Volume 18, Issue 49 (11-2006)
Abstract
Salicylic acid (SA) is a compound that has a basic role in increasing cold tolerance in plants. When two-days old radish seedlings were pretreated with different concentra-tions of SA (0, 0.5, 1, 1.5 and 2 mM) for 24 hours and then imposed to cold stress at 2.5 ˚C for 48 hours, cold resistance is increased in them. This phenomenon is shown by reduced efflux of K+ ions and soluble sugars and increased root length of seedlings especially at 0.5 mM, SA concentration. This finding shows that there is a straight correlation between SA concentration and reduced cold injury. Measuring the activity of three antioxidant enzymes, ascorbate peroxidase (APX), guaiacol peroxidase (GPX) and catalase (CAT) in shoot and roots of radish seedlings, revealed that SA induced cold resistance is accompanied by increased activity of these antioxidant enzymes.
