Study On Dormancy And Dormancy Breaking Of Tree Peony Seeds

The tree peony which is one of the top ten China’s traditional flowers belongs to the Paeoniaceae,Paeonia woody plants. Tree peony has high ornamental. Moreover, P.ostii ‘Feng Dan’,and P.rockii hybrids have important oil and pharmaceutical value. Seed propagation of tree peony has the advantage of large propagation coefficient and getting a lot of seedlings during a short time. Germination from seeds to seedlings takes at least 6 months in field Condition with a relatively low seedling rate and emergence of arrhythmia. Therefore, study on seed dormancy and seed dormancy breaking of tree peony which could get high germination rate with shorter duration has important implications for peony industry.This research focused on the dormancy traits with seeds of a tree peony cultivar,Paeonia ostii ‘Feng Dan’,P.rockii hybrids by studying water permeability of the seed coat, form and vitality of the seed embryo as well as activity of the endogenous inhibitors and different processing. And the results are as follows:1. The seeds of tree peony has very high vitality.The low germination rate does not due to low vitality but the dormancy the seeds of tree peony.2. The seed coat hindered the speed of water absorption. After 48 hours immersion of the seeds, they almost got saturated. Water permeability of the seed coat does not affect the seed dormancy, but the seed coat has mechanical obstruction on germination.3. The embryos of ripe seeds of tree peony were not fully developed yet. The embryos still needed some stratification to grow and differentiate. The immaturity of seeds of tree peony is a reason of the seed dormancy.4. The endogenous inhibitors from both the seed coat and embryo had significant inhibiting effects on seeds of Brassica pekinensis and tree peony,but the inhibitors from the seed coat were different from those from the seed embryo regarding types and content. The endogenous inhibitors is a reason of the seed dormancy.5. The germinating percentage of the ripe seeds first increased over time, and then decreased. Those having a storage time of 7-21 days had the best germination. Those seeds which are immediately sowed or have a long storage time will have lower germination rate.6. GA 3and peeling could promote the growth and germination of the seeds together. When GA3 reached 300 mg/L, the germination was effectively increased.