American Journal of Botany最新文献

{"title":"Moisture loss rate drives the species-specific sensitivity of shoot flammability to water status.","authors":"Azaj Mahmud, Nursema Aktepe, Dylan W Schwilk","doi":"10.1002/ajb2.70052","DOIUrl":"https://doi.org/10.1002/ajb2.70052","url":null,"abstract":"<p><strong>Premise: </strong>The importance of live fuel moisture content (LFMC), a critical determinant of plant flammability, to crown-fire behavior is subject to debate; physiological mechanisms underlying LFMC dynamics need to be incorporated into fire behavior models to better understand wildfire and vegetation-fire feedback. Here we aimed to determine the relationships among water potential, LFMC, and flammability, and how ecophysiological traits related to LFMC dynamics influence the relationship between plant water status (measured as water potential and LFMC) and flammability across nine native shrubs in Texas.</p><p><strong>Methods: </strong>We assessed ignitability and heat release on excised shoots across a wide range of water potential and measured leaf and shoot ecophysiological traits to answer two questions: (1) What are the relationships between water potential, LFMC, and flammability, and do they vary across species? (2) If the relationship between water status and flammability varies across species, which plant traits predict the strength of this relationship?</p><p><strong>Results: </strong>LFMC covaried with water potential, but the shape of this relationship varied across species. The effect of water status on ignitability and heat release varied significantly across species, and the shoot moisture loss rate was lower in species in which ignitability and heat release was sensitive to water status.</p><p><strong>Conclusions: </strong>This study suggests that the LFMC-flammability relationship across species depends on plant traits that influence water loss during fire weather conditions, and incorporating plant traits shaping LFMC dynamics into fire behavior models will improve our understanding of drought-vegetation-fire feedback.</p>","PeriodicalId":7691,"journal":{"name":"American Journal of Botany","volume":" ","pages":"e70052"},"PeriodicalIF":2.4,"publicationDate":"2025-05-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144135887","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":"Phylogenetic relationships and the identification of allopolyploidy in circumpolar Silene sect. Physolychnis","authors":"Anne-Sophie Quatela,&nbsp;Patrik Cangren,&nbsp;Paola de Lima Ferreira,&nbsp;Yannick Woudstra,&nbsp;Andreas Zsoldos-Skahjem,&nbsp;Christine D. Bacon,&nbsp;Hugo J. de Boer,&nbsp;Bengt Oxelman","doi":"10.1002/ajb2.70051","DOIUrl":"10.1002/ajb2.70051","url":null,"abstract":"<div>\u0000 \u0000 \u0000 <section>\u0000 \u0000 <h3> Premise</h3>\u0000 \u0000 <p>Species complexes are groups of closely related species with ambiguous delimitation, often composed of recently diverged lineages. Polyploidization and uniparental reproduction (i.e., selfing and apomixis) can play important roles in the origin of species complexes. These complexes pose challenges for species-based scientific questions, such as the estimation of species richness or conservation prioritization.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Methods</h3>\u0000 \u0000 <p>We determined the potential of resolving taxonomically complex groups using target enrichment in the circumpolar <i>Silene uralensis</i> complex (Caryophyllaceae). We proposed a metric using genetic distances between phased alleles to distinguish diploids from allopolyploids.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Results</h3>\u0000 \u0000 <p>Our results identified geographic structure of populations, with the northern American and Greenlandic samples having a common ancestor. We found little phylogenetic support for the most recent taxonomic treatment of the <i>Silene uralensis</i> complex.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Conclusions</h3>\u0000 \u0000 <p>The study highlights the use of target enrichment in testing taxonomic hypotheses in diploids and the challenges of studying recently diverged lineages.</p>\u0000 </section>\u0000 </div>","PeriodicalId":7691,"journal":{"name":"American Journal of Botany","volume":"112 6","pages":""},"PeriodicalIF":2.4,"publicationDate":"2025-05-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/ajb2.70051","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144126612","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":"Mast years increase wind pollination and reduce seed predation in sugar maple (Acer saccharum)","authors":"Elizabeth E. Crone,&nbsp;Joshua M. Rapp","doi":"10.1002/ajb2.70046","DOIUrl":"10.1002/ajb2.70046","url":null,"abstract":"<div>\u0000 \u0000 \u0000 <section>\u0000 \u0000 <h3> Premise</h3>\u0000 \u0000 <p>In general, mast seeding (intermittent and synchronous seed production) increases plant fitness through economies of scale in which reproduction is more successful in high-seed years. These benefits have been most studied in wind-pollinated trees. Increased pollination success in mast years has been considered more important for wind- than animal-pollinated species, although this assumption is rarely explicitly tested.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Methods</h3>\u0000 \u0000 <p>In this study, we documented patterns of reproduction in <i>Acer saccharum</i> in central Massachusetts, United States over 15 years. We used pollinator exclusion experiments conducted over 6 years to test whether high-flowering and high-seed years lead to more successful wind pollination, more successful insect pollination, and lower predispersal seed predation. <i>Acer saccharum</i> is both insect- and wind-pollinated, allowing us to compare the strength of these two benefits.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Results</h3>\u0000 \u0000 <p>At our study site, <i>A. saccharum</i> was strongly alternate-bearing, meaning that trees alternated synchronously between high-flowering, high-seed years and low-flowering, low-seed years. Wind pollination was higher and predispersal seed predation lower in mast years, but insect pollination was similar in all years.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Conclusions</h3>\u0000 \u0000 <p>We showed geographic variation in patterns of <i>A. saccharum</i> seed production in comparison to past research. We also showed that synchronous flowering increases wind pollination more than insect pollination and that it decreases seed predation. <i>Acer saccharum</i> is dichogamous; protogynous trees were more likely to flower in mast years, and protandrous trees experienced larger benefits from wind-pollination in mast years. These results highlight masting trees as interesting study systems for future research on sex allocation.</p>\u0000 </section>\u0000 </div>","PeriodicalId":7691,"journal":{"name":"American Journal of Botany","volume":"112 6","pages":""},"PeriodicalIF":2.4,"publicationDate":"2025-05-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/ajb2.70046","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144126611","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":"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,&nbsp;N. Ivalú Cacho,&nbsp;Jacob Macdonald,&nbsp;Deniss J. Martinez,&nbsp;Sharon Y. Strauss","doi":"10.1002/ajb2.70037","DOIUrl":"10.1002/ajb2.70037","url":null,"abstract":"<div>\u0000 \u0000 \u0000 <section>\u0000 \u0000 <h3> Premise</h3>\u0000 \u0000 <p>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>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Methods</h3>\u0000 \u0000 <p>In an integrative approach, we combined techniques from speciation biology, molecular phylogenetics, and geometric morphometrics to assess diversity in the Californian serpentine endemic <i>Streptanthus breweri</i> (Brewer's jewelflower). We assessed reproductive isolation resulting from flowering time differences, mating system differences, and interfertility among four distinct geographic clusters of <i>S. breweri</i> 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>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Results</h3>\u0000 \u0000 <p>Four geographic clusters of <i>S. breweri</i> 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>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Conclusions</h3>\u0000 \u0000 <p>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 <i>S. breweri</i> 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>\u0000 </section>\u0000 </div>","PeriodicalId":7691,"journal":{"name":"American Journal of Botany","volume":"112 5","pages":""},"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,&nbsp;Hervé Sauquet,&nbsp;William K. Cornwell","doi":"10.1002/ajb2.70048","DOIUrl":"10.1002/ajb2.70048","url":null,"abstract":"&lt;p&gt;Each year, approximately 2000 to 2500 plant species are described as new to science (Cheek et al., &lt;span&gt;2020&lt;/span&gt;). However, there are still, at a minimum, tens of thousands of undescribed plant species (Heywood, &lt;span&gt;2017&lt;/span&gt;). Many of these have already been collected, with numerous recently named species described from specimens collected and deposited in herbaria decades—or even centuries—ago. Many more undescribed species still reside as vouchers in herbaria, waiting to be examined and recognized as novel, highlighting the immense importance of these institutions for understanding plant diversity globally.&lt;/p&gt;&lt;p&gt;There are also many undescribed species remaining to be discovered in the field. Traditionally, an important “discovery pathway” for these taxa has been formal collecting expeditions conducted by professional botanists. In some cases, the discovery and description of taxonomic novelties is a primary expedition goal (e.g., Bush Blitz in Australia; Preece et al., &lt;span&gt;2015&lt;/span&gt;). However, for many expeditions, species discovery is just one goal competing with others, including the collection of tissue samples for genomics, ecological monitoring, and the possible rediscovery of potentially extinct species. Furthermore, resources and funding dedicated to discovering new species are limited; finding new opportunities for species discovery is therefore essential.&lt;/p&gt;&lt;p&gt;One such opportunity for discovery is via the citizen science platform iNaturalist (www.inaturalist.org; see Mesaglio, &lt;span&gt;2024&lt;/span&gt;), one of the largest sources of contemporary plant occurrence data globally. As of March 2025, over 92 million verifiable records of plants have been uploaded to iNaturalist from around the globe, covering approximately 172,000 identified species submitted by 2.4 million observers. In addition to the hundreds of scientific papers that use iNaturalist data for ecological and conservation studies, at least 12 new plant species have been discovered, and subsequently formally described, since 2022 through records uploaded to iNaturalist. In some cases, these species had already been collected decades ago, but the specimens had been overlooked or identified as an already described species, while in other cases, the iNaturalist observations were the first known records of those species. Excitingly, these species cover a variety of growth habits, taxonomic groups, vegetation communities, and regions (Figure 1) ranging from a shrub in Rutaceae from the thorn forest of Mexico (&lt;i&gt;Megastigma acarrilloi&lt;/i&gt;; León, &lt;span&gt;2024&lt;/span&gt;), to a geophyte in Iridaceae from the fynbos of South Africa (&lt;i&gt;Moraea anastasia&lt;/i&gt;; Manning et al., &lt;span&gt;2025&lt;/span&gt;), to a mycoheterotrophic herb in Thismiaceae from moist riparian forest in Colombia (&lt;i&gt;Thismia paradisiaca&lt;/i&gt;; Guzmán-Guzmán and Plata-Torres, &lt;span&gt;2023&lt;/span&gt;). All of these cases, however, are united by a critically important common denominator: each species was only recognized as novel ","PeriodicalId":7691,"journal":{"name":"American Journal of Botany","volume":"112 6","pages":""},"PeriodicalIF":2.4,"publicationDate":"2025-05-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/ajb2.70048","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":"OA","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,&nbsp;Timothy Harris,&nbsp;Tomáš Herben","doi":"10.1002/ajb2.70043","DOIUrl":"10.1002/ajb2.70043","url":null,"abstract":"&lt;p&gt;Plant form has been used as a surrogate for studying function from the beginning of the field of plant ecology (Warming, &lt;span&gt;1909&lt;/span&gt;) in multiple approaches, including comparative morphology, growth form and life-form classifications, and plant architecture. Nevertheless, with new methods to directly measure functions such as photosynthesis and an increasing focus on large-scale studies and large data sets, a full consideration of morphology (form) may appear old-fashioned. Still, one branch of plant ecology, trait-based ecology, studies how morphology relates to functions.&lt;/p&gt;&lt;p&gt;Indeed, trait-based ecology, a subdiscipline that has been developing for several decades (Westoby, &lt;span&gt;1998&lt;/span&gt;), uses well-defined morphological or anatomical traits as a proxy for function (Box 1). It represents a culmination of efforts to understand plant strategies using morphological characters, which began with the work of von Humboldt (&lt;span&gt;1807&lt;/span&gt;), and continued through numerous classifications of growth or life forms (e.g., Raunkiaer, &lt;span&gt;1907&lt;/span&gt;). Finally, at the end of the 20th century, elaborate morphological classifications were replaced by a few plant traits that were easy to measure and collect data that could be analyzed statistically (Westoby, &lt;span&gt;1998&lt;/span&gt;; Weiher et al., &lt;span&gt;1999&lt;/span&gt;).&lt;/p&gt;&lt;p&gt;The focus on plant functional traits accelerated this discipline by enabling formalized approaches that could be applied over large scales and ecosystems (Díaz et al., &lt;span&gt;2016&lt;/span&gt;). A few of the traits commonly used for this purpose include acquisitive traits of leaves (e.g., leaf thickness, specific leaf area) and the plant's ability to overtop other plants and acquire aboveground resources (plant height) and to disperse and provision progeny (e.g., seed size) (Westoby, &lt;span&gt;1998&lt;/span&gt;). Acquisitive traits of fine roots have also been added to this portfolio (Bergmann et al., &lt;span&gt;2020&lt;/span&gt;). The ease of data collection for these traits according to standard protocols (Perez-Harguindeguy et al., &lt;span&gt;2013&lt;/span&gt;) has resulted in the assembly of trait values in freely accessible databases (e.g., Kattge et al., &lt;span&gt;2020&lt;/span&gt;) and in the widespread use of functional traits in many ecological disciplines (e.g., invasion ecology, restoration ecology; Westoby, &lt;span&gt;2025&lt;/span&gt;), without directly studying the functions of these traits in an ecological context.&lt;/p&gt;&lt;p&gt;After a quarter century of functional ecology research, we can see some consequences of the restricted focus on a few easily measurable traits that make broad comparisons across ecosystems or continents possible, but that are free from the “burden” of dealing with the diversity of whole-plant growth forms. This reductionistic approach, which has facilitated unprecedented, large synthetic studies of plant form and function in response to challenges of resource availability (Díaz et al., &lt;span&gt;2016&lt;/span&gt;; Bergmann et al., &lt;span&gt;2020&lt;/span&gt;), has at the same ","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/ajb2.70043","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":"OA","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,&nbsp;Rebecca Reicholf,&nbsp;Caryn J. Futrell,&nbsp;Blanca Gallego-Tévar,&nbsp;Brenda J. Grewell","doi":"10.1002/ajb2.70038","DOIUrl":"10.1002/ajb2.70038","url":null,"abstract":"<div>\u0000 \u0000 \u0000 <section>\u0000 \u0000 <h3> Premise</h3>\u0000 \u0000 <p>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 (<i>Ludwigia peploides</i>, diploid; <i>L. hexapetala</i>, decaploid; Onagraceae) differing in their invasiveness in the field.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Methods</h3>\u0000 \u0000 <p>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>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Results</h3>\u0000 \u0000 <p>Counter to expectations, establishing <i>L. peploides</i> expressed more flood tolerance traits in mesocosms than <i>L. hexapetala</i>. For example, <i>L. peploides</i> had greater total leaf area and aerenchyma production than <i>L. hexapetala</i>, supporting its growth under flooding, whereas <i>L. hexapetala</i> expressed more flood escape traits (higher shoot elongation rates, trend for longer shoot internode length). Although <i>L. hexapetala</i> 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. <i>Ludwigia peploides</i> rapidly shifted to sexual reproduction as soils began to dry, whereas <i>L. hexaetala</i> flowered regardless of soil moisture availability.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Conclusions</h3>\u0000 \u0000 <p>These contrasting patterns of flood tolerance versus escape traits demonstrate that invasive <i>Ludwigia</i> congeners have differing strategies to counter physiological stress induced by flooding and emphasize the importance of life stage in response to environmental variation.</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":"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":"Natural autopolyploids: Understanding their formation and establishment","authors":"Patrik Mráz,&nbsp;Barbora Šingliarová","doi":"10.1002/ajb2.70047","DOIUrl":"10.1002/ajb2.70047","url":null,"abstract":"&lt;p&gt;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., &lt;span&gt;2011&lt;/span&gt;). Furthermore, WGM frequently leads to speciation, i.e., the formation of a new evolutionary lineage that differs from its diploid or lower-ploid ancestor.&lt;/p&gt;&lt;p&gt;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, &lt;span&gt;2004&lt;/span&gt;). 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., &lt;span&gt;2024&lt;/span&gt;). Reduced fertility may explain why autopolyploids are considered rare in nature and why they have been less studied compared to allopolyploids (Spoelhof et al., &lt;span&gt;2017&lt;/span&gt;). 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., &lt;span&gt;2012&lt;/span&gt;). Alternatively, synthetic neoautopolyploids have provided important insights into the immediate effect of WGM (Parisod et al., &lt;span&gt;2010&lt;/span&gt;), 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, &lt;span&gt;2017&lt;/span&gt;). Moreover, the synthetic approach skips the formation of neotriploids, which are considered as a bridge to reproductively more-stable autotetraploids (Ramsey and Schemske, &lt;span&gt;1998&lt;/span&gt;). 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}