American Journal of Botany最新文献

{"title":"Taxonomic reassessment of fossil Sequoia and Protosequoia from the Upper Miocene of Central Honshu, Japan, with implications for leaf morphological variation in extant S. sempervirens","authors":"Shun Ikeda,&nbsp;Arata Momohara","doi":"10.1002/ajb2.70227","DOIUrl":"10.1002/ajb2.70227","url":null,"abstract":"<div>\u0000 \u0000 \u0000 <section>\u0000 \u0000 <h3> Premise</h3>\u0000 \u0000 <p>Since its emergence in the Mesozoic, <i>Sequoia</i> (Cupressaceae) has been considered to possess conserved leaf morphology. However, recent studies have shown that the leaves of extant <i>S. sempervirens</i> become smaller, with a scale form, with increasing tree height. The fossil-genus <i>Protosequoia</i> has a similar scale leaf morphology, but its relationship to co-occurring <i>Sequoia</i> fossils, which bear linear leaves, remains unresolved.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Methods</h3>\u0000 \u0000 <p>To resolve this relationship, we re-examined specimens of two fossil species of <i>Sequoia</i> and <i>Protosequoia</i> from the Upper Miocene of Japan, focusing on leaf epidermal morphology and vascular bundle structure in the bract–scale complexes of seed cones.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Results</h3>\u0000 \u0000 <p>We identified fossil specimens with two types of shoots that were preserved in organic connection, but they had previously been classified as different genera. As the leaf shape changed from linear to scale, stomatal orientation shifted from parallel to the midrib to irregular, and epidermal cells gradually became shorter. Seed cones contained fewer than 30 bract–scale complexes with rhombic distal surfaces marked by horizontal grooves. In cross section, scales had rhombically arranged vascular bundles and several abaxial resin canals. Seeds had broad wings, and male strobili were mostly spherical.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Conclusions</h3>\u0000 \u0000 <p>The connected shoots, which shift in leaf stomatal features, and similarities in reproductive structure of the fossils suggest that the two genera represent the same species. Therefore, we propose a new <i>Sequoia</i> species characterized by densely branched twigs bearing smaller scale leaves, possibly reflecting an adaptation to different climatic conditions, compared to other species.</p>\u0000 </section>\u0000 </div>","PeriodicalId":7691,"journal":{"name":"American Journal of Botany","volume":"113 7","pages":""},"PeriodicalIF":2.8,"publicationDate":"2026-07-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/ajb2.70227","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148306589","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":"A case of budding speciation in the California Floristic Province and infraspecific divergence in Abronia villosa","authors":"Eli J. Allen,&nbsp;Eric F. LoPresti,&nbsp;Matthew G. Johnson,&nbsp;Oscar M. Vargas","doi":"10.1002/ajb2.70234","DOIUrl":"10.1002/ajb2.70234","url":null,"abstract":"<div>\u0000 \u0000 \u0000 <section>\u0000 \u0000 <h3> Premise</h3>\u0000 \u0000 <p>Budding speciation occurs when peripheral populations adapt to local ecological conditions and “bud” off from a widespread progenitor species. Traditionally regarded as rare because of its sympatric and parapatric nature, budding speciation is largely understudied. Moreover, recent evidence signals that this type of speciation is prevalent in plants, especially in biodiversity hotspots. In this study, we tested for budding speciation in the narrow endemic <i>Abronia villosa</i> var. <i>aurita</i> from the California Floristic Province (CFP).</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Methods</h3>\u0000 \u0000 <p>We used high-resolution phylogenetics, biogeography, and niche modeling to test the predictions of budding speciation for <i>A. villosa</i> var. <i>aurita</i> from its putative progenitor, the more widespread <i>A. villosa</i> var. <i>villosa</i>. Specifically, we tested for nested phylogenetic relationships of sister taxa, asymmetrical range size, and ecological divergence.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Results</h3>\u0000 \u0000 <p>Our results revealed that <i>A. villosa</i> var. <i>aurita</i> is a recently budded taxon, which phylogenetically nested within another variety of the same species. <i>Abronia villosa</i> var. <i>aurita</i> showed a clear signal of niche divergence into a montane environment and signals of genetic structure between two geographically divided populations, indicating further local adaptation and divergence potential.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Conclusions</h3>\u0000 \u0000 <p>We elucidated a case of budding speciation in the CFP, adding evidence to a growing number of studies that support budding speciation as a prevalent driver of diversification in plants. Furthermore, our analyses uncovered a nuanced history of within-species divergence, illustrating the importance of bridging microevolutionary and macroevolutionary mechanisms.</p>\u0000 </section>\u0000 </div>","PeriodicalId":7691,"journal":{"name":"American Journal of Botany","volume":"113 7","pages":""},"PeriodicalIF":2.8,"publicationDate":"2026-07-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/ajb2.70234","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148395595","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":"Ploidy level predicts differences in minimum leaf conductance in quaking aspen, Populus tremuloides","authors":"Jocelyn Navarro,&nbsp;Roxanne M. Cruz-de Hoyos,&nbsp;John M. Powers,&nbsp;Benjamin Wong Blonder,&nbsp;Brian J. Enquist","doi":"10.1002/ajb2.70235","DOIUrl":"10.1002/ajb2.70235","url":null,"abstract":"<div>\u0000 \u0000 \u0000 <section>\u0000 \u0000 <h3> Premise</h3>\u0000 \u0000 <p>Leaves lose water in parallel between stomata and the cuticle. Plants regulate stomata to reduce leaf water loss in response to atmospheric demand. However, water may still be lost through leaky stomata and the cuticle, as measured by minimum leaf conductance (<i>g</i>_min). We compared <i>g</i>_min between co-occurring diploid and triploid individuals of <i>Populus tremuloides</i> to determine whether ploidy, leaf traits, or microclimate explain variation in <i>g</i>_min. We hypothesized that <i>g</i>_min may increase with increasing ploidy because higher ploidy influences traits related to plant water loss, resulting in greater triploid water loss.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Methods</h3>\u0000 \u0000 <p>We measured <i>g</i>_min in five leaves each of 32 aspen genets in Colorado. We also measured traits associated with plant water-use and structure. We then assessed predictors of differences in <i>g</i>_min, including ploidy level.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Results</h3>\u0000 \u0000 <p>Minimum leaf conductance differed by ploidy level, with higher <i>g</i>_min in triploids than in diploids. Although leaf area and surface-area-to-volume ratio were significant predictors of <i>g</i>_min, neither variable accounted for the difference by ploidy level. Slope and aspect explained additional variation in <i>g</i>_min, suggesting important microsite effects. However, ploidy level remained a significant predictor of <i>g</i>_min across all models, indicating the effect on <i>g</i>_min is robust and not due to covariation with structural traits and topography.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Conclusions</h3>\u0000 \u0000 <p>Triploids consistently had higher <i>g</i>_min than diploids across models; accounting for structural traits and topography. Higher <i>g</i>_min in triploids is consistent with hypothesized physical or genetic effects of a larger genome on leaf traits, resulting in differential drought vulnerability across ploidy levels.</p>\u0000 </section>\u0000 </div>","PeriodicalId":7691,"journal":{"name":"American Journal of Botany","volume":"113 7","pages":""},"PeriodicalIF":2.8,"publicationDate":"2026-07-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148410058","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":"Biomechanics and anatomical investigation on the nodes and internodes of an arborescent monocotyledon","authors":"Desiree Micaela Monarrez,&nbsp;Edward G. Bobich,&nbsp;Vilupanur Ravi,&nbsp;R. Brandon Pratt,&nbsp;Anna L. Jacobsen,&nbsp;Frank W. Ewers","doi":"10.1002/ajb2.70226","DOIUrl":"10.1002/ajb2.70226","url":null,"abstract":"<div>\u0000 \u0000 \u0000 <section>\u0000 \u0000 <h3> Premise</h3>\u0000 \u0000 <p>Bamboos have extremely long internodes, making it possible to measure tensile properties and anatomical features of discrete nodes and internodes and understand how the plants endure mechanical stress and how the tissues function in commercial products. We compared upper, middle, and lower parts of culms in black bamboo, <i>Phyllostachys nigra</i>, to determine whether the nodes comply with the Niklas spring-like joint model.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Methods</h3>\u0000 \u0000 <p>We measured flexural stiffness, modulus of elasticity (<i>E</i>), load at failure (<i>F</i>_max), modulus of rupture (MOR), and density and fiber cap size of vascular bundles and assessed bundle orientations. Microcomputed tomography (microCT) during bending tests were used to determine sites of failure.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Results</h3>\u0000 \u0000 <p>Regardless of shoot position, nodes were less stiff (lower <i>E</i>) and weaker (lower MOR) than adjacent internodes. However, <i>F</i>_max was similar or greater in the nodes, suggesting nodes absorb considerable strain energy. Vascular bundle density was highest in the top internodes and nodes. Apparently, in lower nodes, sustained primary growth thickened the ground tissue between bundles, while size of the fiber caps also increased. Whole-shoot bending experiments and microCT indicated that failure occurred first in hollow internodes parallel to the vertical vascular bundles, not at nodes.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Conclusions</h3>\u0000 \u0000 <p>Vascular bundle positioning and composition allows nodes to bend and absorb considerable strain energy while resisting breakage, consistent with the spring-like joint model of the node. Sustained primary growth allows stems to thicken near the base to remain mechanically adequate. Bamboo nodes are thus areas of remarkable resilience; they will not break before internode tissue.</p>\u0000 </section>\u0000 </div>","PeriodicalId":7691,"journal":{"name":"American Journal of Botany","volume":"113 7","pages":""},"PeriodicalIF":2.8,"publicationDate":"2026-07-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148306560","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":"Species-specific thermal thresholds for postdispersal embryo growth in Apiaceae","authors":"Setayesh Nadi,&nbsp;Keyvan Maleki,&nbsp;Elias Soltani,&nbsp;Majid Ghorbani Javid,&nbsp;Filip Vandelook","doi":"10.1002/ajb2.70231","DOIUrl":"10.1002/ajb2.70231","url":null,"abstract":"<div>\u0000 \u0000 \u0000 <section>\u0000 \u0000 <h3> Premise</h3>\u0000 \u0000 <p>Temperature is a primary regulator of seed development. In seeds with morphological (MD) or morphophysiological (MPD) dormancy, embryo elongation represents a distinct postdispersal developmental phase that precedes germination. However, the thermal thresholds governing this embryo growth phase remain poorly quantified. We quantified species-specific embryo-growth thermal niches to provide a mechanistic framework for understanding regeneration timing and its evolutionary constraints.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Methods</h3>\u0000 \u0000 <p>We estimated cardinal temperatures—base (<i>T</i>_b), optimum (<i>T</i>_o), and maximum (<i>T</i>_m)—for embryo growth in 10 Apiaceae species, a family in which MD and MPD are very common due to the presence of underdeveloped embryos. Seeds were incubated at five temperatures (5–25°C) with and without gibberellic acid (GA₃). Embryo growth rates were modeled using nonlinear thermal performance curves within a multimodel inference framework, followed by phylogenetic signal analyses.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Results</h3>\u0000 \u0000 <p>Substantial interspecific variation was found, with <i>T</i>_b ranging from 0 to 6.5°C, <i>T</i>_o from 5 to 25°C, and <i>T</i>_m from 21.5 to 31°C. GA₃ generally increased growth rates and widened thermal ranges by reducing <i>T</i>_b and raising <i>T</i>_m, though responses were strongly species-specific. Phylogenetic analyses revealed significant signal for all thermal thresholds (<i>T</i>_b, <i>T</i>_o, <i>T</i>_m), indicating that evolutionary history constrains these thermal niches for postdispersal embryo growth.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Conclusions</h3>\u0000 \u0000 <p>Postdispersal embryo growth constitutes a distinct, quantifiable thermal niche rather than a mere proxy for germination. By explicitly treating postdispersal embryo growth as a distinct thermal niche rather than a proxy for germination, this study extends thermal threshold theory to an overlooked developmental phase and provides a mechanistic framework for understanding dormancy release and regeneration timing under variable climatic conditions.</p>\u0000 </section>\u0000 </div>","PeriodicalId":7691,"journal":{"name":"American Journal of Botany","volume":"113 7","pages":""},"PeriodicalIF":2.8,"publicationDate":"2026-07-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148359120","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":"New records of extinct Icacinaceae from Paleocene rainforests of northwestern South America","authors":"Laura M. Puente-Santos,&nbsp;Mónica R. Carvalho,&nbsp;Ethan Shirley,&nbsp;Fabiany Herrera","doi":"10.1002/ajb2.70237","DOIUrl":"10.1002/ajb2.70237","url":null,"abstract":"<div>\u0000 \u0000 \u0000 <section>\u0000 \u0000 <h3> Premise</h3>\u0000 \u0000 <p>This study describes three new records of Icacinaceae—<i>Punctiuga bachue</i> gen. et sp. nov., <i>Palaeophytocrene paramoae</i> sp. nov., and <i>Goweria bacatana</i> sp. nov. from the Paleocene (Selandian–Thanetian) Bogotá Formation in Colombia—improving understanding of the distribution and evolution of this family in the Neotropics.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Methods</h3>\u0000 \u0000 <p>We analyzed 47 fossil endocarps using microscopy and X-ray micro-computed tomography (μCT); we also studied the associated leaf assemblage in search of potential Icacinaceae foliage. We then compared the fossils to extant Icacinaceae specimens from herbaria and the existing literature.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Results</h3>\u0000 \u0000 <p><i>Punctiuga bachue</i> features unique morphological traits that resemble and support a close affinity to Iodeae and Phytocreneae. The presence of <i>Palaeophytocrene paramoae</i> confirms Phytocreneae diversity in South America during the Paleocene, and the occurrence of leaves of Icacinaceae contribute to the history of Icacinaceae on the continent.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Conclusions</h3>\u0000 \u0000 <p>Our results show a previously unacknowledged diversity of Icacinaceae in the Paleocene Neotropics, including two new species of endocarps with affinities to Phytocreneae and Iodeae, clades currently restricted to the Old World tropics. Our findings support an early Paleogene diversification of the family in the Neotropics and the extirpation of tropical lineages in the Neotropics during the later Cenozoic.</p>\u0000 </section>\u0000 </div>","PeriodicalId":7691,"journal":{"name":"American Journal of Botany","volume":"113 7","pages":""},"PeriodicalIF":2.8,"publicationDate":"2026-07-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/ajb2.70237","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148468470","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":"Soil salinity effects on pollen and pollinator visitation in a buzz-pollinated glycophyte, Solanum carolinense","authors":"Kylie Bill,&nbsp;David E. Carr","doi":"10.1002/ajb2.70233","DOIUrl":"10.1002/ajb2.70233","url":null,"abstract":"<div>\u0000 \u0000 \u0000 <section>\u0000 \u0000 <h3> Premise</h3>\u0000 \u0000 <p>Human activity has significantly altered the salt cycle, affecting an estimated 2.5 billion acres of soil worldwide. Elevated soil salinity is a well-known plant stressor, but it may also affect interactions between plants and insects, which are often sodium limited. Elevated sodium in nectar can increase pollinator visitation, but no previous study has examined the effects of elevated soil salinity on visitation by pollen-collecting bees.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Methods</h3>\u0000 \u0000 <p>Our study tested whether increased soil salinity impacts pollen sodium and <i>Bombus</i> spp. visitation to <i>Solanum carolinense</i>, a buzz-pollinated perennial wildflower that rewards pollinators only with pollen. Soil salinity around the root zone of <i>Solanum carolinense</i> growing wild in an early successional field was artificially increased with a salt solution to observe changes in pollen sodium and other cations, pollen viability, and pollinator visitation.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Results</h3>\u0000 \u0000 <p>Salt addition to the soil increased soil salinity by over five-fold, but there was no effect on the sodium levels of <i>S. carolinense</i> pollen. The salt treatment had no effect on pollinator visitation or pollen viability.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Conclusions</h3>\u0000 \u0000 <p>Although high soil salinity has been shown to increase nectar sodium levels and thus pollinator visitation, we infer from our results that <i>S. carolinense</i> is able to largely exclude sodium from its pollen, preventing high salinity soil from affecting pollinator attraction and pollen viability.</p>\u0000 </section>\u0000 </div>","PeriodicalId":7691,"journal":{"name":"American Journal of Botany","volume":"113 7","pages":""},"PeriodicalIF":2.8,"publicationDate":"2026-07-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/ajb2.70233","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148374074","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":"Extroparvum occidentale gen. et sp. nov. and the Cretaceous diversification of Lauraceae","authors":"Keana K. Tang,&nbsp;Kelly K. S. Matsunaga,&nbsp;Brian A. Atkinson","doi":"10.1002/ajb2.70236","DOIUrl":"10.1002/ajb2.70236","url":null,"abstract":"<div>\u0000 \u0000 \u0000 <section>\u0000 \u0000 <h3> Premise</h3>\u0000 \u0000 <p>The fossil record of Lauraceae extends back to the Early Cretaceous and comprises numerous flowers. However, phylogenetic relationships of many of these fossil flowers remain unresolved. To better understand the early evolutionary history of Lauraceae, we conducted phylogenetic analyses of living and extinct members of the family and described a new fossil flower from the Coniacian of British Columbia, Canada.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Methods</h3>\u0000 \u0000 <p>Serial sections of the new fossil flower were prepared and used to create a three-dimensional reconstruction. We performed a series of phylogenetic analyses, including total-evidence analyses using a novel morphological matrix, to analyze the new fossil flower and 16 previously described fossil flowers. Phylogenetic uncertainty was explored for each taxon, and phylogenetic pseudofossilization analyses were conducted to test whether our floral data set can accurately recover systematic relationships within Lauraceae.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Results</h3>\u0000 \u0000 <p>The Eden Main fossil flowers are assignable to Lauraceae and represent a new genus and species: <i>Extroparvum occidentale</i>. Phylogenetic analyses recovered <i>E. occidentale</i> and 12 fossil flowers among Lauraceae. Phylogenetic uncertainty within Lauraceae was high for many of the fossils, but we identified two taxa as crown-group members that can be employed as new node calibrations for the family. Pseudofossilization analyses indicated that our floral data set can accurately recover taxa within crown-group Lauraceae with high support.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Conclusions</h3>\u0000 \u0000 <p>Our work adds to the known Cretaceous diversity of Lauraceae and provides the first phylogenetic evidence of crown-group Lauraceae diversifying by the Late Cretaceous. Furthermore, our novel morphological data set lays an important foundation for directly integrating fossil flowers into macroevolutionary studies of the family.</p>\u0000 </section>\u0000 </div>","PeriodicalId":7691,"journal":{"name":"American Journal of Botany","volume":"113 7","pages":""},"PeriodicalIF":2.8,"publicationDate":"2026-07-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/ajb2.70236","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148519688","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":"Drier conditions diminish plant coexistence via soil microbes in a tropical humid forest","authors":"Vinayak P. Saini,&nbsp;Gaurav S. Kandlikar,&nbsp;Meghna Krishnadas","doi":"10.1002/ajb2.70230","DOIUrl":"10.1002/ajb2.70230","url":null,"abstract":"<div>\u0000 \u0000 \u0000 <section>\u0000 \u0000 <h3> Premise</h3>\u0000 \u0000 <p>Global environmental change can alter ecological mechanisms that maintain biodiversity. Interactions between plants and soil microbes mediate plant species coexistence, which can vary with abiotic factors such as light and soil moisture, and such context dependence is only beginning to be explored.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Methods</h3>\u0000 \u0000 <p>We assessed how variation in light and soil moisture alters soil microbial effects on the predicted coexistence of two common tree species (<i>Litsea floribunda</i> and <i>Symplocos racemosa</i>) native to the Western Ghats, India. We conducted a shade-house reciprocal transplant experiment with different soil origins in factorial combinations of high/low water and light, and predicted coexistence outcomes using metrics that decompose microbial effects into stabilization and fitness differences. For high-water, low-light conditions, we also evaluated whether soil microbes alter plant-plant interactions, using a structural framework that quantifies the feasibility domain of coexistence from species interaction coefficients.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Results</h3>\u0000 \u0000 <p>Soil microbes were predicted to promote plant coexistence in high-water, low-light conditions, where stabilization exceeded the fitness differences due to microbes. Under low-water, high-light conditions, larger fitness differences predicted exclusion of <i>S. racemosa</i>. Microbes had weak effects on plant-plant interactions, but predicted coexistence improved slightly in soils with background microbes not shaped by either species, due to weaker estimated fitness differences in those soils.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Conclusions</h3>\u0000 \u0000 <p>Drier and brighter conditions may weaken the potential for microbially mediated plant coexistence in tropical forests. These findings hint at shifts in microbially mediated plant community dynamics in response to global change factors such as forest fragmentation and drought.</p>\u0000 </section>\u0000 </div>","PeriodicalId":7691,"journal":{"name":"American Journal of Botany","volume":"113 7","pages":""},"PeriodicalIF":2.8,"publicationDate":"2026-07-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148429681","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":"Erratum to “Phylogenomics resolves the evolutionary histories and taxonomy of the long-associated North American legume genera Psorodendron and Psorothamnus”","authors":"","doi":"10.1002/ajb2.70228","DOIUrl":"10.1002/ajb2.70228","url":null,"abstract":"<p>Wojciechowski, M. F., S. Carvalho Madrigal, G. P. Lewis, and M. J. Sanín. 2026. Phylogenomics resolves the evolutionary histories and taxonomy of the long-associated North American legume genera <i>Psorodendron</i> and <i>Psorothamnus</i>. <i>American Journal of Botany</i> 113: e70193.</p><p>Two of the taxonomic names we presented in our Revised Taxonomy section of this article are not correct as per the current Botanical Code. Based on priority within the rank of species, the new combination we published as <i><b>Psorodendron minutifolium</b></i> (Parish) M.F. Wojc. &amp; G.P. Lewis is superfluous and should be replaced with the name <i><b>Psorodendron wheeleri</b></i> (Vail) Rydb. (1919), which was based on the earlier species name <i><b>Parosela wheeleri</b></i> Vail (1897). And the taxon <i><b>Psorothamnus emoryi</b></i> var. <i><b>arenarius</b></i> (Brandegee) Barneby (1977) should be treated as <i><b>Psorothamnus emoryi</b></i> var. <i><b>tinctorius</b></i> based on the autonym <i><b>Dalea tinctoria</b></i> var. <i><b>tinctoria</b></i> Brandegee (1889), which has priority. The correct name for this taxon would thus be <i><b>Psorothamnus emoryi</b></i> var. <i><b>tinctorius</b></i> (Brandegee) M.F. Wojc. &amp; G.P. Lewis, comb. nov.</p><p>Also, author Maria José Sanín's current affiliation is Montgomery Botanical Center, Coral Gables, Florida, USA.</p><p>We apologize for these errors.</p>","PeriodicalId":7691,"journal":{"name":"American Journal of Botany","volume":"113 7","pages":""},"PeriodicalIF":2.8,"publicationDate":"2026-07-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/ajb2.70228","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148306531","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}