{"title":"隐喻电路的短路:在叶片气体交换的欧姆类比中,维管分区和气孔斑块会造成明显的不饱和和二氧化碳梯度反转。","authors":"Fulton E Rockwell","doi":"10.1111/nph.20106","DOIUrl":null,"url":null,"abstract":"<p><p>Analyses of leaf gas exchange rely on an Ohmic analogy that arrays single stomatal, internal air space, and mesophyll conductances in series. Such models underlie inferences of mesophyll conductance and the relative humidity of leaf airspaces, reported to fall as low as 80%. An unresolved question is whether such series models are biased with respect to real leaves, whose internal air spaces are chambered at various scales by vasculature. To test whether unsaturation could emerge from modeling artifacts, we compared series model estimates with true parameter values for a chambered leaf with varying distributions and magnitudes of leaf surface conductance ('patchiness'). Distributions of surface conductance can create large biases in gas exchange calculations. Both apparent unsaturation and internal CO<sub>2</sub> gradient inversion can be produced by the evolution of broader distributions of stomatal apertures consistent with a decrease in surface conductance, as might occur under increasing vapor pressure deficit. In gas exchange experiments, the behaviors of derived quantities defined by simple series models are highly sensitive to the true partitioning of flux and stomatal apertures across leaf surfaces. New methods are needed to disentangle model artifacts from real biological responses.</p>","PeriodicalId":48887,"journal":{"name":"New Phytologist","volume":null,"pages":null},"PeriodicalIF":9.4000,"publicationDate":"2024-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":"{\"title\":\"Shorting the metaphorical circuit: vascular partitioning and stomatal patchiness can create apparent unsaturation and CO<sub>2</sub> gradient inversion in the Ohmic analogy for leaf gas exchange.\",\"authors\":\"Fulton E Rockwell\",\"doi\":\"10.1111/nph.20106\",\"DOIUrl\":null,\"url\":null,\"abstract\":\"<p><p>Analyses of leaf gas exchange rely on an Ohmic analogy that arrays single stomatal, internal air space, and mesophyll conductances in series. Such models underlie inferences of mesophyll conductance and the relative humidity of leaf airspaces, reported to fall as low as 80%. An unresolved question is whether such series models are biased with respect to real leaves, whose internal air spaces are chambered at various scales by vasculature. To test whether unsaturation could emerge from modeling artifacts, we compared series model estimates with true parameter values for a chambered leaf with varying distributions and magnitudes of leaf surface conductance ('patchiness'). Distributions of surface conductance can create large biases in gas exchange calculations. Both apparent unsaturation and internal CO<sub>2</sub> gradient inversion can be produced by the evolution of broader distributions of stomatal apertures consistent with a decrease in surface conductance, as might occur under increasing vapor pressure deficit. In gas exchange experiments, the behaviors of derived quantities defined by simple series models are highly sensitive to the true partitioning of flux and stomatal apertures across leaf surfaces. New methods are needed to disentangle model artifacts from real biological responses.</p>\",\"PeriodicalId\":48887,\"journal\":{\"name\":\"New Phytologist\",\"volume\":null,\"pages\":null},\"PeriodicalIF\":9.4000,\"publicationDate\":\"2024-12-01\",\"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.20106\",\"RegionNum\":1,\"RegionCategory\":\"生物学\",\"ArticlePicture\":[],\"TitleCN\":null,\"AbstractTextCN\":null,\"PMCID\":null,\"EPubDate\":\"2024/9/5 0:00:00\",\"PubModel\":\"Epub\",\"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.20106","RegionNum":1,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"2024/9/5 0:00:00","PubModel":"Epub","JCR":"Q1","JCRName":"Agricultural and Biological Sciences","Score":null,"Total":0}
Shorting the metaphorical circuit: vascular partitioning and stomatal patchiness can create apparent unsaturation and CO2 gradient inversion in the Ohmic analogy for leaf gas exchange.
Analyses of leaf gas exchange rely on an Ohmic analogy that arrays single stomatal, internal air space, and mesophyll conductances in series. Such models underlie inferences of mesophyll conductance and the relative humidity of leaf airspaces, reported to fall as low as 80%. An unresolved question is whether such series models are biased with respect to real leaves, whose internal air spaces are chambered at various scales by vasculature. To test whether unsaturation could emerge from modeling artifacts, we compared series model estimates with true parameter values for a chambered leaf with varying distributions and magnitudes of leaf surface conductance ('patchiness'). Distributions of surface conductance can create large biases in gas exchange calculations. Both apparent unsaturation and internal CO2 gradient inversion can be produced by the evolution of broader distributions of stomatal apertures consistent with a decrease in surface conductance, as might occur under increasing vapor pressure deficit. In gas exchange experiments, the behaviors of derived quantities defined by simple series models are highly sensitive to the true partitioning of flux and stomatal apertures across leaf surfaces. New methods are needed to disentangle model artifacts from real biological responses.
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.