Efficient leaf ion partitioning, an overriding condition for abscisic acid-controlled stomatal and leaf growth responses to NaCl salinization in two legumes.
Two tree medics contrasting in salt tolerance, Medicago arborea and Medicago citrina, were compared to evaluate the relative importance of abscisic acid on leaf growth and stomatal responses to salt stress. Plants were grown for 30 d in solution culture with 1, 50, 100 or 200 mM NaCl. Salinized plants of M. citrina had lower Na+ and Cl- uptake and maintained better leaf growth than M. arborea. In M. citrina, stomatal conductance was only slightly affected by salt and, in consequence, the salt treatment had no significant influence, neither on the CO2 fixation rate nor the transpiration rate in these plants. Moreover, leaf photosynthetic pigments and soluble protein in M. citrina were increased by the presence of NaCl, while a decrease of both parameters with salt was found in M. arborea. However, leaf and xylem ABA increased only in salt-treated M. citrina, while no differences were found among treatments in M. arborea. The role of ion compartmentation, gas exchange parameters and ABA concentrations in relation to salt tolerance in M. arborea and M. citrina is discussed.
Sibole
John V
JV
Department of Biology, Universitat de les Illes Balears, Cra. Valldemossa km. 7.5, 07071 Palma de Mallorca, Spain. dbsji4@clust.uib.es
Cabot
Catalina
C
Poschenrieder
Charlotte
C
Barceló
Juan
J
D000040:Abscisic Acid / Q000494:pharmacology*; D007887:Fabaceae / Q000187:drug effects / Q000254:growth & development / Q000502:physiology; D007477:Ions / Q000378:metabolism; D029902:Medicago / Q000187:drug effects / Q000254:growth & development / Q000502:physiology*; D010788:Photosynthesis / Q000187:drug effects / Q000502:physiology; D018515:Plant Leaves / Q000187:drug effects / Q000254:growth & development / Q000502:physiology*; D010940:Plant Proteins / Q000378:metabolism; D012680:Sensitivity and Specificity; D012965:Sodium Chloride / Q000494:pharmacology*; D014867:Water / Q000378:metabolism
D007477:Ions; D010940:Plant Proteins; D014867:Water; D012965:Sodium Chloride; D000040:Abscisic Acid