Differential modulation of host plant δ13C and δ18O by native and nonnative arbuscular mycorrhizal fungi in a semiarid environment

Authors

  • J. I. Querejeta,

    Corresponding author
    1. Departamento de Conservación de Suelos y Aguas, Centro de Edafología y Biología Aplicada del Segura-Consejo Superior de Investigaciones Científicas (CEBAS-CSIC), PO Box 4195, Campus de Espinardo E−30100 Murcia, Spain;
    2. Center for Conservation Biology, The University of California, Riverside, CA 92521, USA
    • Author for correspondence: J. I. Querejeta Tel: +34 96 8396257 Fax: +34 96 8396213 Email: querejeta@cebas.csic.es

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  • M. F. Allen,

    1. Center for Conservation Biology, The University of California, Riverside, CA 92521, USA
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  • F. Caravaca,

    1. Departamento de Conservación de Suelos y Aguas, Centro de Edafología y Biología Aplicada del Segura-Consejo Superior de Investigaciones Científicas (CEBAS-CSIC), PO Box 4195, Campus de Espinardo E−30100 Murcia, Spain;
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  • A. Roldán

    1. Departamento de Conservación de Suelos y Aguas, Centro de Edafología y Biología Aplicada del Segura-Consejo Superior de Investigaciones Científicas (CEBAS-CSIC), PO Box 4195, Campus de Espinardo E−30100 Murcia, Spain;
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Summary

  • • Native, drought-adapted arbuscular mycorrhizal fungi (AMF) often improve host-plant performance to a greater extent than nonnative AMF in dry environments. However, little is known about the physiological basis for this differential plant response.
  • • Seedlings of Olea europaea and Rhamnus lycioides were inoculated with either a mixture of eight native Glomus species or with the nonnative Glomus claroideum before field transplanting in a semiarid area.
  • • Inoculation with native AMF produced the greatest improvement in nutrient and water status as well as in long-term growth for both Olea and Rhamnus. Foliar δ18O measurements indicated that native AMF enhanced stomatal conductance to a greater extent than nonnative AMF in Olea and Rhamnus.δ13C data showed that intrinsic water-use efficiency in Olea was differentially stimulated by native AMF compared with nonnative AMF.
  • • Our results suggest that modulation of leaf gas exchange by native, drought-adapted AMF is critical to the long-term performance of host plants in semiarid environments. δ18O can provide a time-integrated measure of the effect of mycorrhizal infection on host-plant water relations.

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