American Journal of Botany最新文献

{"title":"Natural autopolyploids: Understanding their formation and establishment","authors":"Patrik Mráz, Barbora Šingliarová","doi":"10.1002/ajb2.70047","DOIUrl":"10.1002/ajb2.70047","url":null,"abstract":"<p>The term “polyploidy”, a state when the cell nucleus possesses more than two haploid sets of chromosomes, was introduced over a century ago. Since then, many monographs and book chapters, as well as tens of thousands of papers, have been published dealing with this phenomenon. This continuous interest testifies to at least two things: (1) a prominent role of polyploidy in plant evolution, ecology, and breeding; and (2) the remaining gaps in our knowledge of this process. Indeed, polyploidy is widespread in plants because all seed plant lineages experienced at least one whole-genome multiplication event (WGM hereafter; Jiao et al., <span>2011</span>). Furthermore, WGM frequently leads to speciation, i.e., the formation of a new evolutionary lineage that differs from its diploid or lower-ploid ancestor.</p><p>Polyploidization is often connected with the emergence of novel traits. This is more easily achievable through WGM associated with interspecific hybridization, since the resulting allopolyploid often expresses intermediate or transgressive traits that can be biologically relevant. However, in such a situation, it is not clear what is the contribution of polyploidization per se, vs. the contribution of hybridization or their mutual interaction. What is well known, however, is that allopolyploidization stabilizes the reproduction of otherwise highly sterile interspecific hybrids by allowing bivalent chromosome pairing in meiosis and formation of functional gametes (Jenczewski and Alix, <span>2004</span>). In contrast, in autopolyploids, i.e., pure polyploids arising within a single species, multivalent pairing of homoeologous chromosomes causes serious problems with proper chromosome segregation. This in turn frequently results in unbalanced and aneuploid gametes, i.e., those showing a different number of chromosomes than an exact multiple (euploid) of the haploid chromosome set, and hence, reduced fertility (Lv et al., <span>2024</span>). Reduced fertility may explain why autopolyploids are considered rare in nature and why they have been less studied compared to allopolyploids (Spoelhof et al., <span>2017</span>). Consequently, most research on autopolyploids has focused on “old” polyploid lineages, where post-polyploidization evolution might mask the direct effect of WGM (e.g., Hollister et al., <span>2012</span>). Alternatively, synthetic neoautopolyploids have provided important insights into the immediate effect of WGM (Parisod et al., <span>2010</span>), but have several disadvantages. These include selection of only the fittest genotypes and karyological and physiological instabilities due to the collateral effect of tubulin inhibitors used to create synthetic neoautopolyploids (Münzbergová, <span>2017</span>). Moreover, the synthetic approach skips the formation of neotriploids, which are considered as a bridge to reproductively more-stable autotetraploids (Ramsey and Schemske, <span>1998</span>). Therefore, studying natural neoautop","PeriodicalId":7691,"journal":{"name":"American Journal of Botany","volume":"112 5","pages":""},"PeriodicalIF":2.4,"publicationDate":"2025-05-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/ajb2.70047","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144075518","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":"Does the abiotic environment influence the distribution of flower and fruit colors?","authors":"Agnes S Dellinger, Leah Meier, Stacey Smith, Miranda Sinnott-Armstrong","doi":"10.1002/ajb2.70044","DOIUrl":"https://doi.org/10.1002/ajb2.70044","url":null,"abstract":"<p><strong>Premise: </strong>Color in flowers and fruits carries multiple functions, from attracting animal partners (pollinators, dispersers) to mitigating environmental stress (cold, drought, UV-B). With research historically focusing on biotic interactions as selective agents, however, it remains unclear whether abiotic stressors impact flower and fruit colors across large spatial scales and shape their global distribution. Moreover, although flowers and fruits are developmentally linked and exposed to the same macroclimatic conditions, whether they have similar (correlated) responses to environmental stress remains unknown.</p><p><strong>Methods: </strong>Leveraging a data set of 2815 animal-pollinated and animal-dispersed species from 51 plant clades, we tested whether the diversity and distribution of flower and fruit colors (scored into eight categories) is shaped by temperature, aridity, and UV-B irradiance.</p><p><strong>Results: </strong>Global diversity of flower and fruit colors was uncoupled, with flower color diversity generally lower than fruit color diversity and peaking in areas of high abiotic stress. Fruit color diversity peaked in tropical areas where the diversity of animal mutualists is highest. These distinct patterns were shaped by different responses of individual flower and fruit colors to abiotic stressors (for flowers, pink and red to cold temperatures, yellow and purple to UV-B irradiance; for fruits, red to cold and wet conditions, black to warm, and yellow, green, and orange to UV-B).</p><p><strong>Conclusions: </strong>Our results challenge the paradigm that flower and fruit colors are primarily shaped by animal partners but instead indicate that abiotic factors may set the macroecological stage for color evolution, with different selective factors acting on flowers and fruits.</p>","PeriodicalId":7691,"journal":{"name":"American Journal of Botany","volume":" ","pages":"e70044"},"PeriodicalIF":2.4,"publicationDate":"2025-05-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143960944","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":"Dacrycarpoides, a new genus of extinct Podocarpaceae (Coniferales) from the early Miocene of New Caledonia","authors":"Nidhi U. Patel,&nbsp;David J. Cantrill,&nbsp;Peter Crane,&nbsp;Romain Garrouste,&nbsp;Porter P. Lowry II,&nbsp;Pierre Maurizot,&nbsp;Jérôme Munzinger,&nbsp;Andrew B. Leslie","doi":"10.1002/ajb2.70041","DOIUrl":"10.1002/ajb2.70041","url":null,"abstract":"<div>\u0000 \u0000 \u0000 <section>\u0000 \u0000 <h3> Premise</h3>\u0000 \u0000 <p>The archipelago of New Caledonia contains one of the world's most distinctive biotas. The presence of notable paleoendemics in this biota suggests that Gondwanan vicariance may have played an important role in its formation, but geological evidence indicates that New Caledonia was submerged until the Oligocene and that its flora formed from more recent long-distance dispersal events. The lack of a fossil record contributes to uncertainties inherent in both interpretations, but newly discovered fossil plant assemblages may help clarify the origins of the New Caledonian flora.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Methods</h3>\u0000 \u0000 <p>We used standard paleobotanical techniques to prepare and describe leafy conifer shoots from an early Miocene deposit (age ~19 Ma) on the Pindaï Peninsula of western New Caledonia. To determine affinities of the fossil material, we compared it to herbarium collections of extant New Caledonian conifers and the broader macrofossil record.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Results</h3>\u0000 \u0000 <p>Fossil leaves contain cellular-level details of leaf morphology and epidermis anatomy consistent with the conifer family Podocarpaceae, in particular the extant genus <i>Dacrycarpus</i>. However, stomata in the fossils are arranged in crowded complexes unlike those of any described Podocarpaceae taxon, and therefore we assign this material to a new extinct genus: <i>Dacrycarpoides</i>.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Conclusions</h3>\u0000 \u0000 <p>New Caledonia is a hotspot of modern conifer biodiversity and was home to now extinct lineages as well. The presence of extinct conifers on Miocene New Caledonia is consistent with floras from neighboring landmasses and highlights the role of extinction in shaping the modern flora of New Caledonia and other Australasian landmasses.</p>\u0000 </section>\u0000 </div>","PeriodicalId":7691,"journal":{"name":"American Journal of Botany","volume":"112 5","pages":""},"PeriodicalIF":2.4,"publicationDate":"2025-05-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143958957","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":"Trait plasticity and adaptive strategies of vascular epiphytes to a large-scale experimental reduction of fog immersion in a tropical montane cloud forest","authors":"Emily M. Anders,&nbsp;Sybil G. Gotsch,&nbsp;Matthew A. Vadeboncoeur,&nbsp;Daniel B. Metcalfe,&nbsp;David C. Bartholomew,&nbsp;Aline B. Horwath,&nbsp;Blanca Espinoza,&nbsp;Darcy Galiano,&nbsp;Heidi Asbjornsen","doi":"10.1002/ajb2.70042","DOIUrl":"10.1002/ajb2.70042","url":null,"abstract":"<div>\u0000 \u0000 \u0000 <section>\u0000 \u0000 <h3> Premise</h3>\u0000 \u0000 <p>Tropical montane cloud forests (TMCF) are characterized by frequent fog immersion and host a rich epiphyte community. Epiphytes rely on atmospheric inputs of water, making them susceptible to reductions in fog immersion, which are predicted with climate change.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Methods</h3>\u0000 \u0000 <p>We experimentally reduced the fog in a Peruvian TMCF to examine the ability of eight abundant species of vascular epiphytes in the families Orchidaceae, Bromeliaceae, Ericaceae, Dryopteridaceae, Piperaceae and Clusiaceae to respond to reduced fog immersion via plasticity in morphological and physiological traits.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Key results</h3>\u0000 \u0000 <p>We found that across all species combined, fog reduction led to a decrease in stomatal length (SL) and foliar water uptake (FWU) capacity. <i>Disterigma</i> sp. (Ericaceae), an epiphytic shrub, reduced leaf thickness (LT) with fog reduction, likely a result of reduced water storage. Comparing across species, we found significant differences in traits related to drought tolerance, including the turgor loss point (TLP), relative water content at TLP (RWC_TLP) and osmotic potential at full saturation (<i>π</i>_o) indicating that two studied fern species in the <i>Elaphoglossum</i> genus (Dryopteridaceae) may tolerate low water potentials.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Conclusion</h3>\u0000 \u0000 <p>Our results revealed that some vascular epiphyte species can adjust certain morphological and physiological traits to acclimate to reduced fog immersion. Additionally, our findings support differences in ecological strategies across epiphyte functional groups to either maximize water storage in specialized tissue or to increase drought tolerance. These results give early indications of the likely vulnerability of some epiphyte groups to projected shifts in fog immersion across TCMFs globally.</p>\u0000 </section>\u0000 </div>","PeriodicalId":7691,"journal":{"name":"American Journal of Botany","volume":"112 5","pages":""},"PeriodicalIF":2.4,"publicationDate":"2025-05-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143953979","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":"Fossils of an endangered, endemic, giant dipterocarp species open a historical portal into Borneo's vanishing rainforests","authors":"Teng-Xiang Wang,&nbsp;王腾翔,&nbsp;Peter Wilf,&nbsp;Antonino Briguglio,&nbsp;László Kocsis,&nbsp;Michael P. Donovan,&nbsp;Xiaoyu Zou,&nbsp;邹啸宇,&nbsp;J. W. Ferry Slik","doi":"10.1002/ajb2.70036","DOIUrl":"10.1002/ajb2.70036","url":null,"abstract":"<div>\u0000 \u0000 \u0000 <section>\u0000 \u0000 <h3> Premise</h3>\u0000 \u0000 <p>Asia's wet tropical forests face a severe biodiversity crisis, but few fossils record their evolutionary history. We recently discovered in situ cuticles on fossil leaves, attributed to the giant rainforest tree <i>Dryobalanops</i> of the iconic Dipterocarpaceae family, from the Plio-Pleistocene of Brunei Darussalam (northern Borneo). Studying these specimens allowed us to validate the generic identification and delineate affinities to living dipterocarp species.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Methods</h3>\u0000 \u0000 <p>We compared the leaf cuticles and architecture of these fossil leaves with the seven living <i>Dryobalanops</i> species.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Results</h3>\u0000 \u0000 <p>The cuticular features shared between the fossils and extant <i>Dryobalanops</i>, including the presence of giant stomata on veins, confirm their generic placement. The leaf characters are identical to those of <i>D. rappa</i>, an IUCN red-listed Endangered, northern Borneo endemic. The <i>D. rappa</i> monodominance at the fossil site, along with <i>Dipterocarpus</i> spp. leaf fossils, indicates a dipterocarp-dominated forest near the mangrove-swamp depocenter, most likely in an adjacent peatland.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Conclusions</h3>\u0000 \u0000 <p>The <i>Dryobalanops rappa</i> fossils are the first fossil evidence of a living endangered tropical tree species and show how analysis of in situ cuticles can help illuminate the poorly known floristic history of the Asian tropics. This discovery highlights new potential for fossils to inform heritage values and paleoconservation in Southeast Asia.</p>\u0000 </section>\u0000 </div>","PeriodicalId":7691,"journal":{"name":"American Journal of Botany","volume":"112 5","pages":""},"PeriodicalIF":2.4,"publicationDate":"2025-05-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/ajb2.70036","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143959978","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":"Leaf functional traits, insect herbivory, and fungal damage on early Eocene leaf compression fossils, Dolus Hill, Wyoming","authors":"Claudia G. Richbourg,&nbsp;Lily J. Jackson,&nbsp;Kevin R. Chamberlain,&nbsp;Ian M. Miller,&nbsp;Kirk R. Johnson,&nbsp;Ellen D. Currano","doi":"10.1002/ajb2.70033","DOIUrl":"10.1002/ajb2.70033","url":null,"abstract":"<div>\u0000 \u0000 \u0000 <section>\u0000 \u0000 <h3> Premise</h3>\u0000 \u0000 <p>In the fossil record, herbivory and fungal damage can be directly measured. Though herbivory is commonly recorded, only rarely has it been examined with fungal damage and through the lens of functional plant traits. Here, we introduce, date, and use a new well-preserved fossil flora to understand relationships between fungal damage, insect feeding, and leaf traits during a hothouse interval.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Methods</h3>\u0000 \u0000 <p>We constrained the age of Dolus Hill using uranium-lead radioisotopic dating of zircons from tuffaceous sandstone. We identified 611 eudicot leaf fossils, quantified insect feeding and fungal damage, and measured leaf traits on appropriate fossils. Generalized linear models, beta regressions, and Fisher's exact test were applied to elucidate relationships between damage and leaf traits.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Results</h3>\u0000 \u0000 <p>Dolus Hill was dated to 52.22 ± 0.21 (95% confidence) million years ago and has 18 eudicot morphospecies. Insect damage occurred on 82% of leaves, and 27% had fungal damage. Leaf mass per area had no relationship with any damage metric; leaf vein density had a positive relationship with the number of damage types on a leaf. Percentage area damaged and fungal damage were not affected by these leaf traits. Fungal and insect feeding damage significantly co-occurred.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Conclusions</h3>\u0000 \u0000 <p>The leaf fossils at the Dolus Hill from the Early Eocene Climatic Optimum provide new insight into plant–fungus interactions and the utility of certain plant trait metrics in the fossil record. These insights will enhance our understanding of plant–fungus–insect interactions within the regime of current rapid climate change.</p>\u0000 </section>\u0000 </div>","PeriodicalId":7691,"journal":{"name":"American Journal of Botany","volume":"112 5","pages":""},"PeriodicalIF":2.4,"publicationDate":"2025-05-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143956355","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":"Disentangling serial chloroplast captures in willows","authors":"Diksha Gambhir,&nbsp;Brian J. Sanderson,&nbsp;Minghao Guo,&nbsp;Nan Hu,&nbsp;Ashmita Khanal,&nbsp;Quentin Cronk,&nbsp;Tao Ma,&nbsp;Jianquan Liu,&nbsp;Diana M. Percy,&nbsp;Matthew S. Olson","doi":"10.1002/ajb2.70039","DOIUrl":"10.1002/ajb2.70039","url":null,"abstract":"<div>\u0000 \u0000 \u0000 <section>\u0000 \u0000 <h3> Premise</h3>\u0000 \u0000 <p>Chloroplast capture is a process through which the chloroplast of a focal species is replaced by the chloroplast from another species during repeated backcrossing of an initial hybrid. Here we investigated serial chloroplast capture from <i>Salix nigra</i> in willows during sequential hybridization events that led to the capture of the same chloroplast lineage across multiple <i>Salix</i> species.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Methods</h3>\u0000 \u0000 <p>Previously generated sequences of nuclear and chloroplast regions from several <i>Salix</i> species were used to identify cases of cytonuclear phylogenetic discordance, a pattern indicating chloroplast capture. Serial chloroplast captures were identified by comparing phylogenetic topologies of the chloroplast trees to discriminate among (1) a single chloroplast capture and subsequent speciation of the lineage with the captured chloroplast, (2) multiple chloroplast captures from the same parent species, and (3) serial chloroplast captures. We also looked for hybridization in genes involved in cytonuclear interactions and in photosynthesis.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Results</h3>\u0000 \u0000 <p>We identified cases of serial chloroplast capture and speciation after chloroplast capture in <i>Salix</i>. Although these chloroplast capture events were accompanied by signals of hybridization in the nuclear genomes, nuclear genes that functionally interact with chloroplast genes and nuclear genes involved in photosynthesis were no more likely to introgress in species with chloroplast captures than in species without chloroplast captures.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Conclusions</h3>\u0000 \u0000 <p>This study illuminates the complex evolution of the chloroplast genomes in <i>Salix</i> and the potential for hybridization and introgression to influence genomic evolution.</p>\u0000 </section>\u0000 </div>","PeriodicalId":7691,"journal":{"name":"American Journal of Botany","volume":"112 5","pages":""},"PeriodicalIF":2.4,"publicationDate":"2025-05-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143968051","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":"Tree height and not climate influences intraspecific variations in wood parenchyma fractions of angiosperm species in a mountain forest of eastern China","authors":"Dan Wu,&nbsp;Xinni Zhou,&nbsp;Jinqi Wang,&nbsp;Hugh Morris,&nbsp;Xijin Zhang,&nbsp;Kun Song","doi":"10.1002/ajb2.70035","DOIUrl":"10.1002/ajb2.70035","url":null,"abstract":"<div>\u0000 \u0000 \u0000 <section>\u0000 \u0000 <h3> Premise</h3>\u0000 \u0000 <p>Parenchyma is an important cell type in the secondary xylem of angiosperm trees, with considerable variability in its abundance. However, the functional significance of these variations and their roles in plant ecological strategies is poorly understood at the inter- and intraspecific levels.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Methods</h3>\u0000 \u0000 <p>For this study, fractions of axial parenchyma cells (AP) and ray parenchyma cells (RP) in xylem tissue were quantified for 156 individuals of 45 tree species along an elevational gradient from 600 to 1600 m a.s.l. in eastern China. Environmental factors and height of sampled trees at each sampling site were also measured. Linear mixed models were employed to assess the relative extent of both intraspecific and interspecific variations in parenchyma cells in xylem tissue fractions and to identify intraspecific variations along environmental gradients (e.g., temperature and humidity) and tree heights.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Results</h3>\u0000 \u0000 <p>Interspecific variations explained the large diversity in AP fractions. Conversely, intraspecific variations accounted for ~50% of the overall variations in RP fractions. Further, intraspecific variations in the RP and the total AP and RP fractions exhibited negative correlations with tree heights but showed no significant relationship with climate.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Conclusions</h3>\u0000 \u0000 <p>Intraspecific variations in parenchyma cells in xylem tissue fractions are not necessarily an adaptation or acclimation to changes in the environment but are coordinated with tree heights.</p>\u0000 </section>\u0000 </div>","PeriodicalId":7691,"journal":{"name":"American Journal of Botany","volume":"112 5","pages":""},"PeriodicalIF":2.4,"publicationDate":"2025-04-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143953935","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":"The spatial distribution of a hummingbird-pollinated plant is not strongly influenced by hummingbird abundance","authors":"Matthew L. Coffey,&nbsp;Andrew M. Simons","doi":"10.1002/ajb2.70034","DOIUrl":"10.1002/ajb2.70034","url":null,"abstract":"<div>\u0000 \u0000 \u0000 <section>\u0000 \u0000 <h3> Premise</h3>\u0000 \u0000 <p>Many angiosperms have evolved specialized systems that promote pollination by specific taxa. Therefore, plant distributions may be limited by the local abundance of their specialist pollinators. In eastern North America, <i>Lobelia cardinalis</i> is thought to be pollinated solely by <i>Archilochus colubris</i>, the only hummingbird species found in the region. Here we tested the hypothesis that the distribution of a plant species with specialized pollination is controlled by the range and abundance of its specialist pollinator.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Methods</h3>\u0000 \u0000 <p>We investigated the importance of <i>A. colubris</i> abundance, sourced from eBird, as a variable in a MaxEnt species distribution model of <i>L. cardinalis</i> using presence data from iNaturalist. We also compared hummingbird abundance between locations of <i>L. cardinalis</i> and congeneric during their respective flowering periods and explored whether the flowering periods of <i>L. cardinalis</i> and congenerics align with the week of peak local hummingbird abundance.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Results</h3>\u0000 \u0000 <p>Unexpectedly, MaxEnt modelling did not suggest that <i>A. colubris</i> abundance is a key driver of the species distribution. <i>Lobelia cardinalis</i> habitat suitability was lowest in the absence of <i>A. colubris</i> and increased with increasing abundance, but habitat suitability was also low in regions where hummingbird abundance is highest. Still, hummingbird abundance at <i>L. cardinalis</i> locations was generally higher than most congenerics, and <i>L. cardinalis</i> tended to flower near the week of local peak <i>A. colubris</i> abundance.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Conclusions</h3>\u0000 \u0000 <p>While populations of hummingbird-pollinated plant species may require the local presence of hummingbirds, fine-scale variation in hummingbird abundance may not strongly influence their spatial distributions.</p>\u0000 </section>\u0000 </div>","PeriodicalId":7691,"journal":{"name":"American Journal of Botany","volume":"112 5","pages":""},"PeriodicalIF":2.4,"publicationDate":"2025-04-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/ajb2.70034","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143956359","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":"Phylogenetic relationships versus environmental impacts on the distribution and traits of Laureae (Lauraceae) species within and outside karst tiankengs","authors":"Yuxin Dai,&nbsp;Yu Song,&nbsp;Jiaojiao Zhang,&nbsp;Bing Zhao,&nbsp;Liwen Li,&nbsp;Zhenyang Huang,&nbsp;Hao Yang","doi":"10.1002/ajb2.70032","DOIUrl":"10.1002/ajb2.70032","url":null,"abstract":"<div>\u0000 \u0000 \u0000 <section>\u0000 \u0000 <h3> Premise</h3>\u0000 \u0000 <p>A karst tiankeng, a unique sinkhole-like terrain with a rare and distinctive habitat, is often likened to an isolated island because of its limited contact with the external environment. This distinctive landscape potentially shapes the evolution and distribution of the associated plant species. However, the relative contributions of environmental impacts versus phylogenetic relationships in shaping plant adaptations to the tiankeng environment remain unclear. We analyzed trait divergence within Laureae, a dominant group in a tiankeng forest, to discern whether trait variations among Laureae populations within and outside the tiankeng were shaped predominantly by environmental influences or phylogenetic heritage.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Methods</h3>\u0000 \u0000 <p>We reconstructed a phylogenetic tree for Laureae within and beyond the Baise Tiankengs using plastid genomes to estimate dispersal times, trace ancestral distributions, and model distributional shifts under various climatic scenarios. We also compared leaf and fruit traits of plants within and outside the tiankeng.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Results</h3>\u0000 \u0000 <p>The uplift of the Qinghai-Tibet Plateau affected the climate in South China, shaping Laureae traits. A discernible phylogenetic signal indicated environmental factors significantly drive trait variations in Laureae in the tiankeng. A markedly smaller leaf length/width ratio endows the Laureae populations in the tiankeng with enhanced resilience to colder microclimates compared to populations in surrounding areas. Maximum and minimum leaf length/width ratios were also significantly lower in the tiankeng.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Conclusions</h3>\u0000 \u0000 <p>These findings advance our understanding on biodiversity and plant trait divergence inside tiankengs, underscoring the importance of preserving unique habitats and restoring vegetation in these terrains.</p>\u0000 </section>\u0000 </div>","PeriodicalId":7691,"journal":{"name":"American Journal of Botany","volume":"112 5","pages":""},"PeriodicalIF":2.4,"publicationDate":"2025-04-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143952550","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}