interactive effects of salicylic acid and cold stress on activities of antioxidant enzymes in glycyrrhiza glabra l.

background & aim: glycyrrhiza l. (fabaceae) consists of perennial herbs grow in sandy soils with hard lightness. three species of the genus grow in iran, among them g. glabra l. has the widest distribution. it is well known in english as licorice and the root extract includes flavonoids and glycyrrhizin are used widely in medicine, food industry, tobacco products and other industries. liquiritin and glabridin are the major constituents of flavonoids in its extract, which have quasi estrogenic, ant oxidative, anti-helicobacter, anti-nephritic activities and ros scavenging. experimental: in this research, the interactive effects of salicylic acid (sa) with cold stress on some antioxidant enzymes such as peroxidase (prx) and polyphenol oxidase (ppo) were studied by spectrophotometric method in a factorial experiment of completely randomized design with three replications. sa pretreatments were included 10, 50, 100 and 500 µm and three levels of cold stress, 5, 10 and 20h in 4 oc were applied. results & discussion: the results showed that cold stress did not affect ppo activity, while sa decreased it. in addition, prx activity was decreased with increasing cold stress and sa resulted in similar response at this condition. it seems that sa can considerably alleviate oxidative damage that occurred under cold stress condition with direct scavenging of reactive oxygen species. thus it resulted in decrease activity of antioxidant enzymes.