Laëtitia M. Bréchet, Roberto L. Salomόn, Katerina Machacova, Clément Stahl, Benoît Burban, Jean‐Yves Goret, Kathy Steppe, Damien Bonal, Ivan A. Janssens
SummaryRecent studies have shown that stem fluxes, although highly variable among trees, can alter the strength of the methane (CH4) sink or nitrous oxide (N2O) source in some forests, but the patterns and magnitudes of these fluxes remain unclear. This study investigated the drivers of subdaily and seasonal variations in stem and soil CH4, N2O and carbon dioxide (CO2) fluxes.CH4, N2O and CO2 fluxes were measured continuously for 19 months in individual stems of two tree species, Eperua falcata (Aubl.) and Lecythis poiteaui (O. Berg), and surrounding soils using an automated chamber system in an upland tropical forest. Subdaily variations in these fluxes were related to environmental and stem physiological (sap flow and stem diameter variations) measurements under contrasting soil water conditions.The results showed that physiological and climatic drivers only partially explained the subdaily flux variations. Stem CH4 and CO2 emissions and N2O uptake varied with soil water content, time of day and between individuals. Stem fluxes decoupled from soil fluxes.Our study contributes to understanding the regulation of stem greenhouse gas fluxes. It suggests that additional variables (e.g. internal gas concentrations, wood‐colonising microorganisms, wood density and anatomy) may account for the remaining unexplained variability in stem fluxes, highlighting the need for further studies.
{"title":"Insights into the subdaily variations in methane, nitrous oxide and carbon dioxide fluxes from upland tropical tree stems","authors":"Laëtitia M. Bréchet, Roberto L. Salomόn, Katerina Machacova, Clément Stahl, Benoît Burban, Jean‐Yves Goret, Kathy Steppe, Damien Bonal, Ivan A. Janssens","doi":"10.1111/nph.20401","DOIUrl":"https://doi.org/10.1111/nph.20401","url":null,"abstract":"Summary<jats:list list-type=\"bullet\"> <jats:list-item>Recent studies have shown that stem fluxes, although highly variable among trees, can alter the strength of the methane (CH<jats:sub>4</jats:sub>) sink or nitrous oxide (N<jats:sub>2</jats:sub>O) source in some forests, but the patterns and magnitudes of these fluxes remain unclear. This study investigated the drivers of subdaily and seasonal variations in stem and soil CH<jats:sub>4</jats:sub>, N<jats:sub>2</jats:sub>O and carbon dioxide (CO<jats:sub>2</jats:sub>) fluxes.</jats:list-item> <jats:list-item>CH<jats:sub>4</jats:sub>, N<jats:sub>2</jats:sub>O and CO<jats:sub>2</jats:sub> fluxes were measured continuously for 19 months in individual stems of two tree species, <jats:italic>Eperua falcata</jats:italic> (Aubl.) and <jats:italic>Lecythis poiteaui</jats:italic> (O. Berg), and surrounding soils using an automated chamber system in an upland tropical forest. Subdaily variations in these fluxes were related to environmental and stem physiological (sap flow and stem diameter variations) measurements under contrasting soil water conditions.</jats:list-item> <jats:list-item>The results showed that physiological and climatic drivers only partially explained the subdaily flux variations. Stem CH<jats:sub>4</jats:sub> and CO<jats:sub>2</jats:sub> emissions and N<jats:sub>2</jats:sub>O uptake varied with soil water content, time of day and between individuals. Stem fluxes decoupled from soil fluxes.</jats:list-item> <jats:list-item>Our study contributes to understanding the regulation of stem greenhouse gas fluxes. It suggests that additional variables (e.g. internal gas concentrations, wood‐colonising microorganisms, wood density and anatomy) may account for the remaining unexplained variability in stem fluxes, highlighting the need for further studies.</jats:list-item> </jats:list>","PeriodicalId":214,"journal":{"name":"New Phytologist","volume":"16 1","pages":""},"PeriodicalIF":9.4,"publicationDate":"2025-01-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142987454","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"At least two functions for BdMUTE during the development of stomatal complexes in Brachypodium distachyon","authors":"Laura Serna","doi":"10.1111/nph.20396","DOIUrl":"https://doi.org/10.1111/nph.20396","url":null,"abstract":"","PeriodicalId":214,"journal":{"name":"New Phytologist","volume":"46 1","pages":""},"PeriodicalIF":9.4,"publicationDate":"2025-01-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142981351","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Karen Michiko Frick, Marcus Daniel Brandbjerg Bohn Lorensen, Nikola Micic, Eddi Esteban, Asher Pasha, Alexander Schulz, Nicholas James Provart, Hussam Hassan Nour‐Eldin, Nanna Bjarnholt, Christian Janfelt, Fernando Geu‐Flores
SummaryLupins are promising protein crops that accumulate toxic quinolizidine alkaloids (QAs) in the seeds, complicating their end‐use. QAs are synthesized in green organs (leaves, stems, and pods) and a subset of them is transported to the seeds during fruit development. The exact sites of biosynthesis and accumulation remain unknown; however, mesophyll cells have been proposed as sources, and epidermal cells as sinks.We investigated the exact sites of QA biosynthesis and accumulation in biosynthetic organs of narrow‐leafed lupin (Lupinus angustifolius) using mass spectrometry‐based imaging (MSI), laser‐capture microdissection coupled to RNA‐Seq, and precursor feeding studies coupled to LC‐MS and MSI.We found that the QAs that accumulate in seeds (‘core’ QAs) were evenly distributed across tissues; however, their esterified versions accumulated primarily in the epidermis. Surprisingly, RNA‐Seq revealed strong biosynthetic gene expression in the epidermis, which was confirmed in leaves by quantitative real‐time polymerase chain reaction. Finally, feeding studies using a stably labeled precursor showed that the lower leaf epidermis is highly biosynthetic.Our results indicate that the epidermis is a major site of QA biosynthesis in narrow‐leafed lupin, challenging the current assumptions. Our work has direct implications for the elucidation of the QA biosynthesis pathway and the long‐distance transport network from source to seed.
{"title":"The aerial epidermis is a major site of quinolizidine alkaloid biosynthesis in narrow‐leafed lupin","authors":"Karen Michiko Frick, Marcus Daniel Brandbjerg Bohn Lorensen, Nikola Micic, Eddi Esteban, Asher Pasha, Alexander Schulz, Nicholas James Provart, Hussam Hassan Nour‐Eldin, Nanna Bjarnholt, Christian Janfelt, Fernando Geu‐Flores","doi":"10.1111/nph.20384","DOIUrl":"https://doi.org/10.1111/nph.20384","url":null,"abstract":"Summary<jats:list list-type=\"bullet\"> <jats:list-item>Lupins are promising protein crops that accumulate toxic quinolizidine alkaloids (QAs) in the seeds, complicating their end‐use. QAs are synthesized in green organs (leaves, stems, and pods) and a subset of them is transported to the seeds during fruit development. The exact sites of biosynthesis and accumulation remain unknown; however, mesophyll cells have been proposed as sources, and epidermal cells as sinks.</jats:list-item> <jats:list-item>We investigated the exact sites of QA biosynthesis and accumulation in biosynthetic organs of narrow‐leafed lupin (<jats:italic>Lupinus angustifolius</jats:italic>) using mass spectrometry‐based imaging (MSI), laser‐capture microdissection coupled to RNA‐Seq, and precursor feeding studies coupled to LC‐MS and MSI.</jats:list-item> <jats:list-item>We found that the QAs that accumulate in seeds (‘core’ QAs) were evenly distributed across tissues; however, their esterified versions accumulated primarily in the epidermis. Surprisingly, RNA‐Seq revealed strong biosynthetic gene expression in the epidermis, which was confirmed in leaves by quantitative real‐time polymerase chain reaction. Finally, feeding studies using a stably labeled precursor showed that the lower leaf epidermis is highly biosynthetic.</jats:list-item> <jats:list-item>Our results indicate that the epidermis is a major site of QA biosynthesis in narrow‐leafed lupin, challenging the current assumptions. Our work has direct implications for the elucidation of the QA biosynthesis pathway and the long‐distance transport network from source to seed.</jats:list-item> </jats:list>","PeriodicalId":214,"journal":{"name":"New Phytologist","volume":"36 1","pages":""},"PeriodicalIF":9.4,"publicationDate":"2025-01-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142974547","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
SummaryMediator, a transcriptional coactivator, regulates plant growth and development by interacting with various transcriptional regulators. MEDIATOR15 (MED15) is a subunit in the Mediator complex potentially involved in developmental control.To uncover molecular functions of Arabidopsis MED15 in development, we searched for its interactors. MED15 was found to interact with DELLA proteins, which negatively regulate gibberellic acid (GA) signaling and positively regulate GA biosynthesis.Mutants and overexpressors of MED15 exhibited multiple GA‐related growth phenotypes, which resembled the phenotypes of the DELLA overexpressor and mutant, respectively. Consistent with this observation, DELLA protein levels were inversely correlated with MED15 protein levels, suggesting that MED15 activates GA signaling through DELLA degradation. MED15 was required not only for DELLA‐mediated induction of GA‐biosynthesis gene expression but also for GA‐mediated degradation of DELLA. Therefore, MED15 facilitates DELLA destruction not only by promoting GA biosynthesis but also by accelerating DELLA turnover. Furthermore, MED15‐mediated GA signaling was required for timely developmental responses to dark and warm conditions.Our results provide insight into developmental control by Mediator via precise regulation of DELLA stability. These findings are potentially useful for the generation of new crop cultivars with ideal body architecture.
{"title":"MEDIATOR15 destabilizes DELLA protein to promote gibberellin‐mediated plant development","authors":"Naohiko Ohama, Teck Lim Moo, KwiMi Chung, Nobutaka Mitsuda, Kulaporn Boonyaves, Daisuke Urano, Nam‐Hai Chua","doi":"10.1111/nph.20397","DOIUrl":"https://doi.org/10.1111/nph.20397","url":null,"abstract":"Summary<jats:list list-type=\"bullet\"> <jats:list-item>Mediator, a transcriptional coactivator, regulates plant growth and development by interacting with various transcriptional regulators. MEDIATOR15 (MED15) is a subunit in the Mediator complex potentially involved in developmental control.</jats:list-item> <jats:list-item>To uncover molecular functions of <jats:italic>Arabidopsis</jats:italic> MED15 in development, we searched for its interactors. MED15 was found to interact with DELLA proteins, which negatively regulate gibberellic acid (GA) signaling and positively regulate GA biosynthesis.</jats:list-item> <jats:list-item>Mutants and overexpressors of <jats:italic>MED15</jats:italic> exhibited multiple GA‐related growth phenotypes, which resembled the phenotypes of the <jats:italic>DELLA</jats:italic> overexpressor and mutant, respectively. Consistent with this observation, DELLA protein levels were inversely correlated with MED15 protein levels, suggesting that MED15 activates GA signaling through DELLA degradation. MED15 was required not only for DELLA‐mediated induction of GA‐biosynthesis gene expression but also for GA‐mediated degradation of DELLA. Therefore, MED15 facilitates DELLA destruction not only by promoting GA biosynthesis but also by accelerating DELLA turnover. Furthermore, MED15‐mediated GA signaling was required for timely developmental responses to dark and warm conditions.</jats:list-item> <jats:list-item>Our results provide insight into developmental control by Mediator via precise regulation of DELLA stability. These findings are potentially useful for the generation of new crop cultivars with ideal body architecture.</jats:list-item> </jats:list>","PeriodicalId":214,"journal":{"name":"New Phytologist","volume":"68 1","pages":""},"PeriodicalIF":9.4,"publicationDate":"2025-01-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142974545","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Valentina Buttò, Drew M. P. Peltier, Tim Rademacher
Wood formation is the Rosetta stone of tree physiology: a traceable, integrated record of physiological and morphological status. It also produces a large and persistent annual sink for terrestrial carbon, motivating predictive understanding. Xylogenesis studies have greatly expanded our knowledge of the intra-annual controls on wood formation, while dendroecology has quantified the environmental drivers of multi-annual variability. But these fields operate on different timescales, making it challenging to predict how short (e.g. turgor) and long timescale processes (e.g. disturbance) interactively influence wood formation. Toward this challenge, wood growth responses to natural climate events provide useful but incomplete explanations of tree growth variability. By contrast, direct manipulations of the tree vascular system have yielded unexpected insights, particularly outside of model species like boreal conifers, but they remain underutilized. To improve prediction of global wood formation, we argue for a new generation of experimental manipulations of wood growth across seasons, species, and ecosystems. Such manipulations should expand inference to diverse forests and capture inter- and intra-specific differences in wood growth. We summarize the endogenous and exogenous factors influencing wood formation to guide future experimental design and hypotheses. We highlight key opportunities for manipulative studies integrating measurements from xylogenesis, dendroanatomy, dendroecology, and ecophysiology.
{"title":"From division to ‘divergence’: to understand wood growth across timescales, we need to (learn to) manipulate it","authors":"Valentina Buttò, Drew M. P. Peltier, Tim Rademacher","doi":"10.1111/nph.20390","DOIUrl":"https://doi.org/10.1111/nph.20390","url":null,"abstract":"Wood formation is the Rosetta stone of tree physiology: a traceable, integrated record of physiological and morphological status. It also produces a large and persistent annual sink for terrestrial carbon, motivating predictive understanding. Xylogenesis studies have greatly expanded our knowledge of the intra-annual controls on wood formation, while dendroecology has quantified the environmental drivers of multi-annual variability. But these fields operate on different timescales, making it challenging to predict how short (e.g. turgor) and long timescale processes (e.g. disturbance) interactively influence wood formation. Toward this challenge, wood growth responses to natural climate events provide useful but incomplete explanations of tree growth variability. By contrast, direct manipulations of the tree vascular system have yielded unexpected insights, particularly outside of model species like boreal conifers, but they remain underutilized. To improve prediction of global wood formation, we argue for a new generation of experimental manipulations of wood growth across seasons, species, and ecosystems. Such manipulations should expand inference to diverse forests and capture inter- and intra-specific differences in wood growth. We summarize the endogenous and exogenous factors influencing wood formation to guide future experimental design and hypotheses. We highlight key opportunities for manipulative studies integrating measurements from xylogenesis, dendroanatomy, dendroecology, and ecophysiology.","PeriodicalId":214,"journal":{"name":"New Phytologist","volume":"155 1","pages":""},"PeriodicalIF":9.4,"publicationDate":"2025-01-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142967964","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Matthew Moir, Hannah Butler, Craig Peter, Tony Dold, Ethan Newman
SummaryPollinators are thought to play a key role in driving incipient speciation within the angiosperms. However, the mechanisms underlying floral divergence in plants with generalist pollination systems, remains understudied.Brunsvigia gregaria displays significant geographical variation in floral traits and are visited by diverse pollinator communities. Because pollinators are often shared between populations, we investigated whether specific pollinators are responsible for driving floral divergence between them.Three distinct ecotypes were identified, each dominated by three different pollinators: bees, swallowtail butterflies, and long‐proboscid flies. Across seven populations, we found a pattern of association between style length and the morphology of pollinators that visit the flowers most frequently and contact the reproductive parts most often. Furthermore, we found significant linear, quadratic and correlational selection on flower number, tepal length and style length within the butterfly‐ and bee‐dominated populations. We also found partial evidence for divergent selection on these traits between experimental sites.Our findings suggest that a handful of key pollinators that vary in their importance have the potential to drive population‐level divergence in floral traits, which may lead to pollination ecotype formation.
{"title":"A test of the Grant–Stebbins pollinator‐shift model of floral evolution","authors":"Matthew Moir, Hannah Butler, Craig Peter, Tony Dold, Ethan Newman","doi":"10.1111/nph.20373","DOIUrl":"https://doi.org/10.1111/nph.20373","url":null,"abstract":"Summary<jats:list list-type=\"bullet\"> <jats:list-item>Pollinators are thought to play a key role in driving incipient speciation within the angiosperms. However, the mechanisms underlying floral divergence in plants with generalist pollination systems, remains understudied.</jats:list-item> <jats:list-item><jats:italic>Brunsvigia gregaria</jats:italic> displays significant geographical variation in floral traits and are visited by diverse pollinator communities. Because pollinators are often shared between populations, we investigated whether specific pollinators are responsible for driving floral divergence between them.</jats:list-item> <jats:list-item>Three distinct ecotypes were identified, each dominated by three different pollinators: bees, swallowtail butterflies, and long‐proboscid flies. Across seven populations, we found a pattern of association between style length and the morphology of pollinators that visit the flowers most frequently and contact the reproductive parts most often. Furthermore, we found significant linear, quadratic and correlational selection on flower number, tepal length and style length within the butterfly‐ and bee‐dominated populations. We also found partial evidence for divergent selection on these traits between experimental sites.</jats:list-item> <jats:list-item>Our findings suggest that a handful of key pollinators that vary in their importance have the potential to drive population‐level divergence in floral traits, which may lead to pollination ecotype formation.</jats:list-item> </jats:list>","PeriodicalId":214,"journal":{"name":"New Phytologist","volume":"35 1","pages":""},"PeriodicalIF":9.4,"publicationDate":"2025-01-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142961490","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Inger K. de Jonge, Peter Convey, Ingeborg J. Klarenberg, Johannes H. C. Cornelissen, Stef Bokhorst
SummaryLichens play important roles in habitat formation and community succession in polar and alpine ecosystems. Despite their significance, the ecological effects of lichen traits remain poorly researched. We propose a trait trade‐off for managing light exposure based on climatic harshness. In the harshest cold environments, where abiotic stress predominates over biotic pressures, lichens should rely on photostable, recalcitrant and immobile substances such as allomelanin and hydrophobic compounds. These compounds provide durable protection without the need for continual synthesis. In milder conditions where biotic interactions – e.g. competition and pathogen presence – become increasingly pronounced, lichens should retain flexibility and produce simple protective secondary compounds that, in addition to functioning as light screens, can leach out to influence their direct environment. Preliminary empirical findings for Antarctic lichen species distribution are consistent with this hypothesised trade‐off, in that lichens producing soluble compounds dominate in milder regions and are less represented at higher southern latitudes, where species producing insoluble compounds with a melanised thallus dominate. As climate change progresses, increasing temperatures and precipitation could make the currently coldest and driest areas more hospitable, allowing the ranges of lichens producing soluble compounds to expand, with cascading effects on rock weathering, nutrient cycling and other ecosystem processes.
{"title":"Flexible or fortified? How lichens balance defence strategies across climatic harshness gradients","authors":"Inger K. de Jonge, Peter Convey, Ingeborg J. Klarenberg, Johannes H. C. Cornelissen, Stef Bokhorst","doi":"10.1111/nph.20380","DOIUrl":"https://doi.org/10.1111/nph.20380","url":null,"abstract":"SummaryLichens play important roles in habitat formation and community succession in polar and alpine ecosystems. Despite their significance, the ecological effects of lichen traits remain poorly researched. We propose a trait trade‐off for managing light exposure based on climatic harshness. In the harshest cold environments, where abiotic stress predominates over biotic pressures, lichens should rely on photostable, recalcitrant and immobile substances such as allomelanin and hydrophobic compounds. These compounds provide durable protection without the need for continual synthesis. In milder conditions where biotic interactions – e.g. competition and pathogen presence – become increasingly pronounced, lichens should retain flexibility and produce simple protective secondary compounds that, in addition to functioning as light screens, can leach out to influence their direct environment. Preliminary empirical findings for Antarctic lichen species distribution are consistent with this hypothesised trade‐off, in that lichens producing soluble compounds dominate in milder regions and are less represented at higher southern latitudes, where species producing insoluble compounds with a melanised thallus dominate. As climate change progresses, increasing temperatures and precipitation could make the currently coldest and driest areas more hospitable, allowing the ranges of lichens producing soluble compounds to expand, with cascading effects on rock weathering, nutrient cycling and other ecosystem processes.","PeriodicalId":214,"journal":{"name":"New Phytologist","volume":"20 1","pages":""},"PeriodicalIF":9.4,"publicationDate":"2025-01-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142961489","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"The evolutionary history evident in grass pollen morphology","authors":"Surangi W. Punyasena","doi":"10.1111/nph.20387","DOIUrl":"https://doi.org/10.1111/nph.20387","url":null,"abstract":"","PeriodicalId":214,"journal":{"name":"New Phytologist","volume":"3 1","pages":""},"PeriodicalIF":9.4,"publicationDate":"2025-01-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142939894","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Karen Vázquez‐Segovia, Mark E. Olson, Julio Campo, Guillermo Ángeles, Cristina Martínez‐Garza, Susanne Vetter, Julieta A. Rosell
SummaryAlong their lengths, stems experience different functional demands. Because bark and wood traits are usually studied at single points on stems, it remains unclear how carbon allocation changes along tip‐to‐base trajectories across species.We examined bark vs wood allocation by measuring cross‐sectional areas of outer and inner bark (OB and IB), IB regions (secondary phloem, cortex, and phelloderm), and wood from stem tips to bases of 35 woody angiosperm species of diverse phylogenetic lineages, climates, fire regimes, and bark morphologies. We examined how varied bark vs wood allocation was and how it was affected by precipitation, temperature, soil fertility, leaf habit, and fire regime.Allocation to phloem (relative to wood) varied little across species, whereas allocation to other tissues, strongly affected by the environment or shed in ontogeny, varied widely. Allocation to parenchyma‐rich cortex and phloem was higher at drier sites, suggesting storage. Higher allocation to phloem and cortex also occurred on infertile soils, and to phloem in drought‐deciduous vs cold‐deciduous and evergreen species. Allocation to OB was highest at sites with frequent fires and decreased with fire frequency.Our approach contextualizes inferences from across‐species studies, allows testing functional hypotheses, and contributes to disentangling the functional roles of poorly understood bark tissues.
{"title":"Tip‐to‐base bark cross‐sectional areas contribute to understanding the drivers of carbon allocation to bark and the functional roles of bark tissues","authors":"Karen Vázquez‐Segovia, Mark E. Olson, Julio Campo, Guillermo Ángeles, Cristina Martínez‐Garza, Susanne Vetter, Julieta A. Rosell","doi":"10.1111/nph.20379","DOIUrl":"https://doi.org/10.1111/nph.20379","url":null,"abstract":"Summary<jats:list list-type=\"bullet\"> <jats:list-item>Along their lengths, stems experience different functional demands. Because bark and wood traits are usually studied at single points on stems, it remains unclear how carbon allocation changes along tip‐to‐base trajectories across species.</jats:list-item> <jats:list-item>We examined bark vs wood allocation by measuring cross‐sectional areas of outer and inner bark (OB and IB), IB regions (secondary phloem, cortex, and phelloderm), and wood from stem tips to bases of 35 woody angiosperm species of diverse phylogenetic lineages, climates, fire regimes, and bark morphologies. We examined how varied bark vs wood allocation was and how it was affected by precipitation, temperature, soil fertility, leaf habit, and fire regime.</jats:list-item> <jats:list-item>Allocation to phloem (relative to wood) varied little across species, whereas allocation to other tissues, strongly affected by the environment or shed in ontogeny, varied widely. Allocation to parenchyma‐rich cortex and phloem was higher at drier sites, suggesting storage. Higher allocation to phloem and cortex also occurred on infertile soils, and to phloem in drought‐deciduous vs cold‐deciduous and evergreen species. Allocation to OB was highest at sites with frequent fires and decreased with fire frequency.</jats:list-item> <jats:list-item>Our approach contextualizes inferences from across‐species studies, allows testing functional hypotheses, and contributes to disentangling the functional roles of poorly understood bark tissues.</jats:list-item> </jats:list>","PeriodicalId":214,"journal":{"name":"New Phytologist","volume":"2 1","pages":""},"PeriodicalIF":9.4,"publicationDate":"2025-01-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142939922","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Melissa Bredow, Ekkachai Khwanbua, Aline Sartor Chicowski, Yunhui Qi, Matthew W. Breitzman, Katerina L. Holan, Peng Liu, Michelle A. Graham, Steven A. Whitham
SummaryIncreasing atmospheric CO2 levels have a variety of effects that can influence plant responses to microbial pathogens. However, these responses are varied, and it is challenging to predict how elevated CO2 (eCO2) will affect a particular plant–pathogen interaction. We investigated how eCO2 may influence disease development and responses to diverse pathogens in the major oilseed crop, soybean.Soybean plants grown in ambient CO2 (aCO2, 419 parts per million (ppm)) or in eCO2 (550 ppm) were challenged with bacterial, viral, fungal, and oomycete pathogens. Disease severity, pathogen growth, gene expression, and molecular plant defense responses were quantified.In eCO2, plants were less susceptible to Pseudomonas syringae pv. glycinea (Psg) but more susceptible to bean pod mottle virus, soybean mosaic virus, and Fusarium virguliforme. Susceptibility to Pythium sylvaticum was unchanged, although a greater loss in biomass occurred in eCO2. Reduced susceptibility to Psg was associated with enhanced defense responses. Increased susceptibility to the viruses was associated with reduced expression of antiviral defenses.This work provides a foundation for understanding how future eCO2 levels may impact molecular responses to pathogen challenges in soybean and demonstrates that microbes infecting both shoots and roots are of potential concern in future climatic conditions.
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