title: Sensitive Detection of Phosphorus Deficiency in Plants Using Chlorophyll a Fluorescence.
abstract: Phosphorus (P) is a finite natural resource and an essential plant macronutrient with major impact on crop productivity and global food security. Here, we demonstrate that time-resolved chlorophyll a fluorescence is a unique tool to monitor bioactive P in plants and can be used to detect latent P deficiency. When plants suffer from P deficiency, the shape of the time-dependent fluorescence transients is altered distinctively, as the so-called I step gradually straightens and eventually disappears. This effect is shown to be fully reversible, as P resupply leads to a rapid restoration of the I step. The fading I step suggests that the electron transport at photosystem I (PSI) is affected in P-deficient plants. This is corroborated by the observation that differences at the I step in chlorophyll a fluorescence transients from healthy and P-deficient plants can be completely eliminated through prior reduction of PSI by far-red illumination. Moreover, it is observed that the barley (Hordeum vulgare) mutant Viridis-zb(63), which is devoid of PSI activity, similarly does not display the I step. Among the essential plant nutrients, the effect of P deficiency is shown to be specific and sufficiently sensitive to enable rapid in situ determination of latent P deficiency across different plant species, thereby providing a unique tool for timely remediation of P deficiency in agriculture.
authors.affiliation: Department of Plant and Environmental Sciences, Faculty of Science, University of Copenhagen, 1871 Frederiksberg C, Denmark (J.F., M.v.M., A.C., S.M., S.B.S., P.R.P., K.H.L., J.K.S., S.H.); and FOSS Analytical A/S, 3400 Hillerød, Denmark (M.v.M.) jfr@plen.ku.dk shu@plen.ku.dk.
authors.forename: Jens
authors.identifier: http://orcid.org/0000-0001-9294-1227
authors.initials: J
authors.lastname: Frydenvang
authors.affiliation: Department of Plant and Environmental Sciences, Faculty of Science, University of Copenhagen, 1871 Frederiksberg C, Denmark (J.F., M.v.M., A.C., S.M., S.B.S., P.R.P., K.H.L., J.K.S., S.H.); and FOSS Analytical A/S, 3400 Hillerød, Denmark (M.v.M.).
authors.forename: Marie
authors.identifier: http://orcid.org/0000-0002-2748-3239
authors.initials: M
authors.lastname: van Maarschalkerweerd
authors.affiliation: Department of Plant and Environmental Sciences, Faculty of Science, University of Copenhagen, 1871 Frederiksberg C, Denmark (J.F., M.v.M., A.C., S.M., S.B.S., P.R.P., K.H.L., J.K.S., S.H.); and FOSS Analytical A/S, 3400 Hillerød, Denmark (M.v.M.).
authors.forename: Andreas
authors.identifier: http://orcid.org/0000-0001-5029-7015
authors.initials: A
authors.lastname: Carstensen
authors.affiliation: Department of Plant and Environmental Sciences, Faculty of Science, University of Copenhagen, 1871 Frederiksberg C, Denmark (J.F., M.v.M., A.C., S.M., S.B.S., P.R.P., K.H.L., J.K.S., S.H.); and FOSS Analytical A/S, 3400 Hillerød, Denmark (M.v.M.).
authors.forename: Simon
authors.identifier: http://orcid.org/0000-0002-2128-8061
authors.initials: S
authors.lastname: Mundus
authors.affiliation: Department of Plant and Environmental Sciences, Faculty of Science, University of Copenhagen, 1871 Frederiksberg C, Denmark (J.F., M.v.M., A.C., S.M., S.B.S., P.R.P., K.H.L., J.K.S., S.H.); and FOSS Analytical A/S, 3400 Hillerød, Denmark (M.v.M.).
authors.forename: Sidsel Birkelund
authors.identifier: http://orcid.org/0000-0002-4193-4454
authors.initials: SB
authors.lastname: Schmidt
authors.affiliation: Department of Plant and Environmental Sciences, Faculty of Science, University of Copenhagen, 1871 Frederiksberg C, Denmark (J.F., M.v.M., A.C., S.M., S.B.S., P.R.P., K.H.L., J.K.S., S.H.); and FOSS Analytical A/S, 3400 Hillerød, Denmark (M.v.M.).
authors.forename: Pai Rosager
authors.identifier: http://orcid.org/0000-0001-6733-7300
authors.initials: PR
authors.lastname: Pedas
authors.affiliation: Department of Plant and Environmental Sciences, Faculty of Science, University of Copenhagen, 1871 Frederiksberg C, Denmark (J.F., M.v.M., A.C., S.M., S.B.S., P.R.P., K.H.L., J.K.S., S.H.); and FOSS Analytical A/S, 3400 Hillerød, Denmark (M.v.M.).
authors.forename: Kristian Holst
authors.identifier: http://orcid.org/0000-0001-7900-3324
authors.initials: KH
authors.lastname: Laursen
authors.affiliation: Department of Plant and Environmental Sciences, Faculty of Science, University of Copenhagen, 1871 Frederiksberg C, Denmark (J.F., M.v.M., A.C., S.M., S.B.S., P.R.P., K.H.L., J.K.S., S.H.); and FOSS Analytical A/S, 3400 Hillerød, Denmark (M.v.M.).
authors.forename: Jan K
authors.identifier: http://orcid.org/0000-0002-2852-3298
authors.initials: JK
authors.lastname: Schjoerring
authors.affiliation: Department of Plant and Environmental Sciences, Faculty of Science, University of Copenhagen, 1871 Frederiksberg C, Denmark (J.F., M.v.M., A.C., S.M., S.B.S., P.R.P., K.H.L., J.K.S., S.H.); and FOSS Analytical A/S, 3400 Hillerød, Denmark (M.v.M.) jfr@plen.ku.dk shu@plen.ku.dk.
authors.forename: Søren
authors.identifier: http://orcid.org/0000-0003-2020-1902
authors.initials: S
authors.lastname: Husted
mesh_terms: D002734:Chlorophyll / Q000378:metabolism*; D000077194:Chlorophyll A; D005453:Fluorescence; D001467:Hordeum / Q000378:metabolism; D018527:Hydroponics; D016018:Least-Squares Analysis; D010758:Phosphorus / Q000172:deficiency*; D018515:Plant Leaves / Q000254:growth & development / Q000378:metabolism; D025341:Principal Component Analysis
chemical_list: D002734:Chlorophyll; D010758:Phosphorus; D000077194:Chlorophyll A