Highlighted articles for January 2022.

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American Journal of BotanyVolume 109, Issue 1 p. 1-3 NEWS & VIEWSFree Access Highlighted articles for January 2022 First published: 28 January 2022 https://doi.org/10.1002/ajb2.1813AboutReferencesRelatedInformationPDFSections A GLOBAL REVIEW OF FERN NECTARIESReferences DNA BARCODING REVEALS LEAF FUNGI SPECIFIC TO DIFFERENT PINE SPECIESReferences CIRCADIAN THERMOGENIC EVENTS IN CONES OF CYCADSReferences NOT DEAD YET! METHUSALEH OF THE DIATOM WORLDReferences MEDITERRANEAN CLIMATE AND QUATERNARY GLACIATIONS AS DRIVERS OF GENETIC DIFFERENTIATION IN AN IBERIAN ENDEMIC PLANTReferencesPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessClose modalShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinkedInRedditWechat A GLOBAL REVIEW OF FERN NECTARIES Plants frequently offer nectar to attract mutualistic animals. Nectaries, the sugar-releasing structures, are best known from flowers and leaves of angiosperms but extrafloral nectaries also occur on leaves of non-flowering plants such as ferns and may attract mutualistic ants to protect plants from leaf-damaging insects. Mehltreter et al. found evidence for nectaries in over 100 fern species, primarily tree ferns and epiphytes, and studied 16 of these species under greenhouse conditions. Protected against rainfall and desiccation, nectar droplets were mainly produced on the lower leaf surface and during higher air humidity conditions at night. Nectar sugar composition and concentrations differed among fern species. In the greenhouse, introduced insects and snails exploited the nectar. Further studies in natural fern habitats are needed to clarify which insects visit and possibly protect nectar-bearing ferns from their natural enemies. References Klaus Mehltreter et al. 2022. Nectaries in ferns: their taxonomic distribution, structure, function, and sugar composition. American Journal of Botany. https://doi.org/10.1002/ajb2.1781 DNA BARCODING REVEALS LEAF FUNGI SPECIFIC TO DIFFERENT PINE SPECIES All plants are inhabited by a diverse community of microbes, including fungi. Culturing techniques have been used to show that some fungi are restricted to certain plant species. However, because culturing and identifying hundreds of fungal isolates from any single plant is extremely time-consuming, Sarver et al. explored whether faster barcode DNA sequencing techniques (i.e., sequencing just the species-identifying portion of the genome from a community of fungi) could reveal specific relationships between plants and fungi. Pine needles are commonly inhabited by a genus of fungi called Lophodermium, and the authors found that barcode sequencing quickly identified many patterns of host-specificity among different pine species of the northeastern U.S. (e.g., loblolly pine, red pine, white pine) and different Lophodermium species. This method is promising for future endeavors to quickly uncover new and diverse host-specific relationships between plants and their fungal endophytes. References Jake Sarver et al. 2022. Deep sequencing across multiple host species tests pine-endophyte specificity. American Journal of Botany. https://doi.org/10.1002/ajb2.1792 CIRCADIAN THERMOGENIC EVENTS IN CONES OF CYCADS Circadian mechanisms are important in controlling the timing of many critical processes in plants. Most circadian studies in plants have involved angiosperms, with only a few performed in gymnosperms. Roemer et al. conducted experiments on Macrozamia lucida and M. macleayi cycad cones and found that the timing of their daily thermogenic events is under circadian clock control. These events, during which cones reach up to 15°C above ambient, are strongly affected by ambient temperature cycles, but less so by light cycles, an unusual combination in circadian systems. Maintaining the appropriate mid-day timing of the diel thermogenic event of these dioecious cycads is central to the movement of pollinators between pollen and ovulate cones in this obligate pollination mutualism—and therefore to the survival of both plant and pollinator. These results shed light on the evolutionary timeline of thermogenesis and circadian activity in an ancient lineage of gymnosperms. [Photo credits: L.I. Terry and J. Kessler] References Robert B. Roemer et al. 2022. Insights from an ancient gymnosperm lineage: ambient temperature and light and the timing of thermogenesis in cycad cones. American Journal of Botany. https://doi.org/10.1002/ajb2.1810 NOT DEAD YET! METHUSALEH OF THE DIATOM WORLD Resting spores of diatoms can persist over long timescales—but for how long? Sanyal et al. found that ~6600-year-old Chaetoceros muelleri var. subsalsum resting spores buried in Baltic Sea sediments are still viable. The time required for germination ranges from 3 hours to 2–3 days in both recent and ancient resting spores, but the germination rate of the resting spores decreased with increasing age (~41% in recent spores to ~31 and ~12% in ancient resting spores). Revived spores of this widely distributed species will contribute to understanding the evolution of diatoms under diverse and changing environmental conditions. References Anushree Sanyal et al. 2022. Not dead yet: Diatom resting spores can survive in nature for several millennia. American Journal of Botany. https://doi.org/10.1002/ajb2.1780 MEDITERRANEAN CLIMATE AND QUATERNARY GLACIATIONS AS DRIVERS OF GENETIC DIFFERENTIATION IN AN IBERIAN ENDEMIC PLANT The Iberian Peninsula is a recognized hotspot of plant diversity, and many species survived there despite the challenging environmental conditions of the Quaternary climatic oscillations. There is increasing evidence that there were several isolated refugia within the Iberian Peninsula during the Quaternary, making the phylogeographic patterns of many European species more complex than expected. Is this also the case for Iberian endemic plants? To what extent did adaptation to Mediterranean climate and Quaternary glaciation cycles affect the intraspecific genetic variation of these regionally exclusive species? To investigate these questions, Pinto-Carrasco et al. selected Odontites recordonii as a case study and used Ecological Niche Models together with correlations between allele presences and environmental variables. Some of the most meaningful parameters defining Mediterranean type climates, such as temperature and precipitation seasonality and drought intensity, were likely involved in the differentiation of the main intraspecific lineages, supporting the hypothesis that these lineages were restricted to narrow refugia during Quaternary glaciations. References Daniel Pinto-Carrasco et al. 2022. Phylogeography and ecological differentiation of strictly Mediterranean taxa: the case of the Iberian endemic Odontites recordonii. American Journal of Botany. https://doi.org/10.1002/ajb2.1787 Volume109, Issue1January 2022Pages 1-3 ReferencesRelatedInformation Metrics Full text views:606Usage represents full text views on Wiley Online Library since January 4th 2022.For articles published or journals transferred to Wiley after this date, usage represents views since the article/chapter was first published on Wiley Online Library. Details © 2022 Botanical Society of America Check for updates Publication History Issue Online: 28 January 2022 Version of Record online: 28 January 2022