The effect of light on ROS-scavenging systems and lipid peroxidation under cold conditions in saffron (Crocus sativus L.)

Abstract

Saffron is one of the most important crops cultivated in Iran. Because of low water demand and tolerance to winter cold as well as its high price and quality compared to that of other countries, Iranian saffron deserves closer attention. This experiment was conducted to study the effect of light under low temperature on the defense mechanisms of this plant. Corms of saffron were cultivated on the education and research farmlands of the University of Maragheh on October 1st2007. Following the drop in weather temperature on December 23rd, 2007, some of the plants were covered in a way that sunlight could not reach them. After 6 h, the samples of saffron leaves were taken and the activity levels of superoxide dismutase (SOD, EC 1.15.1.1), catalases (CAT, EC 1.11.1.6), glutathione reductase (GR, EC 1.6.4.2) and ascorbate peroxidase (APX, EC 1.11.1.11) enzymes as well as the amount of lipid peroxidation (MDA content) in the samples were measured. The results indicated that the activity level of CAT, GR and APX in light and low temperature conditions were significantly higher than that of dark and low temperature conditions. Meanwhile, SOD activity was significantly lower in light and low temperature conditions compared to that of dark and low temperature conditions. Increased activity of CAT, GR and APX alleviated the damaging effect of light presence at a low temperature on cell membranes. Key words: Antioxidant enzyme, lipid peroxidation, low temperature, saffron.