American Journal of Botany最新文献

{"title":"Patterns of within- and among-plant variation in nectar production in the beetle-pollinated Amianthium muscaetoxicum","authors":"Sarah J. McPeek,&nbsp;Connor L. Erwin,&nbsp;Edmund D. Brodie III","doi":"10.1002/ajb2.70069","DOIUrl":"10.1002/ajb2.70069","url":null,"abstract":"<div>\u0000 \u0000 \u0000 <section>\u0000 \u0000 <h3> Premise</h3>\u0000 \u0000 <p>Plant interactions with different pollinator species have shaped the evolution of remarkable diverse nectar production, presentation, and composition traits across the angiosperms. These traits can allow plants to manipulate and reward the behaviors of specific pollinators to enhance pollen donation and receipt with some precision. One group of animal-pollinated flowers notably lack characterizations of nectar trait diversity: plants that are pollinated by nectar-feeding beetles.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Methods</h3>\u0000 \u0000 <p>In a series of studies, we characterized variation in nectar traits within flowers, within plants, within populations and investigated the behavior of beetles feeding on nectar in a single population of the beetle-pollinated perennial monocot, <i>Amianthium muscaetoxicum</i> (Melanthiaceae).</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Results</h3>\u0000 \u0000 <p>At the flower level, nectar accumulated throughout an individual flower's lifetime, peaking at anthesis and ceasing thereafter. Lifetime nectar production of flowers on a plant was highly consistent. At the population level, plants had high among-individual variation in nectar volume and nectar sugar concentration. Feeding experiments with a primary beetle pollinator further revealed that beetles spent significantly more time interacting with flowers with higher nectar volumes, but not flowers with higher sugar concentrations or total sugar content.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Conclusions</h3>\u0000 \u0000 <p>Our findings begin to shed light on the mutualistic interaction between <i>Amianthium</i> and its beetle pollinators and on the commonalities and differences between beetles and other species of nectar-feeding pollinators.</p>\u0000 </section>\u0000 </div>","PeriodicalId":7691,"journal":{"name":"American Journal of Botany","volume":"112 7","pages":""},"PeriodicalIF":2.4,"publicationDate":"2025-07-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/ajb2.70069","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144582814","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":"Deciphering fire tolerance of trees at the Amazonia-Cerrado transition by trait-based approach: Implications from species to communities.","authors":"Wesley Jonatar A Cruz, Manoela S Machado, Francisco Navarro-Rosales, Maria Antonia Carniello, Marcelo Leandro F Andrade, Flávio C Oliveira, Immaculada Oliveras Menor","doi":"10.1002/ajb2.70066","DOIUrl":"10.1002/ajb2.70066","url":null,"abstract":"<p><strong>Premise: </strong>Understanding how fire impacts trees is essential for predicting the effects of novel fire regimes on plant diversity in the transition between the world's two most diverse biomes, the Cerrado and the Amazonia. Here we addressed knowledge gaps regarding physiological damage and mortality in transitional species within fire-prone ecosystems.</p><p><strong>Methods: </strong>In a manipulative fire experiment, we burned a transitional woodland savanna for six consecutive years after it had been fire-excluded for 33 years. We classified the most abundant tree species according to their fire tolerance and examined the relationship between fire tolerance and key morphological and ecophysiological functional traits. These traits were related to leaf economics spectrum, bark investment, wood density, flammability, and physiological drought tolerance.</p><p><strong>Results: </strong>Species had three main fire tolerance strategies, reflected in their investment in the outer and inner bark, wood density in branches and the main trunk, changes in leaf water potential, and water and dry matter ratios in leaves. The inner and outer bark and the level of protection of the sprouting buds better explained tree mortality and topkill. Under very frequent fires, fire-sensitive species had the highest mortality rates and fire-thrivers became the most abundant species.</p><p><strong>Conclusions: </strong>Transitional tree species had different response strategies to fire based on their tolerance, which directly influences their survival and the overall structure of the community. Our findings suggest likely shifts in tree community structure in response to novel fire regimes.</p>","PeriodicalId":7691,"journal":{"name":"American Journal of Botany","volume":" ","pages":"e70066"},"PeriodicalIF":2.4,"publicationDate":"2025-07-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144551735","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 interplay among space, environment, and gene flow drives genetic differentiation in endemic Baja California Agave sobria subspecies","authors":"Anastasia Klimova,&nbsp;Jesús Gutiérrez Rivera,&nbsp;Oscar E. Juárez,&nbsp;Alfredo Ortega Rubio,&nbsp;Luis E. Eguiarte","doi":"10.1002/ajb2.70062","DOIUrl":"10.1002/ajb2.70062","url":null,"abstract":"<div>\u0000 \u0000 \u0000 <section>\u0000 \u0000 <h3> Premise</h3>\u0000 \u0000 <p>Research on neutral and adaptive processes that lead to the divergence of species and populations is a crucial component in evolutionary and conservation genetics. <i>Agave sobria</i> is an endemic group of subspecies scattered on canyons along a latitudinal gradient and distinct environments of the Baja California Peninsula, Mexico. <i>Agave sobria</i> represents a unique opportunity to study the process of genetic differentiation in a highly heterogeneous environment.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Methods</h3>\u0000 \u0000 <p>Using genotyping-by-sequencing, we genotyped 8453 single-nucleotide polymorphisms (SNPs) in all <i>A. sobria</i> subspecies, including 19 <i>A. sobria</i> and three closely related <i>A. cerulata</i> ssp. <i>subcerulata</i> populations. We assessed neutral genetic structure and diversity at both the interspecific and intraspecific levels, evaluated the amount and direction of gene flow, and identified putatively adaptive SNPs.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Results</h3>\u0000 \u0000 <p>We found low support for the currently recognized subspecies. We detected neutral (i.e., isolation by distance) and adaptive divergence linked to eco-geographic characteristics of the habitat. High genetic connectivity indicated that gene flow between central and northern populations may have homogenizing effects preventing population differentiation. For the southernmost <i>A. sobria</i> ssp. <i>frailensis</i>, temperature and geographic isolation appear to be the main drivers of adaptive differentiation, with outlier SNPs located in coding regions involved in response to abiotic stress and immunology.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Conclusions</h3>\u0000 \u0000 <p>In <i>A. sobria</i>, environmental isolation and geographic gradients affect the genetic structure, creating opportunities for local adaptation. Our results emphasize the importance of including neutral and adaptive perspectives, the combination of which allows a better understanding of the complexity of the processes that lead to population differentiation.</p>\u0000 </section>\u0000 </div>","PeriodicalId":7691,"journal":{"name":"American Journal of Botany","volume":"112 7","pages":""},"PeriodicalIF":2.4,"publicationDate":"2025-07-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/ajb2.70062","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144551736","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":"Floral scent of artificial hybrids between two Schiedea species that share a moth pollinator","authors":"John M. Powers,&nbsp;Stephen G. Weller,&nbsp;Ann K. Sakai,&nbsp;Diane R. Campbell","doi":"10.1002/ajb2.70065","DOIUrl":"10.1002/ajb2.70065","url":null,"abstract":"<div>\u0000 \u0000 \u0000 <section>\u0000 \u0000 <h3> Premise</h3>\u0000 \u0000 <p>In flowering plants, pollinators' ability to recognize chemical displays of hybrids may erode reproductive barriers. Hybrids may produce novel or altered floral scent blends that are unattractive, or scents similar to either parent that remain attractive and promote backcrossing. We characterized the floral scent of hybrids of sympatric species with a shared pollinator and tested whether scent is sufficient for pollinator attraction.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Methods</h3>\u0000 \u0000 <p>Floral volatiles of artificial F₁ hybrids between Hawaiian <i>Schiedea kaalae</i> and <i>S. hookeri</i> (Caryophyllaceae) were characterized by dynamic headspace sampling and GC-MS. Behavioral choice tests with the native moth <i>Pseudoschrankia brevipalpis</i> measured the effect of adding <i>S. kaalae</i> scent (with flowers bagged to remove visual cues) to inflorescences of relatively unattractive wind-pollinated relatives (<i>S. kealiae</i> and <i>S. globosa</i>) from the same island.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Results</h3>\u0000 \u0000 <p>Most hybrids produced a combination of the distinct sets of floral volatiles from each parent at rates of emission that often differed from the expectation under completely additive inheritance. Floral scent did not depend on cross direction, and no novel compounds were detected in hybrids. <i>Pseudoschrankia brevipalpis</i> preferred inflorescences of <i>S. globosa</i> and <i>S. kealiae</i> that were augmented with the scent of hidden <i>S. kaalae</i> flowers.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Conclusions</h3>\u0000 \u0000 <p>Intermediate hybrid floral scent blends could potentially attract moths if they do not rely on precise compound ratios. Moth attraction to the floral scent of <i>S. kaalae</i> flowers indicates that moths can discriminate the floral scent of this species against a background of volatiles and visual cues from wind-pollinated relatives, showing the importance of scent variation in this genus.</p>\u0000 </section>\u0000 </div>","PeriodicalId":7691,"journal":{"name":"American Journal of Botany","volume":"112 7","pages":""},"PeriodicalIF":2.4,"publicationDate":"2025-06-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/ajb2.70065","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144526116","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":"Climatic determinants of plant phenology in vernal pool habitats","authors":"Brandon Thomas Hendrickson,&nbsp;Jenna Aubrie Benterou,&nbsp;Robert Martin,&nbsp;Jason P. Sexton","doi":"10.1002/ajb2.70064","DOIUrl":"10.1002/ajb2.70064","url":null,"abstract":"<div>\u0000 \u0000 \u0000 <section>\u0000 \u0000 <h3> Premise</h3>\u0000 \u0000 <p>The floral phenology of vernal pool plants is little understood despite being a crucial developmental stage for producing seeds and determining population growth rates. Vernal pools are ephemerally aquatic habitats harboring species adapted to predictable seasonal fluctuations between desiccated and inundated conditions; thus, vernal pool plant phenology is predicted to be particularly responsive to interannual climate variability.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Methods</h3>\u0000 \u0000 <p>For two vernal pool species, <i>Limnanthes douglasii</i> subsp. <i>rosea</i> (meadowfoam), a vernal pool specialist, and <i>Trifolium variegatum</i> (whitetip clover), a generalist vernal pool associate, we characterized flowering onset, termination, and duration in response to interannual variation of winter precipitation and growing degree hours (GDH). We recorded phenology over 7 years from 2016 to 2022 during a period of high climatic variability, which served as a robust data set.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Results</h3>\u0000 \u0000 <p>Warmer and drier environmental conditions during early growth periods were strongly associated with advanced floral phenology later in the life cycle for both species. The floral duration of the vernal pool specialist was influenced by position along the inundation gradient, whereas no such pattern was observed for the vernal pool associate.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Conclusions</h3>\u0000 \u0000 <p>To our knowledge, this is the first study quantifying the relationship between vernal pool floral phenology and climate, offering insights into how phenology may shift in response to modern climate change.</p>\u0000 </section>\u0000 </div>","PeriodicalId":7691,"journal":{"name":"American Journal of Botany","volume":"112 7","pages":""},"PeriodicalIF":2.4,"publicationDate":"2025-06-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/ajb2.70064","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144526115","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":"Floral syndromes predict the most effective pollinators in five species of Salvia","authors":"Arturo Tavera,&nbsp;Martín H. de Santiago-Hernández,&nbsp;Víctor Rosas-Guerrero,&nbsp;Clementina González,&nbsp;Eduardo Cuevas","doi":"10.1002/ajb2.70067","DOIUrl":"10.1002/ajb2.70067","url":null,"abstract":"<div>\u0000 \u0000 \u0000 <section>\u0000 \u0000 <h3> Premise</h3>\u0000 \u0000 <p>Pollination syndromes are suites of floral traits associated with the most effective functional group of pollinators. Particular floral traits may not necessarily preclude visitation by different visitor guilds that could also contribute to plant reproduction. The genus <i>Salvia</i> comprises ca. 1000 species with floral traits almost exclusively associated with bee or hummingbird pollination syndromes. Nevertheless, the effectiveness of their floral visitors has rarely been evaluated. Here, the pollination effectiveness of floral visitors in five <i>Salvia</i> species was analyzed to assess the reliability of floral syndromes.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Methods</h3>\u0000 \u0000 <p>The contribution to seed production of the most frequent floral visitors of <i>Salvia</i> species with melittophilous, ornithophilous, and mixed phenotypes was evaluated through single-visit experiments. In addition, the relationship between floral morphological traits and pollinator effectiveness was explored using principal component analysis to test the reliability of floral syndromes.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Results</h3>\u0000 \u0000 <p>Despite multiple floral visitor guilds to the plants, bees and hummingbirds were the most effective pollinators of plants with melittophilous and ornithophilous pollination syndrome, respectively. These two functional groups effectively pollinated the plant species with mixed floral traits. <i>Salvia</i> species pollinated by the same functional group were closer in the multivariate ordination space.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Conclusions</h3>\u0000 \u0000 <p>Even when floral syndromes precisely predict the most effective pollinators in <i>Salvia</i>, secondary pollinators also play a crucial role in plant sexual reproduction, especially for plant species with mixed floral phenotypes. This study highlights the importance of evaluating the effectiveness of floral visitors to assess the reliability of floral syndromes.</p>\u0000 </section>\u0000 </div>","PeriodicalId":7691,"journal":{"name":"American Journal of Botany","volume":"112 7","pages":""},"PeriodicalIF":2.4,"publicationDate":"2025-06-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144493453","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":"Navigating the possibilities and pitfalls of biocrust recovery in a changing climate","authors":"Michala L. Phillips,&nbsp;Kristina E. Young,&nbsp;Cara Lauria,&nbsp;Sierra Jech,&nbsp;Ana Giraldo-Silva,&nbsp;Sasha C. Reed","doi":"10.1002/ajb2.70055","DOIUrl":"10.1002/ajb2.70055","url":null,"abstract":"<p>Biological soil crusts are complex communities composed of lichens, mosses, bacteria, and cyanobacteria that create a living skin on the soil surface across drylands worldwide. Although small in size, the vast area that biocrusts cover and the critical functions they provide make them a cornerstone of dryland health and resiliency. In addition to being important, biocrusts are exceptionally vulnerable to certain types of disturbance. Although they can withstand a wide range of temperatures and long periods without precipitation, biocrusts are highly sensitive to land-use change and are vulnerable to physical and compressional disturbance (i.e., trampling, vehicles, cattle, heavy machinery). In the face of these disturbances, a critical, long-standing question of interest to dryland ecologists is: Can biocrusts recover following disturbance without active intervention. If so, how long does it take? Early estimates of biocrust recovery suggested recovery can be incredibly slow (on the order of thousands of years), with more modern studies finding potential for faster recovery, especially with intervention. Multiple lines of evidence agree that recovery is context dependent, differing across climates, soils, and with the types of disturbance and biocrust. Additionally, active restoration of biocrusts is becoming more common as tractable strategies are developed for facilitating the establishment of biocrusts after disturbance. Here, we add to the body of knowledge about biocrust recovery following disturbances by reviewing recovery patterns, their connection to climate change, considerations for recovery in changing climates, and the role of restoration.</p>","PeriodicalId":7691,"journal":{"name":"American Journal of Botany","volume":"112 6","pages":""},"PeriodicalIF":2.4,"publicationDate":"2025-06-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/ajb2.70055","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144332314","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":"Rare species do not disproportionately contribute to phylogenetic diversity in a subalpine plant community","authors":"Leah N. Veldhuisen,&nbsp;Verónica Zepeda,&nbsp;Brian J. Enquist,&nbsp;Katrina M. Dlugosch","doi":"10.1002/ajb2.70061","DOIUrl":"10.1002/ajb2.70061","url":null,"abstract":"<div>\u0000 \u0000 \u0000 <section>\u0000 \u0000 <h3> Premise</h3>\u0000 \u0000 <p>Within plant communities, few species are abundant, and most are locally rare. Worldwide, 36% of plant species are exceedingly rare and often face high extinction risk. However, the community phylogenetic impact of the loss of rare plants is largely unknown in many systems. We address this gap by investigating how rare species contribute to phylogenetic diversity, considering multiple metrics of rarity and multiple elevations in a subalpine plant community.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Methods</h3>\u0000 \u0000 <p>We collected abundance data at three sites near the Rocky Mountain Biological Laboratory (Colorado, USA). We calculated each species' range size from public occurrence data. We calculated phylogenetic signal for abundance and range size, compared community phylogenetic metrics weighted by range size and abundance to unweighted metrics, and quantified the change in phylogenetic diversity when removing single species and groups of species ranked by rarity.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Results</h3>\u0000 \u0000 <p>We found phylogenetic signal for abundance, but not range size. There was no difference between rarity-weighted and -unweighted phylogenetic diversity metrics. Finally, phylogenetic diversity did not decline more when we removed single rare species or groups of rare species than when we removed single common species and groups of common species.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Conclusions</h3>\u0000 \u0000 <p>We found that rare species, whether at low abundance or with a small range, do not disproportionately contribute to phylogenetic diversity in our subalpine plant community. These results were consistent across elevations. Instead, rare species might provide phylogenetic redundancy with common species. Deeper understanding of functional differentiation is needed to understand contributions of rare species to this system.</p>\u0000 </section>\u0000 </div>","PeriodicalId":7691,"journal":{"name":"American Journal of Botany","volume":"112 6","pages":""},"PeriodicalIF":2.4,"publicationDate":"2025-06-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/ajb2.70061","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144324179","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":"Rare recombination in Salix nivalis and the maintenance of homomorphic sex chromosomes in willows","authors":"Ashmita Khanal,&nbsp;Nan Hu,&nbsp;Minghao Guo,&nbsp;Diksha Gambhir,&nbsp;Brian Sanderson,&nbsp;Matthew S. Olson","doi":"10.1002/ajb2.70059","DOIUrl":"10.1002/ajb2.70059","url":null,"abstract":"<div>\u0000 \u0000 \u0000 <section>\u0000 \u0000 <h3> Premise</h3>\u0000 \u0000 <p>Most dioecious angiosperms have homomorphic sex chromosomes, and non-recombining sex-linked regions (SLRs) likely comprise a small portion of the sex chromosome. The fountain of youth hypothesis posits that rare recombination within heterogametic SLRs may act to maintain homomorphy. Alternatively, turnovers of the sex-determining genes could also contribute to sex chromosome homomorphy.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Methods</h3>\u0000 \u0000 <p>We used reduced representation sequencing and mapping to the <i>Salix purpurea</i> reference genome to determine the size of the sex-linked region in three dwarf willows (<i>Salix phlebophylla</i>, <i>S. reticulata</i>, and <i>S. nivalis</i>). To test the fountain of youth hypotheses, we performed allelic state and linkage disequilibrium (LD) analyses.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Results</h3>\u0000 \u0000 <p>For all three species, sex-linked single nucleotide polymorphisms (SNPs) were identified on chromosome 15. Mean heterozygosity was higher in females, confirming that all three species were female heterogametic (ZW). A recombinant haplotype between the Z and W chromosomes was identified in <i>S. nivalis</i>, contributing to higher-than-expected mean heterozygosity in SLR and slow LD decay in males.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Conclusions</h3>\u0000 \u0000 <p>We propose that the uncommon ZW haplotype resulting from a recombination event identified here initiates the homogenization of Z and W chromosomes, leading to the maintenance of their homomorphy. Based on comparisons across all three SLRs, we further speculate that ongoing rare recombination events have influenced the shared patterns of sex-linked SNPs across <i>S. phlebophylla</i>, <i>S. reticulata</i>, and <i>S. nivalis</i> and is a process that influences sex chromosome evolution throughout the Salicaceae and flowering plants with homomorphic sex chromosomes.</p>\u0000 </section>\u0000 </div>","PeriodicalId":7691,"journal":{"name":"American Journal of Botany","volume":"112 6","pages":""},"PeriodicalIF":2.4,"publicationDate":"2025-06-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144315730","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":"CRABS CLAW-independent floral nectary development in Penstemon barbatus","authors":"Amanda M. Katzer,&nbsp;Carolyn A. Wessinger,&nbsp;Brooklyn M. Anaya,&nbsp;Lena C. Hileman","doi":"10.1002/ajb2.70058","DOIUrl":"10.1002/ajb2.70058","url":null,"abstract":"<div>\u0000 \u0000 \u0000 <section>\u0000 \u0000 <h3> Premise</h3>\u0000 \u0000 <p>Plants secrete carbohydrate-rich nectar from specialized floral nectary glands to attract pollinators. <i>Arabidopsis</i> and <i>Petunia</i> (rosid and asterid core eudicots, respectively) share genetic control of nectary development requiring activation of <i>CRABS CLAW</i> by <i>euAGAMOUS</i> and <i>PLENA</i>. This module is conserved despite striking differences in nectary morphology between the two species. We tested whether the <i>euAGAMOUS/PLENA-CRABS CLAW</i> module likely extends to an asterid species with novel nectary morphology, <i>Penstemon barbatus</i>.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Methods</h3>\u0000 \u0000 <p>To test conservation of the <i>euAGAMOUS/PLENA-CRABS CLAW</i> module and nectar sugar metabolism in <i>P. barbatus</i>, we carried out comparative transcriptomics, leveraging <i>Penstemon</i>'s unique nectary morphology. Specifically, lateral and ventral stamen filaments develop with and without nectaries at their base, respectively, allowing straightforward differential expression analyses to uncover nectary-specific gene expression.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Results</h3>\u0000 \u0000 <p>Many genes were differentially expressed between nectary and non-nectary tissues, and pre- and post-nectar-removal. Differentially expressed genes pointed to key phloem, abaxial specification, and epidermal cell shape functions during nectary development. Differentially expressed genes pointed to regulation of sugar processing and secretion after nectary maturation.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Conclusions</h3>\u0000 \u0000 <p>Our results suggest that <i>P. barbatus</i> nectaries develop independently of the canonical core-eudicot <i>CRABS CLAW</i> genetic module, despite being positioned within reproductive floral organ whorls, and that <i>P. barbatus</i> nectar production follows conserved sugar metabolic pathways.</p>\u0000 </section>\u0000 </div>","PeriodicalId":7691,"journal":{"name":"American Journal of Botany","volume":"112 6","pages":""},"PeriodicalIF":2.4,"publicationDate":"2025-06-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/ajb2.70058","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144309365","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}