Is the induction of H2O2-detoxifying antioxidant enzyme activities sufficient to protect barley cultivars from oxidative stress by UV-B irradiation alone or pretreatment with high temperature and NaCl?

Authors : Hüsnü ÇAKIRLAR, Nuran ÇİÇEK, Yasemin EKMEKÇİ

Pages : 59-68

View : 23 | Download : 11

Publication Date : 2011-12-01

Article Type : Research Paper

Abstract :Ultraviolet B insert ignore into journalissuearticles values(UV-B); irradiation has an adverse effect on plant cells because it causes the generation of reactive oxygen species insert ignore into journalissuearticles values(ROS);. This is scavenged by some endogenous defense systems. In this study, the activities of H2O2-detoxifying antioxidant enzymes in 4 barley cultivars pretreated with high temperature or NaCl before UV-B irradiation were investigated. The stress response in the seedlings was determined by measuring the photosynthetic performance index insert ignore into journalissuearticles values(PI);, which significantly decreased in all barley cultivars under almost all treatments compared to their controls. Activities of 3 H2O2-detoxifying antioxidant enzymes insert ignore into journalissuearticles values(ascorbate peroxidase, glutathione reductase, and peroxidase); significantly increased as a result of all treatments. The results may suggest that UV-B irradiation induces major H2O2-detoxifying enzyme activities, and pretreatments, especially with 200 mM of NaCl, enhance the response of enzyme activities in these 4 barley cultivars. Changes in the PI responses could indicate that the induction of antioxidant enzymes might not be enough to protect from oxidative stress induced by UV-B radiation in the barley cultivars investigated in the study.
Keywords : Key words Ascorbate peroxidase, barley, glutathione reductase, high temperature, NaCl, peroxidase, photosynthetic performance index, UV B irradiation