Premium
The oxidative stress caused by salinity in two barley cultivars is mitigated by elevated CO 2
Author(s) -
PérezLópez Usue,
Robredo Anabel,
Lacuesta Maite,
Sgherri Cristina,
MuñozRueda Alberto,
NavariIzzo Flavia,
MenaPetite Amaia
Publication year - 2009
Publication title -
physiologia plantarum
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.351
H-Index - 146
eISSN - 1399-3054
pISSN - 0031-9317
DOI - 10.1111/j.1399-3054.2008.01174.x
Subject(s) - apx , antioxidant , hordeum vulgare , glutathione reductase , catalase , superoxide dismutase , lipid peroxidation , peroxidase , chemistry , oxidative stress , biochemistry , glutathione peroxidase , biology , enzyme , botany , poaceae
Changes in antioxidant metabolism because of the effect of salinity stress (0, 80, 160 or 240 m M NaCl) on protective enzyme activities under ambient (350 μmol mol −1 ) and elevated (700 μmol mol −1 ) CO 2 concentrations were investigated in two barley cultivars ( Hordeum vulgare L., cvs Alpha and Iranis). Electrolyte leakage, peroxidation, antioxidant enzyme activities [superoxide dismutase (SOD), EC 1.15.1.1; ascorbate peroxidase (APX), EC 1.11.1.11; catalase (CAT), EC 1.11.1.6; dehydroascorbate reductase (DHAR), EC 1.8.5.1; monodehydroascorbate reductase (MDHAR), EC 1.6.5.4; glutathione reductase (GR), EC 1.6.4.2] and their isoenzymatic profiles were determined. Under salinity and ambient CO 2 , upregulation of antioxidant enzymes such as SOD, APX, CAT, DHAR and GR occurred. However, this upregulation was not enough to counteract all ROS formation as both ion leakage and lipid peroxidation came into play. The higher constitutive SOD and CAT activities together with a higher contribution of Cu,Zn‐SOD 1 detected in Iranis might possibly contribute and make this cultivar more salt‐tolerant than Alpha. Elevated CO 2 alone had no effect on the constitutive levels of antioxidant enzymes in Iranis, whereas in Alpha it induced an increase in SOD, CAT and MDHAR together with a decrease of DHAR and GR. Under combined conditions of elevated CO 2 and salinity the oxidative damage recorded was lower, above all in Alpha, together with a lower upregulation of the antioxidant system. So it can be concluded that elevated CO 2 mitigates the oxidative stress caused by salinity, involving lower ROS generation and a better maintenance of redox homeostasis as a consequence of higher assimilation rates and lower photorespiration, being the response dependent on the cultivar analysed.