Flower Bud Differentiation Of Southward Moving Tree Peony And The Effect Of Exogenous GA₃ On Its Process And Physiological Indices

Tree peony(Paeonia suffruticosa Andr.), one of the ten traditional famous flowers, is very popular for its big flowers, rich colors and varied cultivars. The cultivation of Tree peony spreaded over China with the development of garden and horticulture industry. Some areas in the south of the Yangtze River also introduced tree peony. But the southward moving tree peony showed some disadaptability such as low blossom rates. This research based on the two varieties' flower bud differentiation of tree peony introduced from Heze of Shandong province. The effects of exogenous GA₃ on flower bud differentiation and some related physiological indices were studied in order to select the suitable varieties in Hunan province and provided scientific evidence for its' control of florescence after southward.The main results were as follows:1. Results of the Micro-observation and Exfoliative Observation of Southward Moving Tree Peony's Flower Bud Differentiation showed that: two Central Plain tree peony could differentiate successfully outdoor in Changsha and every phases were integrated. But the initiating time and the duration of the flower bud differentiation stages in Changsha were greatly different from it in Heze. The initiating time was one month earlier. The plants came into preparative status at late April. The bract primordium appeared at middle June. The sepal primordium differentiated at early July. Petal primordium differentiation began at late July. The duration of bract primordium phase, sepal primordium phase and petal primordium phase were longer than it in Heze. Petalody improved in some low-double varieties and flowering reversion took place during the differentiation process for the change of environment.2. Results of the Exfoliative Observation showed that:Exogenous GA3 could promote the flower bud differentiation of tree peony by different treatment (50mg/L,100mg/L,200mg/L).But there were certain differences between different treatments and different varieties. The flower bud differentiation process could be advanced more than ten to fifteen days by 50mg/L or 100mg/L and one month by 200mg/ L.3. There were certain effects on the content of soluble sugar, soluble starch, soluble protein, chlorophyl and cursory C/N in the process of tree peony's flower bud differentiation by exogenous GA3. The effects varied from variety to variety, and differed from different consistencies. As to variety, 'Zi Xialing' was more sensitive than 'Jin Paohong' on the effects of exogenous GA3. As to consistencies, the changes of physiological indices of 'Zi Xialing' was more remarkable than 'Zi Xialing'. The changes of indices contacted with the effet of exogenous GA₃ on the tree peony's flower differentiation stages. The flower differentiation initiating of tree peony was advanced by high cursory C/N at the early stage.