Abstract:

We studied the effect of temperature, GA₃ and ethephon treatment on seed dormancy release of Paeonia ludlowii whose seeds were collected from Linzhi and Milin County, Tibet on semptember. The seeds were naturally dried up for 3 months indoor. The result showed that: (1) The seeds were soaked in water at ordinary temperature for 7 d before they were sowed in outdoor seedbed in Kunming, Yunnan province. They began to root 140 d later; started sprouting after 288 d and the course was terminated on the 490^th day with seed germination rate 35%. (2) Temperature affected seed germination significantly. The seeds could not root when it was lower than 10 ℃ or higher than 25 ℃. 15 ℃ was the best temperature for hypocotyl dormancy release; 15 ℃ and 20 ℃ were the appropriate temperature for epicotyl dormancy release. (3) There was no significant difference of seed rooting rate between the treatments and control, which was both more than 96%. (4) GA₃ could break the epicotyl dormancy obviously, of which 300 mg·L^-1 was most effective. (5) In conclusion, the optimum procedure for seed germination was as followed: first, the seeds should be soaked in water at ordinary temperature for 7 d, after that sowed in outdoor seedbed; the seeds were put in 300 mg ·L^-1GA₃ solution for 2 h when their roots grew up to 3 cm in length. According to the procedure, the seed germination duration was about 120 d and germination rate could be more than 95%, accelerated 370 d and increased 171.4% respectively compared with conventional seeding.

Key words: Paeonia ludlowii, seed, hypocotyl, epicotyl, seed dormancy