Uptake of inorganic phosphorus by the aquatic plant Isoetes australis inhabiting oligotrophic vernal rock pools

Nina H. Christiansen, Cristina Pulido, Ole Pedersen, Timothy D. Colmer, Frede Andersen, Henning S. Jensen, Dennis Konnerup

    Research output: Contribution to journalArticle

    Abstract

    The submerged aquatic freshwater macrophyte Isoetes australis S. Williams grows in rock pools situated in south-western Australia, an environment where dissolved inorganic phosphorus (Pi) availability possibly limits growth. In contrast to the two coexisting aquatic species, Glossostigma drummundii and Crassula natans, I. australis did not form relationships with mycorrhiza. Pi uptake kinetics were determined for I. australis in experiments using radioactive 33Pi. Roots had a higher Pi affinity (lower Km) than leaves, but roots also had a lower Vmax, which is discussed in relation to the low ambient Pi concentrations. I. australis showed morphological adaptation which could relate to the low Pi environment by having approximately twice as much root tissue as leaf tissue (by dry mass), facilitating access to the higher P pools in the sediment compared with the shallow water column. A short-term translocation experiment revealed high amounts of Pi translocation internally in the plant which seemed to go from roots and oldest leaves to younger leaves. As a result of the high root to shoot ratio, high surface area, root uptake kinetics, and sediment Pi availability, roots accounted for 87% of plant Pi uptake and the green parts of the leaves for about the remaining 13%. As a result the estimated P budget for the rock pools showed that the surface water had a Pi turnover of about 1.5 days, whereas the porewater Pi pool was renewed about 10 times per day to satisfy the P requirements of I. australis.

    Original languageEnglish
    Pages (from-to)64-73
    Number of pages10
    JournalAquatic Botany
    Volume138
    DOIs
    Publication statusPublished - 1 Feb 2017

    Fingerprint

    Isoetes
    rock pool
    inorganic phosphorus
    aquatic plant
    aquatic plants
    rocks
    uptake mechanisms
    leaves
    translocation
    Crassula
    kinetics
    sediments
    dissolved inorganic phosphorus
    root shoot ratio
    mycorrhizae
    mycorrhiza
    South Australia
    Western Australia
    macrophyte
    surface area

    Cite this

    Christiansen, Nina H. ; Pulido, Cristina ; Pedersen, Ole ; Colmer, Timothy D. ; Andersen, Frede ; Jensen, Henning S. ; Konnerup, Dennis. / Uptake of inorganic phosphorus by the aquatic plant Isoetes australis inhabiting oligotrophic vernal rock pools. In: Aquatic Botany. 2017 ; Vol. 138. pp. 64-73.
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    abstract = "The submerged aquatic freshwater macrophyte Isoetes australis S. Williams grows in rock pools situated in south-western Australia, an environment where dissolved inorganic phosphorus (Pi) availability possibly limits growth. In contrast to the two coexisting aquatic species, Glossostigma drummundii and Crassula natans, I. australis did not form relationships with mycorrhiza. Pi uptake kinetics were determined for I. australis in experiments using radioactive 33Pi. Roots had a higher Pi affinity (lower Km) than leaves, but roots also had a lower Vmax, which is discussed in relation to the low ambient Pi concentrations. I. australis showed morphological adaptation which could relate to the low Pi environment by having approximately twice as much root tissue as leaf tissue (by dry mass), facilitating access to the higher P pools in the sediment compared with the shallow water column. A short-term translocation experiment revealed high amounts of Pi translocation internally in the plant which seemed to go from roots and oldest leaves to younger leaves. As a result of the high root to shoot ratio, high surface area, root uptake kinetics, and sediment Pi availability, roots accounted for 87{\%} of plant Pi uptake and the green parts of the leaves for about the remaining 13{\%}. As a result the estimated P budget for the rock pools showed that the surface water had a Pi turnover of about 1.5 days, whereas the porewater Pi pool was renewed about 10 times per day to satisfy the P requirements of I. australis.",
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    Uptake of inorganic phosphorus by the aquatic plant Isoetes australis inhabiting oligotrophic vernal rock pools. / Christiansen, Nina H.; Pulido, Cristina; Pedersen, Ole; Colmer, Timothy D.; Andersen, Frede; Jensen, Henning S.; Konnerup, Dennis.

    In: Aquatic Botany, Vol. 138, 01.02.2017, p. 64-73.

    Research output: Contribution to journalArticle

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    T1 - Uptake of inorganic phosphorus by the aquatic plant Isoetes australis inhabiting oligotrophic vernal rock pools

    AU - Christiansen, Nina H.

    AU - Pulido, Cristina

    AU - Pedersen, Ole

    AU - Colmer, Timothy D.

    AU - Andersen, Frede

    AU - Jensen, Henning S.

    AU - Konnerup, Dennis

    PY - 2017/2/1

    Y1 - 2017/2/1

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    KW - Crassula natans

    KW - Glossostigma drummundii

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    KW - Mycorrhiza

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    KW - P uptake kinetics

    KW - Phosphate

    KW - Re-mobilization

    KW - Translocation

    KW - Vernal rock pools

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