Abstract:
In order to evaluate cardinal temperatures and optimum thermal range of germination of three medicinal plants including Ajowan, Fennel and Dill an experiment was conducted in a Completely Randomized Design with three replications. Temperatures considered for this study were: 5, 10, 15, 20, 25, 30 and 35 ºC. Results indicated that temperature affected germination rate and percentage of these crops. Optimum thermal range for Ajowan and Fennel seeds were determined as 10-20 ºC and 10ºC for Dill. The basic optimum and maximum temperatures were 2.88, 20 and 38.35 for Ajowan, 3.86, 20 and 34.98 for Fennel and 5, 13 and 33.7 for Dill. In general, as it is expected, germination response of these crops to temperature was correlated with the nature of growth of these plants. At higher temperatures, Dill as a winter crop showed a lower germination percentage compared to Ajowan and Fennel.
Machine summary:
"Evaluation of cardinal temperature for three species of medicinal plants, Ajowan (Trachyspermum ammi), Fennel (Foeniculum vulgare) and Dill (Anethum graveolens) Abstract In order to evaluate cardinal temperatures and optimum thermal range of germination of three medicinal plants including Ajowan, Fennel and Dill an experiment was conducted in a Completely Randomized Design with three replications.
At higher temperatures, Dill as a winter crop showed a lower germination percentage compared to Ajowan and Fennel.
Since cardinal temperature is important for germination and this temperature has not been determined for medicinal plants, the purpose of present investigation is to evaluate the effect of this temperature for three important medicinal species including Ajowan, Fennel and Dill.
Materials and Methods In order to determine cardinal temperature for Ajowan, Fennel and Dill, seeds of these species were exposed to a wide range of temperature as 5, 10, 15, 20, 25, 30 and 35ºC in a germinator.
In general, rate of germination for Dill in all temperature levels, particularly temperatures higher than 10ºC, was lower compared with Ajowan and Fennel.
However, by increasing temperature from 10 to 25 ºC for Ajowan and from 10 to 25ºC for Fennel, no difference was observed while for Dill, the percentage of germination was reduced by increasing temperature beyond 10ºC and the maximum percentage for these species was observed at 10ºC.
Table 2: Cardinal temperatures for three species Ajowan, Fennel and Dill (view the image of this page) Conclusion In conclusion, the optimal range of temperature for Ajowan and Dill was 10- 20ºC at which the maximum percentage of germination were 67."