engleski

Short-term heat stress induces quick antioxidative response by peroxidase action in barley (Hordeum vulgare L.)

High temperature stress is one of the major abiotic stresses that causes different physiological and molecular responses in crops. Class III peroxidase reduce the levels of reactive oxygen species (ROS) in the cells and therefore, represent effective part of the antioxidant system. We investigated physiological and biochemical response of two barley varieties, modern Zlatko and old autochthonous variety Mursa, to short-term heat stress. Plants were grown under controlled conditions with a daytime temperature of 23 ℃ (16 hours) and a night temperature of 18 ℃ (8 hours). After 14 days of cultivation, barley seedlings were exposed to heat stress during 24 hours at 35 ℃ (day) and 23 ℃ (night). Oxidative stress parameters, hydrogen peroxide and lipid peroxidation, didn’t increased. However, significantly increased guaiacol peroxidase activity was observed in both genotypes. Measurements of photosynthetic efficiency indicated that shortterm heat stress decreased values of photosynthetic efficiency index (PIABS) and the maximum quantum yield (Fv/Fm) in both varieties. In conclusion, old variety Mursa showed increased total chlorophyll, carotenoid and protein concentrations in comparison to modern variety Zlatko indicating better activation of protective mechanisms. The antioxidative defense triggered efficient and fast activation of peroxidase directed to diminish deleterious action of ROS generated by short-term heat stress in both barley varieties.

peroxidase ; barley ; heat stress ; oxidative stress ; photosynthesis

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