Effect of Different Temperature on Germination Properties of Fennel (Foeniculum vulgare Mill.), Cannabis (Cannabis sativa L.) and Sesame (Sesamus indicum L.)

Due to importance of medicinal plants، understanding the seed germination response to temperature is agronomically important. A laboratory study was conducted to investigate the effect of different temperatures on seed germination of fennel، cannabis and sesame in a completely randomized design with four replications. Various constant temperatures (5، 10، 15، 20، 25، 30، 35 and 40° C) were considered. According to the results، the effect of temperature on germination rate and percentage in all species was significant. The seeds of fennel were not germinated in 5، 35 and 40 0C and seeds of sesame germinated only in 5 0C. Maximum rate of germination obtained in 30 °C for fennel and 25 °C for sesame and cannabis. The highest germination percentage of fennel، and cannabis and sesame were in 20، 25 and 30 0C respectively. The lowest of germination uniformity (GU) were observed in 20 0C for fennel and in 15 0C for cannabis and sesame. Amount of seedling vigor maximized for fennel and cannabis in 250C and for sesame in the 300C. The values of length and weight of radical and plumule were enhanced with increase of temperature and record on maximum in special temperature and then reduced slowly. The quantitative information provided by this study can be used in prediction of emergence under diverse temperature conditions. Germination of cannabis seeds occurred in a wide range of temperatures and this seed are less sensitive to temperature compared to the other two plants. Germination of fennel seeds was less، except at 200C. The sesame seeds had good germination at 15-35 0C.