Study On The Cutting Rooting And Stem Anatomical Structure Development Of Tree Peony

Tree peony is a famous traditional flower in China which is beloved to many people.Traditional propagation methods of tree peony are mainly sowing,grafting and dividing,and their reproduction efficiency are too low to meet the market demand.To improve the breeding efficiency of tree peony,softwood cutting and hardwood cutting experiments were carried,and anatomical structure of stem development and cutting rooting process were observed in this experiment.The results are as followed:1.In the softwood cutting experiment,Itoh hybrids rooted in 43 days and its highest rooting rate was 89.9%,P.x lemoinei ’High Noon’ rooted in 33 days and its highest rooting rate was 56%.P.ostii’Feng Dan’ rooted in 30 days and its rooting rate was 17.9%.Because of stem and leaves being perishable,cuttings of P.ostii ’Feng Dan’ died from decay.P.rockii had low rooting rate of 7.45%and P.suffruticosa didn’t root in this experiment.2.Different varieties behaved differently in hard-wood cutting.Itoh hybrids,P.x lemoinei ’High Noon’ and P.ostii did’t root.2 of 8P.rockii varieties rooted with the highest rooting rate of 5.13%.All of the P.suffruticosa varieties rooted and P.suffruticosa ’Yao Huang’ rooted best with the rooting rate of 12.8%.Hard-wood cutting of tree peony is suitable to start in the last ten-day of October.3.In the cutting conditions screening experiment,perlite was benefit for P.x lemoinei’High Noon’and P.rockii to survival.The medium of perlite:vermiculite(3:1)contributed most to P.rockii survival.The medium of perlite:peat(1:3),1000mg L-1 IBA,Whole leaf left amount were suitable for P.x lemoinei ’High Noon’ cuttings rooting.perlite:peat(1:3),1500mg·L-1 IBA were suitable for Itoh hybrids cuttings rooting.4.The secondary structure of tree peony stem was:epidermis,collenchyma,cortex,vasculartissue and pith.The process of secondary xylem developed fast of P.rockii ’Shi Li Xiang’ and P.suffruticosa’Yao Huang’ and secondary xylem quitely lignified one week before blooming and cork layer appeared near their phloem around blooming.There was no phellogen movement in Bartzella’ and x lemoinei ’High Noon’ before blooming and their secondary xylem didn’t lignify until blooming.It is speculated that the blocking of the cork layer and the high degree of lignification lead to the difficulties in rooting cuttings of the softwood cutting of P.rockii‘’Shi Li Xiang’ and P.suffruticosa ’Yao Huang’.5.Tree peony was induced-rooting type and the root primordium mainly originated from the vascllar cambium.P.xlemoinei ’High Noon’ had a unique phenomenon whose pith near the xylem area can produce small cell mass and then differentiate into vessel,cell mass gradually grew thicker and form a circle,which was the first discovery in Paeoniaceae cutting experiment.