Abstract
Abstract:
A biotic stress mostly controls medicinal compounds productivity in the plant. This study was to investigate effect of gamma irradiation on some medicinal compounds in shoot and root of Chicory. Irradiated seeds with 20, 40 and 80 gray (Gy) by cobalt 60 gamma irradiation were cultivated under normal field conditions. Results showed that the plant dry weight was induced at the first growth stages but was inhibited at the following stages. Photosynthetic pigments (chl. a and b) were inhibited by the gamma radiation but the carotenoids increased as a defensive effect to increasing gamma doses. Chicory alkaloids content was double the phenolic and many times the saponin content under the control plant and dose of irradiation changes this trend slightly. Saponin content in the plant root increased with all gamma doses and the highest increase (69.5%) was at 40 Gy compared to the control. Also the total alkaloids content was increased by 49.7% at the 40 Gy in the plant shoot. Accumulation of alkaloids was more sensitive to gamma radiation in shoot than in root of the plant. The 40 Gy dose enhanced also accumulation of total phenolic compounds in root of Chicory. Increasing gamma dose to 80 Gy inhibited the accumulation of the three secondary medicinal metabolites in plant shoot and root especially the alkaloids content that was reduced per plant to the half. The study suggested 40 Gy dose as an efficient dose to induce the metabolism and accumulation of the medicinal compounds of Chicory plants. In addition it certified the vegetative stage for the production of such compounds from the total plant (shoots and root).

Key words: Chicory, Cichorium pumilum, Abiotic stresses, Gamma Irradiation Secondary metabolite, Alkaloids, Phenolic compounds, Saponin