Study On The Micropropagation Of Tree Peony And The Effect Of Polyamines On In Vitro Rooting

Micropropagation in vitro does not find its use in propagation of tree peonies with the existence of some problems such as low multiplication rate, rooting and transplant difficulty of vitroplants, even though some advancement have been made in the latest twenty years in this field. The resolving of these problems and establishment of a smooth protocol for micropropagation of tree peony were the objective of this study. A lot of in-depth studies in the paper from sterilization of explants, choosing of plant growth regulators and their concentrations and combinations, inducement and culture of adventitious buds, prevention and cure of browning and rhizogenesis, releasing from dormancy to acclimatization and transplant of rooted plantlets. The polyamines were involved for the first time in rooting of micropropagation of tree peony. Main results were as follows:1. Sterilization of explants: The optimal method for sterilization of explants differed in cultivars, bud collected time and so on.2. Choosing of plant growth regulators and their concentrations and combinations: the optimal concentration of BAP in the test was 1.0 or 1.5 mg·L-1 and that of GA3 was 0.5 mg·L-1. The combination of BAP 1.0 mg·L-1 and GA3 0.5 mg·L-1 was best for multiplication and growth of'Jin Pao Hong'vitroplants.3. Rooting: rooting of'Wu Long Peng Sheng'and'Jin Pao Hong'could be improved by exogenous PUT and SPM incorporation from 1～20mg?L-1.The optimal treatment for rooting of'Wu Long Peng Sheng'was combined use of IBA 1.0 mg?L-1 and PUT 1mg?L-1 for 30 days. The optimal treatment for rooting of'Jin Pao Hong'was PUT 10mg?L-1 for 30 days. With the most suitable concentration of PUT and SPM, it also result in increasement of root number. Use of SPD promoted the rate of rooting ,but meantime have bad results of axillry buds of'Wu Long Peng Sheng'.With the inducing time was prolong ,the root rate was gradually downtrend . 4. Releasing from dormancy, acclimatization and transplant of rooted plantlets: To reclaim bud growing , it is helpful to chill the plantlet at 4℃for 30～60days. 0.5 mg?L-1 GA3 treatment is also have obvious effect.Survival rate after transplant in a mixture with vermiculite +perlite+peat (1:1:1) was higher than other medium.