Cadmium-Induced Changes in Antioxidative Systems, Hydrogen Peroxide Content, and Differentiation in Scots Pine Roots

Because it is not known whether Cd induces common plant defense pathways, we investigated the sequence of physiological reactions, including H2O2 production, changes in ascorbate-glutathione-related antioxidant systems, secondary metabolism, developmental changes, and cell death, occurring in roots after Cd exposure

Andres Schützendübel

2008

Scholarcy highlights

  • To investigate whether Cd induces common plant defense pathways or unspecific necrosis, the temporal sequence of physiological reactions, including hydrogen peroxide production, changes in ascorbate-glutathione-related antioxidant systems, secondary metabolism, and developmental changes, was characterized in roots of hydroponically grown Scots pine seedlings
  • Histochemical analysis showed that soluble phenolics accumulated in the cytosol of Cd-treated roots but lignification was confined to newly formed protoxylem elements, which were found in the region of the root tip that normally constitutes the elongation zone
  • In plant-pathogen interactions, H2O2 induces an orchestrated sequence of reactions involving the activation of peroxidases, the stimulation of secondary metabolism, structural changes such as lignin deposition, and eventually cell death. Because it is not known whether Cd induces common plant defense pathways, we investigated the sequence of physiological reactions, including H2O2 production, changes in ascorbate-glutathione-related antioxidant systems, secondary metabolism, developmental changes, and cell death, occurring in roots after Cd exposure
  • Roots exposed to the higher Cd concentration completely stopped growth after 12 h, whereas those treated with the lower Cd concentration continued to grow at a 20% diminished rate
  • Cd treatment initially had no effect on nonspecific peroxidase activities, i.e. peroxidases reducing H2O2 by the oxidation of aromatic substrates like phenolics or monolignols
  • It is interesting to note that the Cd-induced stimulation in POD activities was delayed as compared with ascorbate peroxidases or CAT activities and that initial reductions in POD activities did not occur
  • For the extraction of water soluble antioxidants, 60 to 100 mg of frozen root tips were powdered in liquid nitrogen, mixed with 1 mL of 2% meta-phosphoric acid containing 1 mm EDTA and 1 mg polyvinylpolypyrrolidone per mg of sample, and centrifuged

Need more features? Save interactive summary cards to your Scholarcy Library.