Volume 7, Issue 4 pp. 358-368
Full Access

Ultrastructure and Lipid Alterations Induced by Cadmium in Tomato (Lycopersicon esculentum) Chloroplast Membranes

W. Djebali

Corresponding Author

W. Djebali

Laboratoire de Physiologie Végétale, U.R. “Nutrition et Métabolisme Azotés et Protéines de Stress”, Département de Biologie, Faculté des Sciences de Tunis, Campus Universitaire, 1060 Tunis, Tunisia

Laboratoire de Physiologie Végétale U.R. “Nutrition et Métabolisme Azotés et Protéines de Stress” Département de Biologie Faculté des Sciences de Tunis Campus Universitaire 1060 Tunis Tunisia [email protected]Search for more papers by this author
M. Zarrouk

M. Zarrouk

Laboratoire de Caractérisation et Qualité de l'Huile d'Olive, Institut National de Recherche Scientifique et Technique, BP 95-2050 Hammam-Lif, Tunisia

Search for more papers by this author
R. Brouquisse

R. Brouquisse

UMR de Physiologie Cellulaire Végétale, Département Réponse et Dynamique Cellulaire, CEA-Grenoble, 17 rue des Martyrs, 38054 Grenoble cedex 9, France

Search for more papers by this author
S. El Kahoui

S. El Kahoui

Laboratoire Interactions Légumineuses-Microorganismes, Institut National de Recherche Scientifique et Technique, BP 95-2050 Hammam-Lif, Tunisia

Search for more papers by this author
F. Limam

F. Limam

Laboratoire Interactions Légumineuses-Microorganismes, Institut National de Recherche Scientifique et Technique, BP 95-2050 Hammam-Lif, Tunisia

Search for more papers by this author
M. H. Ghorbel

M. H. Ghorbel

Laboratoire de Physiologie Végétale, U.R. “Nutrition et Métabolisme Azotés et Protéines de Stress”, Département de Biologie, Faculté des Sciences de Tunis, Campus Universitaire, 1060 Tunis, Tunisia

Search for more papers by this author
W. Chaïbi

W. Chaïbi

Laboratoire de Physiologie Végétale, U.R. “Nutrition et Métabolisme Azotés et Protéines de Stress”, Département de Biologie, Faculté des Sciences de Tunis, Campus Universitaire, 1060 Tunis, Tunisia

Search for more papers by this author
First published: 14 February 2008
Citations: 119

Abstract

Abstract: The effects of cadmium (Cd) uptake on ultrastructure and lipid composition of chloroplasts were investigated in 28-day-old tomato plants (Lycopersicon esculentum var. Ibiza F1) grown for 10 days in the presence of various concentrations of CdCl2. Different growth parameters, lipid and fatty acid composition, lipid peroxidation, and lipoxygenase activity were measured in the leaves in order to assess the involvement of this metal in the generation of oxidative stress. We first observed that the accumulation of Cd increased with external metal concentration, and was considerably higher in roots than in leaves. Cadmium induced a significant inhibition of growth in both plant organs, as well as a reduction in the chlorophyll and carotenoid contents in the leaves. Ultrastructural investigations revealed that cadmium induced disorganization in leaf structure, essentially marked by a lowered mesophyll cell size, reduced intercellular spaces, as well as severe alterations in chloroplast fine structure, which exhibits disturbed shape and dilation of thylakoid membranes. High cadmium concentrations also affect the main lipid classes, leading to strong changes in their composition and fatty acid content. Thus, the exposure of tomato plants to cadmium caused a concentration-related decrease in the fatty acid content and a shift in the composition of fatty acids, resulting in a lower degree of fatty acid unsaturation in chloroplast membranes. The level of lipid peroxides and the activity of lipoxygenase were also significantly enhanced at high Cd concentrations. These biochemical and ultrastructural changes suggest that cadmium, through its effects on membrane structure and composition, induces premature senescence of leaves.

Abbreviations:

  • DGDG
  • digalactosyldiacyl glycerol
  • MDA
  • malondialdehyde
  • MGDG
  • monogalactosyldiacyl glycerol
  • NL
  • neutral lipid
  • PA
  • phosphatidic acid
  • PG
  • phosphatidyl glycerol
  • PI
  • phosphatidylinositol
  • SL
  • sulfolipid
  • PUFAs
  • polyunsaturated fatty acid species
  • TBARS
  • thiobarbituric acid reactive substances
    • The full text of this article hosted at iucr.org is unavailable due to technical difficulties.