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1.	Alatalo, J. M., et al. (author) Effects of ambient climate and three warming treatments on fruit production in an alpine, subarctic meadow community 2021 In: American Journal of Botany. - Oxford : Wiley. - 0002-9122 .- 1537-2197. ; 108:3, s. 411-422 Journal article (peer-reviewed)abstract Premise Climate change is having major impacts on alpine and arctic regions, and inter-annual variations in temperature are likely to increase. How increased climate variability will impact plant reproduction is unclear. Methods In a 4-year study on fruit production by an alpine plant community in northern Sweden, we applied three warming regimes: (1) a static level of warming with open-top chambers (OTC), (2) press warming, a yearly stepwise increase in warming, and (3) pulse warming, a single-year pulse event of higher warming. We analyzed the relationship between fruit production and monthly temperatures during the budding period, fruiting period, and whole fruit production period and the effect of winter and summer precipitation on fruit production. Results Year and treatment had a significant effect on total fruit production by evergreen shrubs, Cassiope tetragona, and Dryas octopetala, with large variations between treatments and years. Year, but not treatment, had a significant effect on deciduous shrubs and graminoids, both of which increased fruit production over the 4 years, while forbs were negatively affected by the press warming, but not by year. Fruit production was influenced by ambient temperature during the previous-year budding period, current-year fruiting period, and whole fruit production period. Minimum and average temperatures were more important than maximum temperature. In general, fruit production was negatively correlated with increased precipitation. Conclusions These results indicate that predicted increased climate variability and increased precipitation due to climate change may affect plant reproductive output and long-term community dynamics in alpine meadow communities.
2.	Anderberg, Arne A., et al. (author) Phylogenetic relationships in the order Ericales s.l. : analyses of molecular data from five genes from the plastid and mitochondrial genomes 2002 In: American Journal of Botany. - : Wiley. - 0002-9122 .- 1537-2197. ; 89:4, s. 677-687 Journal article (peer-reviewed)abstract Phylogenetic interrelationships in the enlarged order Ericales were investigated by jackknife analysis of a combination of DNA sequences from the plastid genes rbcL, ndhF, atpB, and the mitochondrial genes atp1 and matR. Several well‐supported groups were identified, but neither a combination of all gene sequences nor any one alone fully resolved the relationships between all major clades in Ericales. All investigated families except Theaceae were found to be monophyletic. Four families, Marcgraviaceae, Balsaminaceae, Pellicieraceae, and Tetrameristaceae form a monophyletic group that is the sister of the remaining families. On the next higher level, Fouquieriaceae and Polemoniaceae form a clade that is sister to the majority of families that form a group with eight supported clades between which the interrelationships are unresolved: Theaceae‐Ternstroemioideae with Ficalhoa, Sladenia, and Pentaphylacaceae; Theaceae‐Theoideae; Ebenaceae and Lissocarpaceae; Symplocaceae; Maesaceae, Theophrastaceae, Primulaceae, and Myrsinaceae; Styracaceae and Diapensiaceae; Lecythidaceae and Sapotaceae; Actinidiaceae, Roridulaceae, Sarraceniaceae, Clethraceae, Cyrillaceae, and Ericaceae.
3.	Andersson, Stefan (author) Does inbreeding promote evolutionary reduction of flower size? Experimental evidence from Crepis tectorum (Asteraceae). 2012 In: American Journal of Botany. - : Wiley. - 1537-2197 .- 0002-9122. ; 99:8, s. 1388-1398 Journal article (peer-reviewed)abstract • Premise of the study: Small, autogamous flowers have evolved repeatedly in the plant kingdom. While much attention has focused on the mechanisms that promote the shift to autogamy, there is still a paucity of information on the factors that underlie the reduction of flower size so prevalent in selfing lineages. In this study of Crepis tectorum, I examine the role of inbreeding, acting alone or together with selection, in promoting evolutionary reduction of flower size. • Methods: Experimental crosses were performed to produce progeny populations that differed in inbreeding and (or) selection history. Progenies were grown in two different environments and scored for flower size and other characters. • Key results: Inbreeding depressed flower and fruit size, but also caused changes in flowering time and the number of heads produced. Despite some inconsistencies in the results for the last progeny generation, the decline in flower size was persistent over generations, consistent across environments, and similar in magnitude to the effects of selection for small flower size and the floral reduction inferred to have taken place during the shift toward autogamy within the study species. The floral size reduction was largely independent of changes in overall vigor, and there was considerable adaptive potential in flower size (measured by sib analyses and parent-offspring comparisons) after inbreeding. • Conclusions: The results of this study indicate that inbreeding can promote evolutionary reduction of flower size and highlight the close, persistent association between flower and fruit size in the study species.
4.	Andersson, Stefan (author) Pollinator and nonpollinator selection on ray morphology in Leucanthemum vulgare (oxeye daisy, Asteraceae) 2008 In: American Journal of Botany. - : Wiley. - 0002-9122 .- 1537-2197. ; 95:9, s. 1072-1078 Journal article (peer-reviewed)abstract Despite evidence that both pollinators and nonpollinator agents of selection can shape the evolution of floral characters, there have been few attempts to compare the strengths and directions of selection from pollinators and other agents in the same study system. In this investigation of Leucanthemum vulgare, a self-incompatible composite known for its conspicuous white rays, I obtained data from a ray removal experiment in the field and from a segregating F2 population in an experimental garden to assess the role of pollinator and nonpollinator selection as stabilizing factors on floral evolution in this species. Removal of all rays reduced the pollination success of heads by 31–35%, but did not significantly affect the level of infestation by larvae of the fly Tephritis neesii. Data from F2 plants indicated a potential for indirect selection on ray morphology, mediated through links between ray morphology and measures of vegetative size and plant vigor. The results of this study show that individuals of the normal, rayed phenotype have a clear selective advantage, in terms of both pollinator attraction and general plant vigor. Thus, there were no conflicting selection pressures between the pollinators and the other selective agents considered in this study.
5.	Antonelli, Alexandre, 1978, et al. (author) Settling a family feud: a high-level phylogenomic framework for the Gentianales based on 353 nuclear genes and partial plastomes 2021 In: American Journal of Botany. - : Wiley. - 0002-9122 .- 1537-2197. ; 108:7, s. 1143-1165 Journal article (peer-reviewed)abstract Premise: Comprising five families that vastly differ in species richness—ranging from Gelsemiaceae with 13 species to the Rubiaceae with 13,775 species—members of the Gentianales are often among the most species-rich and abundant plants in tropical forests. Despite considerable phylogenetic work within particular families and genera, several alternative topologies for family-level relationships within Gentianales have been presented in previous studies. Methods: Here we present a phylogenomic analysis based on nuclear genes targeted by the Angiosperms353 probe set for approximately 150 species, representing all families and approximately 85% of the formally recognized tribes. We were able to retrieve partial plastomes from off-target reads for most taxa and infer phylogenetic trees for comparison with the nuclear-derived trees. Results: We recovered high support for over 80% of all nodes. The plastid and nuclear data are largely in agreement, except for some weakly to moderately supported relationships. We discuss the implications of our results for the order’s classification, highlighting points of increased support for previously uncertain relationships. Rubiaceae is sister to a clade comprising (Gentianaceae + Gelsemiaceae) + (Apocynaceae + Loganiaceae). Conclusions: The higher-level phylogenetic relationships within Gentianales are confidently resolved. In contrast to recent studies, our results support the division of Rubiaceae into two subfamilies: Cinchonoideae and Rubioideae. We do not formally recognize Coptosapelteae and Luculieae within any particular subfamily but treat them as incertae sedis. Our framework paves the way for further work on the phylogenetics, biogeography, morphological evolution, and macroecology of this important group of flowering plants.
6.	Bacon, Christine D., et al. (author) The impact of species complexes on tree abundance patterns in Amazonia 2022 In: American Journal of Botany. - : Wiley. - 0002-9122 .- 1537-2197. ; 109:10, s. 1525-1528 Journal article (peer-reviewed)
7.	Barres, L., et al. (author) RECONSTRUCTING THE EVOLUTION AND BIOGEOGRAPHIC HISTORY OF TRIBE CARDUEAE (COMPOSITAE) 2013 In: American Journal of Botany. - : Wiley. - 0002-9122 .- 1537-2197. ; 100:5, s. 867-882 Journal article (peer-reviewed)abstract • Premise of the study: Tribe Cardueae (thistles) forms one of the largest tribes in the family Compositae (2400 species), with representatives in almost every continent. The greatest species richness of Cardueae occurs in the Mediterranean region where it forms an important element of its flora. New fossil evidence and a nearly resolved phylogeny of Cardueae are used here to reconstruct the spatiotemporal evolution of this group. • Methods: We performed maximum parsimony and Bayesian phylogenetic inference based on nuclear ribosomal DNA and chloroplast DNA markers. Divergence times and ancestral area reconstructions for main lineages were estimated using penalized likelihood and dispersal–vicariance analyses, respectively, and integrated over the posterior distribution of the phylogeny from the Bayesian Markov chain Monte Carlo analysis to accommodate uncertainty in phylogenetic relationships. • Key results: The phylogeny shows that subtribe Cardopatiinae is sister to the remaining subtribes, and subtribes Carlininae and Echinopsinae appear as consecutive sister-clades to the Carduinae/Centaureinae. Tribe Cardueae is inferred to have originated around the Mid Eocene in West Asia, which is also the ancestral area of most subtribes within Cardueae. Diversification within each subtribe began during the Oligocene-Miocene period. • Conclusions: Most diversification events within Cardueae are related to the continuous cycles of area connection and division between the Anatolian microplate and the western Mediterranean Basin during the Oligocene-Miocene and with the uplift of the Himalayan range from the Miocene onward. From these two regions, thistles dispersed and colonized the rest of the continents (e.g., the New World, Africa, and Australia), most likely during the colder Pliocene-Pleistocene period.
8.	Bartish, Igor V., et al. (author) Fewer chromosomes, more co-occurring species within plant lineages : A likely effect of local survival and colonization 2023 In: American Journal of Botany. - : Wiley. - 0002-9122 .- 1537-2197. ; 110:4 Journal article (peer-reviewed)abstract Premise:Plant lineages differ markedly in species richness globally, regionally, and locally. Differences in whole-genome characteristics (WGCs) such as monoploid chromosome number, genome size, and ploidy level may explain differences in global species richness through speciation or global extinction. However, it is unknown whether WGCs drive species richness within lineages also in a recent, postglacial regional flora or in local plant communities through local extinction or colonization and regional species turnover.Methods:We tested for relationships between WGCs and richness of angiosperm families across the Netherlands/Germany/Czechia as a region, and within 193,449 local vegetation plots.Results:Families that are species-rich across the region have lower ploidy levels and small monoploid chromosomes numbers or both (interaction terms), but the relationships disappear after accounting for continental and local richness of families. Families that are species-rich within occupied localities have small numbers of polyploidy and monoploid chromosome numbers or both, independent of their own regional richness and the local richness of all other locally co-occurring species in the plots. Relationships between WGCs and family species-richness persisted after accounting for niche characteristics and life histories.Conclusions:Families that have few chromosomes, either monoploid or holoploid, succeed in maintaining many species in local communities and across a continent and, as indirect consequence of both, across a region. We suggest evolutionary mechanisms to explain how small chromosome numbers and ploidy levels might decrease rates of local extinction and increase rates of colonization. The genome of a macroevolutionary lineage may ultimately control whether its species can ecologically coexist.
9.	Bell, David, et al. (author) Organellomic data sets confirm a cryptic consensus on (unrooted) land-plant relationships and provide new insights into bryophyte molecular evolution 2020 In: American Journal of Botany. - : Wiley. - 0002-9122 .- 1537-2197. ; 107:1, s. 91-115 Journal article (peer-reviewed)abstract Premise Phylogenetic trees of bryophytes provide important evolutionary context for land plants. However, published inferences of overall embryophyte relationships vary considerably. We performed phylogenomic analyses of bryophytes and relatives using both mitochondrial and plastid gene sets, and investigated bryophyte plastome evolution. Methods We employed diverse likelihood-based analyses to infer large-scale bryophyte phylogeny for mitochondrial and plastid data sets. We tested for changes in purifying selection in plastid genes of a mycoheterotrophic liverwort (Aneura mirabilis) and a putatively mycoheterotrophic moss (Buxbaumia), and compared 15 bryophyte plastomes for major structural rearrangements. Results Overall land-plant relationships conflict across analyses, generally weakly. However, an underlying (unrooted) four-taxon tree is consistent across most analyses and published studies. Despite gene coverage patchiness, relationships within mosses, liverworts, and hornworts are largely congruent with previous studies, with plastid results generally better supported. Exclusion of RNA edit sites restores cases of unexpected non-monophyly to monophyly for Takakia and two hornwort genera. Relaxed purifying selection affects multiple plastid genes in mycoheterotrophic Aneura but not Buxbaumia. Plastid genome structure is nearly invariant across bryophytes, but the tufA locus, presumed lost in embryophytes, is unexpectedly retained in several mosses. Conclusions A common unrooted tree underlies embryophyte phylogeny, [(liverworts, mosses), (hornworts, vascular plants)]; rooting inconsistency across studies likely reflects substantial distance to algal outgroups. Analyses combining genomic and transcriptomic data may be misled locally for heavily RNA-edited taxa. The Buxbaumia plastome lacks hallmarks of relaxed selection found in mycoheterotrophic Aneura. Autotrophic bryophyte plastomes, including Buxbaumia, hardly vary in overall structure.
10.	Bienau, Miriam J, et al. (author) Clonality increases with snow depth in the arctic dwarf shrub Empetrum hermaphroditum. 2016 In: American Journal of Botany. - : Botanical Society Of America. - 0002-9122 .- 1537-2197. ; 103:12, s. 2105-2114 Journal article (peer-reviewed)abstract PREMISE OF THE STUDY: Vegetative reproduction and spread through clonal growth plays an important role in arctic-alpine ecosystems with short cool growing seasons. Local variation in winter snow accumulation leads to discrete habitat types that may provide divergent conditions for sexual and vegetative reproduction. Therefore, we studied variation in clonal structure of a dominant, evergreen, dwarf shrub (Empetrum nigrum s.l. with the two taxa E. nigrum L. s.s. and E. hermaphroditum Hagerup) along a snow cover gradient and compared clonal diversity and spatial genetic structure between habitats.METHODS: We studied 374 individual shoots using 105 polymorphic AFLP markers and analyses based on hierarchical clustering, clonal diversity indices, and small-scale spatial genetic structure with pairwise kinship coefficient. We used two approaches to define a threshold of genotypic distance between two samples that are considered the same clone. Clonality was examined among three habitats (exposed ridges, sheltered depressions, birch forest) differing in snow conditions replicated in four study regions in Norway and Sweden.KEY RESULTS: Clonality of E. hermaphroditum differed between habitats with an increase in clonal diversity with decreasing snow depth. Small-scale spatial genetic structure increased with decreasing clonal diversity and increasing clone size. In three study regions, E. hermaphroditum was the only species, whereas in one region E. nigrum also occurred, largely confined to exposed ridges.CONCLUSIONS: Our results demonstrated that snow cover in conjunction with associated habitat conditions plays an important role for the mode of propagation of the dwarf shrub E. hermaphroditum.
11.	Blanco-Pastor, José Luis, et al. (author) Evolutionary networks from RADseq loci point to hybrid origins of Medicago carstiensis and Medicago cretacea 2019 In: American Journal of Botany. - : Wiley. - 0002-9122 .- 1537-2197. ; 106:9, s. 1219-1228 Journal article (peer-reviewed)abstract Premise Although hybridization has played an important role in the evolution of many plant species, phylogenetic reconstructions that include hybridizing lineages have been historically constrained by the available models and data. Restriction-site-associated DNA sequencing (RADseq) has been a popular sequencing technique for the reconstruction of hybridization in the next-generation sequencing era. However, the utility of RADseq for the reconstruction of complex evolutionary networks has not been thoroughly investigated. Conflicting phylogenetic relationships in the genus Medicago have been mainly attributed to hybridization, but the specific hybrid origins of taxa have not been yet clarified. Methods We obtained new molecular data from diploid species of Medicago section Medicago using single-digest RADseq to reconstruct evolutionary networks from gene trees, an approach that is computationally tractable with data sets that include several species and complex hybridization patterns. Results Our analyses revealed that assembly filters to exclusively select a small set of loci with high phylogenetic information led to the most-divergent network topologies. Conversely, alternative clustering thresholds or filters on the number of samples per locus had a lower impact on networks. A strong hybridization signal was detected for M. carstiensis and M. cretacea, while signals were less clear for M. rugosa, M. rhodopea, M. suffruticosa, M. marina, M. scutellata, and M. sativa. Conclusions Complex network reconstructions from RADseq gene trees were not robust under variations of the assembly parameters and filters. But when the most-divergent networks were discarded, all remaining analyses consistently supported a hybrid origin for M. carstiensis and M. cretacea.
12.	Bolinder, Kristina, et al. (author) AERODYNAMICS AND POLLEN ULTRASTRUCTURE IN EPHEDRA 2015 In: American Journal of Botany. - : Wiley. - 0002-9122 .- 1537-2197. ; 102:3, s. 457-470 Journal article (peer-reviewed)abstract Premise of the study: Pollen dispersal is affected by the terminal settling velocity (U-t) of the grains, which is determined by their size, bulk density, and by atmospheric conditions. The likelihood that wind-dispersed pollen is captured by ovulate organs is influenced by the aerodynamic environment created around and by ovulate organs. We investigated pollen ultrastructure and U-t of Ephedra foeminea (purported to be entomophilous), and simulated the capture efficiency of its ovules. Results were compared with those from previously studied anemophilous Ephedra species. Methods: U-t was determined using stroboscopic photography of pollen in free fall. The acceleration field around an average ovule was calculated, and inflight behavior of pollen grains was predicted using computer simulations. Pollen morphology and ultrastructure were investigated using SEM and STEM. Key results: Pollen wall ultrastructure was correlated with U-t in Ephedra. The relative proportion and amount of granules in the infratectum determine pollen bulk densities, and (together with overall size) determine U-t and thus dispersal capability. Computer simulations failed to reveal any functional traits favoring anemophilous pollen capture in E. foeminea. Conclusion: The fast U-t and dense ultrastructure of E. foeminea pollen are consistent with functional traits that distinguish entomophilous species from anemophilous species. In anemophilous Ephedra species, ovulate organs create an aerodynamic microenvironment that directs airborne pollen to the pollination drops. In E. foeminea, no such microenvironment is created. Ephedroid palynomorphs from the Cretaceous share the ultrastructural characteristics of E. foeminea, and at least some may, therefore, have been produced by insect-pollinated plants.
13.	Bouchal, Johannes Martin, 1979- (author) EVOLUTIONARY TRENDS AND ECOLOGICAL DIFFERENTIATION IN EARLY CENOZOIC FAGACEAE OF WESTERN NORTH AMERICA 2014 In: American Journal of Botany. - : Wiley. - 0002-9122 .- 1537-2197. ; 101:8, s. 1332-1349 Journal article (peer-reviewed)abstract • Premise of the study: The early Cenozoic was a key period of evolutionary radiation in Fagaceae. The common notion is thatspecies thriving in the modern summer-dry climate of California originated in climates with ample summer rain during thePaleogene.• Methods: We investigated in situ and dispersed pollen of Fagaceae from the uppermost Eocene Florissant fossil beds, Colorado,United States, using a combined light and scanning electron microscopy approach.• Key results: Pollen types of Castaneoideae with affi nities to modern Castanea , Lithocarpus , and Castanopsis were recognized.Pollen of the extinct genus Fagopsis represents a derived type of Castaneoideae pollen. Infrageneric groups of Quercus werewell represented, including pollen of Group Protobalanus. The taxonomic diversity of Fagaceae and of the total plant assemblageindicates a mosaic of microclimates, that range from pronounced to weakly seasonal climates and depend on slope aspectand elevation. Continental climatic conditions may have triggered the evolution of sclerophyllous leaves and adaptive radiationin Quercus and other taxa thriving today under distinctly summer-dry and winter-dry climates.• Conclusions: Vegetation types similar to modern vegetation belts of the Coastal Ranges (chaparral, nemoral conifer forest)were established in the Front Range in the late Eocene. Coeval plant assemblages from the Coastal Ranges of California indicatedistinctly subtropical, moist climates. Hence, characteristic elements found today in the summer-dry and winter-dry climatesof Pacifi c North America ( Quercus Group Protobalanus, Notholithocarpus ) may opportunistically have dispersed intotheir modern ranges later in the Cenozoic. This scenario is in contrast to the evolution and migration patterns of their westernEurasian Mediterranean counterparts ( Quercus Group Ilex).
14.	Calvente, Alice, et al. (author) Spiny but photogenic : amateur sightings complement herbarium specimens to reveal the bioregions of cacti 2023 In: American Journal of Botany. - : John Wiley & Sons. - 0002-9122 .- 1537-2197. ; 110:10 Journal article (peer-reviewed)abstract Premise: Cacti are characteristic elements of the Neotropical flora and of major interest for biogeographic, evolutionary, and ecological studies. We tested global biogeographic boundaries for Neotropical Cactaceae using specimen-based occurrences, coupled with data from visual observations, as a means to tackle the known collection biases in the family.Methods: Species richness and record density were assessed for preserved specimens and human observations, and a bioregional scheme tailored to Cactaceae was produced using the interactive web application Infomap Bioregions, based on data from 261,272 point records cleaned through automated and manual steps.Results: We found that areas in Mexico and southwestern USA, in eastern Brazil, and along the Andean region have the greatest density of records and the highest species richness. Human observations complement information from preserved specimens substantially, especially along the Andes. We propose 24 cactus bioregions, among which the most species-rich are northern Mexico/southwestern USA, central Mexico, southern central Mexico, Central America, Mexican Pacific coast, central and southern Andes, northwestern Mexico/extreme southwestern USA, southwestern Bolivia, northeastern Brazil, and Mexico/Baja California.Conclusions: The bioregionalization proposed shows biogeographic boundaries specific to cacti and can thereby aid further evolutionary, biogeographic, and ecological studies by providing a validated framework for further analyses. This classification builds upon, and is distinctive from, other expert-derived regionalization schemes for other taxa. Our results showcase how observation data, including citizen-science records, can complement traditional specimen-based data for biogeographic research, particularly for taxa with specific specimen collection and preservation challenges and those that are threatened or internationally protected.
15.	Cardinale, B. J., et al. (author) THE FUNCTIONAL ROLE OF PRODUCER DIVERSITY IN ECOSYSTEMS 2011 In: American Journal of Botany. - : Wiley. - 0002-9122 .- 1537-2197. ; 98:3, s. 572-592 Journal article (peer-reviewed)
16.	CARPENTER, RAYMOND, et al. (author) EARLY EVIDENCE OF XEROMORPHY IN ANGIOSPERMS: STOMATAL ENCRYPTION IN A NEW EOCENE SPECIES OF BANKSIA (PROTEACEAE) FROM WESTERN AUSTRALIA 2014 In: American Journal of Botany. - : Wiley. - 0002-9122 .- 1537-2197. ; 101:9, s. 1486-1497 Journal article (peer-reviewed)abstract Premise of the study: Globally, the origins of xeromorphic traits in modern angiosperm lineages are obscure but are thought to be linked to the early Neogene onset of seasonally arid climates. Stomatal encryption is a xeromorphic trait that is prominent in Banksia , an archetypal genus centered in one of the world’s most diverse ecosystems, the ancient infertile landscape of Mediterranean-climate southwestern Australia.Methods: We describe Banksia paleocrypta , a sclerophyllous species with encrypted stomata from silcretes of the Walebing and Kojonup regions of southwestern Australia dated as Late Eocene.Key results: Banksia paleocrypta shows evidence of foliar xeromorphy ~20 Ma before the widely accepted timing for the onset of aridity in Australia. Species of Banksia subgenus Banksia with very similar leaves are extant in southwestern Australia. The conditions required for silcrete formation infer fl uctuating water tables and climatic seasonality in southwestern Australia in the Eocene, and seasonality is supported by the paucity of angiosperm closed-forest elements among the fossil taxa preserved with B. paleocrypta. However, climates in the region during the Eocene are unlikely to have experienced seasons as hot and dry as present-day summers.Conclusions: The presence of B. paleocrypta within the center of diversity of subgenus Banksia in edaphically ancient southwestern Australia is consistent with the continuous presence of this lineage in the region for ≥ 40 Ma, a testament to the success of increasingly xeromorphic traits in Banksia over an interval in which numerous other lineages became extinct.
17.	Dauphinee, Adrian (author) The role of auxin in developmentally regulated programmed cell death in lace plant 2020 In: American Journal of Botany. - : Wiley. - 0002-9122 .- 1537-2197. ; 107, s. 577-586 Journal article (peer-reviewed)abstract Premise Lace plant (Aponogeton madagascariensis) leaves are remodeled via developmental programmed cell death (PCD) to produce perforations located equidistantly between longitudinal and transverse veins. Auxin has been implicated in other developmental PCD processes in plants; however, the role of auxin in perforation formation in lace plant is unknown. Here the role of auxin in developmental PCD in lace plant was studied using two auxin inhibitors N-1-naphthylphthalamic acid (NPA), an auxin transport inhibitor, and auxinole, a potent auxin antagonist.Methods Sterile cultures of lace plants were propagated and treated with NPA or auxinole. Leaf length, leaf width, and number of perforations were then analyzed. Vein patterning and perforation area were further examined in NPA-treated plants. Downstream PCD transduction events were investigated via spectrophotometric assays, histochemical staining, and immuno-probing.Results Lace plants treated with NPA or auxinole produced leaves with fewer perforations compared to their respective controls. Although NPA treatment was insufficient to completely alter vein patterning, NPA-treated leaves did have significantly more atypical areoles compared to control leaves. Events involved in perforation formation in lace plant leaves were altered following treatment with NPA, including anthocyanin production, reactive oxygen species (ROS) accumulation, and the release of mitochondrial cytochrome c.Conclusions Our results indicated that inhibition of auxin signaling disrupts several downstream features of the lace plant PCD signaling cascade and results in fewer or no perforations. Therefore, we concluded that auxin signaling is important for developmentally regulated PCD in lace plant leaves.
18.	Delgado-Salinas, Alfonso, et al. (author) Vigna (Leguminosae) sensu lato : The names and identities of the American segregate 2011 In: American Journal of Botany. - : Wiley. - 0002-9122 .- 1537-2197. ; 98:10, s. 1694-1715 Journal article (peer-reviewed)abstract • Premise of study: The legume genus Vigna and close relatives have highly elaborated floral morphologies that involve the coiling, bending, and intricate connection of flower parts. Banners, levers, platforms, and pumps have evolved that attract pollinators and then manipulate their movement. Given this three-dimensional floral complexity, the taxonomy of Vigna and relatives has been confounded by the study of mostly two-dimensional museum specimens. A molecular phylogenetic analysis was undertaken in the effort to resolve long-standing taxonomic questions centered on floral morphology. • Methods: The phylogenetic analysis included cpDNA trnK and nuclear ribosomal ITS/5.8S (ITS) sequence variation. The American species were comprehensively sampled and outgroups included Old World relatives. • Key results: The trnK and ITS data analyses concurred in resolving six well-supported clades of American Vigna that are most closely related to other American genera: Dolichopsis, Macroptilium, Mysanthus, Oryxis, Oxyrhynchus, Phaseolus, Ramirezella, and Strophostyles. These 14 American clades ranked here as genera are resolved as sister to a clade comprising the mainly Old World species of Vigna. • Conclusions: American Vigna clades were reassigned to the genera Ancistrotropis, Cochliasanthus, Condylostylis, Leptospron, Sigmoidotropis, and the newly described Helicotropis. Vigna sensu stricto in the Americas now includes relatively few and mostly pantropical species. Elaborate floral asymmetries are readily used to apomorphically diagnose nearly all of the American genera. The age estimates of the extant diversification of the American and its Old World sister clade are approximately coeval at ca. 6–7 million yr, which belies much greater floral variation in the Americas.
19.	Denk, Thomas, et al. (author) New Fagaceous pollen taxa from the Miocene Søby flora of Denmark and their biogeographic implications 2021 In: American Journal of Botany. - : John Wiley & Sons. - 0002-9122 .- 1537-2197. ; 108, s. 1500-1524 Journal article (peer-reviewed)abstract Premise: The Fagaceae comprise around 1000 tree species in the Northern Hemisphere.Despite an extensive fossil pollen record, reconstructing biogeographic patternsis hampered because it is difficult to achieve good taxonomic resolution withlight microscopy alone. We investigate dispersed pollen of Fagaceae from the Miocene Søby flora, Denmark. We explore the latitudinal gradient in Fagaceae distribution during the Miocene Climatic Optimum (MCO) in Europe and the Northern Hemisphere to compare it with the Eocene Warmhouse and the present.Methods: We investigated dispersed pollen using light and scanning electron microscopy. We assessed biogeographic patterns in Fagaceae during two warm periods in Earth history (MCO, Eocene) and the present.Results: Eight species of Fagaceae were recognized in the Søby flora. Of these, Fagus had a continuous Mediterranean to subarctic distribution during MCO; Quercus sect. Cerris and castaneoids had northern limits in Denmark, and evergreen Quercus sect. Ilex in Central Europe. In a northern hemispheric context, Fagus and sections of Quercus had more northerly distribution limits during Eocene and MCO with maximum northward extensions during Eocene (Fagus, castaneoids) or Oligo‐Miocene (Quercus sects. Cerris and Ilex). The known distribution of the extinct Tricolporopollenites theacoides during MCO included Central Europe and East China, while this taxon thrived in South China during Eocene.Conclusions: More northerly distributions during MCO and Eocene probably were determined by temperature. In contrast, fossil occurrences in areas that are arid or semi‐humid today were determined by maritime conditions in these areas (western North America, Central Asia) during the Cenozoic.
20.	Dinnétz, Patrik (author) Male sterility, Protogyny and Pollen-Pistil interference in Plantago maritima (Plantaginaceae) a wind-pollinated, self-incompatible perennial 1997 In: American Journal of Botany. - 0002-9122 .- 1537-2197. ; 84:11, s. 1588-1594 Journal article (peer-reviewed)abstract Evolution and maintenance of male sterility in seed plants can be explained by the maternal inheritance of mitochondria, which encode the trait, and by adaptive functions that enhance female fecundity in male-sterile compared to hermaphrodite individuals. Protogyny and male sterility can independently decrease the negative effect of pollen–pistil interference in selfincompatible species. In Plantago maritima, which possesses both traits, protogyny increases seed set in hermaphrodite individuals. This is shown both by a significantly positive association between seed set and retarded dehiscence of the anthers and by a more than 50% reduction in seed set following self-pollination. Male sterility does not seem to increase seed set further, as female and hermaphrodite plants do not differ significantly in mean seed set per capsule. Bagging experiments demonstrate strong self-incompatibility in the study populations. Hence, in P. maritima male sterility seems neither to prevent selfing nor to reduce the effect of pollen–pistil interference. Females had significantly larger stigmas than hermaphrodites, but seed set varied negatively with stigma length among females, indicating that the evolution of unisexuality in P. maritima is not due to prefertilization sex allocation. I therefore conclude that the genetical system of nucleocytoplasmic determination of gender is the main cause for maintenance of male sterility in P. maritima.
21.	Eggens, F., et al. (author) The origin and number of introductions of the Hawaiian endemic Silene species (Caryophyllaceae) 2007 In: American Journal of Botany. - : Wiley. - 0002-9122 .- 1537-2197. ; 94:2, s. 210-218 Journal article (peer-reviewed)abstract The Hawaiian endemic Silene are a small group of woody or semiwoody representatives from a large, predominantly herbaceous, species-rich genus. We here investigated the origin and number of introductions of the endemic Hawaiian Silene based on phylogenetic relationships inferred from DNA sequences from both the plastid (the rps16 intron) and the nuclear (ribosomal internal transcribed sequences, ITS, and intron 23 of the RPB2 gene) genomes. Silene antirrhina, a widespread weedy American annual, is strongly supported as sister to a monophyletic group consisting of the Hawaiian Silene, indicating a single colonization event. There are no obvious morphological similarities between S. antirrhina and any of the species of Hawaiian Silene. Our results suggest an American origin for the Hawaiian endemics because that would require only a single trans-ocean dispersal. Two of the Hawaiian endemics (S. struthioloides and S. hawaiiensis) that form a subclade in the analyses have evolved woodiness after introduction to the Hawaiian Islands. Our results contribute to other recent results based on molecular phylogenetics that emphasize the American continent as a source area for the Hawaiian flora and support a striking morphological radiation and evolution of woodiness from a single introduction to the archipelago.
22.	Eisen, Katherine E., et al. (author) Among- and within-population variation in morphology, rewards, and scent in a hawkmoth-pollinated plant 2022 In: American Journal of Botany. - : Wiley. - 0002-9122 .- 1537-2197. ; 109:11, s. 1794-1810 Journal article (peer-reviewed)abstract Premise: Floral scent is a complex trait that mediates many plant–insect interactions, but our understanding of how floral scent variation evolves, either independently or in concert with other traits, remains limited. Assessing variation in floral scent at multiple levels of biological organization and comparing patterns of variation in scent to variation in other floral traits can contribute to our understanding of how scent variation evolves in nature. Methods: We used a greenhouse common garden experiment to investigate variation in floral scent at three scales—within plants, among plants, and among populations—and to determine whether scent, alone or in combination with morphology and rewards, contributes to population differentiation in Oenothera cespitosa subsp. marginata. Its range spans most of the biomes in the western United States, such that variation in both the abiotic and biotic environment could contribute to trait variation. Results: Multiple analytical approaches demonstrated substantial variation among and within populations in compound-specific and total floral scent measures. Overall, populations were differentiated in morphology and reward traits and in scent. Across populations, coupled patterns of variation in linalool, leucine-derived compounds, and hypanthium length are consistent with a long-tongued moth pollination syndrome. Conclusions: The considerable variation in floral scent detected within populations suggests that, similar to other floral traits, variation in floral scent may have a heritable genetic component. Differences in patterns of population differentiation in floral scent and in morphology and rewards indicate that these traits may be shaped by different selective pressures.
23.	Eiserhardt, W. L., et al. (author) A roadmap for global synthesis of the plant tree of life 2018 In: American Journal of Botany. - : Wiley. - 0002-9122 .- 1537-2197. ; 105:3, s. 614-622 Journal article (peer-reviewed)abstract Providing science and society with an integrated, up-to-date, high quality, open, reproducible and sustainable plant tree of life would be a huge service that is now coming within reach. However, synthesizing the growing body of DNA sequence data in the public domain and disseminating the trees to a diverse audience are often not straightforward due to numerous informatics barriers. While big synthetic plant phylogenies are being built, they remain static and become quickly outdated as new data are published and tree-building methods improve. Moreover, the body of existing phylogenetic evidence is hard to navigate and access for non-experts. We propose that our community of botanists, tree builders, and informaticians should converge on a modular framework for data integration and phylogenetic analysis, allowing easy collaboration, updating, data sourcing and flexible analyses. With support from major institutions, this pipeline should be re-run at regular intervals, storing trees and their metadata long-term. Providing the trees to a diverse global audience through user-friendly front ends and application development interfaces should also be a priority. Interactive interfaces could be used to solicit user feedback and thus improve data quality and to coordinate the generation of new data. We conclude by outlining a number of steps that we suggest the scientific community should take to achieve global phylogenetic synthesis.
24.	Falahati-Anbaran, Mohsen, et al. (author) Genetic consequences of seed banks in the perennial herb Arabidopsis lyrata subsp. petraea (Brassicaceae) 2011 In: American Journal of Botany. - : Wiley. - 0002-9122 .- 1537-2197. ; 98:9, s. 1475-1485 Journal article (peer-reviewed)abstract Premise of the Study: Seed banks may increase the effective population size (N(e)) of plants as a result of elevated coalescence times for alleles residing in the populations. This has been empirically demonstrated in populations of the annual Arabidopsis thaliana, whereas comparable data for perennial species are currently lacking. We studied the contribution of seed banks to effective sizes of natural populations of the self-incompatible, perennial Arabidopsis lyrata subsp. petraea, a close relative of A. thaliana. Methods: Fourteen populations of A. lyrata collected throughout the Norwegian distribution range were analyzed using micro-satellite markers. Key Results: The genetic composition of seed-bank and aboveground cohorts was found to be highly similar, with little genetic differentiation between cohorts in most populations. However, the proportion of private alleles was higher in aboveground than in seed-bank cohorts. The presence of seed banks significantly increased total N(e), but the contribution from seed banks to overall N(e) were lower than the contribution from aboveground cohorts in most populations. Estimated historical N(e) values, reflecting the effective sizes of populations throughout the history of the species, were considerably higher than estimates of contemporary N(e), reflecting number of reproducing individuals within the past few generations. Conclusions: The results show that the seed bank contributes to total N(e) in the perennial herb A. lyrata. However, the contribution is similar to or lower than that of the above-ground fraction of the population and markedly weaker than that previously documented in the annual A. thaliana.
25.	Fogelström, Elsa, et al. (author) Spring and autumn phenology in an understory herb are uncorrelated and driven by different factors 2022 In: American Journal of Botany. - : John Wiley & Sons. - 0002-9122 .- 1537-2197. ; 109:2, s. 226-236 Journal article (peer-reviewed)abstract Premise Climate warming has altered the start and end of growing seasons in temperate regions. Ultimately, these changes occur at the individual level, but little is known about how previous seasonal life-history events, temperature, and plant-resource state simultaneously influence the spring and autumn phenology of plant individuals.Methods We studied the relationships between the timing of leaf-out and shoot senescence over 3 years in a natural population of the long-lived understory herb Lathyrus vernus and investigated the effects of spring temperature, plant size, reproductive status, and grazing on spring and autumn phenology.Results The timing of leaf-out and senescence were consistent within individuals among years. Leaf-out and senescence were not correlated with each other within years. Larger plants leafed out and senesced later, and size had no effect on growing season length. Reproductive plants leafed out earlier and had longer growing seasons than nonreproductive plants. Grazing had no detectable effects on phenology. Colder spring temperatures delayed senescence in two of three study years.Conclusions The timing of seasonal events, such as leaf-out and senescence in plants can be expressed largely independently within and among seasons and are influenced by different factors. Growing season start and length can often be dependent on plant condition and reproductive status. Knowledge about the drivers of growing season length of individuals is essential to more accurately predict species and community responses to environmental variation.
26.	Friis, Else Marie, et al. (author) Tanispermum, a new genus of distinctive hemi-orthotropous to hemi-anatropous angiosperm seeds from the Early Cretaceous of eastern North America 2018 In: American Journal of Botany. - USA : Wiley. - 0002-9122 .- 1537-2197. ; 105, s. 1369-1388 Journal article (peer-reviewed)abstract PREMISE OF THE STUDY:Exotestal seeds with characters that indicate relationship to extant Austrobaileyales and Nymphaeales are abundant in Early Cretaceous sediments from Portugal and eastern North America, but their variety and unique features provide evidence of extensive extinct diversity among early angiosperms.METHODS:The fossils were extracted from Early Cretaceous sediments from Virginia and Maryland, United States, by sieving in water. After cleaning with HF, HCl and water, they were examined using SEM and SRXTM and compared to seeds of extant and fossil angiosperms.KEY RESULTS:A new genus, Tanispermum gen. nov., with four species (T. hopewellense sp. nov., T. marylandense sp. nov., T. drewriense sp. nov., and T. antiquum sp. nov.) is recognized. Relationship with extant Austrobaileyales and Nymphaeales is indicated by an exotesta of tall palisade sclerenchyma with undulate anticlinal walls forming a jigsaw puzzle-like surface pattern. However, seeds of Tanispermum differ from those of Austrobaileyales and Nymphaeales in their hemi-orthotropous-hemi-anatropous organization. Attempts to place Tanispermum in a phylogenetic context confront a variety of problems, including lack of information on other parts of these extinct plants.CONCLUSIONS:The discovery highlights the extent to which the morphology of extant angiosperms is not representative of the diversity that once existed among early-diverging members of the group. The relictual nature of extant taxa near the base of the angiosperm tree greatly complicates the reconstruction of ancestral character states and emphasizes the need for focused paleobotanical studies to elucidate the extinct diversity that existed early in angiosperm evolution.
27.	Gaudeul, Myriam, et al. (author) Landscape structure, clonal propagation, and genetic diversity in Scandinavian populations of Arabidopsis lyrata (Brassicaceae) 2007 In: American Journal of Botany. - 0002-9122 .- 1537-2197. ; 94:7, s. 1146-1155 Journal article (peer-reviewed)abstract Colonization history, landscape structure, and environmental conditions may influence patterns of neutral genetic variation because of their effects on gene flow and reproductive mode. We compared variation at microsatellite loci within and among 26 Arabidopsis lyrata populations in two disjunct areas of its distribution in northern Europe (Norway and Sweden). The two areas probably share a common colonization history but differ in size (Norwegian range markedly larger than Swedish range), landscape structure (mountains vs. coast), and habitat conditions likely to affect patterns of gene flow and opportunities for sexual reproduction. Within-population genetic diversity was not related to latitude but was higher in Sweden than in Norway. Population differentiation was stronger among Norwegian than among Swedish populations (F-ST = 0.23 vs. F-ST = 0.18). The frequency of clonal propagation (proportion of identical multilocus genotypes) increased with decreasing population size, was higher in Norwegian than in Swedish populations, but was not related to altitude or substrate. Differences in genetic structure are discussed in relation to population characteristics and range size in the two areas. The results demonstrate that the possibility of clonal propagation should be considered when developing strategies for sampling and analyzing data in ecological and genetic studies of this emerging model species.
28.	Ghebretinsae, Amanuel G., et al. (author) Relationships of cucumbers and melons unraveled : molecular phylogenetics of Cucumis and related genera (Benincaseae, Cucurbitaceae) 2007 In: American Journal of Botany. - 0002-9122 .- 1537-2197. ; 94:7, s. 1256-1266 Journal article (peer-reviewed)abstract Cucumis (Cucurbitaceae) comprises 33 species of annuals and perennials with a major native center of diversity in tropical and southern Africa. The genus includes some economically important and widely grown vegetables such as cucumbers and melons. Monophyly of the genus has been disputed in previous studies, but with only limited sampling. Relationships within Cucumis are thus poorly understood; moreover, the validity of the closely related genera has not been thoroughly tested. The present study was undertaken to test the monophyly of Cucumis and several closely related genera, to test sectional circumscriptions within Cucumis, and to understand the biogeographical history of the genus. We sequenced the nuclear ITS and plastid trnS-trnG regions for 40 ingroup and three outgroup taxa, representing all recognized subgenera and sections. Parsimony, maximum likelihood, and Bayesian analyses found Cucumella, Oreosyce, Mukia, Myrmecosicyos, and Dicaelospermum nested within Cucumis. The clades recovered within the Cucumis complex in some instances represent the first phylogenetically derived hypothesis of relationships, whereas others correspond to previous subgeneric and sectional classifications. At least four introductions from Africa to Asia, as well as one reintroduction to Africa, are suggested within the Cucumis complex. Cucumis sativus (cucumber) is strongly supported as sister to the eastern Asian C. hystrix, whereas C. melo (melon) is strongly supported as sister to C. sagittatus in southern Africa.
29.	Gundale, Michael (author) Herbivore resistance in congeneric and sympatric Nothofagus species is not related to leaf habit 2019 In: American Journal of Botany. - : Wiley. - 0002-9122 .- 1537-2197. ; 106, s. 788-797 Journal article (peer-reviewed)abstract Premise Two fundamental hypotheses on herbivore resistance and leaf habit are the resource availability hypothesis (RAH) and the carbon-nutrient balance hypothesis (CNBH). The RAH predicts higher constitutive resistance by evergreens, and the CNBH predicts higher induced resistance by deciduous species. Although support for these hypotheses is mixed, they have rarely been examined in congeneric species. Methods We compared leaf constitutive and induced resistance (as leaf polyphenol and tannin concentrations, and as damage level in non-choice experiments) and leaf traits associated with herbivory of coexisting Nothofagus species using (1) a defoliation experiment and (2) natural defoliation caused by an outbreak of a common defoliator of Nothofagus species. Results In the defoliation experiment, polyphenol and tannin concentrations were similar between deciduous and evergreen species; regardless of leaf habit, polyphenols increased in response to defoliation. In the natural defoliation survey, N. pumilio (deciduous) had significantly higher herbivory, lower carbon/nitrogen ratio and leaf mass per area, and higher nitrogen and phosphorus concentrations than N. betuloides (evergreen); N. antarctica (deciduous) had intermediate values. Polyphenol concentrations and herbivore resistance indicated by the non-choice experiment were lower in N. pumilio than in N. antarctica and N. betuloides, which had similar values. Conclusions Higher herbivory in N. pumilio was associated with a higher nutritional value and a lower level of leaf carbon-based defenses compared to both the evergreen and the other deciduous species, indicating that herbivore resistance in Nothofagus species cannot be attributed to only leaf habit as predicted by the RAH or CNBH.
30.	Helm, Michael, et al. (author) KDEL-tailed cysteine endopeptidases involved in programmed cell death, intercalation of new cells, and dismantling of extensin scaffolds 2008 In: American Journal of Botany. - 0002-9122 .- 1537-2197. ; 95:9, s. 1049-1062 Journal article (peer-reviewed)
31.	Jandér, K. Charlotte, et al. (author) Host sanctions in Panamanian Ficus are likely based on selective resource allocation 2016 In: American Journal of Botany. - : Wiley. - 0002-9122 .- 1537-2197. ; 103:10, s. 1753-1762 Journal article (peer-reviewed)
32.	Johnson, Mark D., et al. (author) Environmental DNA as an emerging tool in botanical research 2023 In: American Journal of Botany. - : John Wiley & Sons. - 0002-9122 .- 1537-2197. ; 110:2 Research review (peer-reviewed)abstract Over the past quarter century, environmental DNA (eDNA) has been ascendant as a tool to detect, measure, and monitor biodiversity (species and communities), as a means of elucidating biological interaction networks, and as a window into understanding past patterns of biodiversity. However, only recently has the potential of eDNA been realized in the botanical world. Here we synthesize the state of eDNA applications in botanical systems with emphases on aquatic, ancient, contemporary sediment, and airborne systems, and focusing on both single-species approaches and multispecies community metabarcoding. Further, we describe how abiotic and biotic factors, taxonomic resolution, primer choice, spatiotemporal scales, and relative abundance influence the utilization and interpretation of airborne eDNA results. Lastly, we explore several areas and opportunities for further development of eDNA tools for plants, advancing our knowledge and understanding of the efficacy, utility, and cost-effectiveness, and ultimately facilitating increased adoption of eDNA analyses in botanical systems.
33.	Jones, Faith (author) The role of genotypic and climatic variation at the range edge: A case study in winegrapes 2024 In: American Journal of Botany. - 0002-9122 .- 1537-2197. ; 111 Journal article (peer-reviewed)abstract Premise: Changes in habitat suitability due to climate change are causing range shifts, with new habitat potentially available at cold range edges. We must predict these range shifts, but forecasters have limited knowledge of how genetic differences in plant physiological tolerances influence range shifts. Here, we focus on a major determinant of species ranges-physiological tolerance to extreme cold-to ask how warming over recent decades and genetic variation shape expansion across complex landscapes.Methods: We examined how genotypes vary in maximum cold tolerance from 9 years of cold hardiness data across 18 genotypes from 13 sites, using winegrapes (Vitis vinifera subsp. vinifera) as a case study. Combining a Bayesian hierarchical dose-response model with gridded climate data, we then project changes in climatic suitability near winegrapes' current cold range-edge between 1949 and 2016.Results: Plants increased maximum cold hardiness non-linearly with decreasing air temperature (maximum cold hardiness: -23.6(degrees)C), but with substantial (by 2(degrees)C) variation across genotypes. Our results suggest, since the 1980s, decreasing freeze injury risk has made conditions more favorable for all genotypes at the cold range-edge, but conditions remained more favorable for more cold hardy genotypes and in warmer areas. There was substantial spatial variation in habitat suitability, with the majority of suitably warm habitat located in a narrow north-south oriented strip.Conclusions: We highlight the importance of genotypic differences in physiological tolerances when assessing range shift potential with climate change. Habitat improvements were unevenly distributed over the spatially complex landscape, though, emphasizing the importance of dispersal in range expansion.
34.	Järvinen, Pia, et al. (author) Phylogenetic relationships of Betula species (Betulaceae) based on nuclear Adh and chloroplast matK sequences 2004 In: American Journal of Botany. - : John Wiley & Sons. - 0002-9122 .- 1537-2197. ; 91:11, s. 1834-1845 Journal article (peer-reviewed)abstract The phylogenetic relationships within the genus Betula (Betulaceae) were investigated using a part of the nuclear ADH gene and DNA sequences of the chloroplast matK gene with parts of its flanking regions. Two well‐supported phylogenetic groups could be identified in the chloroplast DNA sequence: one containing the three American species B. lenta, B. alleghaniensis, and B. papyrifera and the other including all the other species studied. The ADH gene displayed more variation, and three main groups could be identified. In disagreement with the classical division of the genus Betula, B. schmidtii and B. nana grouped with the species in subgenus Betula, and B. ermanii grouped with species in subgenus Chamaebetula, including B. humilis and B. fruticosa. The ADH phylogeny suggests that several independent polyploidizations within the genus Betula could have taken place. The ADH and chloroplast phylogenies were in part incongruent due to the placement of B. papyrifera. The most likely reason for this seems to be cytoplasmic introgression.
35.	Kainulainen, Kent, 1978-, et al. (author) Molecular systematics and morphological character evolution of the Condamineeae (Rubiaceae) 2010 In: American Journal of Botany. - : Wiley. - 0002-9122 .- 1537-2197. ; 97:12, s. 1961-1981 Journal article (peer-reviewed)abstract • Premise of the study: The Condamineeae have in previous molecular studies been shown to be part of an early-divergent cladewithin the subfamily Ixoroideae, together with the tribes Calycophylleae, and Hippotideae, and genera of the former Cinchoneae and Rondeletieae. Generic relationships within this clade have, however, remained largely unresolved .• Methods: In this study, the systematics of the Condamineeae was further examined by phylogenetic reconstruction of six cpDNA regions and one nrDNA region using parsimony and Bayesian Markov chain Monte Carlo inference. Morphological character evolution within the tribe was assessed by ancestral state reconstruction using likelihood optimization of characters onto Bayesian trees. • Key results: Calycophylleae appears polyphyletic. “Hippotideae” is monophyletic but nested within the Condamineeae. The phylogenetic hypotheses presented support a resurrection of the genera Holtonia, Schizocalyx, and Semaphyllanthe. Furthermore, Bathysa is found to be polyphyletic, Tresanthera is found nested within Rustia, and the taxonomically disputed genus Dialypetalanthus is here shown to be sister to a Bothriospora–Wittmackanthus clade. Morphological ancestral state reconstructions indicate that protogyny have evolved at least two times within the tribe and that indehiscent fruits, loculicidal fruit dehiscence, and intrapetiolar stipules have evolved independently several times. The occurrence of calycophylls (leaf-like calyx lobes), poricidal anthers, and winged seeds also appear homoplastic within the tribe. • Conclusions : A diagnosis and delimitation of the tribe Condamineeae is presented, with taxonomic proposals to synonymize Tresanthera and to transfer several species of Bathysa as well as Phitopis to a resurrected Schizocalyx.
36.	Kemp, Jurene Ellen, et al. (author) Pollen dispensing schedules in buzz-pollinated plants : Experimental comparison of species with contrasting floral morphologies 2021 In: American Journal of Botany. - : John Wiley & Sons. - 0002-9122 .- 1537-2197. ; 108:6, s. 993-1005 Journal article (peer-reviewed)abstract Premise Plants can mitigate the fitness costs associated with pollen consumption by floral visitors by optimizing pollen release rates. In buzz-pollinated plants, bees apply vibrations to remove pollen from anthers with small pores. These poricidal anthers potentially function as mechanism staggering pollen release, but this has rarely been tested across plant species differing in anther morphology.Methods In Solanum Section Androceras, three pairs of buzz-pollinated species have undergone independent evolutionary shifts between large- and small-flowers, which are accompanied by replicate changes in anther morphology. We used these shifts in anther morphology to characterize the association between anther morphology and pollen dispensing schedules. We applied simulated bee-like vibrations to anthers to elicit pollen release, and compared pollen dispensing schedules across anther morphologies. We also investigated how vibration velocity affects pollen release.Results Replicate transitions in Solanum anther morphology are associated with consistent changes in pollen dispensing schedules. We found that small-flowered taxa release their pollen at higher rates than their large-flowered counterparts. Higher vibration velocities resulted in quicker pollen dispensing and more total pollen released. Finally, both the pollen dispensing rate and the amount of pollen released in the first vibration were negatively related to anther wall area, but we did not observe any association between pore size and pollen dispensing.Conclusions Our results provide the first empirical demonstration that the pollen dispensing properties of poricidal anthers depend on both floral characteristics and bee vibration properties. Morphological modification of anthers could thus provide a mechanism to exploit different pollination environments.
37.	Korall, Petra, 1968-, et al. (author) A molecular phylogeny of scaly tree ferns (Cyatheaceae) 2007 In: American Journal of Botany. - : Wiley. - 0002-9122 .- 1537-2197. ; 94:5, s. 873-886 Journal article (peer-reviewed)abstract Tree ferns recently were identified as the closest sister group to the hyperdiverse clade of ferns, the polypods. Although most of the 600 species of tree ferns are arborescent, the group encompasses a wide range of morphological variability, from diminutive members to the giant scaly tree ferns, Cyatheaceae. This well-known family comprises most of the tree fern diversity (similar to 500 species) and is widespread in tropical, subtropical, and south temperate regions of the world. Here we investigate the phylogenetic relationships of scaly tree ferns based on DNA sequence data from five plastid regions (rbcL, rbcL-accD IGS, rbcL-atpB IGS, trnG-trnR, and trnL-trnF). A basal dichotomy resolves Sphaeropteris as sister to all other taxa and scale features support these two clades: Sphaeropteris has conform scales, whereas all other taxa have marginate scales. The marginate-scaled clade consists of a basal trichotomy, with the three groups here termed (1) Cyathea (including Cnemidaria, Hymenophyllopsis, Trichipteris), (2) Alsophila sensu stricto, and (3) Gymnosphaera (previously recognized as a section within Alsophila) + A. capensis. Scaly tree ferns display a wide range of indusial structures, and although indusium shape is homoplastic it does contain useful phylogenetic information that supports some of the larger clades recognised.
38.	Korall, Petra, 1968-, et al. (author) PHYLOGENETIC RELATIONSHIPS IN SELAGINELLACEAE BASED ON RBCL SEQUENCES 2002 In: American Journal of Botany. - 0002-9122 .- 1537-2197. ; 89:3, s. 506-517 Journal article (peer-reviewed)abstract A phylogenetic framework is developed for the clubmoss family Selaginellaceae based on maximum parsimony analyses of molecular data. The chloroplast gene rbcL was sequenced for 62 species, which represent nearly 10% of living species diversity in the family. Taxa were chosen to reflect morphological, geographical, and ecological diversity. The analyses provide support for monophyly of subgenera Selaginella and Tetragonostachys. Stachygynandrum and Heterostachys are polyphyletic. Monophyly of Ericetorum is uncertain. Results also indicate a large number of new groupings not previously recognized on morphological grounds. Some of these new groups seem to have corresponding morphological synapomorphies, such as the presence of rhizophores (distinctive root-like structures), aspects of rhizophore development, and leaf and stem morphology. Others share distinctive ecological traits (e.g., xerophytism). For many groups, however, no morphological, ecological, or physiological markers are known. This could reflect patchy sampling and a lack of detailed knowledge about many species. Despite a lengthy fossil record dating from the Carboniferous Period, cladogram topology indicates that most of the living tropical species are probably the products of more recent diversifications. Resurrection plants, extreme xerophytes characterized by aridity-driven inrolling of branches and rapid revival on rehydration, have evolved at least three times in quite different clades.
39.	Kårehed, Jesper (author) Multiple origin of the tropical forest tree family Icacinaceae 2001 In: American Journal of Botany. - 0002-9122 .- 1537-2197. ; 88:12, s. 2259-2274 Journal article (peer-reviewed)
40.	Laestadius, Lars (author) Inconvenient realities and the path toward science-based forest restoration policies: A reply to Veldman et al 2017 In: American Journal of Botany. - : Wiley. - 0002-9122 .- 1537-2197. ; 104, s. 652-653 Other publication (peer-reviewed)
41.	Lagomarsino, L. P., et al. (author) Phylogeny, classification, and fruit evolution of the species-rich Neotropical bellflowers (Campanulaceae: Lobelioideae) 2014 In: American Journal of Botany. - : Wiley. - 0002-9122 .- 1537-2197. ; 101:12, s. 2097-2112 Journal article (peer-reviewed)abstract Premise of the study: The species-rich Neotropical genera Centropogon, Burmeistera, and Siphocampylus represent more than half of the similar to 1200 species in the subfamily Lobelioideae (Campanulaceae). They exhibit remarkable morphological variation in floral morphology and habit. Limited taxon sampling and phylogenetic resolution, however, obscures our understanding of relationships between and within these genera and underscores our uncertainty of the systematic value of fruit type as a major diagnostic character. Methods: We inferred a phylogeny from five plastid DNA regions (rpl32-trnL, ndhF-rpl32, rps16-trnK, trnG-trnG-trns, rbcL) using maximum-likelihood and Bayesian inference. Ancestral character reconstructions were applied to infer patterns of fruit evolution. Key results: Our results demonstrate that the majority of species in the genera Centropogon, Burmeistera, and Siphocampylus together form a primarily mainland Neotropical clade, collectively termed the "centropogonids." Caribbean Siphocampylus, however, group with other Caribbean lobelioid species. We find high support for the monophyly of Burmeistera and the polyphyly of Centropogon and mainland Siphocampylus. The ancestral fruit type of the centropogonids is a capsule; berries have evolved independently multiple times. Conclusions: Our plastid phylogeny greatly improves the phylogenetic resolution within Neotropical Lobelioideae and highlights the need for taxonomic revisions in the subfamily. Inference of ancestral character states identifies a dynamic pattern of fruit evolution within the centropogonids, emphasizing the difficulty of diagnosing broad taxonomic groups on the basis of fruit type. Finally, we identify that the centropogonids, Lysipomia, and Lobelia section Tupa form a Pan-Andean radiation with broad habitat diversity. This clade is a prime candidate for investigations of Neotropical biogeography and morphological evolution.
42.	Lankinen, Åsa, et al. (author) Enhancing Pollen Competition By Delaying Stigma Receptivity: Pollen Deposition Schedules Affect Siring Ability, Paternal Diversity, And Seed Production In Collinsia Heterophylla (Plantaginaceae) 2011 In: American Journal of Botany. - : Wiley. - 0002-9122 .- 1537-2197. ; 98:7, s. 1191-1200 Journal article (peer-reviewed)abstract Premise of the study: Even though pollen deposition schedules may have profound effects on the evolutionary outcome of pollen competition, few studies have investigated such effects in relation to pistil traits such as delayed stigma receptivity that enhance pollen competition. In Collinsia heterophylla, a largely outcrossing species with delayed stigma receptivity, we performed a series of controlled crosses involving several donors to understand how timing of pollen deposition influences siring ability, paternal diversity, and offspring fitness. Methods: Pollen was applied to fully receptive stigmas either as mixtures or consecutively with or without a time lag to mimic cases with early or delayed stigma receptivity. We used a genetic marker to assess offspring paternity. Key results: As expected, siring ability was affected by application order in crosses without a time lag, providing a first-donor advantage for pollen arriving on unreceptive stigmas. However, because pollen donor identity influenced siring ability, delaying stigma receptivity may still favor pollen of high competitive ability. In crosses on fully receptive pistils with a time lag of 24 h, a surprisingly high proportion of seeds (12-47%) were sired by pollen applied last. A novel finding was that pollen applied only once (as a mixture), mimicking delayed stigma receptivity, led to higher paternal diversity within progeny families, which was associated with increased seed production. Conclusions: Our results suggest fitness advantages of enhancing pollen competition by delaying stigma receptivity in C. heterophylla, particularly in relation to increased paternal diversity.
43.	Lankinen, Åsa, et al. (author) Selection on pollen and pistil traits during pollen competition is affected by both sexual conflict and mixed mating in a self-compatible herb. 2016 In: American Journal of Botany. - : Wiley. - 1537-2197 .- 0002-9122. ; 103:3, s. 541-552 Journal article (peer-reviewed)abstract Although much attention has focused on the diversity of plant mating systems, only a few studies have considered the joint effects of mating system and sexual conflict in plant evolution. In mixed-mating Collinsia heterophylla, a sexual conflict over timing of stigma receptivity is proposed: pollen with a capacity to induce early onset of stigma receptivity secures paternity for early-arriving pollen (at the expense of reduced maternal seed set), whereas late onset of stigma receptivity mitigates the negative effects of early-arriving pollen. Here we investigated whether selection on pollen and pistil traits involved in sexual conflict is affected by the presence of both outcross- and self-pollen (mixed mating) during pollen competition.
44.	Leinonen, Päivi H., et al. (author) Local adaptation in European populations of Arabidopsis lyrata (Brassicaceae) 2009 In: American Journal of Botany. - : Wiley. - 0002-9122 .- 1537-2197. ; 96:6, s. 1129-1137 Journal article (peer-reviewed)abstract We studied local adaptation to contrasting environments usingan organism that is emerging as a model for evolutionary plantbiology—the outcrossing, perennial herb Arabidopsis lyratasubsp. petraea (Brassicaceae). With reciprocal transplant experiments,we found variation in cumulative fitness, indicating adaptivedifferentiation among populations. Nonlocal populations didnot have significantly higher fitness than the local population.Experimental sites were located in Norway (alpine), Sweden (coastal),and Germany (continental). At all sites after one year, thelocal population had higher cumulative fitness, as quantifiedby survival combined with rosette area, than at least one ofthe nonlocal populations. At the Norwegian site, measurementswere done for two additional years, and fitness differencespersisted. The fitness components that contributed most to differencesin cumulative fitness varied among sites. Relatively small rosettearea combined with a large number of inflorescences producedby German plants may reflect differentiation in life history.The results of the current study demonstrate adaptive populationdifferentiation in A. lyrata along a climatic gradient in Europe.The studied populations harbor considerable variation in severalcharacters contributing to adaptive population differentiation.The wealth of genetic information available makes A. lyrataa highly attractive system also for examining the functionaland genetic basis of local adaptation in plants.
45.	Mayfield, Margaret M., et al. (author) DIFFERENCES IN FOREST PLANT FUNCTIONAL TRAIT DISTRIBUTIONS ACROSS LAND-USE AND PRODUCTIVITY GRADIENTS 2013 In: American Journal of Botany. - : Wiley. - 0002-9122 .- 1537-2197. ; 100:7, s. 1356-1368 Journal article (peer-reviewed)abstract Premise of study: Plant functional traits are commonly used as proxies for plant responses to environmental challenges, yet few studies have explored how functional trait distributions differ across gradients of land-use change. By comparing trait distributions in intact forests with those across land-use change gradients, we can improve our understanding of the ways land-use change alters the diversity and functioning of plant communities. Methods: We examined how the variation and distribution of trait values for seven plant functional traits differ between reference natural forest and three types of land-use conversion (pasture, old-field, or legacy sites-regrowth following logging), landscape productivity (NPP) and vegetation strata (tree or non-tree understory), in a meta-analysis of studies from 15 landscapes across five continents. Key results: Although trait variation often differed between land-uses within a landscape, these patterns were rarely consistent across landscapes. The variance and distribution of traits were more likely to differ consistently between natural forest and land-use conversion categories for understory (non-tree) plants than for trees. Landscape productivity did not significantly alter the difference in trait variance between natural forest and land-use conversion categories for any trait except dispersal. Conclusions: Our results suggest that even for traits well linked to plant environmental response strategies, broad classes of land-use change and landscape productivity are not generally useful indicators of the mechanisms driving compositional changes in human-modified forest systems.
46.	Mazer, Susan J., et al. (author) Flowering date of taxonomic families predicts phenological sensitivity to temperature: Implications for forecasting the effects of climate change on unstudied taxa. 2013 In: American Journal of Botany. - : Wiley. - 0002-9122 .- 1537-2197. ; 100:7, s. 1381-1397 Journal article (peer-reviewed)abstract Premise of the study: Numerous long-term studies in seasonal habitats have tracked interannual variation in first flowering date (FFD) in relation to climate, documenting the effect of warming on the FFD of many species. Despite these efforts, long-term phenological observations are still lacking for many species. If we could forecast responses based on taxonomic affinity, however, then we could leverage existing data to predict the climate-related phenological shifts of many taxa not yet studied. Methods: We examined phenological time series of 1226 species occurrences (1031 unique species in 119 families) across seven sites in North America and England to determine whether family membership (or family mean FFD) predicts the sensitivity of FFD to standardized interannual changes in temperature and precipitation during seasonal periods before flowering and whether families differ significantly in the direction of their phenological shifts. Key results: Patterns observed among species within and across sites are mirrored among family means across sites; early-flowering families advance their FFD in response to warming more than late-flowering families. By contrast, we found no consistent relationships among taxa between mean FFD and sensitivity to precipitation as measured here. Conclusions: Family membership can be used to identify taxa of high and low sensitivity to temperature within the seasonal, temperate zone plant communities analyzed here. The high sensitivity of early-flowering families (and the absence of early-flowering families not sensitive to temperature) may reflect plasticity in flowering time, which may be adaptive in environments where early-season conditions are highly variable among years.
47.	McLoughlin, Stephen, 1964-, et al. (author) Seed ferns survived the end-Cretaceous mass extinction in Tasmania. 2008 In: American Journal of Botany. - : Wiley. - 0002-9122 .- 1537-2197. ; 95:4, s. 465-71 Journal article (peer-reviewed)abstract Seed ferns, dominant elements of the vegetation in many parts of the world from the Triassic to Cretaceous, were considered to have disappeared at the end of the Cretaceous together with several other groups that had occupied key positions in terrestrial and marine ecosystems such as dinosaurs, plesiosaurs, and ammonoids. Seed-fern demise is generally correlated with competition from diversifying flowering plants through the Cretaceous and the global environmental crisis related to the Chicxulub impact event in the paleotropics at the end of the period. New fossils from Tasmania show that one seed-fern lineage survived into the Cenozoic by at least 13 million years. These fossils are described here as a new species, Komlopteris cenozoicus. Komlopteris is a genus of seed ferns attributed to Corystospermaceae and until now was not known from sediments younger than the Early Cretaceous. Discovery of this "Lazarus taxon," together with the presence of a range of other relictual fossil and extant organisms in Tasmania, other southern Gondwanan provinces, and some regions of northern North America and Asia, underscores high-latitude regions as biodiversity refugia during global environmental crises and highlights their importance as sources of postextinction radiations.
48.	Mellado-Mansilla, D., et al. (author) The relationship between chlorophyllous spores and mycorrhizal associations in ferns: evidence from an evolutionary approach 2022 In: American Journal of Botany. - : Wiley. - 0002-9122 .- 1537-2197. ; 109:12, s. 2068-2081 Journal article (peer-reviewed)abstract PremiseApproximately 14% of all fern species have physiologically active chlorophyllous spores that are much more short-lived than the more common and dormant achlorophyllous spores. Most chlorophyllous-spored species (70%) are epiphytes and account for almost 37% of all epiphytic ferns. Chlorophyllous-spored ferns are also overrepresented among fern species in habitats with waterlogged soils, of which nearly 60% have chlorophyllous spores. Ferns in these disparate habitat types also have a low incidence of mycorrhizal associations. We therefore hypothesized that autotrophic chlorophyllous spores represent an adaptation of ferns to habitats with scarce mycorrhizal associations. MethodsWe evaluated the coevolution of chlorophyllous spores and mycorrhizal associations in ferns and their relation to habitat type using phylogenetic comparative methods. ResultsAlthough we did not find support for the coevolution of spore type and mycorrhizal associations, we did find that chlorophyllous spores and the absence of mycorrhizal associations have coevolved with epiphytic and waterlogged habitats. Transition rates to epiphytic and waterlogged habitats were significantly higher in species with chlorophyllous spores compared to achlorophyllous lineages. ConclusionsSpore type and mycorrhizal associations appear to play important roles in the radiation of ferns into different habitat types. Future work should focus on clarifying the functional significance of these associations.
49.	Moreira, Xoaquín, et al. (author) Effects of latitude and conspecific plant density on insect leaf herbivory in oak saplings and seedlings 2021 In: American Journal of Botany. - : Wiley. - 0002-9122 .- 1537-2197. ; 108:1, s. 172-176 Journal article (peer-reviewed)abstract PremiseAbiotic 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.MethodsWe measured insect herbivory and conspecific plant density (CPD) of oak (Quercus robur) seedlings and saplings along a 17° latitudinal gradient (2700 km) to test whether herbivory exhibited a latitudinal gradient, whether herbivory was associated with CPD, and whether such an association changed with latitude.ResultsWe found a positive but saturating association between latitude and leaf herbivory. Furthermore, we found no significant relationship between CPD and herbivory, and such lack of density effects remained consistent throughout the sampled latitudinal gradient.ConclusionsDespite the apparently negligible influence of plant density on herbivory for Q. robur, further research with other plant taxa and in different types of plant communities are needed to investigate density‐dependent processes shaping geographical variation in plant–herbivore interactions.
50.	Mouly, Arnaud, et al. (author) Phylogeny and classification of the species-rich pantropical showy genus Ixora (Rubiaceae-Ixoreae) with indications of geographical monophyletic units and hybrids 2009 In: American Journal of Botany. - : Wiley. - 0002-9122 .- 1537-2197. ; 96, s. 686-706 Journal article (peer-reviewed)abstract Species-rich genera often have various conflicting circumscriptions from independent regional fl ora treatments. Testing the monophyly of these groups of plants is an important step toward the establishment of a phylogenetic classifi cation. The genus Ixora of the tribe Ixoreae in the subfamily Ixoroideae (coffee family or Rubiaceae) is a species-rich pantropical genus of ca. 500 species. Phylogenetic analyses of Ixoreae based on combined sequence data from one nuclear (nrETS) and two chloroplast ( rps16 and trnT-F ) markers reveal the paraphyly of Ixora as presently delimited and also show that the tribe can be subdivided into three major clades: the Mascarene/neotropical/Malagasy/African clade, the Pacifi c clade, and the Asian clade. Given the lack of morphological synapomorphies supporting the different Ixora clades and the morphological consistency of the ingroup taxa, we propose a broad circumscription of Ixora including all its satellite genera: Captaincookia , Doricera , Hitoa , Myonima , Sideroxyloides , Thouarsiora, and Versteegia . The current infrageneric classifi cation of Ixora is not supported. The different Ixora subclades represent geographical units. Nuclear and chloroplast tree topologies were partially incongruent, indicating at least four potential natural hybridization events. Other confl icting positions for the cultivated species are most likely due to anthropogenic hybridization.

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