Factors Affecting Germination Performance of Four Endemic SideritisSpecies in Turkey

The genus Sideritis is an indigenous plant to temperate and subtropical regions of Turkey, especially for Mediterraneanand Aegean region, and is extensively used as herbal tea and spice. The seeds of Sideritis species have a difficulty in germination, which limits their cultivation. This study was conducted to evaluate the germination performance of 4 endemic Sideritis species (Sideritis condensata, S. libanotica ssp. linearis, S. leptoclada and S. tmolea) harvested freshly or stored for 1 and 2 years in terms of germination percentage and mean germination time and to determine the suitability of seed treatments (Hydration and gibberellic acid (GA ) application, and their combination with pre-chilling) for overcoming germination difficulty in the species. Germination percentages of these species ranged from 28.5% to 77.0%. The lowest germination rate and the highest mean germination time (11.9 day) were determined in S. libanotica ssp. linearis in fresh seeds. Improved germination and shortened mean germination time were achieved using 200 mg L^-1 GA application. Seed storage did not influence the germination of the Sideritis species. It was found that pre-chilling did not prerequisite for germination of the species. It was concluded that GA treatment should effectively be used as a method for improving germination of endemic Sideritis species regardless of seed age.