marjan azarafshan

Pelargonium graveolens L ′Her is an aromatic and medicinal plant which is widely used in pharmaceutical, perfumery and food industry. In this study, the effect of ultraviolet radiation with different intensities (0, 0.12, 0.26 and 0.38 W/m2) was investigated on P. graveolens in InVitro condition. The amount of total phenol, flavonoid and anthocyanin, activity of phenylalanine ammonia lyase (PAL), photosynthetic pigments, carbohydrates, proteins and activity of some anti-oxidant enzymes (Catalase, peroxidase and superoxide dismutase) were evaluated. The antioxidant activity of methanolic extract was measured by using 2-2-di-phenyl-1-picaril hydrazil (DPPH) method. Total protein content and chlorophylls a, b showed a significant decrease (P≤ 0.05), while the amount of carotenoid increased significantly (P≤ 0.05), when ultraviolet radiation increased. With increasing UV-B radiation, the activity of studied enzymes, total phenols, flavonoids and anthocyanins content increased significantly (P≤ 0.05). Also, with increasing radiation intensity, the mean IC50 of methanolic extract decreased. The decreasing pattern of IC50 was consistent with the trend of increasing the mean of phenols. The present results show that P.graveolens in response to UVB stress has increased its antioxidant capacity by increasing the activity of antioxidant enzymes and increasing the phenols.

Pelargonium graveolens L′Her is an aromatic and medicinal plant that is widely used in pharmaceutical, perfumery and food industry. Ultraviolet radiation has many effects on plants and can cause many morphological and physiological changes that often decreased plant growth. In this study to investigate the effect of ultraviolet radiation on the anatomical structure of different organs of P.graveolens, the plant cuttings were exposed to different intensities of ultraviolet radiation -B (0, 0.12, 0.26 , 0.38 W/m2). The structure of leaves, stem, petiole and root of the plants were studied by light microscope. The results indicated that with increasing UV radiation, leaf thickness decreased and the size petiole thickness increased. Maximum level of the central vascular bundle diameter of petiole and stem were seen in high UV-B intensity treatment. Also results showed in petiole and stem of treated plants, parenchyma thickness decreased and the area of the stele increased by enhancing UV radiation intensity. However, in all treatments, the root structure was not affected. Considering alteration in results, it seems that shoots anatomy were affected by UV-B radiation especially in higher dose, but this radiation had no effect on root structure.

In order to understand the response of Lotus corniculatus to salt stress, ions content and some growth factors were analyzed in three varieties of this plant, namely, Ardebil, Karaj, and Jolfa. Lotus corniculatus plants were exposed to 0, 50, 100, and 150 mM NaCl in hydroponic condition. The amounts of anions (Cl-and NO3-) and cations (K and Na) in leaves as well as shoot and root dry weights, stem and root length, leaf area, and number of leaves were analyzed. The amount of Na and Cl- significantly increased in all varieties. However, with an increase in NaCl concentration, K and No3- content decreased significantly in all varieties (p

Salinity is a main and common stress which decreases the amount of agriculture products and natural plants in many areas of the world. In this study, the effect of salt stress on three varieties of Lotus corniculatus 'Karaj', 'Jolfa', and 'Ardabil' was investigated. Plants were cultured in hydroponic condition with four NaCl treatments (0, 50, 100, 150 mM). The amounts of proline, glycine betaine, soluble sugars as well as Na+ and Cl- were analyzed. The results showed that sodium and chloride content in all varieties significantly increased in shoot (p<0.05). The amounts of proline and soluble sugars significantly increased in all varieties (p<0.05). However, increasing in NaCl concentration raised significantly glycine betaine content in leaves of the varieties (p<0.05). As far as the measured factors are concerned, it seems that 'Jolfa' and 'Karaj' have a higher capacity to tolerate salt stress particularly in 100-150 mM NaCl compared with 'Ardabil'.