title: Calcium supply effects on wheat cultivars differing in salt resistance with special reference to leaf cytosol ion homeostasis.
abstract: Salinity causes changes in cytosolic Ca(2+), [Ca(2+)]cyt, Na(+), [Na(+)]cyt and pH, pH cyt , which induce specific reactions and signals. Reactions causing a rebalancing of the physiological homeostasis of the cytosol could result in plant resistance and growth. Two wheat cultivars, Triticum aestivum, Seds1 and Vinjett, were grown in nutrient solution for 7 days under moderate salinity (0 and 50 mM NaCl) with and without extra addition of 5 mM CaSO4 to investigate the seedling-ion homeostasis under salinity. In the leaf protoplasts [Ca(2+) ]cyt, [Na(+)]cyt and pH cyt were detected using acetoxymethyl esters of the ion-specific dyes, Fura 2, SBFI and BCECF, respectively, and fluorescence microscopy. In addition, both cultivars were grown for 3 weeks at 0, 50 and 125 mM NaCl with, or without, extra addition of 5 mM CaSO4 to detect overall Na(+) and Ca(2+) concentrations in leaves and salinity effects on dry weights. In both cultivars, salinity decreased [Ca(2+)]cyt, while at extra Ca(2+) supplied, [Ca(2+)]cyt increased. The [Ca(2+) ]cyt increase was accompanied by increase in the overall Ca(2+) concentrations in leaves and decrease in the overall Na(+) concentration. Moreover, irrespective of Ca(2+) treatment under salinity, the cultivars reacted in different ways; [Na(+) ]cyt significantly increased only in cv. Vinjett, while pH cyt increased only in cv. Seds1. Even at rather high total Na(+) concentrations, the cytosolic concentrations were kept low in both cultivars. It is discussed whether the increase of [Ca(2+)]cyt and pH cyt can contribute to salt tolerance and if the cytosolic changes are due to changes in overall Ca(2+) and Na(+) concentrations.
authors: Institute for Plant Nutrition and Soil Science, Christian Albrechts University, Hermann Rodewald Strasse 2, D-24118, Kiel, Germany; Plant Physiology Section, Plant Botany Department, Faculty of Agriculture, Cairo University, 12613, Giza, Egypt.
authors: Sherif H
authors: SH
authors: Morgan
authors: Sylvia
authors: S
authors: Lindberg
authors: Karl H
authors: KH
authors: Mühling
mesh_terms: D002118:Calcium / Q000502:physiology*; D003600:Cytosol / Q000378:metabolism*; D006706:Homeostasis; D006863:Hydrogen-Ion Concentration; D018515:Plant Leaves / Q000378:metabolism; D011523:Protoplasts / Q000378:metabolism; D054712:Salinity; D055049:Salt Tolerance; D012964:Sodium / Q000378:metabolism*; D014908:Triticum / Q000502:physiology*
chemical_list: D012964:Sodium; D002118:Calcium