American Journal of Botany最新文献

{"title":"From the Shenzhen Code to the Madrid Code: New rules and recommendations for naming algae, fungi, and plants","authors":"Nicholas J. Turland","doi":"10.1002/ajb2.70026","DOIUrl":"10.1002/ajb2.70026","url":null,"abstract":"<div>\u0000 \u0000 \u0000 <section>\u0000 \u0000 <h3> Premise</h3>\u0000 \u0000 <p>A universally understood, precise, and stable system of naming organisms is essential for effective scientific communication. The <i>International Code of Nomenclature for algae, fungi, and plants</i>, of which the most recently published edition is the <i>Shenzhen Code</i> of 2018, provides this system for algae, fungi, and plants. This <i>Code</i> is regularly revised at an International Botanical Congress (IBC), usually held every 6 years, most recently in Madrid, Spain, in July 2024. The Madrid IBC amended the <i>Shenzhen Code</i>, and the changes took effect on 27 July 2024, when the closing plenary session of the IBC approved the decisions of the Nomenclature Section. It is important to promptly publicize this information because the new edition of the <i>Code</i> resulting from these amendments, the <i>Madrid Code</i>, will not be published until mid-2025.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Methods</h3>\u0000 \u0000 <p>I selected some of the more important of the 433 published proposals to amend the <i>Code</i> at the Madrid IBC. I sourced details from the proposals themselves, the “Synopsis of Proposals” and the “Report of Congress Action” (all published in the journal <i>Taxon</i>) and from the records made during the Nomenclature Section in Madrid.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Results</h3>\u0000 \u0000 <p>For a general botanical audience, I discuss the background, outcomes (acceptance or rejection), and consequences of acceptance of the proposals.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Conclusions</h3>\u0000 \u0000 <p>This commentary supplements the technical reports already published and provides an overview of some of the new or amended rules and recommendations in the upcoming <i>Madrid Code</i>.</p>\u0000 </section>\u0000 </div>","PeriodicalId":7691,"journal":{"name":"American Journal of Botany","volume":"112 4","pages":""},"PeriodicalIF":2.4,"publicationDate":"2025-04-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/ajb2.70026","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143787521","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":"Interaction network of Phoradendron and its hosts and the influence of phylogenetic, geographic, and environmental factors on the probability of interaction","authors":"Eurídice Tinoco-Domínguez,&nbsp;Guadalupe Amancio,&nbsp;Ángel L. Robles-Fernández,&nbsp;Andrés Lira-Noriega","doi":"10.1002/ajb2.70025","DOIUrl":"10.1002/ajb2.70025","url":null,"abstract":"<div>\u0000 \u0000 \u0000 <section>\u0000 \u0000 <h3> Premise</h3>\u0000 \u0000 <p><i>Phoradendron</i> (Santalaceae) mistletoes consist of approximately 230 hemiparasitic species across the Americas. As obligate hemiparasites, their distribution depends partly on the distribution of their hosts, reflecting a shared evolutionary history.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Methods</h3>\u0000 \u0000 <p>Using network analysis and statistical modeling, we explored the bipartite host–parasite network, focusing on species organization and the likelihood of hosts sharing a <i>Phoradendron</i> species based on phylogenetic, geographic, and environmental factors.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Results</h3>\u0000 \u0000 <p>Our analysis suggests a modular and highly specialized interaction network influenced by evolutionary and biogeographical factors. <i>Phoradendron</i> parasitized hosts in genera from various families and orders, primarily Fabales, Malpighiales, and Sapindales. The network exhibited modularity and connectivity, with hosts sharing a higher likelihood of being parasitized by the same <i>Phoradendron</i> species when they were closer in phylogeny, geography, and environment, while phylogenetic distance emerged as the most relevant determinant. Moreover, we established a link between <i>Phoradendron</i> within-module connectivity and host phylogenetic distance, providing an evolutionary framework for understanding ecological patterns and network connectance.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Conclusions</h3>\u0000 \u0000 <p>The network of <i>Phoradendron</i>–host interactions is highly specialized, and the structure of this network depends mainly on the phylogenetic distance of the hosts.</p>\u0000 </section>\u0000 </div>","PeriodicalId":7691,"journal":{"name":"American Journal of Botany","volume":"112 4","pages":""},"PeriodicalIF":2.4,"publicationDate":"2025-04-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143771049","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":"Phylogenomics, historical biogeography, and diversification of leaf traits in the Malagasy-endemic genus Uncarina (Pedaliaceae)","authors":"Jeffrey P. Rose,&nbsp;John G. Zaborsky,&nbsp;Nisa Karimi,&nbsp;Kenneth J. Sytsma","doi":"10.1002/ajb2.70028","DOIUrl":"10.1002/ajb2.70028","url":null,"abstract":"<div>\u0000 \u0000 \u0000 <section>\u0000 \u0000 <h3> Premise</h3>\u0000 \u0000 <p><i>Uncarina</i> contains 14 species of woody plants endemic to Madagascar. Its occurrence across dryland biomes on the island make it an interesting system to study the diversification of the flora.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Methods</h3>\u0000 \u0000 <p>Using samples of all species and 512 nuclear loci, we reconstructed phylogenetic trees to examine species relationships and assess their monophyly. We also studied the historical biogeography of the genus and combined leaf trait data derived from SEM photography of trichomes and geometric morphometric analysis of leaf shape to better understand its diversification across dryland biomes.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Results</h3>\u0000 \u0000 <p><i>Uncarina</i> is monophyletic, and major clades showed a clear biogeographical signal. Leaf traits also corroborated relationships among major clades. Although most species are monophyletic, at least one cryptic species exists. <i>Uncarina</i>, like many arid-adapted plant lineages in Madagascar originated in the Miocene or Pleistocene. Geographic movement has been primarily along a south–north axis, with river basins apparently acting as barriers to gene flow. The evolution of leaf traits corroborated movement from the spiny thicket to the dry forest biome.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Conclusions</h3>\u0000 \u0000 <p>As with Malagasy lemurs and other animals, riverine barriers may have been involved in the diversification of <i>Uncarina</i> and may apply more broadly to epizoochorous angiosperms of Madagascar. Leaf traits suggest either a loss of adaptations to extremely arid, high irradiance environments or a release from herbivores. As is likely needed in other Malagasy lineages, more thorough population-level sampling and specimen collecting is needed to fully understand the taxonomic and morphological diversity in the genus.</p>\u0000 </section>\u0000 </div>","PeriodicalId":7691,"journal":{"name":"American Journal of Botany","volume":"112 4","pages":""},"PeriodicalIF":2.4,"publicationDate":"2025-04-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/ajb2.70028","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143771050","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":"Extreme cold reduces seedling establishment, but native species appear more susceptible than non-native species","authors":"Peter W. Guiden,&nbsp;Barbara Roca","doi":"10.1002/ajb2.70023","DOIUrl":"10.1002/ajb2.70023","url":null,"abstract":"<div>\u0000 \u0000 \u0000 <section>\u0000 \u0000 <h3> Premise</h3>\u0000 \u0000 <p>Extreme-cold events are increasingly recognized as one of the most damaging aspects of climate change in northern temperate ecosystems. However, little data exists describing how native and non-native species may respond to these extreme events, especially as seeds. We used a greenhouse experiment to test how extreme cold reduces seedling establishment in seven woody species common to eastern North America. We hypothesized that the effects of extreme cold depend on provenance (native vs. non-native) and chilling period.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Methods</h3>\u0000 \u0000 <p>Following chilling periods of 80, 100, or 120 days, seeds experienced a false-spring with temperatures at 15°C for one week; half of the seeds in each dormancy treatment group experienced a two-day extreme-cold event (–13.9°C) while the rest returned to mild winter temperatures (4°C).</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Results</h3>\u0000 \u0000 <p>Extreme-cold events universally decreased seedling establishment, but non-native species had four times greater survival in the extreme-cold treatment (mean ± s.e.: 0.108 ± 0.024) compared to native species (0.024 ± 0.018). Furthermore, native seeds were increasingly susceptible to extreme-cold damage following a 120-day chilling period, whereas non-native seeds were able to resist extreme cold equally following all chilling periods.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Conclusions</h3>\u0000 \u0000 <p>These results suggest that in eastern North America, cold resistance could be a trait facilitating the success of non-native species. The introduction of non-native species may synergize with climate change to alter community composition, which could have important consequences for forest biodiversity in the Anthropocene.</p>\u0000 </section>\u0000 </div>","PeriodicalId":7691,"journal":{"name":"American Journal of Botany","volume":"112 4","pages":""},"PeriodicalIF":2.4,"publicationDate":"2025-03-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143717884","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":"Viewing the ecological consequences of synthetic auxin herbicides from the ground up","authors":"Veronica Iriart,&nbsp;Tia-Lynn Ashman","doi":"10.1002/ajb2.70024","DOIUrl":"10.1002/ajb2.70024","url":null,"abstract":"&lt;p&gt;Herbicides, although often less emphasized than other pesticides like insecticides, pose a significant risk to wild plant communities (Iriart et al., &lt;span&gt;2021&lt;/span&gt;). Synthetic auxin or “auxinic” herbicides such as 2,4-D and dicamba have recently surged in use due to the commercialization of transgenic crops tolerant to auxinic herbicides (Johnson et al., &lt;span&gt;2023&lt;/span&gt;). These chemicals act by mimicking the natural phytohormone auxin (indole-3-acetic acid [IAA]) to cause abnormal growth and death in target weeds, but are also linked to a long-standing issue known as herbicide drift, i.e., when herbicide particles (i.e., ~0.1–5% of application rate) move through the atmosphere and away from target sites, that can impair nontarget plants (Johnson et al., &lt;span&gt;2023&lt;/span&gt;). More insidious, however, are the potential consequences beneath the soil. For example, in the symbiotic mutualism between leguminous plants (legumes) and nitrogen-fixing soil rhizobial bacteria (hereafter rhizobia), plants exchange carbohydrates for rhizobia-fixed nitrogen (N) from the atmosphere, contributing to the N cycle and soil fertility (Ahemad and Khan, &lt;span&gt;2013&lt;/span&gt;). However, studies have shown that auxinic herbicides can be especially damaging to legumes (Blanchett et al., &lt;span&gt;2015&lt;/span&gt;; Jones et al., &lt;span&gt;2019&lt;/span&gt;; Iriart et al., &lt;span&gt;2022&lt;/span&gt;), and under certain conditions can directly reduce the growth of free-living rhizobia (Fabra et al., &lt;span&gt;1997&lt;/span&gt;). Moreover, because legume–rhizobia interactions are partly regulated by IAA, symbiotic interactions can be disrupted by synthetic auxins (Ahemad and Khan, &lt;span&gt;2013&lt;/span&gt;; Iriart et al., &lt;span&gt;2024&lt;/span&gt;; Iriart et al., unpublished manuscript)—yet, studies on the effects of auxinic herbicide drift on legume–rhizobia interactions or other phytohormone-regulated symbioses such as the mutualism between a plant and arbuscular mycorrhizal fungi (AMF), are limited. Here, we identify the major gaps in our knowledge of the impacts of low-dose exposures to auxinic herbicides on plant–microbe symbioses in the rhizosphere and the pathways and mechanisms that mediate them. We highlight research areas that will shed light on this issue, including some of the overlooked broader ecological consequences, potentially contributing to the footprint of disruption caused by auxinic herbicides.&lt;/p&gt;&lt;p&gt;Research has largely focused on the direct effects of synthetic auxin exposures on plants and some plant-associated rhizospheric microbes (i.e., Paths 1 and 2, Figure 1; Iriart et al., &lt;span&gt;2021&lt;/span&gt;; Ruuskanen et al., &lt;span&gt;2023&lt;/span&gt;), but rarely on the ecological interactions between them which could likewise be affected via indirect pathways (i.e., Path 3 and 4, Figure 1). For instance, genotypes of plants or of microbes can differ in their physiological or biochemical responses to synthetic auxins (Ahemad and Khan, &lt;span&gt;2013&lt;/span&gt;; Hage-Ahmed et al., &lt;span&gt;2019&lt;/span&gt;; Iriart et al., &lt;span&gt;2022&lt;/","PeriodicalId":7691,"journal":{"name":"American Journal of Botany","volume":"112 4","pages":""},"PeriodicalIF":2.4,"publicationDate":"2025-03-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/ajb2.70024","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143707918","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":"Phylogenomics and biogeography of Guadua: Insights into a neotropical woody bamboo genus","authors":"Eduardo Ruiz-Sanchez,&nbsp;Carlos Maya-Lastra,&nbsp;María de la Luz Perez-Garcia,&nbsp;Miguel Angel Garcia-Martinez","doi":"10.1002/ajb2.70022","DOIUrl":"10.1002/ajb2.70022","url":null,"abstract":"<div>\u0000 \u0000 \u0000 <section>\u0000 \u0000 <h3> Premise</h3>\u0000 \u0000 <p>The genus <i>Guadua</i> includes some of the largest bamboo species in the neotropics, with certain species of significant economic importance and used since pre-Hispanic times to build houses using the traditional bajareque technique. <i>Guadua</i> species are distributed from Mexico to South America. The potential monophyly of this genus has been suggested based on plastid markers and limited sampling. Here we included more species and nuclear data to study the morphological classification of <i>Guadua</i> and to reconstruct its ancestral area distribution.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Methods</h3>\u0000 \u0000 <p>Samples were collected for 16 <i>Guadua</i> taxa (13 species) to use nuclear single nucleotide polymorphisms (SNPs) derived from restriction-site associated DNA sequencing (RADSeq) data to construct a phylogenetic hypothesis using maximum likelihood and coalescent methods. We estimated divergence times using the RelTime method and reconstructed ancestral geographic areas using S-DEC analysis.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Results</h3>\u0000 \u0000 <p>The SNP data supported the monophyly of the genus <i>Guadua</i> and the existence of two distinct clades, Amplexifolia and Angustifolia. The origin of <i>Guadua</i> was estimated as approximately 10.47 million years ago in Mesoamerica. The biogeographic distribution of <i>Guadua</i> can likely be explained by a combination of dispersal and vicariant events.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Conclusions</h3>\u0000 \u0000 <p>Our study sheds new light on the phylogenetic relationships within <i>Guadua</i> and on its evolutionary history and biogeography, enhancing our understanding of its diversification and distribution across various biogeographic regions.</p>\u0000 </section>\u0000 </div>","PeriodicalId":7691,"journal":{"name":"American Journal of Botany","volume":"112 4","pages":""},"PeriodicalIF":2.4,"publicationDate":"2025-03-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143690504","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":"Global patterns in community-scale leaf mass per area distributions of extant woody non-monocot angiosperms and their utility in the fossil record","authors":"Alexander J. Lowe,&nbsp;Dana L. Royer,&nbsp;Daniel J. Wieczynski,&nbsp;Matthew J. Butrim,&nbsp;Tammo Reichgelt,&nbsp;Lauren Azevedo-Schmidt,&nbsp;Daniel J. Peppe,&nbsp;Brian J. Enquist,&nbsp;Andrew J. Kerkoff,&nbsp;Sean T. Michaletz,&nbsp;Caroline A. E. Strömberg","doi":"10.1002/ajb2.70019","DOIUrl":"10.1002/ajb2.70019","url":null,"abstract":"<div>\u0000 \u0000 \u0000 <section>\u0000 \u0000 <h3> Premise</h3>\u0000 \u0000 <p>Leaf mass per area (LMA) links leaf economic strategies, community assembly, and climate and can be reconstructed from woody non-monocot angiosperm (WNMA) fossils using the petiole metric (PM; petiole width²/leaf area). Reliable interpretation of LMA reconstructed from the fossil record is limited by an incomplete understanding of how PM and LMA are correlated at the community scale and what climatic parameters drive variation of both measured and reconstructed LMA of WNMAs globally.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Methods</h3>\u0000 \u0000 <p>A modern, global, community-scale data set of in situ WNMA LMA and PM was compiled to test leading hypotheses for environmental drivers of LMA and quantify LMA-PM relationships. Correlations among PM, LMA, climate (Köppen types and continuous data), and leaf habit were assessed and quantified using several uni- and multivariate methods.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Results</h3>\u0000 \u0000 <p>Community mean LMA increased under warmer and less seasonal temperatures. Drought-prone communities had the highest LMA variance, likely due to disparity between riparian and non-riparian microhabitats. PM and LMA were correlated for community mean and variance, and their correlations with climate were similar. These patterns indicate that climatic correlatives of modern LMA can inform relative trends in reconstructed fossil LMA. In contrast, matching “absolute” LMA distributions between fossil and modern sites does not allow reliable inference of analogous climate types.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Conclusions</h3>\u0000 \u0000 <p>This study furthers our understanding of processes influencing the assembly of WNMA leaf economic strategies in plant communities, highlighting the importance of temperature seasonality and habitat heterogeneity. We also provide a method to reconstruct, and refine the framework to interpret, community-scale LMA in the fossil record.</p>\u0000 </section>\u0000 </div>","PeriodicalId":7691,"journal":{"name":"American Journal of Botany","volume":"112 4","pages":""},"PeriodicalIF":2.4,"publicationDate":"2025-03-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143690539","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":"Soil biome variation of Lupinus nipomensis in wet-cool vs. dry-warm microhabitats and greenhouse","authors":"Peter T. Nguyen,&nbsp;Justin C. Luong,&nbsp;Van Wishingrad,&nbsp;Lisa Stratton,&nbsp;Michael E. Loik,&nbsp;Rachel S. Meyer","doi":"10.1002/ajb2.70020","DOIUrl":"10.1002/ajb2.70020","url":null,"abstract":"<div>\u0000 \u0000 \u0000 <section>\u0000 \u0000 <h3> Premise</h3>\u0000 \u0000 <p>Environmental DNA (eDNA) can be used to determine the composition of the soil biome community, revealing beneficial and antagonistic microbes and invertebrates associated with plants. eDNA analyses can complement traditional soil community studies, offering more comprehensive information for conservation practitioners. Studies are also needed to examine differences between field and greenhouse soil biomes because greenhouse-grown plants are often transplanted in the field during restoration efforts.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Methods</h3>\u0000 \u0000 <p>We used eDNA multilocus metabarcoding to test how the soil biome of the federally and state-endangered species, <i>Lupinus nipomensis</i>, differed between wet-cool and dry-warm microhabitats. At Arroyo Grande, California, 20 experimental plots were sampled, representing a factorial combination of wet-cool vs. dry-warm soil and plots that did or did not contain <i>L. nipomensis</i>. In a simultaneous greenhouse study, <i>L. nipomensis</i> was grown in drought and well-watered conditions to compare soil communities between field and greenhouse.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Results</h3>\u0000 \u0000 <p>A diversity of carbon-cycling microorganisms but not nitrogen-fixers were overrepresented in the field, and nitrogen-fixing bacteria were overrepresented in some greenhouse treatments. The microbial communities in the field soils were more species-rich and evenly distributed than in greenhouse communities. In field plots, microhabitats significantly influenced community beta diversity, while field plots with or without <i>L. nipomensis</i> had no significant differences in alpha or beta diversity.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Conclusions</h3>\u0000 \u0000 <p>Our study shows the utility of eDNA soil analysis in elucidating soil biome community differences for conservation and highlights the influence of plant microhabitats on soil microbe associations.</p>\u0000 </section>\u0000 </div>","PeriodicalId":7691,"journal":{"name":"American Journal of Botany","volume":"112 4","pages":""},"PeriodicalIF":2.4,"publicationDate":"2025-03-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/ajb2.70020","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143668894","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":"Extreme fire severity interacts with seed traits to moderate post-fire species assemblages.","authors":"Michi Sano, Ryan Tangney, Alexandria Thomsen, Mark K J Ooi","doi":"10.1002/ajb2.70012","DOIUrl":"https://doi.org/10.1002/ajb2.70012","url":null,"abstract":"<p><strong>Premise: </strong>Climate change is globally pushing fire regimes to new extremes, with unprecedented large-scale severe fires. Persistent soil seed banks are a key mechanism for plant species recovery after fires, but extreme fire severity may generate soil temperatures beyond thresholds seeds are adapted to. Seeds are protected from lethal temperatures through soil burial, with temperatures decreasing with increasing depth. However, smaller seeds, due to their lower mass and corresponding energy stores, are restricted to emerging from shallower depths compared to the depths for larger seeds. We examined recruitment patterns across a landscape-scale gradient of fire severity to determine whether seed mass and dormancy class mediate shifts in community assemblages.</p><p><strong>Methods: </strong>We surveyed 25 sites in wet sclerophyll forests in southeastern Australia that had been burnt at either moderate, high, or extreme severity during the 2019-2020 Black Summer Fires. We measured abundance and calculated density of seedlings from 27 common native shrub species.</p><p><strong>Results: </strong>Extreme severity fires caused significant declines in seedling recruitment. Recruitment patterns differed between dormancy class, with steeper declines in seedling emergence for species with physiologically dormant (PD) than for physically dormant (PY) seeds at extreme fire severity. Relative emergence proportions differed between fire severity and seed size groups for both PY and PD species.</p><p><strong>Conclusions: </strong>Large-scale extreme severity fires favor larger-seeded species, shifting community composition. Future recurrent extreme fire events could therefore place smaller-seeded species at risk. Seed mass, dormancy class, and other seed traits should be considered when exploring post-fire responses, to better predict impacts on plant species.</p>","PeriodicalId":7691,"journal":{"name":"American Journal of Botany","volume":" ","pages":"e70012"},"PeriodicalIF":2.4,"publicationDate":"2025-03-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143646777","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":"A phylogenomic investigation into the biogeography of the Mexico–eastern U.S. disjunction in Symphyotrichum","authors":"Sushil Dahal,&nbsp;Carolina M. Siniscalchi,&nbsp;Ryan A. Folk","doi":"10.1002/ajb2.70021","DOIUrl":"10.1002/ajb2.70021","url":null,"abstract":"<div>\u0000 \u0000 \u0000 <section>\u0000 \u0000 <h3> Premise</h3>\u0000 \u0000 <p>Biotic disjunctions have attracted scientific attention for the past 200 years. Despite being represented in many familiar plants (such as bald cypress, flowering dogwood, sweetgum, partridgeberry, etc.), the eastern North American (ENA)–Mexican (M) disjunction remains poorly understood. Major outstanding questions include the divergence times of taxa exhibiting the disjunction and environmental/geological processes that may underlie the disjunction. <i>Symphyotrichum</i> Nees (Asteraceae), one of the most diverse genera in the eastern USA, displays several examples of disjunct ENA–M taxa.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Methods</h3>\u0000 \u0000 <p>We generated target capture data using the Angiosperms353 baitset and generated the first well-sampled phylogenomic hypothesis for <i>Symphyotrichum</i> and its close relatives. Focusing on <i>S</i>. subgenus <i>Virgulus</i>, we used MCMC_TREE to perform divergence time estimation and the R package BioGeoBEARS to infer ancestral regions and biogeographic transitions between North America and Mexico. Finally, we used the ancestral niche reconstruction method Utremi to test for a role of historical aridification in generating the disjunction.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Results</h3>\u0000 \u0000 <p>Our molecular data suggest a recent radiation of <i>Symphyotrichum</i> at the Plio-Pleistocene boundary (~2.5 mya), with early connections to Mexico in ancestral lineages that closed off shortly after and were followed by vicariance across this region. Except for some present-day broadly distributed species, there is a complete lack of movement between ENA and M after ~0.5 mya.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Conclusions</h3>\u0000 \u0000 <p>A reconstructed disjunct distribution of suitable habitat in Pleistocene climatic models corroborates results from biogeographic modeling and confirms glacial cycles are more likely to be associated with the breakup of ENA–M biogeographic connections.</p>\u0000 </section>\u0000 </div>","PeriodicalId":7691,"journal":{"name":"American Journal of Botany","volume":"112 3","pages":""},"PeriodicalIF":2.4,"publicationDate":"2025-03-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143646776","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}