{"title":"H2 18O 蒸汽标记显示了径向贝克莱特效应,但并非所有叶片都有这种效应。","authors":"Margaret M Barbour, Melissa A White, Lulu Liu","doi":"10.1111/nph.20087","DOIUrl":null,"url":null,"abstract":"<p><p>Contradictory evidence exists regarding the relevance of Péclet-like gradients in leaf water isotopes, making it difficult to accurately predict variation in isotope composition. Here, we use H<sub>2</sub> <sup>18</sup>O vapour labelling to directly test whether leaf water isotopes diffuse back into the xylem to be carried forward to more distal leaf portions. Backward diffusion has been assumed, due to observations of increasing enrichment towards the tip and outer edges of some leaves. Further complicating the selection of leaf water isotope models is the observation that some, but not all, leaves demonstrate a radial Péclet effect in bulk leaf water and that the hydraulic design of leaves may influence the development of isotope gradients in leaves. Carry-forward of H<sub>2</sub> <sup>18</sup>O vapour label was detected in the two monocot species assessed (oat and corn), but not in the two dicot species (foxglove and sunflower). Further, bulk leaf water measurements at differing transpiration rates indicated that a bulk leaf water Péclet effect was relevant for foxglove only. We conclude that both leaf hydraulic design and relative velocities of water within transport pathways influence leaf water isotope composition, reconciling seemingly contradictory previous results regarding the relevance of Péclet effects to leaf water isotopes.</p>","PeriodicalId":48887,"journal":{"name":"New Phytologist","volume":null,"pages":null},"PeriodicalIF":9.4000,"publicationDate":"2024-09-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":"{\"title\":\"H<sub>2</sub> <sup>18</sup>O vapour labelling reveals evidence of radial Péclet effects, but in not all leaves.\",\"authors\":\"Margaret M Barbour, Melissa A White, Lulu Liu\",\"doi\":\"10.1111/nph.20087\",\"DOIUrl\":null,\"url\":null,\"abstract\":\"<p><p>Contradictory evidence exists regarding the relevance of Péclet-like gradients in leaf water isotopes, making it difficult to accurately predict variation in isotope composition. Here, we use H<sub>2</sub> <sup>18</sup>O vapour labelling to directly test whether leaf water isotopes diffuse back into the xylem to be carried forward to more distal leaf portions. Backward diffusion has been assumed, due to observations of increasing enrichment towards the tip and outer edges of some leaves. Further complicating the selection of leaf water isotope models is the observation that some, but not all, leaves demonstrate a radial Péclet effect in bulk leaf water and that the hydraulic design of leaves may influence the development of isotope gradients in leaves. Carry-forward of H<sub>2</sub> <sup>18</sup>O vapour label was detected in the two monocot species assessed (oat and corn), but not in the two dicot species (foxglove and sunflower). Further, bulk leaf water measurements at differing transpiration rates indicated that a bulk leaf water Péclet effect was relevant for foxglove only. We conclude that both leaf hydraulic design and relative velocities of water within transport pathways influence leaf water isotope composition, reconciling seemingly contradictory previous results regarding the relevance of Péclet effects to leaf water isotopes.</p>\",\"PeriodicalId\":48887,\"journal\":{\"name\":\"New Phytologist\",\"volume\":null,\"pages\":null},\"PeriodicalIF\":9.4000,\"publicationDate\":\"2024-09-05\",\"publicationTypes\":\"Journal Article\",\"fieldsOfStudy\":null,\"isOpenAccess\":false,\"openAccessPdf\":\"\",\"citationCount\":\"0\",\"resultStr\":null,\"platform\":\"Semanticscholar\",\"paperid\":null,\"PeriodicalName\":\"New Phytologist\",\"FirstCategoryId\":\"99\",\"ListUrlMain\":\"https://doi.org/10.1111/nph.20087\",\"RegionNum\":1,\"RegionCategory\":\"生物学\",\"ArticlePicture\":[],\"TitleCN\":null,\"AbstractTextCN\":null,\"PMCID\":null,\"EPubDate\":\"\",\"PubModel\":\"\",\"JCR\":\"Q1\",\"JCRName\":\"Agricultural and Biological Sciences\",\"Score\":null,\"Total\":0}","platform":"Semanticscholar","paperid":null,"PeriodicalName":"New Phytologist","FirstCategoryId":"99","ListUrlMain":"https://doi.org/10.1111/nph.20087","RegionNum":1,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q1","JCRName":"Agricultural and Biological Sciences","Score":null,"Total":0}
H218O vapour labelling reveals evidence of radial Péclet effects, but in not all leaves.
Contradictory evidence exists regarding the relevance of Péclet-like gradients in leaf water isotopes, making it difficult to accurately predict variation in isotope composition. Here, we use H218O vapour labelling to directly test whether leaf water isotopes diffuse back into the xylem to be carried forward to more distal leaf portions. Backward diffusion has been assumed, due to observations of increasing enrichment towards the tip and outer edges of some leaves. Further complicating the selection of leaf water isotope models is the observation that some, but not all, leaves demonstrate a radial Péclet effect in bulk leaf water and that the hydraulic design of leaves may influence the development of isotope gradients in leaves. Carry-forward of H218O vapour label was detected in the two monocot species assessed (oat and corn), but not in the two dicot species (foxglove and sunflower). Further, bulk leaf water measurements at differing transpiration rates indicated that a bulk leaf water Péclet effect was relevant for foxglove only. We conclude that both leaf hydraulic design and relative velocities of water within transport pathways influence leaf water isotope composition, reconciling seemingly contradictory previous results regarding the relevance of Péclet effects to leaf water isotopes.
期刊介绍:
New Phytologist is a leading publication that showcases exceptional and groundbreaking research in plant science and its practical applications. With a focus on five distinct sections - Physiology & Development, Environment, Interaction, Evolution, and Transformative Plant Biotechnology - the journal covers a wide array of topics ranging from cellular processes to the impact of global environmental changes. We encourage the use of interdisciplinary approaches, and our content is structured to reflect this. Our journal acknowledges the diverse techniques employed in plant science, including molecular and cell biology, functional genomics, modeling, and system-based approaches, across various subfields.