Role of Hormones in the Induction of Iron Deficiency Responses in Arabidopsis Roots

  • Wolfgang Schmidt
    Carl von Ossietzky Universität Oldenburg, Fachbereich Biologie, 26111 Oldenburg, Postfach 2503, Germany
  • Julia Tittel
    Carl von Ossietzky Universität Oldenburg, Fachbereich Biologie, 26111 Oldenburg, Postfach 2503, Germany
  • Adam Schikora
    Carl von Ossietzky Universität Oldenburg, Fachbereich Biologie, 26111 Oldenburg, Postfach 2503, Germany

抄録

<jats:title>Abstract</jats:title> <jats:p>In “strategy I” plants, several alterations in root physiology and morphology are induced by Fe deficiency, although the mechanisms by which low Fe levels are translated into reactions aimed at alleviating Fe shortage are largely unknown. To prove whether changes in hormone concentration or sensitivity are involved in the adaptation to suboptimal Fe availability, we tested 45 mutants of Arabidopsis defective in hormone metabolism and/or root hair formation for their ability to increase Fe(III) chelate reductase activity and to initiate the formation and enlargement of root hairs. Activity staining for ferric chelate reductase revealed that all mutants were responsive to Fe deficiency, suggesting that hormones are not necessary for the induction. Treatment of wild-type plants with the ethylene precursor 1-aminocyclopropane-1-carboxylic acid caused the development of root hairs in locations normally occupied by non-hair cells, but did not stimulate ferric reductase activity. Ectopic root hairs were also formed in −Fe roots, suggesting a role for ethylene in the morphological responses to Fe deficiency. Ultrastructural analysis of rhizodermal cells indicated that neither Fe deficiency nor 1-aminocyclopropane-1-carboxylic acid treatment caused transfer-cell-like alterations in Arabidopsis roots. Our data indicate that the morphological and physiological components of the Fe stress syndrome are regulated separately.</jats:p>

収録刊行物

  • Plant Physiology

    Plant Physiology 122 (4), 1109-1118, 2000-04-01

    Oxford University Press (OUP)

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