Effects of NaCl on the growth, ion accumulation and photosynthetic parameters of Thellungiella halophila.
Thellungiella halophila seedlings grown on a solid substrate for 25 days on standard medium were challenged with NaCl. Growth, tissue hydration, ion accumulation, photosynthesis, lipid peroxidation and antioxidant enzymatic activities were studied on rosette leaves. Three accessions of Arabidopsis thaliana were cultivated under the same conditions. During the first two weeks of salt treatment, the growth of T. halophila leaves was restricted by NaCl. No significant difference appeared between T. halophila and A. thaliana concerning biomass deposition, or hydric and ionic parameters. However, all A. thaliana plants displayed foliar damage, and died during the third week of salt (50mM NaCl) treatment. Almost all (94%) T. halophila plants remained alive, but did not display any sign of altered physiological condition. Tissue hydration, chlorophyll content, stomatal conductance, photosynthetic quantum yield, and photosynthetic rate were very similar to those of control plants. Lipid peroxidation, estimated from thermoluminescence, was very low and insensitive to salt treatment. Only slight changes occurred in antioxidant enzymatic activities (SOD, several peroxidases, and catalase). From the absence of physiological disorder symptoms, we infer that salt was efficiently compartmentalized in leaf vacuoles. In salt-treated A. thaliana, the photosynthetic quantum yield was diminished, and lipid peroxidation was augmented. These observations reinforce the conclusion that T. halophila could accumulate salt in its leaves without damage, in contrast to A. thaliana.
M'rah
Sabah
S
Physiologie et Biochimie de la Tolérance au Sel des Plantes, Faculté des Sciences de Tunis, Campus Universitaire, 1060 Tunis, Tunisia.
Ouerghi
Zeineb
Z
Berthomieu
Catherine
C
Havaux
Michel
M
Jungas
Colette
C
Hajji
Mokhtar
M
Grignon
Claude
C
Lachaâl
Mokhtar
M
D000975:Antioxidants / Q000032:analysis; D017360:Arabidopsis / Q000187:drug effects / Q000254:growth & development / Q000378:metabolism; D019607:Brassicaceae / Q000187:drug effects / Q000254:growth & development* / Q000378:metabolism*; D007477:Ions / Q000378:metabolism*; D010788:Photosynthesis / Q000187:drug effects*; D018515:Plant Leaves / Q000737:chemistry / Q000187:drug effects / Q000201:enzymology; D010940:Plant Proteins / Q000032:analysis; D012965:Sodium Chloride / Q000494:pharmacology*
D000975:Antioxidants; D007477:Ions; D010940:Plant Proteins; D012965:Sodium Chloride