Study of seed germination properties and determination of cardinal temperatures of Bitter Apple ( Citrullus colocynthis L.) as a medicinal plant

Bitter apple (Citrullus colocynthis) is one of the medicinal plant that grows in semi-arid and desert condition which have been used in traditional medicine. There is a few research on cardinal temperatures of Bitter apple in the literature. In order to determine Germination characteristics and cardinal temperatures for Bitter apple, a laboratory experiment was down in petri dish based on completely randomized design with four replications. The experimental treatments were nine different temperatures (5, 10, 15, 20, 25, 30, 35, 40, 45 °c). The measured traits were germination percentage, germination rate and mean germination time. Cardinal temperature was calculated using dental, dual, and beta functions. The results showed that with increasing temperature up to 30 ° C, percentage and germination speed increased. The highest germination percentage (70%) and germination rate (2.8 seeds / day) were observed at 30 ° C. The lowest germination time (4.48 days) was observed at 30°C. The base, favorite and maximum temperatures (cardinal temperatures) for this plant were12, 30 and 45 °c, respectively.