ببررسی اثر متقابل تاثیر پرتوهای UV-B و UV-C و سالیسیلیک اسید بر برخی پارامترهای فیزیولوژیکی و بیو شیمیایی بادرنجبویه (Melissa Officinalis L.)

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 ºC temperature for about 60 days. The light intensity was 150 µ E mˉ² Sˉ¹ and the lightness-darkness condition was8-16 hours. UV treatment was applied after the six-leaf stage and UV-B radiation was applied for a period of 15 days in every other day the time for each application was 20 minutes. But UV-C radiation was applied for 15 days in every other day 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 wet weight, root elongation and shoots. The radiations also reduced the photosynthetic pigments (chlorophyll a, chlorophyll b and carotenoid) and sugar rate and total soluble proteins amount. The Malondialdehyde and phenylalanine ammonialyase compounds rate and UV- absorbing compounds were increased under the effect of UV-B and UV-C radiations. Surveying results showed that treatment with salicylic acid caused a reduced damage to the plant which had been created due to UV-B and UV-C radiations and was able compensate for changed factors that had been changed because of ultra violet radiations.