ROS Accumulation and TTC Reduction in Growing Embryo of Crithmum maritimum L. Isolated from Water or Salt Imbibed Seeds

Abstract

The salinity induced inhibition of seeds germination remains not clear at physiological levels. The aims of this study is to investigate the effect of salt on germination, embryo growth, superoxide anion radical (O₂^•–) and the respiratory activity (TTC reduction) in Crithmum maritimum L. seeds. Thus the embryo growth, in situ localization of respiratory activity and superoxide anion radical (O₂^•–) localization, were investigated. Chlorure 2, 3, 5-triphényltétrazolium (TTC) reduction test and superoxide anion radical (O₂^•–) localization with Nitroblue Tetrazolium Chloride (NBT) were performed in embryo isolated from seeds of the halophyte Crithmum maritimum L either sown in distilled water or in 200 mM NaCl. The key results show that germination was maximal (90 %) in distilled water, but was fully inhibited following seed exposure to NaCl. The completion of the embryo growth (ca. 2 mm length) leading to the radicle emergence took 6 d in H₂O, but was markedly delayed by salt. NaCl reduced the elongation zone in the embryo axis, hence indicating that the cell division and/or cell elongation were disturbed by salinity. The respiratory activity (TTC reduction) and O₂^•– production in the cotyledon were significantly lowered by salinity.