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Scientia Silvae Sinicae ›› 2016, Vol. 52 ›› Issue (5): 101-110.doi: 10.11707/j.1001-7488.20160512

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Establishment of in vitro Rapid Propagation System for Tree Peony(Paeonia ostii)

Wang Xin1, Cheng Fangyun1,2, Zhong Yuan1, Wen Shusheng1, Li Liu1, Huang Nongzhang1   

  1. 1. College of Landscape Architecture, Beijing Forestry University Beijing 100083;
    2. National Engineering Research Center for Floriculture Beijing 100083
  • Received:2015-12-31 Revised:2016-01-28 Online:2016-05-25 Published:2016-06-01

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Abstract:

[Objective] An in vitro rapid propagation protocol was developed for Paeonia ostii to provide new method for the rapid propagation and cultivating elite varieties of oil tree peony. [Method] Buds were collected as explants in spring from selected individual plants of P. ostii and inoculated in the medium WPM+6-BA 0.5 mg·L-1+GA3 0.2 mg·L-1. Individuals or genotypes suitable for in vitro culture were selected by induction and multiplication ratios at initiation stage, among which the optimal one was studied further to set up rapid propagation protocol. During multiplication, the Ca(NO3)2 concentrations in the basal medium and combinations of plant growth regulators (PGRs: 6-BA, GA3, NAA, KT and TDZ) were studied by single-factor and randomized block design. During root inducing phase, the effects of cold treatments and IBA concentrations were evaluated by single-factor design. And at acclimation stage, in vitro rooted plantlets were classified by the rooting quality and transplanted into a greenhouse to investigate their survival rates. [Result] 1) The initiation performance of P. ostii in vitro culture was genotype-dependent. In 17 selected individuals with high seed yield, 7 individuals were suitable for in vitro initiation with induction rate≥50% and multiplication rate≥2.50, and the best FD10 (induction rate=100%, multiplication rate=4.58) was selected to set up rapid propagation protocol. 2) The optimal multiplication medium was WPM (Ca(NO3)2 1 544 mg·L-1)+6-BA 0.5 mg·L-1+GA3 0.2 mg·L-1, on which the highest multiplication rate (3.87) was obtained after 40 days of culture. And 6 subcultures were carried out. 3) By the effects of cold treatments and IBA concentrations in rooting, a two-step rooting protocol was set up. The shoots were cultured in the medium 1/2 MS+IBA 2.0 mg·L-1+putrescine 1.0 mg·L-1 for 30 days (including a 4℃ cold treatment of 8 days at the beginning) for root induction, and finished within 30 days, followed by culture in the medium 1/2 MS (double strength of CaCl2) +activated charcoal 4.0 g·L-1 for 20 days for root formation. The highest rooting percentage (56.67%) was obtained. 4) The in vitro rooted plantlets were classified into 3 grades by their rooting quality, and the percentage of grade 1 was 84%, while the grade 2 and grade 3 were 12.5% and 3.5%. During acclimatization the rooted plantlets were transferred into pots containing a mix of peat:vermiculite:perlite(1:1:1 by volume)substrate. After 60 days, plantlets of the grade 1 that had less callus survived 66.67%, but those plantlets that had obvious callus development died away totally, indicating the rooting quality was really an essential factor for survival of in vitro rooted plantlets of tree peony. [Conclusion] The rapid cloning propagation of P. ostii was genotype-dependent, and a rapid propagation protocol of FD10 was developed. The optimal medium for multiplication was WPM (Ca(NO3)2 1 544 mg·L-1)+6-BA 0.5 mg·L-1+GA3 0.2 mg·L-1, and the protocol for optimal rooting was 1/2MS+IBA 2.0 mg·L-1+ putrescine 1.0 mg·L-1, with 8 days cold treatment at the beginning of the rooting stage. The survival rate of transplanted plantlets in grade 1 was 66.67% 60 days after transplanting.

Key words: Paeonia ostii, genotype, Ca(NO3)2, plant growth regulator, rooting, acclimatization and transplanting

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