Ecophysiological aspects of Liquorice (Glycyrrhiza glabra L.) germination under different temperatures

Glycyrrhiza is an industrial/medicinal plant however, in Iran is known as a weedy species in dry lands and orchards. Germination of Glycyrrhiza seeds collected from Kermanshah and Fars (Zarghan) were studied in a range of temperatures (0, 3, 10, 15, 20, 25, 30, 35 and 40 C). The highest germination percentage for both Kermanshah and Fars populations were obtained at 20 and 25 C while maximum germination percentage of Fars seeds was higher than Kermanshah. At 40 C maximum germination of 27 and 43% was observed for Kermanshah and Fars seeds, respectively. The same trend was observed for germination rate. Time period for 10, 50 and 90% germination was lowest between20-30C for both seed populations. Base, optimum and ceiling temperatures were obtained respectively, 2.2, 29.1, and 45.3 C for Kermanshah and 2.4, 29,2 and 44 C for Fars populations.