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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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SOD isoforms detected in native gel. The protein concentration loaded in each well was the same. C, control; CN, cyanide; S1, 40 mM NaCl; S2, 80 mM NaCl; ZI, zone I; ZII, zone II.
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fig5: SOD isoforms detected in native gel. The protein concentration loaded in each well was the same. C, control; CN, cyanide; S1, 40 mM NaCl; S2, 80 mM NaCl; ZI, zone I; ZII, zone II.

Mentions: The isozyme composition of SODs was determined on native gels stained for SOD activity. Two Cu,Zn-SODs, one Mn-SOD, and one Fe-SOD were identified in root samples (Fig. 5). Fe-SOD, Mn-SOD, and Cu,Zn-SOD II activities can be observed in all samples. However, Cu,Zn-SOD I can be observed only in zone I at 7 d. In general, Fe-SOD seems to be the main isozyme. The analysis of the activities of the different isozymes is well correlated with the total activity. In zone I at 7 d, Fe-SOD is induced at 80 mM NaCl, and Cu,Zn-SOD I and Mn-SOD are similarly induced (Fig. 5).


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)

SOD isoforms detected in native gel. The protein concentration loaded in each well was the same. C, control; CN, cyanide; S1, 40 mM NaCl; S2, 80 mM NaCl; ZI, zone I; ZII, zone II.
© Copyright Policy - open-access
Related In: Results  -  Collection

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

fig5: SOD isoforms detected in native gel. The protein concentration loaded in each well was the same. C, control; CN, cyanide; S1, 40 mM NaCl; S2, 80 mM NaCl; ZI, zone I; ZII, zone II.
Mentions: The isozyme composition of SODs was determined on native gels stained for SOD activity. Two Cu,Zn-SODs, one Mn-SOD, and one Fe-SOD were identified in root samples (Fig. 5). Fe-SOD, Mn-SOD, and Cu,Zn-SOD II activities can be observed in all samples. However, Cu,Zn-SOD I can be observed only in zone I at 7 d. In general, Fe-SOD seems to be the main isozyme. The analysis of the activities of the different isozymes is well correlated with the total activity. In zone I at 7 d, Fe-SOD is induced at 80 mM NaCl, and Cu,Zn-SOD I and Mn-SOD are similarly induced (Fig. 5).

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