The germination test of celery seeds at different temperatures and illumination showed, the optimum temperature for germination of the four cultivars (local smallage Ching Tung "107" and "99", Ching Yeh Pai Ku "Tian Wei", celery "UTAH") was 15℃-25℃.  The germination rate decreased significantly at lower or higher temperature, and all cultivars could not germinate at 35℃. The inhibition of germination in dark at low temperature (10℃) and high temperature (above 30℃) is more significant than that at appropriate temperature. Among them, "UTAH" is most sensitive to temperature and illumination (figure. 1 top). Alternating temperatures can promote the germination of celery seeds and reduce the inhibitory effect of dark (figure. 1 bottom).

▲Fig. 1. The effect of temperature and illumination on germination of celery seeds.

In addition, celery seeds were treated with different priming solvents(GA₃, KNO₃, NaCl, Salicylic acid, Chitosan) and temperature (6, 12, 24 hours at 15℃). The test results show that different priming solvents have different effects on the germination of celery seeds. GA₃ only significantly increased the germination rate of celery "Utah" in the dark at 20/30℃. In addition to the low temperature of 15℃, potassium nitrate (KNO₃) can significantly improve the germination rate in light and dark. NaCl can significantly improve the germination rate at all temperatures in dark, salicylic acid can improve the germination at the higher temperature and alternating temperatures in dark, chitosan can improve the germination at the lower temperature and alternating temperature in dark (table 1). All priming solvents could decrease the time to 50% germination (GT50)(table 2).

▲Fig. 2.  The effect of priming treatment on germination of celery seeds.

▲Fig. 3. The effect of priming treatment to decrease the time to 50% germination of celery seeds.