American Journal of Botany最新文献

{"title":"Toward a phylogenomic classification of magnoliids","authors":"Andrew J. Helmstetter,&nbsp;Zacky Ezedin,&nbsp;Elton John de Lírio,&nbsp;Sylvia M. de Oliveira,&nbsp;Lars W. Chatrou,&nbsp;Roy H. J. Erkens,&nbsp;Isabel Larridon,&nbsp;Kevin Leempoel,&nbsp;Olivier Maurin,&nbsp;Shyamali Roy,&nbsp;Alexandre R. Zuntini,&nbsp;William J. Baker,&nbsp;Thomas L. P. Couvreur,&nbsp;Félix Forest,&nbsp;Hervé Sauquet","doi":"10.1002/ajb2.16451","DOIUrl":"10.1002/ajb2.16451","url":null,"abstract":"<div>\u0000 \u0000 \u0000 <section>\u0000 \u0000 <h3> Premise</h3>\u0000 \u0000 <p>Magnoliids are a strongly supported clade of angiosperms. Previous phylogenetic studies based primarily on analyses of a limited number of mostly plastid markers have led to the current classification of magnoliids into four orders and 18 families. However, uncertainty remains regarding the placement of several families.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Methods</h3>\u0000 \u0000 <p>For the first comprehensive phylogenomic analysis of magnoliids as a whole, we sampled 235 species from 199 (74%) genera and representing all families and most subfamilies and tribes. We analyzed newly generated data from the Angiosperms353 probe set using both coalescent and concatenation analyses and testing the impact of multiple filtering and alignment strategies.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Results</h3>\u0000 \u0000 <p>While our results generally provide further support for previously established phylogenetic relationships in both magnoliids as a whole and large families including Annonaceae and Lauraceae, they also provide new evidence for previously ambiguous relationships. In particular, we found support for the position of Hydnoraceae as sister to the remainder of Piperales, though evidence was conflicting, and resolved the backbone of relationships among most genera of Myristicaceae. Different analytical strategies tended to have rather small effects on branch support and topology.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Conclusions</h3>\u0000 \u0000 <p>Although some of our results are limited by low gene recovery for a number of taxa and significant gene tree conflict for some relationships, this study represents a significant step toward reconstructing the evolutionary history of a major lineage of angiosperms. Based on these results, we present an updated phylogenetic classification for magnoliids, recognizing 21 families, summarizing previously established subfamilies and tribes, and describing new tribes for Myristicaceae.</p>\u0000 </section>\u0000 </div>","PeriodicalId":7691,"journal":{"name":"American Journal of Botany","volume":"112 1","pages":""},"PeriodicalIF":2.4,"publicationDate":"2025-01-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11744432/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142982448","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":"Rapid detection of RNase-based self-incompatibility in Lysimachia monelli (Primulaceae)","authors":"Karolis Ramanauskas,&nbsp;Francisco J. Jiménez-López,&nbsp;Mercedes Sánchez-Cabrera,&nbsp;Marcial Escudero,&nbsp;Pedro L. Ortiz,&nbsp;Montserrat Arista,&nbsp;Boris Igić","doi":"10.1002/ajb2.16449","DOIUrl":"10.1002/ajb2.16449","url":null,"abstract":"<div>\u0000 \u0000 \u0000 <section>\u0000 \u0000 <h3> Premise</h3>\u0000 \u0000 <p>Primroses famously employ a system that simultaneously expresses distyly and filters out self-pollen. Other species in the Primulaceae family, including <i>Lysimachia monelli</i> (blue pimpernel), also express self-incompatibility (SI), but involving a system with distinct features and an unknown molecular genetic basis.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Methods</h3>\u0000 \u0000 <p>We utilize a candidate-based transcriptome sequencing (RNA-seq) approach, relying on candidate T2/S-RNase Class III and S-linked F-box-motif-containing genes and harnessing the unusual evolutionary and genetic features of SI, to examine whether an RNase-based mechanism underlies SI in <i>L. monelli</i>. We term this approach \"SI detection with RNA-seq\" (SIDR).</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Results</h3>\u0000 \u0000 <p>The results of sequencing, crossing, population genetics, and molecular evolutionary features each support a causal association linking the recovered genotypes with SI phenotypes. The finding of RNase-based SI in Primulaceae (Ericales) all but cements the long-held view that this mechanism was present in the ancestral pentapetal eudicot, whose descendants now comprise two-thirds of angiosperms. It also significantly narrows the plausible maximum age for the heterostyly evolution within the family.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Conclusions</h3>\u0000 \u0000 <p>SIDR is powerful, flexible, inexpensive, and most critically enables work in often-neglected species. It may be used with or without candidate genes to close enormous gaps in understanding the genetic basis of SI and the history of breeding system evolution.</p>\u0000 </section>\u0000 </div>","PeriodicalId":7691,"journal":{"name":"American Journal of Botany","volume":"112 1","pages":""},"PeriodicalIF":2.4,"publicationDate":"2025-01-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11744440/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142976988","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":"Comparative diversification analyses of Hydrangeaceae and Loasaceae reveal complex evolutionary history as species disperse out of Mesoamerica","authors":"John J. Schenk,&nbsp;Sarah Jacobs,&nbsp;Larry Hufford","doi":"10.1002/ajb2.16455","DOIUrl":"10.1002/ajb2.16455","url":null,"abstract":"<div>\u0000 \u0000 \u0000 <section>\u0000 \u0000 <h3> Premise</h3>\u0000 \u0000 <p>The movement of lineages into novel areas can promote ecological opportunity and adaptive radiation, leading to significant species diversity. Not all studies, however, have identified support for ecological opportunity associated with novel intercontinental colonizations. To gain key insights into the drivers of ecological opportunity, we tested whether intercontinental dispersals resulted in ecological opportunity using the Hydrangeaceae-Loasaceae clade, which has numerous centers of diversity across the globe.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Methods</h3>\u0000 \u0000 <p>A time-calibrated phylogeny was reconstructed from four molecular markers. We tested for bursts of speciation rates followed by a decrease as expected phylogenetic patterns under an ecological opportunity model. Ancestral ranges were estimated using historical biogeographic analyses to examine the relationships of ancestral distributions and habitats with speciation and extinction rates.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Results</h3>\u0000 \u0000 <p>Hydrangeaceae and Loasaceae originated in arid Mesoamerica, then dispersed into South America, Eurasia, and eastern North America. Six clades experienced increased diversification rates, but those increases were not associated with transitions into new continental areas. <i>Mentzelia</i> section <i>Bartonia</i> was the only clade that exhibited a burst of speciation followed by a decrease. Both families originated in arid environments and experienced multiple transitions into mesic and tropical environments, but Loasaceae experienced a higher speciation-to-extinction ratio than Hydrangeaceae in the western Nearctic.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Conclusions</h3>\u0000 \u0000 <p>Dispersal between continents did not trigger speciation rate shifts in Loasaceae and Hydrangeaceae. Instead, shifts occurred in regions inhabited by intrafamilial relatives and were likely driven by climate change in the Miocene, where species in drier microhabitats diversified into newly created habitats.</p>\u0000 </section>\u0000 </div>","PeriodicalId":7691,"journal":{"name":"American Journal of Botany","volume":"112 1","pages":""},"PeriodicalIF":2.4,"publicationDate":"2025-01-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11744445/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142969510","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":"Flood-driven survival and growth of dominant C4 grasses helps set their distributions along tallgrass prairie moisture gradients","authors":"Robert W. Wernerehl,&nbsp;Thomas J. Givnish","doi":"10.1002/ajb2.16457","DOIUrl":"10.1002/ajb2.16457","url":null,"abstract":"<div>\u0000 \u0000 \u0000 <section>\u0000 \u0000 <h3> Premise</h3>\u0000 \u0000 <p>Five C₄ grasses (<i>Bouteloua curtipendula</i>, <i>Schizachyrium scoparium</i>, <i>Andropogon gerardii</i>, <i>Sorghastrum nutans</i>, <i>Spartina pectinata</i>) dominate different portions of a moisture gradient from dry to wet tallgrass prairies in the Upper Midwest of the United States. We hypothesized that their distributions may partly reflect differences in flooding tolerance and context-specific growth relative to each other.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Methods</h3>\u0000 \u0000 <p>We tested these ideas with greenhouse flooding and drought experiments, outdoor mesocosm experiments, and a natural experiment involving a month-long flood in two wet-mesic prairies.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Results</h3>\u0000 \u0000 <p><i>Bouteloua</i> promptly succumbed to inundation, so flooding intolerance likely excludes it from wet and wet-mesic prairies. Competition is likely to exclude short-statured <i>Bouteloua</i> from productive mesic sites. <i>Schizachyrium</i> is excluded from wet prairies by low flooding tolerance, demonstrated by all experiments. <i>Sorghastrum</i> had low flooding tolerance in both greenhouse and natural experiments, suggesting that physiological intolerance excludes it from wet prairies. <i>Spartina</i> had by far the greatest growth under the wettest mesocosm conditions; this and comparisons of species growth in monocultures vs. mixtures suggests that competition helps it dominate wet prairies. Indeed, quadrat presence of <i>Spartina</i> increased by 57% two years after flooding of two prairies, while that of upland grasses declined by 44%. The high flooding tolerance, lack of significant differences from other species in drought tolerance, and tall stature of <i>Andropogon</i> suggest that broad physiological tolerance combined with competitive ability allows it to thrive across the prairie moisture gradient.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Conclusions</h3>\u0000 \u0000 <p>Flooding helps shape the distributions of dominant prairie grasses, and its effects may become more important as extreme rain events continue to increase.</p>\u0000 </section>\u0000 </div>","PeriodicalId":7691,"journal":{"name":"American Journal of Botany","volume":"112 1","pages":""},"PeriodicalIF":2.4,"publicationDate":"2025-01-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11744443/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142942644","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":"Multiple genotypes of Phelipanche ramosa indicate repeated introduction to the Americas","authors":"Adam C. Schneider","doi":"10.1002/ajb2.16456","DOIUrl":"10.1002/ajb2.16456","url":null,"abstract":"<div>\u0000 \u0000 \u0000 <section>\u0000 \u0000 <h3> Premise</h3>\u0000 \u0000 <p><i>Phelipanche ramosa</i> is an economically damaging parasitic plant that has been reported in North America since the late 1800s. While this species comprises a variety of genetically distinct host races in its native range, the genetic composition of adventive populations in the New World remains unexplored. On the basis of morphological and ecological variation, some have suggested that the closely related <i>P. nana</i> may also be present.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Methods</h3>\u0000 \u0000 <p>Genome skimming was used to assess the relationships of 30 populations of <i>Phelipanche</i> spanning the geographic and host ranges in North and South America, plus one <i>P. nana</i> reference population from Lebanon.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Results</h3>\u0000 \u0000 <p>Phylogenetic analysis indicated four distinct genetic groups, though plastome and nrDNA data supported conflicting signals of relationships among them. First, specimens from Chilean tomato fields were nearly indistinguishable genetically from the reference <i>P. nana</i>. Second, a pair of samples from Virginia showed similar nrDNA as the first group, but divergent plastomes. The remaining 24 samples sorted into two groups, one which parasitizes cultivated plants, especially tomato, and the other on roadside weeds in different parts of the United States.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Conclusions</h3>\u0000 \u0000 <p>The geographic and ecological cohesiveness of four distinct genetic groups supports a hypothesis of multiple introductions to the Americas, presumably from Eurasia, followed by little to no subsequent gene flow among them. However, such groups do not align with existing morphological or ecological species concepts for <i>P. ramosa</i> and <i>P. nana</i>. In practice, threat assessment of <i>Phelipanche</i> populations to agricultural settings should be evaluated regionally given the phylogeographic and ecological heterogeneity.</p>\u0000 </section>\u0000 </div>","PeriodicalId":7691,"journal":{"name":"American Journal of Botany","volume":"112 1","pages":""},"PeriodicalIF":2.4,"publicationDate":"2025-01-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11744424/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142998689","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":"Fire in the tree: The origin and distribution of fire–adapted traits within conifers and their influence on speciation rates across the conifer phylogeny","authors":"Daniel F. Turck,&nbsp;Orlando Schwery,&nbsp;Luke J. Harmon,&nbsp;David C. Tank","doi":"10.1002/ajb2.16454","DOIUrl":"10.1002/ajb2.16454","url":null,"abstract":"<div>\u0000 \u0000 \u0000 <section>\u0000 \u0000 <h3> Premise</h3>\u0000 \u0000 <p>Considering rapidly changing fire regimes due to anthropogenic disturbances to climate and fuel loads, it is crucial to understand the underpinnings driving fire-adapted trait evolution. Among the oldest lineages affected by fire is Coniferae. This lineage occupies a variety of fire prone and non-fire prone habitats across all hemispheres and has four fire-adapted traits: (1) thick bark; (2) serotiny; (3) seedling grass stage; and (4) resprouting ability. We seek to determine the historic origins of these traits, the degree of convergent evolution among species, how fire adaptations affect diversification rates in conifers, and if there is a link between climate and the evolution of fire adaptations.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Methods</h3>\u0000 \u0000 <p>To investigate these questions, we use a combination of ancestral state reconstructions, multiple diversification analyses, and Pagel trait correlations.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Results</h3>\u0000 \u0000 <p>Our results point to multiple evolutionary origins of fire adaptations. We find certain climates, particularly Subtropical and Mediterranean, are highly correlated with species possessing fire adaptations. Several lineages evolved fire adaptations after the Mid-Miocene Climactic Optimum, which coincides with the expansion of the then novel Mediterranean Climate type. Generally possessing a fire adaptation does not increase diversification rates, with the possible exceptions of <i>Pinus</i> subsections <i>Australes</i> and <i>Ponderosae</i>.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Conclusions</h3>\u0000 \u0000 <p>The appearance of novel climates and associated fire regimes seem to have been the primary drivers of fire adaptation evolution in conifers. However, most increases in diversification rates are within clades that responded favorably to cooler drier climates post Mid-Miocene Climactic Optimum, regardless of whether the clade is fire adapted.</p>\u0000 </section>\u0000 </div>","PeriodicalId":7691,"journal":{"name":"American Journal of Botany","volume":"112 1","pages":""},"PeriodicalIF":2.4,"publicationDate":"2025-01-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142926286","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 geographic scale of population-level variation in growth and nodulation differs for two species of prairie clover","authors":"Adrien C. M. Pozzi,&nbsp;Ruth G. Shaw,&nbsp;Georgiana May","doi":"10.1002/ajb2.16450","DOIUrl":"10.1002/ajb2.16450","url":null,"abstract":"<div>\u0000 \u0000 \u0000 <section>\u0000 \u0000 <h3> Premise</h3>\u0000 \u0000 <p>Prairies are among the most threatened biomes due to changing patterns of climate and land use, yet information on genetic variation in key species that would inform conservation is often limited. We assessed evidence for the geographic scale of population-level variation in growth of two species of prairie clover and of their symbiotic associations with nitrogen-fixing bacteria.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Methods</h3>\u0000 \u0000 <p>Seed representing two species, <i>Dalea candida</i> and <i>D. purpurea</i>, from the same five source populations were planted into an experimental site in Minnesota. We assessed variation within and among source populations in plant growth and in numbers of nodules and evaluated the relationship of growth and nodulation levels.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Results</h3>\u0000 \u0000 <p>Plant growth varied among source populations, with greater differences among populations of <i>D. purpurea</i> than of <i>D. candida</i>. We did not detect a relationship between plant growth and distance of source populations from the experimental site. Populations of both species were equally likely to develop nodules at the experimental site, but the numbers of nodules were lowest for the most distantly sourced populations. Plant growth was positively correlated with the number of nodules, and this relationship varied considerably within and among populations.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Conclusions</h3>\u0000 \u0000 <p>Environmental heterogeneity at local and regional scales maintains substantial levels of genetic variation in plant populations within remnant prairie preserves. Further, association with rhizobia at a restoration site can improve growth of widely sourced plant populations. The in situ maintenance of plant genetic variation and species diversity provides resources for conservation and maintenance of prairie biomes.</p>\u0000 </section>\u0000 </div>","PeriodicalId":7691,"journal":{"name":"American Journal of Botany","volume":"112 1","pages":""},"PeriodicalIF":2.4,"publicationDate":"2025-01-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142926288","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 memory of past water abundance shapes trees 7 years later","authors":"Alana R. O. Chin,&nbsp;Arthur Gessler,&nbsp;Omar Laín,&nbsp;Isabella Østerlund,&nbsp;Marcus Schaub,&nbsp;Guillaume Théroux-Rancourt,&nbsp;Klara Voggeneder,&nbsp;Janneke Hille Ris Lambers","doi":"10.1002/ajb2.16452","DOIUrl":"10.1002/ajb2.16452","url":null,"abstract":"<div>\u0000 \u0000 \u0000 <section>\u0000 \u0000 <h3> Premise</h3>\u0000 \u0000 <p>Tree structure and function are constrained by and acclimate to climatic conditions. Drought limits plant growth and carbon acquisition and can result in “legacy” effects that last beyond the period of water stress. Leaf and twig-level legacy effects of past water abundance, such as that experienced by trees that established under wetter conditions are unknown.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Methods</h3>\u0000 \u0000 <p>In an 18-year forest irrigation experiment, we explored the lasting structural impact of past water richness on leaves and twigs of <i>Pinus sylvestris</i> using synchrotron-based X-ray microscopy. We compared 47 anatomical traits among never-irrigated control trees, trees irrigated for 18 years, and formerly irrigated trees, 7 years after their return to control-level water availability in this naturally dry forest.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Results</h3>\u0000 \u0000 <p>We found that legacy effects induced by a period of experimental irrigation continue to shape the structure of new leaves and twigs long after a sharp decrease in water availability. Legacy effects shaping twigs were present but dissipating, while leaf traits displayed long-lasting effects on structural strategy, with extreme values for traits associated with high water stress and low productivity.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Conclusions</h3>\u0000 \u0000 <p>Mature trees acclimating to an increasingly dry world may be at a disadvantage compared to young trees that have known only chronic drought. However, these young trees may be capable of thriving in sites of drought-related forest decline especially if planted while larger individuals are still present to support tree establishment. Without a legacy of past water abundance, trees in future forests may be better equipped to cope with our rapidly changing climate.</p>\u0000 </section>\u0000 </div>","PeriodicalId":7691,"journal":{"name":"American Journal of Botany","volume":"112 1","pages":""},"PeriodicalIF":2.4,"publicationDate":"2024-12-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142880873","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":"Spatiotemporal variation in population dynamics of a narrow endemic, Ranunculus austro-oreganus","authors":"Riley D. Thoen,&nbsp;Lauren B. Hendricks,&nbsp;Graham T. Bailes,&nbsp;Bart R. Johnson,&nbsp;Laurel Pfeifer-Meister,&nbsp;Paul B. Reed,&nbsp;Bitty A. Roy,&nbsp;Megan L. DeMarche","doi":"10.1002/ajb2.16446","DOIUrl":"10.1002/ajb2.16446","url":null,"abstract":"<div>\u0000 \u0000 \u0000 <section>\u0000 \u0000 <h3> Premise</h3>\u0000 \u0000 <p>Understanding how population dynamics vary in space and time is critical for understanding the basic life history and conservation needs of a species, especially for narrow endemic species whose populations are often in similar environments and therefore at increased risk of extinction under climate change. Here, we investigated the spatial and temporal variation in population dynamics of <i>Ranunculus austro-oreganus</i>, a perennial buttercup endemic to fragmented prairie habitat in one county in southern Oregon.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Methods</h3>\u0000 \u0000 <p>We performed demographic surveys of three populations of <i>R. austro-oreganus</i> over 4 years (2015–2018). We used size-structured population models and life table response experiments to investigate vital rates driving spatiotemporal variation in population growth.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Results</h3>\u0000 \u0000 <p>Overall, <i>R. austro-oreganus</i> had positive or stable stochastic population growth rates, though individual vital rates and overall population growth varied substantially among sites and years. All populations had their greatest growth in the same year, suggesting potential synchrony associated with climate conditions. Differences in survival contributed most to spatial variation in population growth, while differences in reproduction contributed most to temporal variation in population growth.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Conclusions</h3>\u0000 \u0000 <p>Populations of this extremely narrow endemic appear stable, with positive growth during our study window. These results suggest that populations of <i>R. austro-oreganus</i> are able to persist if their habitat is not eliminated by land-use change. Nonetheless, its narrow distribution and synchronous population dynamics suggest the need for continued monitoring, particularly with ongoing habitat loss and climate change.</p>\u0000 </section>\u0000 </div>","PeriodicalId":7691,"journal":{"name":"American Journal of Botany","volume":"112 1","pages":""},"PeriodicalIF":2.4,"publicationDate":"2024-12-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11744433/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142845590","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":"Within-leaf variation in embolism resistance is not a rule for compound-leaved angiosperms","authors":"Ian M. Rimer,&nbsp;Scott A. M. McAdam","doi":"10.1002/ajb2.16447","DOIUrl":"10.1002/ajb2.16447","url":null,"abstract":"<div>\u0000 \u0000 \u0000 <section>\u0000 \u0000 <h3> Premise</h3>\u0000 \u0000 <p>Hydraulic segmentation, caused by the difference in embolism resistance across plant organs, provides a sacrificial layer of cheaper plant organs, like leaves, to protect more costly organs, such as stems, during drought. Within-leaf hydraulic segmentation has been observed in two compound-leaved tree species, with leaflets being more vulnerable than the rachis or petiole. Many herbaceous species have compound leaves, and some species have leaflets that are associated with pulvini at the base of the lamina, which could provide an anatomical means of preventing embolism from spreading within a leaf because of the higher number of vessel endings in the pulvinus.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Methods</h3>\u0000 \u0000 <p>We used the optical vulnerability method to investigate whether differences in embolism resistance were observed across the leaf tissues of six herbaceous species and one deciduous tree species with compound leaves. Our species selection included both palmately and pinnately-compound leaved species, one of each with a pulvinus at the base of the leaflets.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Results</h3>\u0000 \u0000 <p>We found considerable variation in embolism resistance across the species measured, but no evidence of variation in embolism resistance within the leaf. In two species with pulvini, we observed major embolism events crossing the pulvinus, spreading from the rachis or petiole into the lamina, and embolizing both tissues at the same water potential.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Conclusions</h3>\u0000 \u0000 <p>We conclude that within-leaf hydraulic segmentation, caused by variation in embolism resistance, is not a universal phenomenon to compound-leaved species and that the presence of a pulvinus does not provide a barrier to embolism spread in compound leaves.</p>\u0000 </section>\u0000 </div>","PeriodicalId":7691,"journal":{"name":"American Journal of Botany","volume":"111 12","pages":""},"PeriodicalIF":2.4,"publicationDate":"2024-12-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/ajb2.16447","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142833550","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}