Thymus daenensis is an aromatic medicinal plant endemic to Iran. We used inter simple sequence repeat (ISSR) markers to detect genetic polymorphism in this herb using 17 T. daenensis accessions collected from different geographic regions in Iran. The 15 primers chosen for analysis revealed 256 bands, of which 228 (88.9%) were polymorphic. Jaccard's similarity indices based on ISSR profiles were subjected to UPGMA cluster analysis. The generated dendrogram revealed two major groups. The Tc group included the accessions collected from the center of the Zagros Mountains, and the Te group was collected from the extremes of the Zagros range. A principal coordinate analysis confirmed the results of clustering. The results showed that the divergence of accessions based on the Zagros Mountains is more logical in comparison with classification on the basis of provincial borders. Gene diversity and expected heterozygosity were greater in the Tc group than in the Te group, suggesting that the germplasm collected from the center of the Zagros Mountains is more variable.

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Echinacea purpurea (L.) is one of the most important medicinal plants in the world showing different biochemical reactions as affected by drought stress and nitrogen fertilizer. The purpose of this study was to determine the effect of nitrogen on soluble protein, enzyme activities, carotenoids metabolism, greenness and biological yield of the Echinacea purpurea under different levels of irrigation. The experiment was conducted in a research field in Iran during 2013-2015. Irrigation treatments included irrigation after 25, 50 and 75% soil water depletion, and nitrogen sources were no nitrogen (N), nitroxin, 40 kg N ha-1 , 40 kg N ha-1 ? nitroxin and 80 kg N ha-1. Nitroxin is a biofertilizer including Azotobacter and Azospirillum. The activity of catalase (11.9-21.3 mmol g-1 fw min-1), peroxidase (40.1-48.9 lmol g-1 fw min-1), polyphenoloxidase (0.79-3.63 mmol g-1 fw min-1) increased in both years under drought stress conditions. The lowest greenness (50.1-45.9) was achieved from no-application of nitrogen in the irrigation treatment after 75% water depletion. The results demonstrated the beneficial effects of nitrogen sources on physiological reactions, especially peroxidase, polyphenol oxidase and carotenoids metabolism. It is concluded that irrigation of E. purpurea based on 50% water depletion and 80 kg nitrogen as well as the combination of nitroxin and 40 kg nitrogen treatments should be an appropriate choice for 2 years.