In Vitro Rapid Propagation Of Paeonia Ostii ’Feng Dan’

In vitro culture of Paeonia ostii ’Feng Dan’ are more focus on the callus induction with embryo, petioles and roots as explants. Micropropagation in vitro with buds as explants has a few reports, and does not find its use in propagation with the existence of some problems such as low multiplication rate, rooting and transplant difficulty of vitroplants. Resolving these problems and establishing an efficient protocol for micropropagation of Paeonia ostii ’Feng Dan’ were the objective of this study. A lot of in-depth studies such as selecting individuals suitable for in vitro culture, establishing the multiplication and rooting protocol of the optimal one (FD6), and releasing from dormancy to acclimatization and transplant of the rooted vitroplants was conducted. Main results were as follows:1. Selecting of individuals suitable for in vitro culture:the indexes of initiation, multiplication and rooting were dramatically different, in 17 selected individuals with high seed yield,5 ones were suitable for in vitro culture with induction rate≥50%, multiplication rate≥2.50 and rooting percentage≥10%, which were FD2, FD4, FD6, FD8 and FD10.2. The multiplication protocol of FD6:Leaf necrosis was lightened with 40 days subculture cycle, multiplication and growth of shoots were also be improved by these methods. Modification of WPM basal medium on four-fold strength of Ca(NO3)2 were available to the improvement of multiplication and growth. The combination of BAP (0.5 mg·L-1), GA3(0.2 mg·L-1) and KT (0.1 mg·L-1) was best for the multiplication and growth of shoots; as an additive organic, chitosan was not suitable for shoots multiplication. The multiplication rate of initiation was highest, then being lowest in the first subculture, with the increasing of subculture times, the multiplication rate was being improved until to the third subculture, and then decreased. The multiplication rate of shoots could be improved significantly after being cultured on WPM(four-fold strength of Ca(NO3)2)+6-BA0.5 mg·L-1+KT 0.1 mg·L-1 for 30 days, or the tips of long stem segments(≥2 cm) were cutted.3. Rooting of FD6:The rooting percentage could be improved exchanging 6-BA to MT on the last subculture before rooting. The shoots were cultured on 1/2MS (double strength of CaCl2)+activated charcoal 1.0 g·L-1 for 30 days before the root induction-phase could reduce the content of hormone and improve rooting percentage. Rooting parcentage and quality could be improved by a low temperature treatment (4℃) for 8 days under dark condition before the root induction-phase. The abundant of sucrose could provide adequate carbon source for shoots and strengthen the hardness of the stem, the best concentration is 40 g·L-1 for FD6. The rooting parcentage was higher and the callus was less under the treatment of IBA2.0 mg·L-1. Rooting was improved by a longer period of root inducement,40 days was the best for FD6. The subculture times had a significantly influence on the rooting parcentage of FD6, the highest rooting parcentage could obtained after 7 subculture.4. Releasing from dormancy, acclimatization and transplant of FD6 rooted plantlets:30 days under 4 ℃ treatment could release the plantlets from dormancy. After 60 days of transplant, the survival rate of the class 1 that had the better rooting quality was highest, and then was the class 2, the survival rate of the class 3 was lowest The survival rate was not influenced by the plant growth regulators on the multiplication phase.