Krasylenko; Jakub Těšitel; Gregorio Ceccantini; Mariana Oliveira‐da‐Silva; Václav Dvořák; Daniel Steele; Yevhen Sosnovsky; Renata Piwowarczyk; David M. Watson; Luiza Teixeira‐Costa
All organisms engage in parasitic relations, as either parasites or hosts. Some species may even play both roles simultaneously. Among flowering plants, the most widespread form of parasitism is characterized by the development of an intrusive organ called the haustorium, which absorbs water and nutrients from the host. Despite this functionally unifying feature of parasitic plants, haustoria are not
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Population responses to a historic drought across the range of the common monkeyflower (Mimulus guttatus) Am. J. Bot. (IF 3.038) Pub Date : 2021-01-05 Nicholas J. Kooyers; Kelsie A. Morioka; Jack M. Colicchio; Kaitlyn S. Clark; Abigail Donofrio; Shayne K. Estill; Catalina R. Pascualy; Ian C. Anderson; Megan Hagler; Chloe Cho; Benjamin K. Blackman
Due to climate change, more frequent and intense periodic droughts are predicted to increasingly pose major challenges to the persistence of plant populations. When a severe drought occurs over a broad geographical region, independent responses by individual populations provide replicated natural experiments for examining the evolution of drought resistance and the potential for evolutionary rescue
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A quick glance at noteworthy articles for December 2020 Am. J. Bot. (IF 3.038) Pub Date : 2020-12-14
Host genotype determines the effects of root‐associated fungi on a dominant coastal plant species Root‐associated fungi provide a range of functions for their hosts and can strongly influence plant structural and physiological traits. A better understanding of intraspecific variation in plant‐fungal relationships is needed, particularly in non‐model systems of high ecological importance, where these
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Limits and constraints to crop domestication Am. J. Bot. (IF 3.038) Pub Date : 2020-12-15 Markus G. Stetter
INTRODUCTION The domestication of plants and animals was one of the most significant changes in human history. A managed cultivation of crops allowed a sedentary lifestyle and the division of work, which freed capacities to develop modern societies. The change from a wild plant to a crop required substantial morphological and physiological adaptation. Crops with similar uses display similar trait changes
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Interspecific anatomical differences result in similar highly flexible stems in Bignoniaceae lianas Am. J. Bot. (IF 3.038) Pub Date : 2020-12-03 Caian S. Gerolamo; Anselmo Nogueira; Marcelo R. Pace; Veronica Angyalossy
Lianas are intriguing forest components in the tropics worldwide. They are characterized by thin and flexible stems, which have been related to a unique stem anatomy. Here, we hypothesized that the anatomical diversity of lianas, varying in shapes, proportions, and dimensions of tissues and cell types, would result in different stem bending stiffnesses across species. To test this hypothesis, we chose
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Light availability influences the intensity of nectar robbery and its effects on reproduction in a tropical shrub via multiple pathways Am. J. Bot. (IF 3.038) Pub Date : 2020-11-14 Gordon Fitch; John H. Vandermeer
The multiple exogenous pathways by which light availability affects plant reproduction (e.g., via influence on attraction of mutualists and antagonists) remain surprisingly understudied. The light environment experienced by a parent can also have transgenerational effects on offspring via these same pathways.
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Plant response to fungal root endophytes varies by host genotype in the foundation species Spartina alterniflora Am. J. Bot. (IF 3.038) Pub Date : 2020-11-30 A. Randall Hughes; Althea F. P. Moore; Catherine Gehring
Root‐associated fungi provide a wide range of functions for their host plants, including nutrient provisioning, pathogen protection, and stress alleviation. In so doing, they can markedly influence host‐plant structural and physiological traits, although the degree to which these effects vary within particular plant host species is not well understood.
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The mycorrhizal community of the epiphytic orchid Thrixspermum japonicum is strongly biased toward a single Ceratobasidiaceae fungus, despite a wide range of fungal partners Am. J. Bot. (IF 3.038) Pub Date : 2020-12-11 Kento Rammitsu; Tomohisa Yukawa; Yumi Yamashita; Shiro Isshiki; Yuki Ogura‐Tsujita
Orchids depend primarily on mycorrhizal fungi to obtain nutrients throughout their life cycle. Epiphytic orchids account for 69% of orchid diversity. The unstable availability of water and nutrients in their arboreal habitats often results in severe water and nutrient stresses. Consequently, mycorrhizal associations may be important for the survival of epiphytic orchids, but our understanding thereof
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How specialized is a soil specialist? Early life history responses of a rare Eriogonum to site‐level variation in volcanic soils Am. J. Bot. (IF 3.038) Pub Date : 2020-12-11 Jamey D. McClinton; Thomas L. Parchman; Kathleen L. Torrence; Paul S. Verburg; Elizabeth A. Leger
Understanding edaphic specialization is crucial for conserving rare plants that may need relocation due to habitat loss. Focusing on Eriogonum crosbyae, a rare soil specialist in the Great Basin of the United States, we asked how site‐level variation among volcanic soil outcrops affected plant growth and population distribution.
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Adaptive associations among life history, reproductive traits, environment, and origin in the Wisconsin angiosperm flora Am. J. Bot. (IF 3.038) Pub Date : 2020-12-14 Thomas J. Givnish; Ricardo Kriebel; John G. Zaborsky; Jeffrey P. Rose; Daniel Spalink; Donald M. Waller; Kenneth M. Cameron; Kenneth J. Sytsma
We tested 25 classic and novel hypotheses regarding trait–origin, trait–trait, and trait–environment relationships to account for flora‐wide variation in life history, habit, and especially reproductive traits using a plastid DNA phylogeny of most native (96.6%, or 1494/1547 species) and introduced (87.5%, or 690/789 species) angiosperms in Wisconsin, USA.
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Nucleic acid damage and DNA repair are affected by freezing stress in annual wheat (Triticum aestivum) and by plant age and freezing in its perennial relative (Thinopyrum intermedium) Am. J. Bot. (IF 3.038) Pub Date : 2020-12-19 Nikhil S. Jaikumar; Kevin M. Dorn; Dean Baas; Brook Wilke; Christian Kapp; Sieglinde S. Snapp
Nucleic acid integrity can be compromised under many abiotic stresses. To date, however, few studies have considered whether nucleic acid damage and damage repair play a role in cold‐stress adaptation. A further insufficiently explored question concerns how age affects cold stress adaptation among mature perennials. As a plant ages, the optimal trade‐off between growth and stress tolerance may shift
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Hybrid capture of 964 nuclear genes resolves evolutionary relationships in the mimosoid legumes and reveals the polytomous origins of a large pantropical radiation Am. J. Bot. (IF 3.038) Pub Date : 2020-11-30 Erik J. M. Koenen; Catherine Kidner; Élvia R. de Souza; Marcelo F. Simon; João R. Iganci; James A. Nicholls; Gillian K. Brown; Luciano P. de Queiroz; Melissa Luckow; Gwilym P. Lewis; R. Toby Pennington; Colin E. Hughes
Targeted enrichment methods facilitate sequencing of hundreds of nuclear loci to enhance phylogenetic resolution and elucidate why some parts of the “tree of life” are difficult (if not impossible) to resolve. The mimosoid legumes are a prominent pantropical clade of ~3300 species of woody angiosperms for which previous phylogenies have shown extensive lack of resolution, especially among the species‐rich
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Genetic insights into the evolution of genera with the eastern Asia–eastern North America floristic disjunction: a transcriptomics analysis Am. J. Bot. (IF 3.038) Pub Date : 2020-12-06 Anthony E. Melton; Shichao Chen; Yunpeng Zhao; Chengxin Fu; Qiu‐Yun (Jenny) Xiang; Shifeng Cheng; Gane K.‐S. Wong; Pamela S. Soltis; Douglas E. Soltis; Matthew A. Gitzendanner
Large disjunctions in species distributions provide excellent opportunities to study processes that shape biogeographic patterns. One such disjunction is the eastern Asia–eastern North America (EA‐ENA) floristic disjunction. For many genera with this disjunction, species richness is greater in EA than in ENA; this pattern has been attributed, in part, to higher rates of molecular evolution and speciation
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New physaloid fruit‐fossil species from early Eocene South America Am. J. Bot. (IF 3.038) Pub Date : 2020-11-28 Rocío Deanna; Peter Wilf; Maria A. Gandolfo
Solanaceae is a scientifically and economically important angiosperm family with a minimal fossil record and an intriguing early evolutionary history. Here, we report a newly discovered fossil lantern fruit with a suite of features characteristic of Physalideae within Solanaceae. The fossil comes from the early Eocene Laguna del Hunco site (ca. 52 Ma) in Chubut, Argentina, which previously yielded
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52 million years old Eucalyptus flower sheds more than pollen grains Am. J. Bot. (IF 3.038) Pub Date : 2020-12-03 Maria C. Zamaloa; Maria A. Gandolfo; Kevin C. Nixon
Fossils provide fundamental evidence of the evolutionary processes that crafted today’s biodiversity and consequently for understanding life on Earth. We report the finding of Myrtaceidites eucalyptoides pollen grains preserved within the anthers of a 52‐million‐year‐old Eucalyptus flower collected at Laguna del Hunco locality of Argentinean Patagonia and discuss its implications in understanding the
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Leaf‐economic strategies across the Eocene–Oligocene transition correlate with dry season precipitation and paleoelevation Am. J. Bot. (IF 3.038) Pub Date : 2020-12-08 Matthew J. Butrim; Dana L. Royer
The Eocene–Oligocene transition (EOT; 34–33 Ma) was marked by global cooling and increased seasonality and aridity, leading to a shift in North American floras from subtropical forests to deciduous hardwood forests similar to today. This shift is well documented taxonomically and biogeographically, but its ecological nature is less known.
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Reconstructing leaf area from fragments: testing three methods using a fossil paleogene species Am. J. Bot. (IF 3.038) Pub Date : 2020-12-14 Agathe Toumoulin; Lutz Kunzmann; Karolin Moraweck; Lawren Sack
Fossil leaf traits can enable reconstruction of ancient environments and climates. Among these, leaf size has been particularly studied because it reflects several climatic forcings (e.g., precipitation and surface temperature) and, potentially, environment characteristics (e.g., nutrient availability, local topography, and openness of vegetation). However, imperfect preservation and fragmentation
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Allopatry, hybridization, and reproductive isolation in Arctostaphylos Am. J. Bot. (IF 3.038) Pub Date : 2020-12-03 V. Thomas Parker; Christina Y. Rodriguez; Gail Wechsler; Michael C. Vasey
Hybridization plays a key role in introgressive adaptation, speciation, and adaptive radiation as a source of evolutionary innovation. Hybridization is considered common in Arctostaphylos, yet species boundaries are retained in stands containing multiple species. Arctostaphylos contains diploids and tetraploids, and recent phylogenies indicate two clades; we hypothesize combinations of these traits
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Two cryptic species of California mustard within Caulanthus lasiophyllus Am. J. Bot. (IF 3.038) Pub Date : 2020-12-28 Justen B. Whittall; Timothy M. Butler; Cynthia Dick; Brody Sandel
Cryptic species are evolutionarily distinct lineages lacking distinguishing morphological traits. Hidden diversity may be lurking in widespread species whose distributions cross phylogeographic barriers. This study investigates molecular and morphological variation in the widely distributed Caulanthus lasiophyllus (Brassicaceae) in comparison to its closest relatives.
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Velocity of the falling dispersal units in Zelkova abelicea: remarkable evolutionary conservation within the relict tree genus Am. J. Bot. (IF 3.038) Pub Date : 2020-12-20 Daniele Certini; Laurence Fazan; Naomi Nakayama; Ignazio Maria Viola; Gregor Kozlowski
Seed dispersal is extremely important for the recovery and restoration of forest communities. Relict tree genus Zelkova possesses a unique dispersal mechanism: mature fruits fall with the entire twig, and the dried leaves that are still attached function as a drag‐enhancing appendage, carrying the fruits away from the parent tree. This singular adaptation has never been investigated in Z. abelicea
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Starch storage capacity of sapwood is related to dehydration avoidance during drought Am. J. Bot. (IF 3.038) Pub Date : 2020-12-21 R. Brandon Pratt; Michael F. Tobin; Anna L. Jacobsen; Courtney A. Traugh; Mark E. De Guzman; Christine C. Hayes; Hayden S. Toschi; Evan D. MacKinnon; Marta I. Percolla; Michael E. Clem; Paul T. Smith
The xylem tissue of plants performs three principal functions: transport of water, support of the plant body, and nutrient storage. Tradeoffs may arise because different structural requirements are associated with different functions or because suites of traits are under selection that relate to resource acquisition, use, and turnover. The structural and functional basis of xylem storage is not well
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Asymmetry in fitness‐related traits of later‐generation hybrids between two invasive species Am. J. Bot. (IF 3.038) Pub Date : 2020-12-14 Chengjun Li; Sara Ohadi; Mohsen B. Mesgaran
The importance of hybridization to invasion has been frequently discussed, with most studies focusing on the comparison of fitness‐related traits between F1 hybrids and their parents and the consequences of such fitness differences. However, relatively little attention has been given to late‐generation hybrids. Different fitness landscapes could emerge in later generations after hybrids cross with
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Phylogenetic signal and climatic niche of stem photosynthesis in the mediterranean and desert regions of California and Baja California Peninsula Am. J. Bot. (IF 3.038) Pub Date : 2020-12-06 Eleinis Ávila‐Lovera; Pedro P. Garcillán
Woody plants with photosynthetic stems are common in the drylands of the world; however, we know little about the origin(s) and geographical distribution of photosynthetic stems. Therefore, we set to answer the following questions: (1) Is stem photosynthesis phylogenetically conserved? (2) Do green‐stemmed and fleshy‐stemmed species have identifiable climatic niches?
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Strategies of desiccation tolerance vary across life phases in the moss Syntrichia caninervis Am. J. Bot. (IF 3.038) Pub Date : 2020-11-29 Kirsten K. Coe; Joshua L. Greenwood; Mandy L. Slate; Theresa A. Clark; John C. Brinda; Kirsten M. Fisher; Brent D. Mishler; Matthew A. Bowker; Melvin J. Oliver; Sotodeh Ebrahimi; Lloyd R. Stark
Desiccation tolerance (DT) is a widespread phenomenon among land plants, and variable ecological strategies for DT are likely to exist. Using Syntrichia caninervis, a dryland moss and model system used in DT studies, we hypothesized that DT is lowest in juvenile (protonemal) tissues, highest in asexual reproductive propagules (gemmae), and intermediate in adults (shoots). We tested the long‐standing
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A quick glance at noteworthy articles for November 2020 Am. J. Bot. (IF 3.038) Pub Date : 2020-11-18
Viburnum genome size variation is associated with multiple polyploidy events but not physiology Genome size may influence several aspects of plant biology, from gene regulation and cell size to physiology and speciation, but do global genome size‐trait relationships always hold up in different evolutionary contexts? Moeglein et al. used genome size estimates, in combination with chromosome counts and
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Flora of the hot deserts: emerging patterns from phylogeny‐based diversity studies Am. J. Bot. (IF 3.038) Pub Date : 2020-10-28 Rosa A. Scherson; Federico Luebert; Patricio Pliscoff; Taryn Fuentes‐Castillo
Relatively recent increases in molecular and geographic data for many taxa in different areas of the world have provided scientists with tools to evaluate biodiversity using evolutionary or phylogeny‐based indices (reviewed by Laffan, 2018). These measures provide quantitative estimates of the portion of the tree of life contained in a taxon or community, aiming to answer the question of what percentage
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Leaf dorsoventrality candidate gene CpARF4 has conserved expression pattern but divergent tasiR‐ARF regulation in the water fern Ceratopteris pteridoides Am. J. Bot. (IF 3.038) Pub Date : 2020-11-20 Jun Sun; Gui‐Sheng Li
Leaves are traditionally classified into microphylls and megaphylls, and recently have been regarded as independently originating in lycophytes, ferns, and seed plants. The developmental genetics of leaf dorsoventrality, a synapomorphy in vascular plants, has been extensively studied in flowering plants. AUXIN RESPONSE FACTOR4 (ARF4) genes are key to leaf abaxial identity in flowering plants, but whether
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Nondestructive estimation of leaf area for 15 species of vines with different leaf shapes Am. J. Bot. (IF 3.038) Pub Date : 2020-11-09 Xiaojing Yu; Peijian Shi; Julian Schrader; Karl J. Niklas
The nondestructive measurement of leaf area is important for expediting data acquisition in the field. The Montgomery equation (ME) assumes that leaf area (A) is a proportional function of the product of leaf length (L) and width (W), i.e., A = cLW, where c is called the Montgomery parameter. The ME has been successfully applied to calculate the surface area of many broad‐leaved species with simple
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Temperature is a regulator of leaf production in the family Dipterocarpaceae of equatorial Southeast Asia Am. J. Bot. (IF 3.038) Pub Date : 2020-11-14 Masaki J. Kobayashi; Kevin Kit Siong Ng; Soon Leong Lee; Norwati Muhammad; Naoki Tani
Leaf phenology is an essential developmental process in trees and an important component in understanding climate change. However, little is known about the regulation of leaf phenology in tropical trees.
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Pollen dispersal patterns differ among sites for a wind‐pollinated species and an insect‐pollinated species Am. J. Bot. (IF 3.038) Pub Date : 2020-10-27 Chelsea L. Butcher; Berish Y. Rubin; Sylvia L. Anderson; James D. Lewis
Pollen dispersal, the main component of overall plant gene flow, generally decreases with increasing distance from the pollen source, but the pattern of this relationship may differ among sites. Although site‐based differences in pollen dispersal may lead to over‐ or underestimation of gene flow, no studies have investigated pollen dispersal patterns among differing urban site types, despite the incongruent
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Strong stabilizing selection on timing of germination in a Mediterranean population of Arabidopsis thaliana Am. J. Bot. (IF 3.038) Pub Date : 2020-10-14 Giulia Zacchello; Mariona Vinyeta; Jon Ågren
Timing of germination can strongly influence plant fitness by affecting seedling survival and by having cascading effects on later life‐history traits. In seasonal environments, the period favorable for seedling establishment and growth is limited, and timing of germination is likely to be under stabilizing selection because of conflicting selection through survival and fecundity. Moreover, optimal
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Evolutionary dynamics of genome size in a radiation of woody plants Am. J. Bot. (IF 3.038) Pub Date : 2020-10-20 Morgan K. Moeglein; David S. Chatelet; Michael J. Donoghue; Erika J. Edwards
Plant genome size ranges widely, providing many opportunities to examine how genome size variation affects plant form and function. We analyzed trends in chromosome number, genome size, and leaf traits for the woody angiosperm clade Viburnum to examine the evolutionary associations, functional implications, and possible drivers of genome size.
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The role of environment, local adaptation, and past climate fluctuation on the amount and distribution of genetic diversity in two subspecies of Mexican wild Zea mays Am. J. Bot. (IF 3.038) Pub Date : 2020-11-17 Jaime Gasca‐Pineda; Yocelyn T. Gutiérrez‐Guerrero; Erika Aguirre‐Planter; Luis E. Eguiarte
Past climate fluctuations during the Holocene and Pleistocene shaped the distribution of several plant species in temperate areas over the world. Wild maize, commonly known as teosinte, is a good system to evaluate the effects of historical climate fluctuations on genetic diversity due to its wide distribution in Mexico with contrasting environmental conditions. We explored the influence of contemporary
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Population structure, diversifying selection, and local adaptation in Pinus patula Am. J. Bot. (IF 3.038) Pub Date : 2020-11-17 Pablo Peláez; Alfredo Ortiz‐Martínez; Laura Figueroa‐Corona; José Rubén Montes; David S. Gernandt
Climate change is predicted to affect natural and plantation forests. The responses of conifers to overcome changing environments will depend on their adaptation to local conditions; however, intraspecific adaptive genetic variation is unknown for most gymnosperms. Studying genetic diversity associated with phenotypic variability along environmental gradients will enhance our understanding of adaptation
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Two cytotype niche shifts are of different magnitude in Solidago gigantea Am. J. Bot. (IF 3.038) Pub Date : 2020-11-04 Maria Martino; John C. Semple; James B. Beck
Polyploidy may serve to contribute to range size if autopolyploid cytotypes are adapted to differing ecological conditions. This study aims to establish the geographic distribution of cytotypes within the giant goldenrod (Solidago gigantea), and to assess whether cytotypes exhibit differing ecological tolerances and morphology.
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Small herbaria contribute unique biogeographic records to county, locality, and temporal scales Am. J. Bot. (IF 3.038) Pub Date : 2020-11-20 Travis D. Marsico; Erica R. Krimmel; J. Richard Carter; Emily L. Gillespie; Phillip D. Lowe; Ross McCauley; Ashley B. Morris; Gil Nelson; Michelle Smith; Diana L. Soteropoulos; Anna K. Monfils
With digitization and data sharing initiatives underway over the last 15 years, an important need has been prioritizing specimens to digitize. Because duplicate specimens are shared among herbaria in exchange and gift programs, we investigated the extent to which unique biogeographic data are held in small herbaria vs. these data being redundant with those held by larger institutions. We evaluated
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Peak values of twist‐to‐bend ratio in triangular flower stalks of Carex pendula: a study on biomechanics and functional morphology Am. J. Bot. (IF 3.038) Pub Date : 2020-11-14 Olga Speck; Feray Steinhart; Thomas Speck
Because of their own weight and additional wind forces, plants are exposed to various bending and torsional loads that sometimes require contradictory structural characteristics and mechanical properties. The resulting trade‐off between flexural and torsional rigidity can be quantified and compared using the dimensionless twist‐to‐bend ratio.
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Latitudinal clines in bud flush phenology reflect genetic variation in chilling requirements in balsam poplar, Populus balsamifera Am. J. Bot. (IF 3.038) Pub Date : 2020-11-22 Ethan Thibault; Raju Soolanayakanahally; Stephen R. Keller
Boreal and northern temperate forest trees possess finely tuned mechanisms of dormancy, which match bud phenology with local seasonality. After winter dormancy, the accumulation of chilling degree days (CDD) required for rest completion before the accumulation of growing degree days (GDD) during quiescence is an important step in the transition to spring bud flush. While bud flush timing is known to
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Prey exclusion combined with simulated fire increases subsequent prey‐capture potential in the pale pitcher plant, Sarracenia alata Am. J. Bot. (IF 3.038) Pub Date : 2020-11-03 Matthew J. Abbott; J. Stephen Brewer
The association of carnivory (an adaptation to nutrient‐poor soils) with fire has been described as a paradox, given increases in nutrient availability that often accompany fire. The nutrients that increase in availability following fire, however, may not be the same as those provided by prey and may not reduce nutrient limitation if accompanied by even greater increases in light.
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A quick glance at noteworthy articles for October 2020 Am. J. Bot. (IF 3.038) Pub Date : 2020-10-12
One of these mutualisms is not like the other: Interactions between a plant host and two soil microbial partners may have evolved independently Legumes often interact with two types of soil microbial mutualists: arbuscular mycorrhizal (AM) fungi and rhizobia bacteria. Plants are expected to respond synergistically to these microbes, because each partner provides a different limiting nutrient (AM fungi
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Illuminating the incredible journey of pollen. Am. J. Bot. (IF 3.038) Pub Date : 2020-09-23 Bruce Anderson,Corneile Minnaar
Humans have a strange fascination with flowers. From the multi‐billion dollar cut‐flower industry where flowers are bred, grown, admired, and then thrown away to the houses of Christian Dior and Yves Saint Laurent, where floral extracts are used to make us smell less like mammals and more like plants, our flower obsession makes it easy to forget that they evolved not to beguile us, but primarily to
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AJB announces a new Reviews Section Am. J. Bot. (IF 3.038) Pub Date : 2020-10-19 Pamela K. Diggle
I am pleased to announce the creation of the American Journal of Botany Reviews Section, which will feature timely syntheses of major issues and new insights to guide future research. One of my primary goals as Editor‐in‐Chief of the American Journal of Botany, is to ensure that the journal is serving the needs of the members of the Botanical Society of America and plant biologists generally. In wide‐ranging
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From Carlquist’s ecological wood anatomy to Carlquist’s Law: why comparative anatomy is crucial for functional xylem biology Am. J. Bot. (IF 3.038) Pub Date : 2020-10-19 Mark E. Olson
All students of xylem structure–function relations need to be familiar with the work of Sherwin Carlquist. He studies xylem through the lens of the comparative method, which uses the appearance of similar anatomical features under similar conditions of natural selection to infer function. “Function” in biology implies adaptation; maximally supported adaptation inferences require experimental and comparative
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Facilitation with a grain of salt: reduced pollinator visitation is an indirect cost of association with the foundation species creosote bush (Larrea tridentata). Am. J. Bot. (IF 3.038) Pub Date : 2020-09-26 Jenna Braun,Christopher J Lortie
In arid ecosystems, shrub facilitation is a critical process driving plant community structure and assembly, often resulting in increased densities of annual plants beneath shrub canopies. Pollinator‐mediated interactions can have fitness consequences for both plant interactors but are largely unexplored as an indirect consequence of direct shrub‐annual facilitation.
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Specialized cockroach pollination in the rare and endangered plant Vincetoxicum hainanense in China Am. J. Bot. (IF 3.038) Pub Date : 2020-10-24 Wujian Xiong; Jeff Ollerton; Sigrid Liede‐Schumann; Wanyi Zhao; Qiancai Jiang; Hongmei Sun; Wenbo Liao; Wenhui You
Species of Apocynaceae are pollinated by a diverse assemblage of animals. Here we report the first record of specialized cockroach pollination in the family, involving an endangered climbing vine species, Vincetoxicum hainanense in China. Experiments were designed to provide direct proof of cockroach pollination and compare the effectiveness of other flower visitors.
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Life history variation in an invasive plant is associated with climate and recent colonization of a specialist herbivore. Am. J. Bot. (IF 3.038) Pub Date : 2020-09-11 Sophie S Duncan,Jennifer L Williams
Spatial variation in selective pressures can lead to intraspecific variation in life history, favoring some life histories and constraining others depending on the vulnerability of life stages. We examined how spatial variation in herbivory and climate influences flowering size and the occurrence of semelparity (reproducing once) versus iteroparity (reproducing multiple times) in the introduced range
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Niche similarity in diploid-autotetraploid contact zones of Arabidopsis arenosa across spatial scales. Am. J. Bot. (IF 3.038) Pub Date : 2020-09-25 Emma J Morgan,Martin Čertner,Magdalena Lučanová,Kateřina Kubíková,Karol Marhold,Filip Kolář
Whole genome duplication is a major evolutionary event, but its role in ecological divergence remains equivocal. When populations of different ploidy (cytotypes) overlap in space, “contact zones” are formed, allowing the study of evolutionary mechanisms contributing toward ploidy divergence. Multiple contact zones per species’ range are often described but rarely leveraged as natural replicates. We
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Population‐level variation in host plant response to multiple microbial mutualists Am. J. Bot. (IF 3.038) Pub Date : 2020-10-07 James B. Franklin; Kendra Hockey; Hafiz Maherali
Multipartite mutualisms are widespread in nature, but population‐level variation in these interactions is rarely quantified. In the model multipartite mutualism between legumes, arbuscular mycorrhizal (AM) fungi and rhizobia bacteria, host responses to microbial partners are expected to be synergistic because the nutrients provided by each microbe colimit plant growth, but tests of this prediction
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Effect of drought and carbon dioxide on nutrient uptake and levels of nutrient‐uptake proteins in roots of barley Am. J. Bot. (IF 3.038) Pub Date : 2020-10-06 Deepesh R. Bista; Scott A. Heckathorn; Dileepa M. Jayawardena; Jennifer K. Boldt
Atmospheric carbon dioxide (CO2) concentration is increasing, as is the frequency and duration of drought in some regions. Elevated CO2 can decrease the effects of drought by further decreasing stomatal opening and, hence, water loss from leaves. Both elevated CO2 and drought typically decrease plant nutrient concentration, but their interactive effects on nutrient status and uptake are little studied
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Functional traits of leaves and photosynthetic stems of species from a sarcocaulescent scrub in the southern Baja California Peninsula Am. J. Bot. (IF 3.038) Pub Date : 2020-10-14 Eleinis Ávila‐Lovera; Pedro P. Garcillán; Christian Silva‐Bejarano; Louis S. Santiago
Photosynthetic stems represent a source of extra carbon in plants from hot and dry environments, but little is known about how leaves and photosynthetic stems differ in terms of photosynthetic capacity, trait coordination, and responses to seasonal drought in subtropical systems.
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Validating a predictive model of cannabinoid inheritance with feral, clinical, and industrial Cannabis sativa Am. J. Bot. (IF 3.038) Pub Date : 2020-10-25 Jonathan P. Wenger; Clemon J. Dabney; Mahmoud A. ElSohly; Suman Chandra; Mohamed M. Radwan; Chandrani G. Majumdar; George D. Weiblen
How genetic variation within a species affects phytochemical composition is a fundamental question in botany. The ratio of two specialized metabolites in Cannabis sativa, tetrahydrocannabinol (THC) and cannabidiol (CBD), can be grouped into three main classes (THC‐type, CBD‐type, and intermediate type). We tested a genetic model associating these three groups with functional and nonfunctional alleles
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Phylogenetic analysis of fossil flowers using an angiosperm‐wide data set: proof‐of‐concept and challenges ahead Am. J. Bot. (IF 3.038) Pub Date : 2020-10-07 Jürg Schönenberger; Maria von Balthazar; Andrea López Martínez; Béatrice Albert; Charlotte Prieu; Susana Magallón; Hervé Sauquet
Significant paleobotanical discoveries in recent decades have considerably improved our understanding of the early evolution of angiosperms and their flowers. However, our ability to test the systematic placement of fossil flowers on the basis of phylogenetic analyses has remained limited, mainly due to the lack of an adequate, angiosperm‐wide morphological data set for extant taxa. Earlier attempts
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Urticaceae leaves with stinging trichomes were already present in latest early Eocene Okanogan Highlands, British Columbia, Canada Am. J. Bot. (IF 3.038) Pub Date : 2020-10-22 Melanie L. DeVore; Alphonse Nyandwi; Winnie Eckardt; Elias Bizuru; Myriam Mujawamariya; Kathleen B. Pigg
Paleontologists use tooth form to assess diets of fossil mammals. Plants would also be expected to adapt their morphology to respond to herbivory. Fossil nettle leaves with definitive stinging trichomes (tribe Urticeae, family Urticaceae) are described from the early Eocene upland lacustrine floras of the Okanogan Highlands, British Columbia, Canada. This is the first report of stinging trichomes in
更新日期:2020-10-30