The effects of UV-B on flavonoid pigments, relative chlorophyll content and photochemical efficiency of photosystem II in Tea plants

Tea (Camellia sinensis) belongs to the Theaceae family and is an evergreen shrub indigenous to China and India. The plant leaves contain different kinds of important flavonoids and, hence, indicate many biological activities. To study the effects of UV-B radiation on the flavonoid content of tea plants, a greenhouse experiment was performed in a completely randomized design. In this regard, first, tea seedlings were purchased from the Fashalem Research Institute and then kept in greenhouse conditions. Then the UV treatment at ۵ levels was performed, and the plants were harvested to determine the total flavonoids content using spectrophotometry and certain flavonoid levels by the thin layer chromatography (TLC) method in all the treated groups. The results showed that flavonoids levels decreased at the beginning of UV treatment and then increased at ۱۲ KJ/m۲S of UV treatment. On the other hand, the relative chlorophyll content and photochemical efficiency of photosystem II were reduced in the UV-treated tea plants at doses higher than ۹ KJ/m۲S. It was concluded that although cultivation of tea plants in habitats with high UV index tends to result in a considerable reduction in photosynthetic parameters and plant yield, it can cause an elevation in the flavonoids content and pharmacological potential of the tea plant.

Keywords:

Tea , Flavonoids , UV , چای , فلاونوئید , اشعه ماورای بنفش