Document Type : Research Paper
Authors
1 MSc Student, University College of Agriculture & Natural Resources, University of Tehran, Karaj, Iran
2 Horticultural Department, University College of Agriculture & Natural Resources, University of Tehran, Karaj, Iran
3 Medicinal Plants Research Division, Research Institute of Forests and Rangelands, Tehran, Iran
Abstract
In order to evaluate sثرثقشم ecological factors and morphological traits and also to determine ploidy levels and chemical composition of essential oil of Thymus pubescens Boiss. & Kotschy ex Celak two natural habitats, Bostan-Abad and Yam habitats, were chosen in East Azerbaijan province. To study and evaluate quantitative morphological characters, five complete plants and flowering branches were collected from each locality at flowering stage for essential oil extraction. Seeds also were collected in seed production season to study seed characters and chromosome counting. Ecological data of both localities also were recorded. Vegetative and reproductive traits of each population were studied and essential oil of each locality was analyzed by combination of GC-FID and GC-MS. At least 10 mitotic cells of each population were studied to determine chromosome number and ploidy levels. Results revealed that specimens from “Yam” had the longest flowering stems, the largest leaves and flowers, and also the highest number of flowers per inflorescence. Chromosome count results showed that specimens from Bostan-Abad were hexaploid (2n = 6x = 90) and those of Yam were tetraploid (2n = 4x = 60). The total yield of oils based on dry weight was 1.3% and 2.2% (w/w) from Bostan-Abad and Yam, respectively. Thymol was the main valuable phenolic compound similar to most of the species of genus Thymus (Bostan-Abad: 57.6% and Yam: 44.9%).
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