Connor N. Morozumi, Allison M. Reitman, Katy D. Heath, Posy E. Busby, Natalie Christian
Understanding and predicting plant responses to biotic and abiotic environments necessitates grappling with thousands of microbial interactions occurring within aboveground and belowground plant tissues. These distinct microbial communities are indirectly connected through their plant hosts, and aboveground-belowground (AGBG) microbial interactions could play large roles in plant health and drive plant community and ecosystem-level responses. In this review and synthesis, we first discuss mechanisms through which focal microbes directly and indirectly affect other microbes in distal plant compartments. We then add in a layer of complexity: How might microbial community interactions within aboveground plant organs affect root-associated microbiomes, and vice versa? We point to gaps in our knowledge that should drive future research agendas on how “discrete” microbial communities within plants influence one another—a key feature currently missing in plant microbiome research. We also discuss the utility of applying existing ecological theory to enhance the predictive power of plant microbiome research, particularly regarding the outcomes of AGBG microbial interactions across diverse environmental and ecological contexts. These efforts will be especially important within fields such as sustainable agriculture that seek to harness plant-microbiome interactions within a changed and ever-changing world.
{"title":"Aboveground-belowground microbial interactions in plants: A call to recognize the complexity within multispecies microbial communities","authors":"Connor N. Morozumi, Allison M. Reitman, Katy D. Heath, Posy E. Busby, Natalie Christian","doi":"10.1002/ajb2.70100","DOIUrl":"10.1002/ajb2.70100","url":null,"abstract":"<p>Understanding and predicting plant responses to biotic and abiotic environments necessitates grappling with thousands of microbial interactions occurring within aboveground and belowground plant tissues. These distinct microbial communities are indirectly connected through their plant hosts, and aboveground-belowground (AGBG) microbial interactions could play large roles in plant health and drive plant community and ecosystem-level responses. In this review and synthesis, we first discuss mechanisms through which focal microbes directly and indirectly affect other microbes in distal plant compartments. We then add in a layer of complexity: How might microbial community interactions within aboveground plant organs affect root-associated microbiomes, and vice versa? We point to gaps in our knowledge that should drive future research agendas on how “discrete” microbial communities within plants influence one another—a key feature currently missing in plant microbiome research. We also discuss the utility of applying existing ecological theory to enhance the predictive power of plant microbiome research, particularly regarding the outcomes of AGBG microbial interactions across diverse environmental and ecological contexts. These efforts will be especially important within fields such as sustainable agriculture that seek to harness plant-microbiome interactions within a changed and ever-changing world.</p>","PeriodicalId":7691,"journal":{"name":"American Journal of Botany","volume":"112 9","pages":""},"PeriodicalIF":2.7,"publicationDate":"2025-09-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://bsapubs.onlinelibrary.wiley.com/doi/epdf/10.1002/ajb2.70100","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145084775","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}
Anthropogenic activities such as fossil fuel combustion and synthetic fertilizer synthesis have resulted in nitrogen (N) deposition and elevated N availability in ecosystems. Many parasitic plants are adapted to low N environments and have evolved mechanisms to sequester water, N, and other limiting nutrients from hosts. Anthropogenic N deposition may perturb these host–parasite interactions, thereby altering nutrient cycling and ultimately reducing biodiversity.
Methods
To test how N enrichment affects the incidence and degree of plant parasitism, we assayed host–parasite performance and in vitro root growth under supplemental N levels representative of urban areas experiencing N deposition. We focused on the annual hemiparasite Castilleja exserta and two co-occurring host species, Nasella lepida and N. pulchra.
Results
Elevated N decreased haustoria formation and host-seeking behavior by roots but did not affect growth, suggesting N enrichment may reduce parasitism without associated loss of parasite biomass. We confirmed that parasitism decreased host performance and that the degree of parasitism was positively related to host biomass and earlier flowering. We also found N. lepida may be preferred over N. pulchra as a host.
Conclusions
These results indicate that N pollution altered parasitism in C. exserta and highlight the far-reaching ecological effects of N pollution on host–parasite interactions within plant communities.
{"title":"Nitrogen enrichment reduces parasitism in an annual hemiparasite","authors":"Jasmine Taite, Paul D. Nabity","doi":"10.1002/ajb2.70101","DOIUrl":"10.1002/ajb2.70101","url":null,"abstract":"<div>\u0000 \u0000 \u0000 <section>\u0000 \u0000 <h3> Premise</h3>\u0000 \u0000 <p>Anthropogenic activities such as fossil fuel combustion and synthetic fertilizer synthesis have resulted in nitrogen (N) deposition and elevated N availability in ecosystems. Many parasitic plants are adapted to low N environments and have evolved mechanisms to sequester water, N, and other limiting nutrients from hosts. Anthropogenic N deposition may perturb these host–parasite interactions, thereby altering nutrient cycling and ultimately reducing biodiversity.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Methods</h3>\u0000 \u0000 <p>To test how N enrichment affects the incidence and degree of plant parasitism, we assayed host–parasite performance and in vitro root growth under supplemental N levels representative of urban areas experiencing N deposition. We focused on the annual hemiparasite <i>Castilleja exserta</i> and two co-occurring host species, <i>Nasella lepida</i> and <i>N. pulchra</i>.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Results</h3>\u0000 \u0000 <p>Elevated N decreased haustoria formation and host-seeking behavior by roots but did not affect growth, suggesting N enrichment may reduce parasitism without associated loss of parasite biomass. We confirmed that parasitism decreased host performance and that the degree of parasitism was positively related to host biomass and earlier flowering. We also found <i>N. lepida</i> may be preferred over <i>N. pulchra</i> as a host.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Conclusions</h3>\u0000 \u0000 <p>These results indicate that N pollution altered parasitism in <i>C. exserta</i> and highlight the far-reaching ecological effects of N pollution on host–parasite interactions within plant communities.</p>\u0000 </section>\u0000 </div>","PeriodicalId":7691,"journal":{"name":"American Journal of Botany","volume":"112 9","pages":""},"PeriodicalIF":2.7,"publicationDate":"2025-09-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://bsapubs.onlinelibrary.wiley.com/doi/epdf/10.1002/ajb2.70101","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145084750","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}
Bonnie F. Jacobs, Alice Novello, Caroline A. E. Strömberg, Ellen D. Currano, Christine H. S. Kabuye, E. J. Judziewicz, Aaron D. Pan
Premise
Grasses support critically important ecosystems, occupy a large portion of Earth's land surface, and provide essential resources, including maize, other cereal crops, and bamboo. Their radiation and global spread have been documented primarily by microfossils and paleosol isotopic studies, whereas reconstruction of phylogenetic relationships has relied primarily on living species. However, hypothetical dates associated with evolutionary events can be tested only by fossils. We report new, dated Pharoideae phytoliths from Ethiopia (21.73 Ma), pushing back the first occurrence of that subfamily in the Old World by 10 million years. We also formally describe a rare Pharoideae leaf impression reported from Kenya (12.6 Ma). We discuss the relevance of the fossils to phylogenetics, paleobiogeography, and paleoecology.
Methods
Phytoliths and the macrofossil were prepared using standard techniques. Fossils were identified by comparison with online, herbarium, and research collections.
Results
The phytoliths possess characters exclusive to living Pharoideae. The fossil leaf compares favorably to one species in each of the two living Paleotropical Pharoideae genera, Leptaspis and Scrotochloa. Thus, the subfamily was present in Africa by the early Miocene, improving on previous middle Miocene estimates used to date the Neotropical-Paleotropical crown group split. The fossil sites were forests, indicating that Pharoideae occupied the same niche as today; the broad leaf of the macrofossil is consistent with that of living C3 forest grasses.
Conclusions
Early Miocene (21.73 Ma) Pharoideae phytoliths from Ethiopia provide a new, earlier, first occurrence datum for Poaceae trees. The subfamily occupied a forest niche as it does today.
{"title":"New evidence of Miocene forest grasses (Poaceae: Pharoideae L.G. Clark & Judz.) from Ethiopia and Kenya: Implications for biogeography, evolution, and paleoecology","authors":"Bonnie F. Jacobs, Alice Novello, Caroline A. E. Strömberg, Ellen D. Currano, Christine H. S. Kabuye, E. J. Judziewicz, Aaron D. Pan","doi":"10.1002/ajb2.70099","DOIUrl":"10.1002/ajb2.70099","url":null,"abstract":"<div>\u0000 \u0000 \u0000 <section>\u0000 \u0000 <h3> Premise</h3>\u0000 \u0000 <p>Grasses support critically important ecosystems, occupy a large portion of Earth's land surface, and provide essential resources, including maize, other cereal crops, and bamboo. Their radiation and global spread have been documented primarily by microfossils and paleosol isotopic studies, whereas reconstruction of phylogenetic relationships has relied primarily on living species. However, hypothetical dates associated with evolutionary events can be tested only by fossils. We report new, dated Pharoideae phytoliths from Ethiopia (21.73 Ma), pushing back the first occurrence of that subfamily in the Old World by 10 million years. We also formally describe a rare Pharoideae leaf impression reported from Kenya (12.6 Ma). We discuss the relevance of the fossils to phylogenetics, paleobiogeography, and paleoecology.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Methods</h3>\u0000 \u0000 <p>Phytoliths and the macrofossil were prepared using standard techniques. Fossils were identified by comparison with online, herbarium, and research collections.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Results</h3>\u0000 \u0000 <p>The phytoliths possess characters exclusive to living Pharoideae. The fossil leaf compares favorably to one species in each of the two living Paleotropical Pharoideae genera, <i>Leptaspis</i> and <i>Scrotochloa</i>. Thus, the subfamily was present in Africa by the early Miocene, improving on previous middle Miocene estimates used to date the Neotropical-Paleotropical crown group split. The fossil sites were forests, indicating that Pharoideae occupied the same niche as today; the broad leaf of the macrofossil is consistent with that of living C<sub>3</sub> forest grasses.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Conclusions</h3>\u0000 \u0000 <p>Early Miocene (21.73 Ma) Pharoideae phytoliths from Ethiopia provide a new, earlier, first occurrence datum for Poaceae trees. The subfamily occupied a forest niche as it does today.</p>\u0000 </section>\u0000 </div>","PeriodicalId":7691,"journal":{"name":"American Journal of Botany","volume":"112 9","pages":""},"PeriodicalIF":2.7,"publicationDate":"2025-09-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145074062","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}
Zoë H. Dennehy-Carr, Kálmán Könyves, Chris Yesson, John C. David, Alastair Culham
Premise
Previous angiosperm-wide studies estimated that the geophytic family Amaryllidaceae diverged in Africa 87.00–46.77 million years ago (mya), spanning the Cretaceous and Palaeogene periods, including multiple important climatic and geological events. Greater precision on when and where this divergence occurred is lacking due to limited sampling of Amaryllidaceae and the paucity of the monocot fossil record. A robust phylogeny is required to estimate the age and origin of suprageneric groups; however, the evolutionary relationships within Amaryllidaceae are unclear.
Methods
We used 78 plastome protein-coding genes to infer the phylogenetic relationships of Amaryllidaceae and estimated the age of the family using four fossils and five secondary calibration points from across the Asparagales. We conducted a new biogeographic analysis to determine the ancestral origins of Amaryllidaceae and suprageneric groups, providing insights into the drivers of diversification.
Results
Our phylogenetic analyses recovered Amaryllidaceae as monophyletic, with Agapanthoideae sister to Amaryllidoideae and Allioideae. We estimate that Amaryllidaceae diverged in southern Africa 48.6 mya (50.3–46.6 mya) during the early Eocene, a period of elevated global temperatures with increasing seasonal aridity. Our biogeographic analyses indicate that taxa migrated from Africa via the Arabian Peninsula to temperate Asia and beyond during the Miocene.
Conclusions
The comprehensive taxon sampling across Amaryllidaceae, the greater number of genes, and the placement of fossils has made it possible to substantially refine estimates of lineage divergence. Establishing a robust age estimate and reconstructing the biogeographic history has led to a better understanding of evolution within the family, of present-day distributions, and of possible drivers of diversification.
{"title":"The origin and diversification of Amaryllidaceae: A phylogenetic and biogeographic analysis","authors":"Zoë H. Dennehy-Carr, Kálmán Könyves, Chris Yesson, John C. David, Alastair Culham","doi":"10.1002/ajb2.70092","DOIUrl":"10.1002/ajb2.70092","url":null,"abstract":"<div>\u0000 \u0000 \u0000 <section>\u0000 \u0000 <h3> Premise</h3>\u0000 \u0000 <p>Previous angiosperm-wide studies estimated that the geophytic family Amaryllidaceae diverged in Africa 87.00–46.77 million years ago (mya), spanning the Cretaceous and Palaeogene periods, including multiple important climatic and geological events. Greater precision on when and where this divergence occurred is lacking due to limited sampling of Amaryllidaceae and the paucity of the monocot fossil record. A robust phylogeny is required to estimate the age and origin of suprageneric groups; however, the evolutionary relationships within Amaryllidaceae are unclear.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Methods</h3>\u0000 \u0000 <p>We used 78 plastome protein-coding genes to infer the phylogenetic relationships of Amaryllidaceae and estimated the age of the family using four fossils and five secondary calibration points from across the Asparagales. We conducted a new biogeographic analysis to determine the ancestral origins of Amaryllidaceae and suprageneric groups, providing insights into the drivers of diversification.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Results</h3>\u0000 \u0000 <p>Our phylogenetic analyses recovered Amaryllidaceae as monophyletic, with Agapanthoideae sister to Amaryllidoideae and Allioideae. We estimate that Amaryllidaceae diverged in southern Africa 48.6 mya (50.3–46.6 mya) during the early Eocene, a period of elevated global temperatures with increasing seasonal aridity. Our biogeographic analyses indicate that taxa migrated from Africa via the Arabian Peninsula to temperate Asia and beyond during the Miocene.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Conclusions</h3>\u0000 \u0000 <p>The comprehensive taxon sampling across Amaryllidaceae, the greater number of genes, and the placement of fossils has made it possible to substantially refine estimates of lineage divergence. Establishing a robust age estimate and reconstructing the biogeographic history has led to a better understanding of evolution within the family, of present-day distributions, and of possible drivers of diversification.</p>\u0000 </section>\u0000 </div>","PeriodicalId":7691,"journal":{"name":"American Journal of Botany","volume":"112 9","pages":""},"PeriodicalIF":2.7,"publicationDate":"2025-09-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://bsapubs.onlinelibrary.wiley.com/doi/epdf/10.1002/ajb2.70092","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145038959","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}
Emma Fetterly, Anna S. Braum, Chloe (Eun Sun) Kim, Katherine E. Wenzell, Mary V. Ashley, Laura Steger, Jeremie B. Fant
Premise
Evolutionary theory predicts polymorphism should be rare; however, intraspecific variation in floral color is common and can be attributed to genetic drift, plasticity, or variable selection. Examining floral color polymorphism both within contact zones and across a species' range can reveal the mechanisms maintaining this variation. Here, we used a multistep approach to investigate spatially heterogeneous variation in floral bract color in Castilleja coccinea.
Methods
We compared frequencies of color morphs, floral morphology, fitness, and genetic structure in regional populations and in a common garden. Next, we examined habitat differences, including edaphic factors, as potential drivers of variation. Lastly, we leveraged herbarium and iNaturalist occurrence data to investigate whether patterns were consistent at the landscape scale.
Results
Bract color in C. coccinea is genetically heritable, with yellow dominant over red, and is under selection. Populations are predominantly monomorphic, with color distance showing no correlation to genetic or geographic distance, despite significant genetic isolation by distance. Yellow morphs were associated with open wetlands, while red morphs occurred at drier sites with nearby tree cover. Red morphs demonstrated lower fitness in a common garden, suggesting trade-offs associated with pleiotropic effects of floral color.
Conclusions
Differences in floral color between morphs are consistent with diversification associated with a shift in ecological niche. We identified variation in edaphic and habitat conditions as probable drivers of divergence in floral color. Additionally, variation in other floral traits suggests a combined role of pollinators and habitat differences acting in concert to maintain distinct floral color morphs.
{"title":"Selection maintains floral color polymorphism in scarlet paintbrush, Castilleja coccinea, reflecting combined ecological factors","authors":"Emma Fetterly, Anna S. Braum, Chloe (Eun Sun) Kim, Katherine E. Wenzell, Mary V. Ashley, Laura Steger, Jeremie B. Fant","doi":"10.1002/ajb2.70094","DOIUrl":"10.1002/ajb2.70094","url":null,"abstract":"<div>\u0000 \u0000 \u0000 <section>\u0000 \u0000 <h3> Premise</h3>\u0000 \u0000 <p>Evolutionary theory predicts polymorphism should be rare; however, intraspecific variation in floral color is common and can be attributed to genetic drift, plasticity, or variable selection. Examining floral color polymorphism both within contact zones and across a species' range can reveal the mechanisms maintaining this variation. Here, we used a multistep approach to investigate spatially heterogeneous variation in floral bract color in <i>Castilleja coccinea</i>.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Methods</h3>\u0000 \u0000 <p>We compared frequencies of color morphs, floral morphology, fitness, and genetic structure in regional populations and in a common garden. Next, we examined habitat differences, including edaphic factors, as potential drivers of variation. Lastly, we leveraged herbarium and iNaturalist occurrence data to investigate whether patterns were consistent at the landscape scale.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Results</h3>\u0000 \u0000 <p>Bract color in <i>C. coccinea</i> is genetically heritable, with yellow dominant over red, and is under selection. Populations are predominantly monomorphic, with color distance showing no correlation to genetic or geographic distance, despite significant genetic isolation by distance. Yellow morphs were associated with open wetlands, while red morphs occurred at drier sites with nearby tree cover. Red morphs demonstrated lower fitness in a common garden, suggesting trade-offs associated with pleiotropic effects of floral color.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Conclusions</h3>\u0000 \u0000 <p>Differences in floral color between morphs are consistent with diversification associated with a shift in ecological niche. We identified variation in edaphic and habitat conditions as probable drivers of divergence in floral color. Additionally, variation in other floral traits suggests a combined role of pollinators and habitat differences acting in concert to maintain distinct floral color morphs.</p>\u0000 </section>\u0000 </div>","PeriodicalId":7691,"journal":{"name":"American Journal of Botany","volume":"113 1","pages":""},"PeriodicalIF":2.7,"publicationDate":"2025-09-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://bsapubs.onlinelibrary.wiley.com/doi/epdf/10.1002/ajb2.70094","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145032463","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}
Eduardo Narbona, Francisco Perfectti, Adela González-Megías, Luis Navarro, José C. del Valle, Cristina Armas, José M. Gómez
Premise
Floral pigments primarily serve to attract pollinators through color display and also contribute to protection against environmental stress. Although pigment composition can be plastically altered under stress, its impact on pollinator color perception remains poorly understood. Moricandia arvensis (Brassicaceae) exhibits seasonal floral dimorphism, with lilac spring flowers and white summer flowers. This study examines how heat-driven shifts in floral pigments alter flower color and its perception by pollinators.
Methods
We conducted a comparative analysis of spring and summer floral morphs in a natural population by measuring petal spectral reflectance, analyzing absorption spectra of petal extracts, and modeling floral color in the visual systems of major pollinator functional groups. Additionally, UHPLC-ESI-MS/MS analysis was conducted under controlled conditions to characterize differences in phenolic profiles.
Results
Spring flowers exhibited strong UV reflectance and a reduction in reflectance in the green spectrum, whereas summer flowers showed no UV reflectance and high reflectance in the visible range. Anthocyanins were detected only in spring flowers, while summer flowers accumulated high levels of UV-absorbing flavonoids. Despite these differences, both floral morphs remained visually conspicuous to hymenopterans, dipterans, lepidopterans, and coleopterans. Summer flowers produced twice as many phenolic compounds and accumulated higher concentrations, with ferulic acid and kaempferol derivatives the most prominent.
Conclusions
White summer flowers of Moricandia arvensis are not merely anthocyanin-deficient but exhibit a distinct profile of UV-absorbing phenolics that may confer heat tolerance while preserving floral conspicuousness to pollinators. These findings highlight the role of multifunctional traits in the evolution of flower color.
{"title":"Heat drastically alters floral color and pigment composition without affecting flower conspicuousness","authors":"Eduardo Narbona, Francisco Perfectti, Adela González-Megías, Luis Navarro, José C. del Valle, Cristina Armas, José M. Gómez","doi":"10.1002/ajb2.70096","DOIUrl":"10.1002/ajb2.70096","url":null,"abstract":"<div>\u0000 \u0000 \u0000 <section>\u0000 \u0000 <h3> Premise</h3>\u0000 \u0000 <p>Floral pigments primarily serve to attract pollinators through color display and also contribute to protection against environmental stress. Although pigment composition can be plastically altered under stress, its impact on pollinator color perception remains poorly understood. <i>Moricandia arvensis</i> (Brassicaceae) exhibits seasonal floral dimorphism, with lilac spring flowers and white summer flowers. This study examines how heat-driven shifts in floral pigments alter flower color and its perception by pollinators.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Methods</h3>\u0000 \u0000 <p>We conducted a comparative analysis of spring and summer floral morphs in a natural population by measuring petal spectral reflectance, analyzing absorption spectra of petal extracts, and modeling floral color in the visual systems of major pollinator functional groups. Additionally, UHPLC-ESI-MS/MS analysis was conducted under controlled conditions to characterize differences in phenolic profiles.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Results</h3>\u0000 \u0000 <p>Spring flowers exhibited strong UV reflectance and a reduction in reflectance in the green spectrum, whereas summer flowers showed no UV reflectance and high reflectance in the visible range. Anthocyanins were detected only in spring flowers, while summer flowers accumulated high levels of UV-absorbing flavonoids. Despite these differences, both floral morphs remained visually conspicuous to hymenopterans, dipterans, lepidopterans, and coleopterans. Summer flowers produced twice as many phenolic compounds and accumulated higher concentrations, with ferulic acid and kaempferol derivatives the most prominent.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Conclusions</h3>\u0000 \u0000 <p>White summer flowers of <i>Moricandia arvensis</i> are not merely anthocyanin-deficient but exhibit a distinct profile of UV-absorbing phenolics that may confer heat tolerance while preserving floral conspicuousness to pollinators. These findings highlight the role of multifunctional traits in the evolution of flower color.</p>\u0000 </section>\u0000 </div>","PeriodicalId":7691,"journal":{"name":"American Journal of Botany","volume":"113 1","pages":""},"PeriodicalIF":2.7,"publicationDate":"2025-09-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://bsapubs.onlinelibrary.wiley.com/doi/epdf/10.1002/ajb2.70096","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145028709","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}
The diversity–invasibility hypothesis suggests that native plant communities with high species diversity are more resistant to invasions by exotic species compared to those with fewer species. This resistance stems from more complete resource use and stronger biotic interactions in diverse communities, which limit opportunities for invaders to establish. However, this resistance could potentially be weakened by environmental stressors, including elevated tropospheric ozone. Ozone levels have increased globally from 10 ppb in pre-industrial times to around 50 ppb today. Elevated ozone affects plant species differently, depending on their functional traits and physiological tolerances. Yet, no prior study has tested how elevated ozone affects the link between native plant community diversity and invasion resistance. We thus set up an open-top chamber experiment to assess the impact of ozone enrichment on invasive plant growth in native communities of differing species richness.
Methods
We established 16 native plant communities: eight low-diversity and eight high-diversity. Each community was invaded by a single individual from one of nine exotic species and grown in either ambient (40.72 ppb) or elevated (83.10 ppb) ozone.
Results
Elevated ozone reduced the mean aboveground biomass of invasive species by 9.64% overall. The decline was greater in low-diversity communities (–18.46%) than in high-diversity ones (–12.54%). Elevated ozone enhanced the mean proportional aboveground biomass of invasive species in low-diversity communities (11.24%), but not in high-diversity communities.
Conclusions
These findings support the diversity–invasibility hypothesis and suggest that species-rich communities maintain stronger resistance to invasion even in elevated ozone.
{"title":"Elevated ozone promotes the dominance of invasive plant species in low-diversity native plant communities","authors":"Yan Li, Ayub M. O. Oduor","doi":"10.1002/ajb2.70098","DOIUrl":"10.1002/ajb2.70098","url":null,"abstract":"<div>\u0000 \u0000 \u0000 <section>\u0000 \u0000 <h3> Premise</h3>\u0000 \u0000 <p>The diversity–invasibility hypothesis suggests that native plant communities with high species diversity are more resistant to invasions by exotic species compared to those with fewer species. This resistance stems from more complete resource use and stronger biotic interactions in diverse communities, which limit opportunities for invaders to establish. However, this resistance could potentially be weakened by environmental stressors, including elevated tropospheric ozone. Ozone levels have increased globally from 10 ppb in pre-industrial times to around 50 ppb today. Elevated ozone affects plant species differently, depending on their functional traits and physiological tolerances. Yet, no prior study has tested how elevated ozone affects the link between native plant community diversity and invasion resistance. We thus set up an open-top chamber experiment to assess the impact of ozone enrichment on invasive plant growth in native communities of differing species richness.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Methods</h3>\u0000 \u0000 <p>We established 16 native plant communities: eight low-diversity and eight high-diversity. Each community was invaded by a single individual from one of nine exotic species and grown in either ambient (40.72 ppb) or elevated (83.10 ppb) ozone.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Results</h3>\u0000 \u0000 <p>Elevated ozone reduced the mean aboveground biomass of invasive species by 9.64% overall. The decline was greater in low-diversity communities (–18.46%) than in high-diversity ones (–12.54%). Elevated ozone enhanced the mean proportional aboveground biomass of invasive species in low-diversity communities (11.24%), but not in high-diversity communities.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Conclusions</h3>\u0000 \u0000 <p>These findings support the diversity–invasibility hypothesis and suggest that species-rich communities maintain stronger resistance to invasion even in elevated ozone.</p>\u0000 </section>\u0000 </div>","PeriodicalId":7691,"journal":{"name":"American Journal of Botany","volume":"112 9","pages":""},"PeriodicalIF":2.7,"publicationDate":"2025-09-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145013641","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}
Jiayi Song, Deby Arifiani, Jens G. Rohwer, David Kay Ferguson, Yong Yang
Premise
Floristic exchanges between Oceania and tropical Asia have significant asymmetrical characteristics. Many groups of plants have dispersed southward from Asia to Oceania, whereas a northward dispersal from Oceania to tropical Asia (i.e., the “Dacrycarpus pattern”) is rarely reported. The genus Endiandra (Lauraceae) is distributed from tropical Asia to Oceania, with higher species richness in Oceania, so it can contribute to our understanding of paleotropical biogeography.
Methods
We sequenced plastid genomes (plastomes) of 69 species using an herbariomic (genome skimming) approach, with 48 plastomes reported for the first time. We also reconstructed a phylogenomic tree, estimated divergence times, analyzed ancestral areas, and studied the biogeographic history of the genus.
Results
Our well-resolved phylogenomic tree depicts Endiandra as a paraphyletic group in which two Australian species of Beilschmiedia are nested. Dating analysis indicated that the stem and crown ages of the genus are 51.21 and 45.69 million years old, respectively. Ancestral area reconstruction indicates that the genus originated in Oceania and that several independent dispersal events across Wallace's Line shaped its modern distribution.
Conclusions
The geological history and environmental changes in the Neogene likely facilitated the dispersal of Endiandra. However, the inferred dispersal patterns proved more complicated than the classic “Dacrycarpus pattern”, helping improve our understanding of the paleotropical biogeographic history of plants.
{"title":"Dispersal across Wallace's Line: A case study in Endiandra","authors":"Jiayi Song, Deby Arifiani, Jens G. Rohwer, David Kay Ferguson, Yong Yang","doi":"10.1002/ajb2.70097","DOIUrl":"10.1002/ajb2.70097","url":null,"abstract":"<div>\u0000 \u0000 \u0000 <section>\u0000 \u0000 <h3> Premise</h3>\u0000 \u0000 <p>Floristic exchanges between Oceania and tropical Asia have significant asymmetrical characteristics. Many groups of plants have dispersed southward from Asia to Oceania, whereas a northward dispersal from Oceania to tropical Asia (i.e., the “<i>Dacrycarpus</i> pattern”) is rarely reported. The genus <i>Endiandra</i> (Lauraceae) is distributed from tropical Asia to Oceania, with higher species richness in Oceania, so it can contribute to our understanding of paleotropical biogeography.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Methods</h3>\u0000 \u0000 <p>We sequenced plastid genomes (plastomes) of 69 species using an herbariomic (genome skimming) approach, with 48 plastomes reported for the first time. We also reconstructed a phylogenomic tree, estimated divergence times, analyzed ancestral areas, and studied the biogeographic history of the genus.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Results</h3>\u0000 \u0000 <p>Our well-resolved phylogenomic tree depicts <i>Endiandra</i> as a paraphyletic group in which two Australian species of <i>Beilschmiedia</i> are nested. Dating analysis indicated that the stem and crown ages of the genus are 51.21 and 45.69 million years old, respectively. Ancestral area reconstruction indicates that the genus originated in Oceania and that several independent dispersal events across Wallace's Line shaped its modern distribution.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Conclusions</h3>\u0000 \u0000 <p>The geological history and environmental changes in the Neogene likely facilitated the dispersal of <i>Endiandra</i>. However, the inferred dispersal patterns proved more complicated than the classic “<i>Dacrycarpus</i> pattern”, helping improve our understanding of the paleotropical biogeographic history of plants.</p>\u0000 </section>\u0000 </div>","PeriodicalId":7691,"journal":{"name":"American Journal of Botany","volume":"112 9","pages":""},"PeriodicalIF":2.7,"publicationDate":"2025-09-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145013687","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}
Maoqin Xia, Joongku Lee, Limin Yu, Xianyun Mu, Wei-Mei Jiang, Douglas E. Soltis, Luxian Liu, Pan Li
Premise
The demographic histories of temperate plants in Northeast Asia in response to Quaternary climate oscillations have long been the focus of evolutionary biologists, but have rarely been studied in herbaceous plants. Here, we investigated the phylogeographic patterns of Mukdenia and Oresitrophe.
Methods
We sequenced two plastid regions for O. rupifraga (22 populations, 222 individuals), M. acanthifolia (five populations, 50 individuals), and M. rossii (14 populations, 139 individuals). To better understand the phylogeographic patterns of these species, we analyzed genetic diversity/structure, divergence times, demographic history, and distributional changes (with ecological niche modeling). We compared the inferred niche space of these species and addressed isolation by distance (IBD) and isolation by environment (IBE).
Results
We confirmed the monophyly of each species and detected a phylogeographic division corresponding to an arid belt in North China. Oresitrophe rupifraga is inferred to have contracted into four refugia during Pleistocene interglacial periods. Mukdenia acanthifolia and M. rossii appear to have retreated to the Changbai Mountains and Korean Peninsula during that time. In contrast, a larger potential geographic distribution was inferred for each species during glacial periods. Significant ecological niche differentiation was detected among the three species, which may have been associated with their genetic divergence.
Conclusions
Refugial isolation, climatic barriers, and niche differentiation likely influenced the genetic divergence of Oresitrophe and Mukdenia. Our study has implications for the structure of plant diversity in temperate deciduous forests of Northeast Asia and provides insights into conservation units worthy of protection and management for species of both genera.
{"title":"Refugial isolation and ecological niche differentiation promote genetic divergence of Oresitrophe and Mukdenia in Northeast Asia","authors":"Maoqin Xia, Joongku Lee, Limin Yu, Xianyun Mu, Wei-Mei Jiang, Douglas E. Soltis, Luxian Liu, Pan Li","doi":"10.1002/ajb2.70088","DOIUrl":"10.1002/ajb2.70088","url":null,"abstract":"<div>\u0000 \u0000 \u0000 <section>\u0000 \u0000 <h3> Premise</h3>\u0000 \u0000 <p>The demographic histories of temperate plants in Northeast Asia in response to Quaternary climate oscillations have long been the focus of evolutionary biologists, but have rarely been studied in herbaceous plants. Here, we investigated the phylogeographic patterns of <i>Mukdenia</i> and <i>Oresitrophe</i>.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Methods</h3>\u0000 \u0000 <p>We sequenced two plastid regions for <i>O. rupifraga</i> (22 populations, 222 individuals), <i>M. acanthifolia</i> (five populations, 50 individuals), and <i>M. rossii</i> (14 populations, 139 individuals). To better understand the phylogeographic patterns of these species, we analyzed genetic diversity/structure, divergence times, demographic history, and distributional changes (with ecological niche modeling). We compared the inferred niche space of these species and addressed isolation by distance (IBD) and isolation by environment (IBE).</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Results</h3>\u0000 \u0000 <p>We confirmed the monophyly of each species and detected a phylogeographic division corresponding to an arid belt in North China. <i>Oresitrophe rupifraga</i> is inferred to have contracted into four refugia during Pleistocene interglacial periods. <i>Mukdenia acanthifolia</i> and <i>M. rossii</i> appear to have retreated to the Changbai Mountains and Korean Peninsula during that time. In contrast, a larger potential geographic distribution was inferred for each species during glacial periods. Significant ecological niche differentiation was detected among the three species, which may have been associated with their genetic divergence.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Conclusions</h3>\u0000 \u0000 <p>Refugial isolation, climatic barriers, and niche differentiation likely influenced the genetic divergence of <i>Oresitrophe</i> and <i>Mukdenia</i>. Our study has implications for the structure of plant diversity in temperate deciduous forests of Northeast Asia and provides insights into conservation units worthy of protection and management for species of both genera.</p>\u0000 </section>\u0000 </div>","PeriodicalId":7691,"journal":{"name":"American Journal of Botany","volume":"112 9","pages":""},"PeriodicalIF":2.7,"publicationDate":"2025-09-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144991125","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}
Hanna Makowski, Keric Lamb, Austin M. Kim, Emily Scott, Laura F. Galloway
Premise
Transitions from outcrossing to selfing often drive the evolution of floral traits in a predictable way. However, these expectations are not as straightforward for mixed-mating systems. In this study, we examine variation in pollen-collecting hairs, a floral structure involved in secondary pollen presentation within Campanulaceae. While secondary pollen presentation is hypothesized to have evolved to promote outcrossing, we evaluate the association of pollen-collecting hairs with selfing ability.
Methods
We characterized pollen-collecting hair morphology and retraction phenology in 15 populations of Campanula americana with known variation in self-fertilization ability using time-series collections and automated image analysis of pollen-collecting hair length.
Results
There was two-fold variation in the length of pollen-collecting hairs across populations that was associated with a population's within-flower selfing ability. Retraction rate of pollen-collecting hairs also varied among populations and was associated with selfing ability. Populations with greater selfing ability had longer hairs that retracted quickly early in floral anthesis.
Conclusions
We show pollen-collecting hairs, a trait thought to have evolved to promote outcrossing, is associated with within-flower selfing ability. Through developmental changes in length, pollen-collecting hairs appear to be a plastic phenotype that is both associated with autonomous selfing and with outcrossing in C. americana. This provides support for trait specialization rather than trade-offs, and for the ‘best of both worlds’ hypothesis of mixed mating-system evolution.
{"title":"Trait specialization facilitates autonomous selfing ability in a mixed-mating plant","authors":"Hanna Makowski, Keric Lamb, Austin M. Kim, Emily Scott, Laura F. Galloway","doi":"10.1002/ajb2.70095","DOIUrl":"10.1002/ajb2.70095","url":null,"abstract":"<div>\u0000 \u0000 \u0000 <section>\u0000 \u0000 <h3> Premise</h3>\u0000 \u0000 <p>Transitions from outcrossing to selfing often drive the evolution of floral traits in a predictable way. However, these expectations are not as straightforward for mixed-mating systems. In this study, we examine variation in pollen-collecting hairs, a floral structure involved in secondary pollen presentation within Campanulaceae. While secondary pollen presentation is hypothesized to have evolved to promote outcrossing, we evaluate the association of pollen-collecting hairs with selfing ability.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Methods</h3>\u0000 \u0000 <p>We characterized pollen-collecting hair morphology and retraction phenology in 15 populations of <i>Campanula americana</i> with known variation in self-fertilization ability using time-series collections and automated image analysis of pollen-collecting hair length.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Results</h3>\u0000 \u0000 <p>There was two-fold variation in the length of pollen-collecting hairs across populations that was associated with a population's within-flower selfing ability. Retraction rate of pollen-collecting hairs also varied among populations and was associated with selfing ability. Populations with greater selfing ability had longer hairs that retracted quickly early in floral anthesis.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Conclusions</h3>\u0000 \u0000 <p>We show pollen-collecting hairs, a trait thought to have evolved to promote outcrossing, is associated with within-flower selfing ability. Through developmental changes in length, pollen-collecting hairs appear to be a plastic phenotype that is both associated with autonomous selfing and with outcrossing in <i>C. americana</i>. This provides support for trait specialization rather than trade-offs, and for the ‘best of both worlds’ hypothesis of mixed mating-system evolution.</p>\u0000 </section>\u0000 </div>","PeriodicalId":7691,"journal":{"name":"American Journal of Botany","volume":"112 9","pages":""},"PeriodicalIF":2.7,"publicationDate":"2025-09-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://bsapubs.onlinelibrary.wiley.com/doi/epdf/10.1002/ajb2.70095","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144999480","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}
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