Journal of Plant Process and Function

Ultraviolet radiation divides to three bands UV-A (320-390 nm), UV-B (280-320 nm) and UV-C (254-280 nm). Different bands of ultraviolet radiation have different effects on growth, physiological and biochemical plants. In this research the effect of different bands of UV radiation on the shoot and root length, quantity of flavonoids, anthocyanine, protein, ethylene, peroxidase and polyphenol oxidase activities and the concentration of Ca²⁺, K⁺, Mg²⁺ in seedlings of the pepper (Capsicum annuum L.) were studied. After 10 days, seedlings were for 3 days under treatment UV-A, UV-B and UV-C. To assess the effect of ultraviolet treatments on electrophoretic polypeptide patterns, shoot proteins were separated on SDS-PAGE gels. The results showed that under the experimental conditions, UV-B and UV-C radiation reduces the length of shoot and root. Studied showed that irradiation of the plant with UV-B and UV-C caused significant increase in quantity of protein, anthocyanine, flavonoids, ethylene, the concentration of Ca²⁺, K⁺, Mg²⁺, activity of enzymes peroxidase and polyphenol oxidase, while in those plants which were treated with UV-A, the activity of enzymes were not significantly different in comparison to the control. These pigment have high absorption in UV spectrum of light and therefore could be used as UV absorption compounds by plants to prevent penetration of UV to the more sensitive tissues. The role of flavonoids in quenching of hydrogene peroxide and defensive reaction of plants against UV radiation which will discaused in this paper.