بررسي اثر متقابل تاثير پرتوهاي UV-B و UV-C و ساليسيليك اسيد بر برخي پارامترهاي فيزيولوژيكي و بيوشيميايي بادرنجبويه (Melissa officinalis L.)

The interactions of UV-B and UV-C radiation and salicylic acid on some physiological and biochemical parameters in Melissa officinalis L.

اثرات ناشي از كاهش لايه اوزون و افزايش اشعه فرابنفش امروزه توسط بسياري از محققان مورد بررسي قرار گرفته است. هدف اين مطالعه بررسي تاثير پرتوهاي UV-B و UV-C بر روي گياه بادرنجبويه (Melissa officinalis L.) و تاثير ساليسيليك اسيد در كاهش اثرات زيان‌بار اين پرتوها بر روي اين گياه بود. گياهان بادرنجبويه به مدت 60 روز كشت شدند. تيمار فرابنفش بعد از مرحله 6 برگي اعمال گرديد و پرتو UV-B به مدت 15 روز به صورت يك روز در ميان و هر بار به مدت 20 دقيقه و پرتو UV-C به مدت 15 روز و به صورت يك روز در ميان و هر بار به مدت 8 دقيقه اعمال گرديد. اسيد ساليسيليك نيز بعد از مرحله 6 برگي با غلظت 1 ميلي مول به مدت يك هفته بر روي گياهان پاشيده شد. نتايج نشان داد كه پرتوهاي UV-B و UV-C باعث كاهش وزن تر و خشك، رشد طولي ريشه و اندام هوايي شد. اين پرتوها هم چنين ميزان رنگيزه هاي فتوسنتزي (كلروفيل a، كلروفيل b و كاروتنوييد) ميزان قندها و پروتيين هاي محلول را كاهش دادند. ميزان مالون-دي آلدييد و فنيل آلانين آمونيا لياز و تركيبات جاذب UV نيز تحت تاثير پرتوهاي UV-B و UV-C افزايش نشان داد. بررسي نتايج نشان داد تيمار با ساليسيليك اسيد باعث كاهش آسيب هاي وارده به گياه شد كه در اثر پرتوهاي UV-B و UV-C به وجود آمده بودند و توانست فاكتورهايي كه تحت تابش هاي فرابنفش تغيير يافته بودند را جبران كنند.

Nowdays, effects of decreased ozone and increased UV radiation have been studied by many researchers. The aim of this study was to investigate the effects of UV-B and UV-C radiations on Melissa officinalis L and to study the impact of salicylic acid in reducing the harmful effects of radiation on plants. The Melissa officinalis L. plants were treated with 28±2 ?C temperature for about 60 days. The light intensity was 150 µ mol m?² S?¹ and the photoperiod condition was 8-16 hours. UV treatment was applied after the six-leaf stage and UV-B radiation was applied for a period of 15 days application for 20 minutes. But UV-C radiation was applied every other days for 15 days in and time of each application was 8 minutes. Salicylic acid was sprayed on the plants after the six-leaf stage with a concentration of 1 mM. The results indicated that the UV-B and UV-C radiations led to reduction in dry and fresh weight, root elongation and shoots. The radiations also reduced the photosynthetic pigments (chlorophyll a, chlorophyll b and carotenoid) sugar content and total soluble proteins amount. The malondialdehyde and phenylalanine ammonialyase compounds content and UV- absorbing compounds were increased under the effect of UV-B and UV-C radiations. The results showed that treatment with salicylic acid reduced. The damage to the plant which had been created due to UV-B and UV-C radiations and was able to compensate for modified factors that had been changed because of ultra violet radiations.