Plant Growth Regulation

, Volume 71, Issue 2, pp 157–170

Chromium (VI)-induced hormesis and genotoxicity are mediated through oxidative stress in root cells of Allium cepa L.

  • Anita R. Patnaik
  • V. Mohan M. Achary
  • Brahma B. Panda
Original paper

DOI: 10.1007/s10725-013-9816-5

Cite this article as:
Patnaik, A.R., Achary, V.M.M. & Panda, B.B. Plant Growth Regul (2013) 71: 157. doi:10.1007/s10725-013-9816-5
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Abstract

Chromium (VI) genotoxicity was evaluated in Allium bioassay by using different treatment protocols. Treatment of bulbs of Allium cepa L. with Cr(VI) at a range of concentrations for 5 days (120 h) exhibited low dose (12.5 μM) stimulation and high dose (25–200 μM) inhibition of root growth apparently indicating hormesis. Inhibition of root growth was correlated with the dose-dependent increase in generation of reactive oxygen species (ROS), cell death, lipid peroxidation, repression of antioxidative enzymes (catalase, superoxide dismutase, ascorbate peroxidase), induction of DNA damage, chromosome aberrations or micronuclei in root cells. The above effects were, however, reversed when the duration of Cr(VI) treatment was limited to 3–24 h followed by recovery in tap water for 4 days that resulted in the dose-dependent stimulation of root growth, mitosis and increased activity of the antioxidative enzymes that obliterated oxidative stress and genotoxicity. The above Cr(VI)-induced stimulation of root growth was effectively countered by pre- or post-treatments of dimethylthiourea, a ROS-scavenger. These findings underscored that Cr(VI), depending on the magnitude of the dose (concentration × time), could either be stimulatory or inhibitory for root growth that underlined the crucial role of ROS having obvious implications in agriculture, post harvest technology and human health.

Keywords

Antioxidant enzymesCell deathComet assayOxidative stressGenotoxicityHormesis

Abbreviations

APX

Ascorbate peroxidase

CA

Chromosome aberration

CAT

Catalase

DMTU

Dimethylthiourea

EDTA

Ethylenediamine-tetra acetic acid

FW

Fresh weight

GPX

Guaiacol peroxidase

LMPA

Low melting point agarose

MDA

Malondialdehyde

MI

Mitotic index

MN

Micronucleus

NBT

Nitroblue tetrazolium

OTM

Olive tail moment

ROS

Reactive oxygen species

SOD

Superoxide dismutase

TBA

Thiobarbituric acid

TCA

Trichloroacetic acid

Copyright information

© Springer Science+Business Media Dordrecht 2013

Authors and Affiliations

  • Anita R. Patnaik
    • 1
  • V. Mohan M. Achary
    • 2
  • Brahma B. Panda
    • 1
  1. 1.Molecular Biology and Genomics Laboratory, Department of BotanyBerhampur UniversityBerhampurIndia
  2. 2.Plant Molecular Biology GroupInternational Centre for Genetic Engineering and BiotechnologyNew DelhiIndia