title: Magnetorezeption in Arabiodopsis thaliana
title: Magnetoreception in Arabidopsis thaliana : Effects of geomagnetic fields on transcription and translation
Creators: name: Dhiman, Sunil Kumar
Publisher: name: Philipps-Universität Marburg
Year: 2015
Subjects: Arabidopsis thaliana
Botanical sciences
Ackerschmalwand
Magnetorezeption
Magnetoreception

description: Diese Arbeit behandelt die
      Einflüsse von geomagnetischen Feldern auf Pflanzen am
      Beispiel des Kreuzblütlers Ackerschmalwand (Arabidopsis
      thaliana).
description: Very little is known about the
      effects of geomagnetic fields on plants. The present work was
      undertaken to answer the question whether plants can perceive
      the geomagnetic fields (Galland and Pazur 2005). Our findings
      show that the effects of magnetic fields on various responses
      in Arabidopsis thaliana result in a characteristic
      multi-peaked pattern in the stimulus-response curves with
      multiple maxima (peaks) and minima (valleys). These
      multi-peaked stimulus-response curves display a unique
      phenomenon in biology. They are distinctively different from
      the stimulus-response curves, observed in plant physiology,
      showing a pattern of rising exponential functions, with a
      plateau finally. The magnetic response also depended upon the
      fluence rate of the overhead light, the responses being
      higher at higher fluence rates. However, the magnetic fields
      apparently are able to manifest their effects even in
      darkness. The two double mutants displayed variations in
      their response to magnetic fields, as compared to Ler
      seedlings, although the basic pattern of effects remained the
      same. Additionally the effects were enhanced in phyAphyB
      double mutants as compared to cry1cry2 double mutants
      indicating suppression of cryptochrome-mediated magnetic
      effects by phytochromes. These stimulus-response curves are
      difficult to explain on the basis of the criteria required by
      the radical-pair model. The effects of magnetic fields were
      observed not only in darkness but also in cry1cry2 double
      mutants. Experiments also revealed responses of the
      Arabidopsis seedlings to magnetic fields even under red
      light. Interestingly our data are in good correlation with
      data obtained by Binhi (2001) while working on DNA of E.
      coli. They got similar stimulus-response curves with similar
      peak positions as have been observed by us. Binhi and
      coworkers explained their observations in the theoretical
      framework of the “ion-interference mechanism”. A comparison
      of the effects of magnetic fields of the various
      organizational levels of Arabidopsis plant, i.e., on
      hypocotyl length, anthocyanin accumulation, abundance of
      specific mRNA‟s and proteins reveal maximum effects on gene
      transcription (12-fold approx.), which were reduced to about
      6-fold in case of anthocyanin accumulation and were further
      reduced to only about 2.5-fold in case of suppression of
      hypocotyl length by blue light in Arabidopsis. We, therefore
      state that the effects at transcriptional level get balanced
      out at higher levels of organization (biochemical pathway,
      growth response) in order to provide
      “Magnetohomeostasis”.