Studies On Reflowering Of "National-flowering Tree Peonies" On Open Field

Tree peonies(Peaonia suffruticosa Andr.) are traditional plants native to China autumn-flowering cultivars,with the property of secondary growth and flower under appropriate environmental conditions in autumn,are a special kind of tree peonies.At present,They can flower for the second time steadily under simple artificial regulation in autumn on open field.Therefore they have a bright future in China.However,the unstable bud sprouting and the lower flowering quality make them devaluing.It will be have deeper influence on Chinese,if we could utilize these rare resources to force them reflowering in autumn,especially in National Day.Based on previous researches,the author studied on artificial regulation cultivation on autumn-flowering tree peony.The cultivars used in the experiment during 2007 and 2008 in open field were forced to reflower inautumn,especially in Chinese National Day.In this paper,a set reflowering cultivation measure was suggested technically.Morphological differentiation and development of the floral buds were observed to guide for practice.The result manifested those as follows:â‘ The major field culture techniques to improve the reflowering of national-flowering tree poneies on open area are listed:Defoliation for 20 days before GA₃ treatment had a better effect on the quality of leaves and flower than application of GA₃ immediately,mid and late August is the optimum period to GA₃ treatment.GA₃ treatment on buds can effectively increase the flowering rate,the period of bud emergence is the best time and the best concentration of GA₃ is 150mg/L.The most suitable number of branches to retain is 5 or 6,observed the highest rate of flowering and flower quality. Analyzed different kinds of fertilizer treatment on leaves influenced growth of its flowers and leaves.â‘¡Study on the basic rules of peony flower bud differentiation was carried out.The result indicated: Most of autumn-flowering peony terminal bud are precocious,the differentiation patterns of flower bud are similar to common type penoy,but the differentiation of autumn-flowering peony is earlier and faster.The main period of flower bud differentiation is usually completed by the end of August.The growth of terminal bud in the process of change is basically the corresponding period of flower bud differentiation.For a certain period of time after defoliation,bud differentiation process of several rounds of petals and stamens are quickly round 1-2 than those not been treated,stamens flaped earlier,and petals developed more fully.