American Journal of Botany最新文献

{"title":"Salt tolerance in a neotropical orchid in the absence of local adaptation to salt spray","authors":"Thales M. de Lima,&nbsp;Simone F. Silva,&nbsp;Rafael V. Ribeiro,&nbsp;Julia Sánchez-Vilas,&nbsp;Fabio Pinheiro","doi":"10.1002/ajb2.16373","DOIUrl":"10.1002/ajb2.16373","url":null,"abstract":"<div>\u0000 \u0000 \u0000 <section>\u0000 \u0000 <h3> Premise</h3>\u0000 \u0000 <p>Salt tolerance has rarely been investigated regionally in the neotropics and even more rarely in Orchidaceae, one of the largest families. Therefore, investigating local adaptation to salt spray and its physiological basis in <i>Epidendrum fulgens</i>, a neotropical orchid species, brings important new insights.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Methods</h3>\u0000 \u0000 <p>We assessed the degree of salt tolerance in <i>E. fulgens</i> by testing whether coastal populations are more tolerant to salt, which could point to local adaptation. To understand the physiological basis of such salt tolerance, we exposed wild-collected individuals to salt spray for 60 days, then measured leaf expansion, osmotic potential, sodium leaf concentration, chlorophyll leaf index, chlorophyll fluorescence, relative growth rate, and pressure–volume curves.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Results</h3>\u0000 \u0000 <p>There is no local adaptation to salt spray since both inland and coastal plants have a high tolerance to salt stress. This tolerance is explained by the ability to tolerate high concentrations of salt in leaf tissues, which is related to the high succulence displayed by this species.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Conclusions</h3>\u0000 \u0000 <p>We showed an unprecedented salt tolerance level for an orchid species, highlighting our limited knowledge of that trait beyond the traditional studied groups. Another interesting finding is that salt tolerance in <i>E. fulgens</i> is linked to succulence, is widespread, and is not the result of local adaptation. We suggest that <i>E. fulgens</i> and its allied species could be an interesting group to explore the evolution of important traits related to tolerance to salt stress, like succulence.</p>\u0000 </section>\u0000 </div>","PeriodicalId":7691,"journal":{"name":"American Journal of Botany","volume":"111 7","pages":""},"PeriodicalIF":2.4,"publicationDate":"2024-07-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141619089","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":"Effects of anther-stigma position on cross-pollination efficiency in a hermaphroditic plant","authors":"Matias C. Baranzelli,&nbsp;Manuel Ochoa-Sánchez,&nbsp;Sergio E. Ramos,&nbsp;Fernanda Baena-Díaz,&nbsp;Paula Sosenski,&nbsp;Karina Boege,&nbsp;Cesar A. Domínguez,&nbsp;Juan Fornoni","doi":"10.1002/ajb2.16377","DOIUrl":"10.1002/ajb2.16377","url":null,"abstract":"<div>\u0000 \u0000 \u0000 <section>\u0000 \u0000 <h3> Premise</h3>\u0000 \u0000 <p>Evolution of cross-pollination efficiency depends on the genetic variation of flower traits, the pollen vector, and flower trait matching between pollen donors and recipients. Trait matching has been almost unexplored among nonheterostylous species, and we examined whether the match of anther length in pollen donors and stigma length in pollen recipients influences the efficiency of cross-pollination. To explore potential constraints for evolutionary response, we also quantified genetic variation and covariation among sepal length, petal length and width, stamen length, style length, and herkogamy.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Methods</h3>\u0000 \u0000 <p>We created 58 experimental arrays of <i>Turnera velutina</i> that varied in the extent of mismatch in the position of anthers and stigmas between single-flowered plants. Genetic variation and correlations among flower traits were estimated under greenhouse conditions.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Results</h3>\u0000 \u0000 <p>Style length, but not herkogamy, influenced the efficiency of cross-pollination. Plants with stamen length that matched the style length of other plants were more efficient pollen donors, whereas those with the style protruding above the stamens of other plants were more efficient pollen recipients. Significant broad-sense heritability (0.22 &gt; <i>h</i>_B² &lt; 0.42) and moderate genetic correlations (0.33 &gt; <i>r</i> &lt; 0.85) among floral traits were detected.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Conclusions</h3>\u0000 \u0000 <p>Our results demonstrated that anther-stigma mismatch between flowers contributed to variation in the efficiency of cross-pollination. The genetic correlations between stamen length and other floral traits suggests that any change in cross-pollination efficiency would be driven by changes in style rather than in stamen length.</p>\u0000 </section>\u0000 </div>","PeriodicalId":7691,"journal":{"name":"American Journal of Botany","volume":"111 7","pages":""},"PeriodicalIF":2.4,"publicationDate":"2024-07-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/ajb2.16377","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141619088","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":"The timing of visits by large and small bees differentially affects pollination success in Mimulus ringens","authors":"Randall J. Mitchell,&nbsp;Dana Starvaggi,&nbsp;Victor Fitzgerald,&nbsp;Jeffrey D. Karron","doi":"10.1002/ajb2.16375","DOIUrl":"10.1002/ajb2.16375","url":null,"abstract":"<div>\u0000 \u0000 \u0000 <section>\u0000 \u0000 <h3> Premise</h3>\u0000 \u0000 <p>Cross-fertilization in most flowering plants is facilitated by mobile animals that transport pollen while foraging for floral rewards. The contributions of different visitors can vary widely, depending on the amount of pollen transferred during a single visit and on the frequency and timing of the visits of each pollinator taxon.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Methods</h3>\u0000 \u0000 <p>We used three approaches to measure the pollination value of bees that visit <i>Mimulus ringens</i>: pollinator interviews, field population observations, and caging studies.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Results</h3>\u0000 \u0000 <p>The single-visit effectiveness of small bees (primarily Halictidae) was only half that of larger bees (primarily <i>Bombus</i>) for pollen delivery and removal. In five field populations, we found substantial temporal and spatial variation in visitation and pollination. In most sites big bees were active before 08:00 hours, and by 10:00–11:00 hours, stigmas were usually fully pollinated and closed, and little pollen remained in anthers. Small bees seldom visited before 10:00 hours. Excluding big bees from plants confirmed that pollination is reduced and delayed in this ecological context.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Conclusions</h3>\u0000 \u0000 <p>Big bees are the primary pollinators of <i>M. ringens</i>, accounting for at least 75% of seed production. Not only are they more effective per visit, in most situations they also visit before small bees become active. Although small bees are not usually important pollinators of <i>M. ringens</i>, they have the potential to partially replace them as a “fail-safe” pollinator in contexts where big bees are not abundant. In a world where pollinator abundance is declining, such backup pollinators may be important for maintaining plant reproduction.</p>\u0000 </section>\u0000 </div>","PeriodicalId":7691,"journal":{"name":"American Journal of Botany","volume":"111 7","pages":""},"PeriodicalIF":2.4,"publicationDate":"2024-07-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/ajb2.16375","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141615764","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":"Striking genetic homogeneity in the widespread South American bracken","authors":"Agustina Yañez,&nbsp;Sylvia P. Kinosian,&nbsp;M. Mónica Ponce,&nbsp;Diego G. Gutierrez,&nbsp;Pedro B. Schwartsburd,&nbsp;Michael Sundue,&nbsp;Paul G. Wolf","doi":"10.1002/ajb2.16374","DOIUrl":"10.1002/ajb2.16374","url":null,"abstract":"<div>\u0000 \u0000 \u0000 <section>\u0000 \u0000 <h3> Premise</h3>\u0000 \u0000 <p>Bracken (<i>Pteridium</i>, Dennstaedtiaceae) is a cosmopolitan genus of aggressive disturbance colonizers that are toxic to agricultural livestock. The taxonomy of <i>Pteridium</i> has been treated in multiple schemes, ranging from one to six species worldwide, with numerous subspecies and varieties. Recent work has focused on the worldwide distribution and systematics of the bracken fern, but South America has been poorly represented. We present the first continent-wide sampling and analysis of <i>Pteridium esculentum</i>, a Southern Hemisphere diploid species.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Methods</h3>\u0000 \u0000 <p>Within South America, <i>P. esculentum</i> has several morphotypes, distinguished into subspecies by variation in indument and lamina architecture. We used double digest restriction site-associated DNA sequencing (ddRADSeq) to assess the phylogenetic relationships of <i>P. esculentum</i> subspecies.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Results</h3>\u0000 \u0000 <p>We found a striking genetic homogeneity in the species, being able to support only two morphotypes from molecular data: <i>P. e. arachnoideum</i> and <i>P. e. campestre</i>. We had high confidence for shallow and deep phylogenetic relationships, but less support for relationships among crown groups.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Conclusions</h3>\u0000 \u0000 <p>We describe an east-west geographic pattern that would explain the relationships between populations; and, in contrast to previous studies, we detected differences with <i>P. esculentum</i> from Australia. These results will lay the foundations for studying variations in this species' behavior as a weed, as well as its impact on the production of agricultural livestock in South America.</p>\u0000 </section>\u0000 </div>","PeriodicalId":7691,"journal":{"name":"American Journal of Botany","volume":"111 7","pages":""},"PeriodicalIF":2.4,"publicationDate":"2024-07-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141598106","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":"High-intensity light promotes adaptive divergence of photosynthetic traits between sun-exposed and shaded populations in Saxifraga fortunei","authors":"Kana Magota,&nbsp;Eiji Gotoh,&nbsp;Shota Sakaguchi,&nbsp;Hajime Ikeda,&nbsp;Hiroaki Setoguchi","doi":"10.1002/ajb2.16371","DOIUrl":"10.1002/ajb2.16371","url":null,"abstract":"<div>\u0000 \u0000 \u0000 <section>\u0000 \u0000 <h3> Premise</h3>\u0000 \u0000 <p>Light is essential for plants, and local populations exhibit adaptive photosynthetic traits depending on their habitats. Although plastic responses in morphological and/or physiological characteristics to different light intensities are well known, adaptive divergence with genetic variation remains to be explored. This study focused on <i>Saxifraga fortunei</i> (Saxifragaceae) growing in sun-exposed and shaded habitats.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Methods</h3>\u0000 \u0000 <p>We measured the leaf anatomical structure and photosynthetic rate of plants grown in their natural habitats and in a common greenhouse (high- and low-intensity light experimental sites). To assess differences in ecophysiological tolerance to high-intensity light between the sun and shade types, we evaluated the level of photoinhibition of photosystem II and the leaf mortality rate under high-intensity light conditions. In addition, population genetic analysis was conducted to investigate phylogenetic origins.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Results</h3>\u0000 \u0000 <p>Clear phenotypic differences were found between the sun and shade types despite their recent phylogenetic origin. The leaf anatomical structure and photosynthetic rate showed plastic changes in response to growing conditions. Moreover, the sun type had a well-developed palisade parenchyma and a higher photosynthetic rate, which were genetically fixed, and a lower level of photoinhibition under high-intensity light.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Conclusions</h3>\u0000 \u0000 <p>Our findings demonstrate that light intensity is a selective pressure that can rapidly promote phenotypic divergence between the sun and shade types. While phenotypic changes in multiple photosynthetic traits were plastic, genetic divergence in specific traits related to adaptation to high-intensity light would be fundamental for ecotypic divergence to different light regimes.</p>\u0000 </section>\u0000 </div>","PeriodicalId":7691,"journal":{"name":"American Journal of Botany","volume":"111 7","pages":""},"PeriodicalIF":2.4,"publicationDate":"2024-07-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141598105","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":"Plastid genome evolution in leafless members of the orchid subfamily Orchidoideae, with a focus on Degranvillea dermaptera","authors":"Craig F. Barrett,&nbsp;Matthew C. Pace,&nbsp;Cameron W. Corbett","doi":"10.1002/ajb2.16370","DOIUrl":"10.1002/ajb2.16370","url":null,"abstract":"<div>\u0000 \u0000 \u0000 <section>\u0000 \u0000 <h3> Premise</h3>\u0000 \u0000 <p>Leafless, heterotrophic plants are prime examples of organismal modification, the genomic consequences of which have received considerable interest. In particular, plastid genomes (plastomes) are being sequenced at a high rate, allowing continual refinement of conceptual models of reductive evolution in heterotrophs. However, numerous sampling gaps exist, hindering the ability to conduct comprehensive phylogenomic analyses in these plants.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Methods</h3>\u0000 \u0000 <p>Using floral tissue from an herbarium specimen, we sequenced and analyzed the plastome of <i>Degranvillea dermaptera</i>, a rarely collected, leafless orchid species from South America about which little is known, including its phylogenetic affinities.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Results</h3>\u0000 \u0000 <p>The plastome is the most reduced of those sequenced among the orchid subfamily Orchidoideae. In <i>Degranvillea</i>, it has lost the majority of genes found in leafy autotrophic species, is structurally rearranged, and has similar gene content to the most reduced plastomes among the orchids. We found strong evidence for the placement of <i>Degranvillea</i> within the subtribe Spiranthinae using models that explicitly account for heterotachy, or lineage-specific evolutionary rate variation over time. We further found evidence of relaxed selection on several genes and of correlations among substitution rates and several other “traits” of the plastome among leafless members of orchid subfamily Orchidoideae.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Conclusions</h3>\u0000 \u0000 <p>Our findings advance knowledge on the phylogenetic relationships and paths of plastid genome evolution among the orchids, which have experienced more independent transitions to heterotrophy than any other plant family. This study demonstrates the importance of herbarium collections in comparative genomics of poorly known species of conservation concern.</p>\u0000 </section>\u0000 </div>","PeriodicalId":7691,"journal":{"name":"American Journal of Botany","volume":"111 7","pages":""},"PeriodicalIF":2.4,"publicationDate":"2024-07-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141578751","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":"Measuring leaf and root functional traits uncovers multidimensionality of plant responses to arbuscular mycorrhizal fungi","authors":"Katherine N. Stahlhut,&nbsp;Deannah G. Neupert,&nbsp;Josie E. Laing,&nbsp;Lydia J. Witt,&nbsp;Jonathan T. Bauer","doi":"10.1002/ajb2.16369","DOIUrl":"10.1002/ajb2.16369","url":null,"abstract":"<div>\u0000 \u0000 \u0000 <section>\u0000 \u0000 <h3> Premise</h3>\u0000 \u0000 <p>While many studies have measured the aboveground responses of plants to mycorrhizal fungi at a single time point, little is known about how plants respond belowground or across time to mycorrhizal symbiosis. By measuring belowground responses and growth over time in many plant species, we create a more complete picture of how mycorrhizal fungi benefit their hosts.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Methods</h3>\u0000 \u0000 <p>We grew 26 prairie plant species with and without mycorrhizal fungi and measured 14 functional traits to assess above- and belowground tissue quality and quantity responses and changes in resource allocation. We used function-valued trait (FVT) modeling to characterize changes in species growth rate when colonized.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Results</h3>\u0000 \u0000 <p>While aboveground biomass responses were positive, the response of traits belowground were much more variable. Changes in aboveground biomass accounted for 60.8% of the variation in mycorrhizal responses, supporting the use of aboveground biomass response as the primary response trait. Responses belowground were not associated with aboveground responses and accounted for 18.3% of the variation. Growth responses over time were highly variable across species. Interestingly, none of the measured responses were phylogenetically conserved.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Conclusions</h3>\u0000 \u0000 <p>Mycorrhizal fungi increase plant growth in most scenarios, but the effects of these fungi belowground and across time are more complicated. This study highlights how differences in plant allocation priorities might affect how they utilize the benefits from mycorrhizal fungi. Identifying and characterizing these differences is a key step to understanding the effects of mycorrhizal mutualisms on whole plant physiology.</p>\u0000 </section>\u0000 </div>","PeriodicalId":7691,"journal":{"name":"American Journal of Botany","volume":"111 7","pages":""},"PeriodicalIF":2.4,"publicationDate":"2024-07-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/ajb2.16369","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141578750","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":"Evidence for human-caused founder effect in populations of Solanum jamesii at archaeological sites: II. Genetic sequencing establishes ancient transport across the Southwest USA","authors":"Bruce M. Pavlik,&nbsp;Alfonso del Rio,&nbsp;John Bamberg,&nbsp;Lisbeth A. Louderback","doi":"10.1002/ajb2.16365","DOIUrl":"10.1002/ajb2.16365","url":null,"abstract":"<div>\u0000 \u0000 \u0000 <section>\u0000 \u0000 <h3> Premise</h3>\u0000 \u0000 <p>The domestication of wild plant species can begin with gathering and transport of propagules by Indigenous peoples. The effect on genomic composition, especially in clonal, self-incompatible perennials would be instantaneous and drastic with respect to new, anthropogenic populations subsequently established. Reductions in genetic diversity and mating capability would be symptomatic and the presence of unique alleles and genetic sequences would reveal the origins and ancestry of populations associated with archaeological sites. The current distribution of the Four Corners potato, <i>Solanum jamesii</i> Torr. in the Southwestern USA, may thus reflect the early stages of a domestication process that began with tuber transport.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Methods</h3>\u0000 \u0000 <p>Herein genetic sequencing (GBS) data are used to further examine the hypothesis of domestication in this culturally significant species by sampling 25 archaeological and non-archaeological populations.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Results</h3>\u0000 \u0000 <p>Archaeological populations from Utah, Colorado and northern Arizona have lower levels of polymorphic loci, unique alleles, and heterozygosity than non-archaeological populations from the Mogollon region of central Arizona and New Mexico. Principle components analysis, Fst values, and structure analysis revealed that genetic relationships among archaeological populations did not correspond to geographic proximity. Populations in Escalante, Utah were related to those on the Mogollon Rim (400 km south) and had multiple origins and significant disjunctions with those populations in Bears Ears, Chaco Canyon, and Mesa Verde sites.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Conclusions</h3>\u0000 \u0000 <p>Movement of tubers from the Mogollon region may have occurred many times and in multiple directions during the past, resulting in the complex genetic patterns seen in populations from across the Four Corners region.</p>\u0000 </section>\u0000 </div>","PeriodicalId":7691,"journal":{"name":"American Journal of Botany","volume":"111 7","pages":""},"PeriodicalIF":2.4,"publicationDate":"2024-07-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/ajb2.16365","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141589380","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":"An evolutionary disruption of the buzz pollination syndrome in neotropical montane plants","authors":"Eduardo K. Nery,&nbsp;Mayara K. Caddah,&nbsp;Fabian A. Michelangeli,&nbsp;Anselmo Nogueira","doi":"10.1002/ajb2.16367","DOIUrl":"10.1002/ajb2.16367","url":null,"abstract":"<div>\u0000 \u0000 \u0000 <section>\u0000 \u0000 <h3> Premise</h3>\u0000 \u0000 <p>Under pollinator limitations, specialized pollination syndromes may evolve toward contrasting responses: a generalized syndrome with increased pollinator attraction, pollinator reward, and pollen transfer capacity; or the selfing syndrome with increased self-pollen deposition, but reduced pollinator attraction and pollen transfer capacity. The buzz-pollination syndrome is specialized to explore female vibrating bees as pollinators. However, vibrating bees become less-active pollinators at montane areas of the Atlantic Forest (AF) domain. This study investigated whether the specialized buzz-pollination syndrome would evolve toward an alternative floral syndrome in montane areas of the AF domain, considering a generalized and the selfing syndromes as alternative responses.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Methods</h3>\u0000 \u0000 <p>We utilized a lineage within the buzz-pollinated <i>Miconia</i> as study system, contrasting floral traits between montane AF-endemic and non-endemic species. We measured and validated floral traits that were proxies for pollinator attraction, reward access, pollen transfer capacity, and self-pollen deposition. We inferred the evolution of floral trait via phylogenetic comparative methods.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Results</h3>\u0000 \u0000 <p>AF-endemic species have selectively evolved greater reward access and more frequently had generalist pollination. Nonetheless, AF-endemic species also have selectively evolved toward lower pollen transfer capacity and greater self pollination. These patterns indicated a complex evolutionary process that has jointly favored a generalized and the selfing syndromes.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Conclusions</h3>\u0000 \u0000 <p>The buzz pollination syndrome can undergo an evolutionary disruption in montane areas of the AF domain. This floral syndrome is likely more labile than often assumed, allowing buzz-pollinated plants to reproduce in environments where vibrating bees are less-reliable pollinators.</p>\u0000 </section>\u0000 </div>","PeriodicalId":7691,"journal":{"name":"American Journal of Botany","volume":"111 7","pages":""},"PeriodicalIF":2.4,"publicationDate":"2024-07-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141490595","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":"Nitrogen-fixing bacteria boost floral attractiveness in a tropical legume species during nutrient limitation","authors":"Caroline Souza,&nbsp;Lorena B. Valadão-Mendes,&nbsp;Isadora Schulze-Albuquerque,&nbsp;Pedro J. Bergamo,&nbsp;Douglas D. Souza,&nbsp;Anselmo Nogueira","doi":"10.1002/ajb2.16363","DOIUrl":"10.1002/ajb2.16363","url":null,"abstract":"<div>\u0000 \u0000 \u0000 <section>\u0000 \u0000 <h3> Premise</h3>\u0000 \u0000 <p>Legumes establish mutualistic interactions with pollinators and nitrogen (N)-fixing bacteria that are critical for plant reproduction and ecosystem functioning. However, we know little about how N-fixing bacteria and soil nutrient availability affect plant attractiveness to pollinators.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Methods</h3>\u0000 \u0000 <p>In a two-factorial greenhouse experiment to assess the impact of N-fixing bacteria and soil types on floral traits and attractiveness to pollinators in <i>Chamaecrista latistipula</i> (Fabaceae), plants were inoculated with N-fixing bacteria (NF+) or not (NF-) and grown in N-rich organic soil (+N organic soil) or N-poor sand soil (-N sand soil). We counted buds and flowers and measured plant size during the experiment. We also measured leaf, petal, and anther reflectance with a spectrophotometer and analyzed reflectance curves. Using the bee hexagon model, we estimated chromatic contrasts, a crucial visual cues for attracting bees that are nearby and more distant.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Results</h3>\u0000 \u0000 <p>NF+ plants in -N sand soil had a high floral display and color contrasts. On the other hand, NF- plants and/or plants in +N organic soil had severely reduced floral display and color contrasts, decreasing floral attractiveness to bee pollinators.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Conclusions</h3>\u0000 \u0000 <p>Our findings indicate that the N-fixing bacteria positively impact pollination, particularly when nutrients are limited. This study provides insights into the dynamics of plant–pollinator interactions and underscores the significant influence of root symbionts on key floral traits within tropical ecosystems. These results contribute to understanding the mechanisms governing mutualisms and their consequences for plant fitness and ecological dynamics.</p>\u0000 </section>\u0000 </div>","PeriodicalId":7691,"journal":{"name":"American Journal of Botany","volume":"111 12","pages":""},"PeriodicalIF":2.4,"publicationDate":"2024-07-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141490596","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}