American Journal of Botany最新文献

{"title":"The immediate metabolomic effects of whole-genome duplication in the greater duckweed, Spirodela polyrhiza","authors":"Tian Wu,&nbsp;Quinten Bafort,&nbsp;Frederik Mortier,&nbsp;Fabricio Almeida-Silva,&nbsp;Annelore Natran,&nbsp;Yves Van de Peer","doi":"10.1002/ajb2.16383","DOIUrl":"10.1002/ajb2.16383","url":null,"abstract":"<div>\u0000 \u0000 \u0000 <section>\u0000 \u0000 <h3> Premise</h3>\u0000 \u0000 <p>In plants, whole-genome duplication (WGD) is a common mutation with profound evolutionary potential. Given the costs associated with a superfluous genome copy, polyploid establishment is enigmatic. However, in the right environment, immediate phenotypic changes following WGD can facilitate establishment. Metabolite abundances are the direct output of the cell's regulatory network and determine much of the impact of environmental and genetic change on the phenotype. While it is well known that an increase in the bulk amount of genetic material can increase cell size, the impact of gene dosage multiplication on the metabolome remains largely unknown.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Methods</h3>\u0000 \u0000 <p>We used untargeted metabolomics on four genetically distinct diploid-neoautotetraploid pairs of the greater duckweed, <i>Spirodela polyrhiza</i>, to investigate how WGD affects metabolite abundances per cell and per biomass.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Results</h3>\u0000 \u0000 <p>Autopolyploidy increased metabolite levels per cell, but the response of individual metabolites varied considerably. However, the impact on metabolite level per biomass was restricted because the increased cell size reduced the metabolite concentration per cell. Nevertheless, we detected both quantitative and qualitative effects of WGD on the metabolome. Many effects were strain-specific, but some were shared by all four strains.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Conclusions</h3>\u0000 \u0000 <p>The nature and impact of metabolic changes after WGD depended strongly on the genotype. Dosage effects have the potential to alter the plant metabolome qualitatively and quantitatively, but were largely balanced out by the reduction in metabolite concentration due to an increase in cell size in this species.</p>\u0000 </section>\u0000 </div>","PeriodicalId":7691,"journal":{"name":"American Journal of Botany","volume":null,"pages":null},"PeriodicalIF":2.4,"publicationDate":"2024-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141858826","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Lineage diversification and rampant hybridization among subspecies explain taxonomic confusion in the endemic Hawaiian fern Polypodium pellucidum","authors":"Jonas I. Mendez-Reneau,&nbsp;Joseph L. Richards,&nbsp;Julia Hobbie,&nbsp;Emily Bollich,&nbsp;Nicholas J. Kooyers,&nbsp;Erin M. Sigel","doi":"10.1002/ajb2.16379","DOIUrl":"10.1002/ajb2.16379","url":null,"abstract":"<div>\u0000 \u0000 \u0000 <section>\u0000 \u0000 <h3> Premise</h3>\u0000 \u0000 <p><i>Polypodium pellucidum</i>, a fern endemic to the Hawaiian Islands, encompasses five ecologically and morphologically variable subspecies, suggesting a complex history involving both rapid divergence and rampant hybridization.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Methods</h3>\u0000 \u0000 <p>We employed a large target-capture data set to investigate the evolution of genetic, morphological, and ecological variation in <i>P. pellucidum</i>. With a broad sampling across five Hawaiian Islands, we deciphered the evolutionary history of <i>P. pellucidum</i>, identified nonhybrid lineages and intraspecific hybrids, and inferred the relative influence of geography and ecology on their distributions.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Results</h3>\u0000 \u0000 <p><i>Polypodium pellucidum</i> is monophyletic, dispersing to the Hawaiian archipelago 11.53–7.77 Ma and diversifying into extant clades between 5.66 and 4.73 Ma. We identified four nonhybrid clades with unique morphologies, ecological niches, and distributions. Additionally, we elucidated several intraspecific hybrid combinations and evidence for undiscovered or extinct “ghost” lineages contributing to extant hybrid populations.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Conclusions</h3>\u0000 \u0000 <p>We provide a foundation for revising the taxonomy of <i>P. pellucidum</i> to account for cryptic lineages and intraspecific hybrids. Geologic succession of the Hawaiian Islands through cycles of volcanism, vegetative succession, and erosion has determined the available habitats and distribution of ecologically specific, divergent clades within <i>P. pellucidum.</i> Intraspecific hybrids have likely arisen due to ecological and or geological transitions, often persisting after the local extinction of their progenitors. This research contributes to our understanding of the evolution of Hawai'i's diverse fern flora and illuminated cryptic taxa to allow better-informed conservation efforts.</p>\u0000 </section>\u0000 </div>","PeriodicalId":7691,"journal":{"name":"American Journal of Botany","volume":null,"pages":null},"PeriodicalIF":2.4,"publicationDate":"2024-07-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141854533","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Species-tree topology impacts the inference of ancient whole-genome duplications across the angiosperm phylogeny","authors":"Michael T. W. McKibben,&nbsp;Geoffrey Finch,&nbsp;Michael S. Barker","doi":"10.1002/ajb2.16378","DOIUrl":"10.1002/ajb2.16378","url":null,"abstract":"<div>\u0000 \u0000 \u0000 <section>\u0000 \u0000 <h3> Premise</h3>\u0000 \u0000 <p>The history of angiosperms is marked by repeated rounds of ancient whole-genome duplications (WGDs). Here we used state-of-the-art methods to provide an up-to-date view of the distribution of WGDs in the history of angiosperms that considers both uncertainty introduced by different WGD inference methods and different underlying species-tree hypotheses.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Methods</h3>\u0000 \u0000 <p>We used the distribution synonymous divergences (<i>K</i>_s) of paralogs and orthologs from transcriptomic and genomic data to infer and place WGDs across two hypothesized angiosperm phylogenies. We further tested these WGD hypotheses with syntenic inferences and Bayesian models of duplicate gene gain and loss.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Results</h3>\u0000 \u0000 <p>The predicted number of WGDs in the history of angiosperms (~170) based on the current taxon sampling is largely similar across different inference methods, but varies in the precise placement of WGDs on the phylogeny. <i>K</i>_s-based methods often yield alternative hypothesized WGD placements due to variation in substitution rates among lineages. Phylogenetic models of duplicate gene gain and loss are more robust to topological variation. However, errors in species-tree inference can still produce spurious WGD hypotheses, regardless of method used.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Conclusions</h3>\u0000 \u0000 <p>Here we showed that different WGD inference methods largely agree on an average of 3.5 WGD in the history of individual angiosperm species. However, the precise placement of WGDs on the phylogeny is subject to the WGD inference method and tree topology. As researchers continue to test hypotheses regarding the impacts ancient WGDs have on angiosperm evolution, it is important to consider the uncertainty of the phylogeny as well as WGD inference methods.</p>\u0000 </section>\u0000 </div>","PeriodicalId":7691,"journal":{"name":"American Journal of Botany","volume":null,"pages":null},"PeriodicalIF":2.4,"publicationDate":"2024-07-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141747159","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Estimates of late Early Cretaceous atmospheric CO2 from Mongolia based on stomatal and isotopic analysis of Pseudotorellia","authors":"Xiaoqing Zhang,&nbsp;Dana L. Royer,&nbsp;Gongle Shi,&nbsp;Niiden Ichinnorov,&nbsp;Patrick S. Herendeen,&nbsp;Peter R. Crane,&nbsp;Fabiany Herrera","doi":"10.1002/ajb2.16376","DOIUrl":"10.1002/ajb2.16376","url":null,"abstract":"<div>\u0000 \u0000 \u0000 <section>\u0000 \u0000 <h3> Premise</h3>\u0000 \u0000 <p>The Aptian–Albian (121.4–100.5 Ma) was a greenhouse period with global temperatures estimated as 10–15°C warmer than pre-industrial conditions, so it is surprising that the most reliable CO₂ estimates from this time are &lt;1400 ppm. This low CO₂ during a warm period implies a very high Earth-system sensitivity in the range of 6 to 9°C per CO₂ doubling between the Aptian-Albian and today.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Methods</h3>\u0000 \u0000 <p>We applied a well-vetted paleo-CO₂ proxy based on leaf gas-exchange principles (Franks model) to two <i>Pseudotorellia</i> species from three stratigraphically similar samples at the Tevshiin Govi lignite mine in central Mongolia (~119.7–100.5 Ma).</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Results</h3>\u0000 \u0000 <p>Our median estimated CO₂ concentration from the three respective samples was 2132, 2405, and 2770 ppm. The primary reason for the high estimated CO₂ but with relatively large uncertainties is the very low stomatal density in both species, where small variations propagate to large changes in estimated CO₂. Indeed, we found that at least 15 leaves are required before the aggregate estimated CO₂ approaches that of the full data set.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Conclusions</h3>\u0000 \u0000 <p>Our three CO₂ estimates all exceeded 2000 ppm, translating to an Earth-system sensitivity (~3–5°C/CO₂ doubling) that is more in keeping with the current understanding of the long-term climate system. Because of our large sample size, the directly measured inputs did not contribute much to the overall uncertainty in estimated CO₂; instead, the inferred inputs were responsible for most of the overall uncertainty and thus should be scrutinized for their value choices.</p>\u0000 </section>\u0000 </div>","PeriodicalId":7691,"journal":{"name":"American Journal of Botany","volume":null,"pages":null},"PeriodicalIF":2.4,"publicationDate":"2024-07-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141632439","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Are plant traits drivers of endophytic communities in seasonally flooded tropical forests?","authors":"Marion Boisseaux, Valérie Troispoux, Alice Bordes, Jocelyn Cazal, Saint-Omer Cazal, Sabrina Coste, Clément Stahl, Heidy Schimann","doi":"10.1002/ajb2.16366","DOIUrl":"https://doi.org/10.1002/ajb2.16366","url":null,"abstract":"<p><strong>Premise: </strong>In the Amazon basin, seasonally flooded (SF) forests offer varying water constraints, providing an excellent way to investigate the role of habitat selection on microbial communities within plants. However, variations in the microbial community among host plants cannot solely be attributed to environmental factors, and how plant traits contribute to microbial assemblages remains an open question.</p><p><strong>Methods: </strong>We described leaf- and root-associated microbial communities using ITS2 and 16 S high-throughput sequencing and investigated the stochastic-deterministic balance shaping these community assemblies using two null models. Plant ecophysiological functioning was evaluated by focusing on 10 leaf and root traits in 72 seedlings, belonging to seven tropical SF tree species in French Guiana. We then analyzed how root and leaf traits drove the assembly of endophytic communities.</p><p><strong>Results: </strong>While both stochastic and deterministic processes governed the endophyte assembly in the leaves and roots, stochasticity prevailed. Discrepancies were found between fungi and bacteria, highlighting that these microorganisms have distinct ecological strategies within plants. Traits, especially leaf traits, host species and spatial predictors better explained diversity than composition, but they were modest predictors overall.</p><p><strong>Conclusions: </strong>This study widens our knowledge about tree species in SF forests, a habitat sensitive to climate change, through the combined analyses of their associated microbial communities with functional traits. We emphasize the need to investigate other plant traits to better disentangle the drivers of the relationship between seedlings and their associated microbiomes, ultimately enhancing their adaptive capacities to climate change.</p>","PeriodicalId":7691,"journal":{"name":"American Journal of Botany","volume":null,"pages":null},"PeriodicalIF":2.4,"publicationDate":"2024-07-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141619017","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Cretaceous and Paleocene fossils reveal an extinct higher clade within Cornales, the dogwood order","authors":"Austin T. Nguyen,&nbsp;Brian A. Atkinson","doi":"10.1002/ajb2.16372","DOIUrl":"10.1002/ajb2.16372","url":null,"abstract":"<div>\u0000 \u0000 \u0000 <section>\u0000 \u0000 <h3> Premise</h3>\u0000 \u0000 <p>Characterization and phylogenetic integration of fossil angiosperms with uncertain affinities is relatively limited, which may obscure the diversity of extinct higher taxa in the flowering plant tree of life. The order Cornales contains a diversity of extinct taxa with uncertain familial affinities that make it an ideal group for studying turnover in angiosperms. Here, we describe a new extinct genus of Cornales unassignable to an extant family and conduct a series of phylogenetic analyses to reconstruct relationships of fossils across the order.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Methods</h3>\u0000 \u0000 <p>Two permineralized endocarps were collected from the Cedar District Formation (Campanian, 82–80 Ma) of Sucia Island, State of Washington, United States. Fossils were sectioned with the cellulose acetate peel technique and incorporated into a morphological dataset. To assess the utility of this dataset to accurately place taxa in their respective clades, we used a series of phylogenetic pseudofossilization analyses. We then conducted a total-evidence analysis and a scaffold-based approach to determine relationships of fossils.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Results</h3>\u0000 \u0000 <p>Based on their unique combination of characters, the fossils represent a new genus, <i>Fenestracarpa washingtonensis</i> gen. nov. et sp. nov. Pseudofossilization analyses indicate that our morphological dataset can be used to accurately recover taxa at the major clade to family level, generally with moderate to high support. The total-evidence and scaffold-based analyses recovered <i>Fenestracarpa</i> and other fossil genera in an entirely extinct clade within Cornales.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Conclusions</h3>\u0000 \u0000 <p>Our findings increase the reported diversity of extinct Cornales and indicate that the order's initial radiation likely included the divergence of an extinct higher clade that endured the end-Cretaceous Mass extinction but perished during the Cenozoic.</p>\u0000 </section>\u0000 </div>","PeriodicalId":7691,"journal":{"name":"American Journal of Botany","volume":null,"pages":null},"PeriodicalIF":2.4,"publicationDate":"2024-07-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141619087","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Salt tolerance in a neotropical orchid in the absence of local adaptation to salt spray","authors":"Thales M. de Lima,&nbsp;Simone F. Silva,&nbsp;Rafael V. Ribeiro,&nbsp;Julia Sánchez-Vilas,&nbsp;Fabio Pinheiro","doi":"10.1002/ajb2.16373","DOIUrl":"10.1002/ajb2.16373","url":null,"abstract":"<div>\u0000 \u0000 \u0000 <section>\u0000 \u0000 <h3> Premise</h3>\u0000 \u0000 <p>Salt tolerance has rarely been investigated regionally in the neotropics and even more rarely in Orchidaceae, one of the largest families. Therefore, investigating local adaptation to salt spray and its physiological basis in <i>Epidendrum fulgens</i>, a neotropical orchid species, brings important new insights.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Methods</h3>\u0000 \u0000 <p>We assessed the degree of salt tolerance in <i>E. fulgens</i> by testing whether coastal populations are more tolerant to salt, which could point to local adaptation. To understand the physiological basis of such salt tolerance, we exposed wild-collected individuals to salt spray for 60 days, then measured leaf expansion, osmotic potential, sodium leaf concentration, chlorophyll leaf index, chlorophyll fluorescence, relative growth rate, and pressure–volume curves.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Results</h3>\u0000 \u0000 <p>There is no local adaptation to salt spray since both inland and coastal plants have a high tolerance to salt stress. This tolerance is explained by the ability to tolerate high concentrations of salt in leaf tissues, which is related to the high succulence displayed by this species.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Conclusions</h3>\u0000 \u0000 <p>We showed an unprecedented salt tolerance level for an orchid species, highlighting our limited knowledge of that trait beyond the traditional studied groups. Another interesting finding is that salt tolerance in <i>E. fulgens</i> is linked to succulence, is widespread, and is not the result of local adaptation. We suggest that <i>E. fulgens</i> and its allied species could be an interesting group to explore the evolution of important traits related to tolerance to salt stress, like succulence.</p>\u0000 </section>\u0000 </div>","PeriodicalId":7691,"journal":{"name":"American Journal of Botany","volume":null,"pages":null},"PeriodicalIF":2.4,"publicationDate":"2024-07-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141619089","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Effects of anther-stigma position on cross-pollination efficiency in a hermaphroditic plant","authors":"Matias C. Baranzelli,&nbsp;Manuel Ochoa-Sánchez,&nbsp;Sergio E. Ramos,&nbsp;Fernanda Baena-Díaz,&nbsp;Paula Sosenski,&nbsp;Karina Boege,&nbsp;Cesar A. Domínguez,&nbsp;Juan Fornoni","doi":"10.1002/ajb2.16377","DOIUrl":"10.1002/ajb2.16377","url":null,"abstract":"<div>\u0000 \u0000 \u0000 <section>\u0000 \u0000 <h3> Premise</h3>\u0000 \u0000 <p>Evolution of cross-pollination efficiency depends on the genetic variation of flower traits, the pollen vector, and flower trait matching between pollen donors and recipients. Trait matching has been almost unexplored among nonheterostylous species, and we examined whether the match of anther length in pollen donors and stigma length in pollen recipients influences the efficiency of cross-pollination. To explore potential constraints for evolutionary response, we also quantified genetic variation and covariation among sepal length, petal length and width, stamen length, style length, and herkogamy.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Methods</h3>\u0000 \u0000 <p>We created 58 experimental arrays of <i>Turnera velutina</i> that varied in the extent of mismatch in the position of anthers and stigmas between single-flowered plants. Genetic variation and correlations among flower traits were estimated under greenhouse conditions.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Results</h3>\u0000 \u0000 <p>Style length, but not herkogamy, influenced the efficiency of cross-pollination. Plants with stamen length that matched the style length of other plants were more efficient pollen donors, whereas those with the style protruding above the stamens of other plants were more efficient pollen recipients. Significant broad-sense heritability (0.22 &gt; <i>h</i>_B² &lt; 0.42) and moderate genetic correlations (0.33 &gt; <i>r</i> &lt; 0.85) among floral traits were detected.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Conclusions</h3>\u0000 \u0000 <p>Our results demonstrated that anther-stigma mismatch between flowers contributed to variation in the efficiency of cross-pollination. The genetic correlations between stamen length and other floral traits suggests that any change in cross-pollination efficiency would be driven by changes in style rather than in stamen length.</p>\u0000 </section>\u0000 </div>","PeriodicalId":7691,"journal":{"name":"American Journal of Botany","volume":null,"pages":null},"PeriodicalIF":2.4,"publicationDate":"2024-07-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/ajb2.16377","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141619088","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The timing of visits by large and small bees differentially affects pollination success in Mimulus ringens","authors":"Randall J. Mitchell,&nbsp;Dana Starvaggi,&nbsp;Victor Fitzgerald,&nbsp;Jeffrey D. Karron","doi":"10.1002/ajb2.16375","DOIUrl":"10.1002/ajb2.16375","url":null,"abstract":"<div>\u0000 \u0000 \u0000 <section>\u0000 \u0000 <h3> Premise</h3>\u0000 \u0000 <p>Cross-fertilization in most flowering plants is facilitated by mobile animals that transport pollen while foraging for floral rewards. The contributions of different visitors can vary widely, depending on the amount of pollen transferred during a single visit and on the frequency and timing of the visits of each pollinator taxon.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Methods</h3>\u0000 \u0000 <p>We used three approaches to measure the pollination value of bees that visit <i>Mimulus ringens</i>: pollinator interviews, field population observations, and caging studies.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Results</h3>\u0000 \u0000 <p>The single-visit effectiveness of small bees (primarily Halictidae) was only half that of larger bees (primarily <i>Bombus</i>) for pollen delivery and removal. In five field populations, we found substantial temporal and spatial variation in visitation and pollination. In most sites big bees were active before 08:00 hours, and by 10:00–11:00 hours, stigmas were usually fully pollinated and closed, and little pollen remained in anthers. Small bees seldom visited before 10:00 hours. Excluding big bees from plants confirmed that pollination is reduced and delayed in this ecological context.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Conclusions</h3>\u0000 \u0000 <p>Big bees are the primary pollinators of <i>M. ringens</i>, accounting for at least 75% of seed production. Not only are they more effective per visit, in most situations they also visit before small bees become active. Although small bees are not usually important pollinators of <i>M. ringens</i>, they have the potential to partially replace them as a “fail-safe” pollinator in contexts where big bees are not abundant. In a world where pollinator abundance is declining, such backup pollinators may be important for maintaining plant reproduction.</p>\u0000 </section>\u0000 </div>","PeriodicalId":7691,"journal":{"name":"American Journal of Botany","volume":null,"pages":null},"PeriodicalIF":2.4,"publicationDate":"2024-07-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/ajb2.16375","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141615764","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Striking genetic homogeneity in the widespread South American bracken","authors":"Agustina Yañez,&nbsp;Sylvia P. Kinosian,&nbsp;M. Mónica Ponce,&nbsp;Diego G. Gutierrez,&nbsp;Pedro B. Schwartsburd,&nbsp;Michael Sundue,&nbsp;Paul G. Wolf","doi":"10.1002/ajb2.16374","DOIUrl":"10.1002/ajb2.16374","url":null,"abstract":"<div>\u0000 \u0000 \u0000 <section>\u0000 \u0000 <h3> Premise</h3>\u0000 \u0000 <p>Bracken (<i>Pteridium</i>, Dennstaedtiaceae) is a cosmopolitan genus of aggressive disturbance colonizers that are toxic to agricultural livestock. The taxonomy of <i>Pteridium</i> has been treated in multiple schemes, ranging from one to six species worldwide, with numerous subspecies and varieties. Recent work has focused on the worldwide distribution and systematics of the bracken fern, but South America has been poorly represented. We present the first continent-wide sampling and analysis of <i>Pteridium esculentum</i>, a Southern Hemisphere diploid species.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Methods</h3>\u0000 \u0000 <p>Within South America, <i>P. esculentum</i> has several morphotypes, distinguished into subspecies by variation in indument and lamina architecture. We used double digest restriction site-associated DNA sequencing (ddRADSeq) to assess the phylogenetic relationships of <i>P. esculentum</i> subspecies.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Results</h3>\u0000 \u0000 <p>We found a striking genetic homogeneity in the species, being able to support only two morphotypes from molecular data: <i>P. e. arachnoideum</i> and <i>P. e. campestre</i>. We had high confidence for shallow and deep phylogenetic relationships, but less support for relationships among crown groups.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Conclusions</h3>\u0000 \u0000 <p>We describe an east-west geographic pattern that would explain the relationships between populations; and, in contrast to previous studies, we detected differences with <i>P. esculentum</i> from Australia. These results will lay the foundations for studying variations in this species' behavior as a weed, as well as its impact on the production of agricultural livestock in South America.</p>\u0000 </section>\u0000 </div>","PeriodicalId":7691,"journal":{"name":"American Journal of Botany","volume":null,"pages":null},"PeriodicalIF":2.4,"publicationDate":"2024-07-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141598106","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}