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A different role for hydrogen peroxide and the antioxidative system under short and long salt stress in Brassica oleracea roots.

Hernandez M, Fernandez-Garcia N, Diaz-Vivancos P, Olmos E - J. Exp. Bot. (2009)

Bottom Line: The results confirm a drastic decrease in the antioxidant enzymes catalase, ascorbate peroxidase, and peroxidases under short salt treatments.Ascorbate was progressively accumulated and its redox state maintained, but glutathione was highly accumulated at 24 h of salt treatment, but then its concentration and redox state progressively decreased.In conclusion, the increase in ascorbate levels and the maintenance of the redox state seem to be critical for root growth and development under salt stress.

View Article: PubMed Central - PubMed

Affiliation: Department of Abiotic Stress and Plant Pathology, CEBAS-Consejo Superior de Investigaciones Cientificas, Murcia, Spain.

ABSTRACT
Salinity affects normal growth and development of plants depending on their capacity to overcome the induced stress. The present study was focused on the response and regulation of the antioxidant defence system in Brassica oleracea roots under short and long salt treatments. The function and the implications of hydrogen peroxide as a stressor or as a signalling molecule were also studied. Two different zones were analysed--the elongation and differentiation zone and the fully differentiated root zone--in order to broaden the knowledge of the different effects of salt stress in root. In general, an accumulation of hydrogen peroxide was observed in both zones at the highest (80 mM NaCl) concentration. A higher accumulation of hydrogen peroxide was observed in the stele of salt-treated roots. At the subcellular level, mitochondria accumulated hydrogen peroxide in salt-treated roots. The results confirm a drastic decrease in the antioxidant enzymes catalase, ascorbate peroxidase, and peroxidases under short salt treatments. However, catalase and peroxidase activities were recovered under long salt stress treatments. The two antioxidant molecules analysed, ascorbate and glutathione, showed a different trend during salt treatments. Ascorbate was progressively accumulated and its redox state maintained, but glutathione was highly accumulated at 24 h of salt treatment, but then its concentration and redox state progressively decreased. Concomitantly, the antioxidant enzymes involved in ascorbate and glutathione regeneration were modified under salt stress treatments. In conclusion, the increase in ascorbate levels and the maintenance of the redox state seem to be critical for root growth and development under salt stress.

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In situ location of glutathione in control (A, C, and D) and salt-treated roots (80 mM NaCl, E and F)) of Brassica oleracea during 24 h. Root sections were treated with dye solution (monochlorobimane) and images were taken by confocal laser scanning microscopy after an incubation period of 1 h. The fluorescent GSB conjugate was visualized in a single optical section of root. Zone I (A and B; C and D are magnifications of the same image in C and D) and zone II (E and F).
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fig8: In situ location of glutathione in control (A, C, and D) and salt-treated roots (80 mM NaCl, E and F)) of Brassica oleracea during 24 h. Root sections were treated with dye solution (monochlorobimane) and images were taken by confocal laser scanning microscopy after an incubation period of 1 h. The fluorescent GSB conjugate was visualized in a single optical section of root. Zone I (A and B; C and D are magnifications of the same image in C and D) and zone II (E and F).

Mentions: The results presented here showed a high increment of glutathione during the first 24 h at 80 mM NaCl but not at 40 mM NaCl. To confirm this result, the subcellular location of total glutathione was developed using MCB, and fluorescence was located by laser confocal microscopy. Zone I showed a much higher fluorescence in the root tip of salt-treated roots (Fig. 8B) compared with the control (Fig. 8A). At a higher magnification, this higher fluorescence seems to be located in the nuclei of salt-treated roots (Fig. 8D) compared with the control (Fig. 8C). Similarly, zone II of salt-treated roots showed a higher fluorescence in the cytoplasm of the cells (Fig. 8F) compared with the control (Fig. 8E).


A different role for hydrogen peroxide and the antioxidative system under short and long salt stress in Brassica oleracea roots.

Hernandez M, Fernandez-Garcia N, Diaz-Vivancos P, Olmos E - J. Exp. Bot. (2009)

In situ location of glutathione in control (A, C, and D) and salt-treated roots (80 mM NaCl, E and F)) of Brassica oleracea during 24 h. Root sections were treated with dye solution (monochlorobimane) and images were taken by confocal laser scanning microscopy after an incubation period of 1 h. The fluorescent GSB conjugate was visualized in a single optical section of root. Zone I (A and B; C and D are magnifications of the same image in C and D) and zone II (E and F).
© Copyright Policy - open-access
Related In: Results  -  Collection

License 1 - License 2
Show All Figures
getmorefigures.php?uid=PMC2803216&req=5

fig8: In situ location of glutathione in control (A, C, and D) and salt-treated roots (80 mM NaCl, E and F)) of Brassica oleracea during 24 h. Root sections were treated with dye solution (monochlorobimane) and images were taken by confocal laser scanning microscopy after an incubation period of 1 h. The fluorescent GSB conjugate was visualized in a single optical section of root. Zone I (A and B; C and D are magnifications of the same image in C and D) and zone II (E and F).
Mentions: The results presented here showed a high increment of glutathione during the first 24 h at 80 mM NaCl but not at 40 mM NaCl. To confirm this result, the subcellular location of total glutathione was developed using MCB, and fluorescence was located by laser confocal microscopy. Zone I showed a much higher fluorescence in the root tip of salt-treated roots (Fig. 8B) compared with the control (Fig. 8A). At a higher magnification, this higher fluorescence seems to be located in the nuclei of salt-treated roots (Fig. 8D) compared with the control (Fig. 8C). Similarly, zone II of salt-treated roots showed a higher fluorescence in the cytoplasm of the cells (Fig. 8F) compared with the control (Fig. 8E).

Bottom Line: The results confirm a drastic decrease in the antioxidant enzymes catalase, ascorbate peroxidase, and peroxidases under short salt treatments.Ascorbate was progressively accumulated and its redox state maintained, but glutathione was highly accumulated at 24 h of salt treatment, but then its concentration and redox state progressively decreased.In conclusion, the increase in ascorbate levels and the maintenance of the redox state seem to be critical for root growth and development under salt stress.

View Article: PubMed Central - PubMed

Affiliation: Department of Abiotic Stress and Plant Pathology, CEBAS-Consejo Superior de Investigaciones Cientificas, Murcia, Spain.

ABSTRACT
Salinity affects normal growth and development of plants depending on their capacity to overcome the induced stress. The present study was focused on the response and regulation of the antioxidant defence system in Brassica oleracea roots under short and long salt treatments. The function and the implications of hydrogen peroxide as a stressor or as a signalling molecule were also studied. Two different zones were analysed--the elongation and differentiation zone and the fully differentiated root zone--in order to broaden the knowledge of the different effects of salt stress in root. In general, an accumulation of hydrogen peroxide was observed in both zones at the highest (80 mM NaCl) concentration. A higher accumulation of hydrogen peroxide was observed in the stele of salt-treated roots. At the subcellular level, mitochondria accumulated hydrogen peroxide in salt-treated roots. The results confirm a drastic decrease in the antioxidant enzymes catalase, ascorbate peroxidase, and peroxidases under short salt treatments. However, catalase and peroxidase activities were recovered under long salt stress treatments. The two antioxidant molecules analysed, ascorbate and glutathione, showed a different trend during salt treatments. Ascorbate was progressively accumulated and its redox state maintained, but glutathione was highly accumulated at 24 h of salt treatment, but then its concentration and redox state progressively decreased. Concomitantly, the antioxidant enzymes involved in ascorbate and glutathione regeneration were modified under salt stress treatments. In conclusion, the increase in ascorbate levels and the maintenance of the redox state seem to be critical for root growth and development under salt stress.

Show MeSH