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

Abdallah Atia,Chedly Abdelly,Abderrazak Smaoui

doi:10.15835/nsb325884

Abdallah Atia, Chedly Abdelly + Show 1 more

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https://doi.org/10.15835/nsb325884

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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.

Highlights

The germination phase is preceded by the initiation of embryo elongation within the seeds (Nikolaeva, 1977; Baskin and Baskin, 2004), and subsequently the radicle elongation and protrusion through the surrounding tissues
We found that seed germination capacity of C. maritimum L. was maximal in salt free media and that salinity inhibit germination, namely at higher levels (200 mM, NaCl) (Atia et al, 2006; MeotDuros and Magné, 2008)
Some seeds germinated in 200 mM NaCl solution and 300 mM NaCl completely inhibited the germination over time (Fig. 1)

Summary

Introduction

The germination phase is preceded by the initiation of embryo elongation within the seeds (Nikolaeva, 1977; Baskin and Baskin, 2004), and subsequently the radicle elongation and protrusion through the surrounding tissues These modifications constitute the germination sensu stricto (Bewly, 1997). This phase is relatively limited in time and is associated with the increase of the respiration activity, the initiation of cells division and the radicle elongation (Côme, 1982; Bewly, 1997; Homrichhausen et al, 2003; Mûller et al, 2009). There is evidence that the onset of germination metabolism is accompanied by intense production of ROS including hydrogen peroxide (H2O2), the hydroxyl radical (.OH), the singlet oxygen (1O2) and the superoxide anion radical (O2·-) (Bailly et al, 2008)

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