American Journal of Botany最新文献

{"title":"From plant traits to fire behavior: Scaling issues in flammability studies.","authors":"Dylan W Schwilk, Md Azharul Alam, Nathan Gill, Brad R Murray, Rachael H Nolan, Stefania Ondei, George L W Perry, Alistair M S Smith, David M J S Bowman, Alessandra Fidelis, Pedro Jaureguiberry, Imma Oliveras Menor, Bruno H P Rosado, Helena Roland, Marta Yebra, Stephanie G Yelenik, Timothy J Curran","doi":"10.1002/ajb2.70040","DOIUrl":"https://doi.org/10.1002/ajb2.70040","url":null,"abstract":"<p><p>Despite fire being one of the oldest and most important ecological disturbance processes on Earth, many aspects of fire-vegetation feedbacks are poorly understood, limiting their accurate representation in predictive models. Translating plant flammability traits to fire behavior and fire effects on ecosystems has proven a challenge with different disciplines approaching the problem at widely different scales. One approach has been a top-down assessment of ecosystem-level effects of vegetation structural characteristics and plant physiology on fuel properties such as fuel moisture. This approach has had some success, but is often forced to collapse species-specific variation into a small number of functional types and, as a practical necessity, usually focuses on highly plastic traits (e.g., moisture content) that can be modeled across an ecosystem without the need to characterize species-specific characteristics. The other approach grew out of trait-centric comparative ecology and focused on how traits might influence individual plant flammability. However, the degree to which such lab-based flammability trials reflect real species-specific differences maintained during wildland fires has been questioned. We review the history of these approaches, discuss where each has succeeded, and identify areas of research aimed at closing the apparent gap in scale.</p>","PeriodicalId":7691,"journal":{"name":"American Journal of Botany","volume":" ","pages":"e70040"},"PeriodicalIF":2.4,"publicationDate":"2025-05-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144075514","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":"Undescribed species diversity in Brewer's jewelflower illuminates potential mechanisms of diversification associated with serpentine endemism.","authors":"Kyle Christie, N Ivalú Cacho, Jacob Macdonald, Deniss J Martinez, Sharon Y Strauss","doi":"10.1002/ajb2.70037","DOIUrl":"https://doi.org/10.1002/ajb2.70037","url":null,"abstract":"<p><strong>Premise: </strong>Documenting species-level diversity is a fundamental goal of biology, yet undescribed species remain hidden even in well-studied groups. Inaccurate delimitation of species boundaries can limit our understanding of ecological and evolutionary processes and patterns of biodiversity and may further impede conservation and management efforts.</p><p><strong>Methods: </strong>In an integrative approach, we combined techniques from speciation biology, molecular phylogenetics, and geometric morphometrics to assess diversity in the Californian serpentine endemic Streptanthus breweri (Brewer's jewelflower). We assessed reproductive isolation resulting from flowering time differences, mating system differences, and interfertility among four distinct geographic clusters of S. breweri that span the geographic range of the species. We generated a gene tree based on the ribosomal DNA ITS, a diagnostic species-level marker for this clade of jewelflowers, and quantified leaf morphology in plants grown in a greenhouse common garden.</p><p><strong>Results: </strong>Four geographic clusters of S. breweri in northern California represent not a single species, but instead a species complex of at least three putative species. Independent data associated with Biological, Phylogenetic, and Morphological species concepts support these conclusions.</p><p><strong>Conclusions: </strong>This work illustrates that latent biodiversity may be concealed even in well-studied groups and underscores the contribution of edaphic endemism generally, and serpentine endemism specifically, to California's rich plant biodiversity. The existence of unrecognized species diversity within the S. breweri species complex highlights multiple factors including (1) the spatial context of geologic discontinuities, (2) a selfing mating system, and (3) differential selection pressures across discontinuous specialized habitats as potential drivers of evolutionary divergence on serpentine.</p>","PeriodicalId":7691,"journal":{"name":"American Journal of Botany","volume":" ","pages":"e70037"},"PeriodicalIF":2.4,"publicationDate":"2025-05-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144075519","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":"Citizen science records are fuelling exciting discoveries of new plant species.","authors":"Thomas Mesaglio, Hervé Sauquet, William K Cornwell","doi":"10.1002/ajb2.70048","DOIUrl":"https://doi.org/10.1002/ajb2.70048","url":null,"abstract":"","PeriodicalId":7691,"journal":{"name":"American Journal of Botany","volume":" ","pages":"e70048"},"PeriodicalIF":2.4,"publicationDate":"2025-05-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144075512","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":"Morphological knowledge in plant ecology and why it matters.","authors":"Jitka Klimešová, Timothy Harris, Tomáš Herben","doi":"10.1002/ajb2.70043","DOIUrl":"https://doi.org/10.1002/ajb2.70043","url":null,"abstract":"","PeriodicalId":7691,"journal":{"name":"American Journal of Botany","volume":" ","pages":"e70043"},"PeriodicalIF":2.4,"publicationDate":"2025-05-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144075516","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":"Natural autopolyploids: Understanding their formation and establishment.","authors":"Patrik Mráz, Barbora Šingliarová","doi":"10.1002/ajb2.70047","DOIUrl":"https://doi.org/10.1002/ajb2.70047","url":null,"abstract":"","PeriodicalId":7691,"journal":{"name":"American Journal of Botany","volume":" ","pages":"e70047"},"PeriodicalIF":2.4,"publicationDate":"2025-05-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","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":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Functional trait responses of invasive Ludwigia species to contrasting hydrological conditions.","authors":"Rebecca E Drenovsky, Rebecca Reicholf, Caryn J Futrell, Blanca Gallego-Tévar, Brenda J Grewell","doi":"10.1002/ajb2.70038","DOIUrl":"https://doi.org/10.1002/ajb2.70038","url":null,"abstract":"<p><strong>Premise: </strong>Hydrological regime influences wetland plant species distribution and performance. Global warming and extreme weather events are magnifying flooding patterns, and understanding how invasive taxa respond across life stages (establishment vs. established phase) is important for predicting and managing their colonization and spread. Our objective was to measure flood trait responses at contrasting life stages in closely related congeners (Ludwigia peploides, diploid; L. hexapetala, decaploid; Onagraceae) differing in their invasiveness in the field.</p><p><strong>Methods: </strong>In the field, we assessed phenological responses to seasonal hydrological changes, and in mesocosms, we assessed flood stress responses of establishing shoot fragments under deep-flooded, shallow-flooded, and gradual drawdown hydrological treatments.</p><p><strong>Results: </strong>Counter to expectations, establishing L. peploides expressed more flood tolerance traits in mesocosms than L. hexapetala. For example, L. peploides had greater total leaf area and aerenchyma production than L. hexapetala, supporting its growth under flooding, whereas L. hexapetala expressed more flood escape traits (higher shoot elongation rates, trend for longer shoot internode length). Although L. hexapetala expressed some traits associated with drought tolerance, these trends were not significant. In the field, longer-established plants had a reversed pattern for flood escape versus tolerance traits. Ludwigia peploides rapidly shifted to sexual reproduction as soils began to dry, whereas L. hexaetala flowered regardless of soil moisture availability.</p><p><strong>Conclusions: </strong>These contrasting patterns of flood tolerance versus escape traits demonstrate that invasive Ludwigia congeners have differing strategies to counter physiological stress induced by flooding and emphasize the importance of life stage in response to environmental variation.</p>","PeriodicalId":7691,"journal":{"name":"American Journal of Botany","volume":" ","pages":"e70038"},"PeriodicalIF":2.4,"publicationDate":"2025-05-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143966512","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":"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, David J Cantrill, Peter Crane, Romain Garrouste, Porter P Lowry, Pierre Maurizot, Jérôme Munzinger, Andrew B Leslie","doi":"10.1002/ajb2.70041","DOIUrl":"https://doi.org/10.1002/ajb2.70041","url":null,"abstract":"<p><strong>Premise: </strong>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><p><strong>Methods: </strong>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><p><strong>Results: </strong>Fossil leaves contain cellular-level details of leaf morphology and epidermis anatomy consistent with the conifer family Podocarpaceae, in particular the extant genus Dacrycarpus. 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: Dacrycarpoides.</p><p><strong>Conclusions: </strong>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>","PeriodicalId":7691,"journal":{"name":"American Journal of Botany","volume":" ","pages":"e70041"},"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, Sybil G Gotsch, Matthew A Vadeboncoeur, Daniel B Metcalfe, David C Bartholomew, Aline B Horwath, Blanca Espinoza, Darcy Galiano, Heidi Asbjornsen","doi":"10.1002/ajb2.70042","DOIUrl":"https://doi.org/10.1002/ajb2.70042","url":null,"abstract":"<p><strong>Premise: </strong>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><p><strong>Methods: </strong>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><p><strong>Key results: </strong>We found that across all species combined, fog reduction led to a decrease in stomatal length (SL) and foliar water uptake (FWU) capacity. Disterigma 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 (π_o) indicating that two studied fern species in the Elaphoglossum genus (Dryopteridaceae) may tolerate low water potentials.</p><p><strong>Conclusion: </strong>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>","PeriodicalId":7691,"journal":{"name":"American Journal of Botany","volume":" ","pages":"e70042"},"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, Peter Wilf, Antonino Briguglio, László Kocsis, Michael P Donovan, Xiaoyu Zou, J W Ferry Slik","doi":"10.1002/ajb2.70036","DOIUrl":"https://doi.org/10.1002/ajb2.70036","url":null,"abstract":"<p><strong>Premise: </strong>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 Dryobalanops 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><p><strong>Methods: </strong>We compared the leaf cuticles and architecture of these fossil leaves with the seven living Dryobalanops species.</p><p><strong>Results: </strong>The cuticular features shared between the fossils and extant Dryobalanops, including the presence of giant stomata on veins, confirm their generic placement. The leaf characters are identical to those of D. rappa, an IUCN red-listed Endangered, northern Borneo endemic. The D. rappa monodominance at the fossil site, along with Dipterocarpus spp. leaf fossils, indicates a dipterocarp-dominated forest near the mangrove-swamp depocenter, most likely in an adjacent peatland.</p><p><strong>Conclusions: </strong>The Dryobalanops rappa 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>","PeriodicalId":7691,"journal":{"name":"American Journal of Botany","volume":" ","pages":"e70036"},"PeriodicalIF":2.4,"publicationDate":"2025-05-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","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":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}