Flower Bud Differentiation Process And Effects Of Exogenous GA₃ On The Flower Bud Development Of Introduced Paeonia Lactiflora

Paeonia lactiflora is a traditional famous flower of China which is planted mainly in the north region as ornamental plant,but it is mainly planted as a officinal plant in south area.This article have research the effects of exogenous gibberellin acid-3 on flower development which were based on the observation of phenology and flower bud differentiation.Main result were as follows:(1)Three varieties of ornamental paeonia lactiflora(Da Fugui,Zi Furong,Qi Hualushuang) introduced from HeZe of Shandong province and one variety of officinal paeonia lactiflora(Hang Baishao) introduced form Shaoyang of Hunan province were planted experimentally.We recorded their phenophases and measured some main ornamental indexes such as height of the plants,the length and width of the leaves,the diameter and height of the buds.It was founded that the Paeonia lactiflora could grow normally under the outdoor circumstance in Changsha region and their adaptability were well.The height of the plants,the length and width of the leaves,the diameter and height of the buds grew rapidly in the early stages and the increment became more and more slow in the later stages.On the ornamental value, Bud of 'Zi Furong' narrowed seriously,but 'Da Fugui','Qi Hualushuang'and 'Hang Baishao' could blossom successfully.(2)This was found that the bud differentiate leaf primordium at first.The flower bud differentiation took a period of five months which began in middle September and ended in middle February of the follow year.This research observed the entire flower bud differentiation process though paraffin section for the first time.The process could be divided into seven phases:bract primordium differentiation phase, sepal primordium differentiation phase,petal primordium differentiation phase, stamen primordium differentiation phase,pistil primordium differentiation phase, stamen petalody phase and pistil petalody phase.The petal primordium differentiated towards center,but the differentiation of stamen primordium was on the contrary.The differentiation of the stamen primordium and the pistil primordium were not at the same steps.The stamen petalody was more earlier than pistil petalody,but the character of them was similar.This had a high-differentiation rate,high-differentiation quality and high-uniformity.(3)Exogenous GA₃ treatments played a very significant role in the flower bud differentiation process initiate of the two varieties of 'Ying Xionghua' and 'Jin Jianghong'.Every treatment could make every phase differentiate successfully after bract primordium differentiation phase.Interval of the early differentiation process was short.Each of petal primordium differentiation phase,stamen primordium differentiation phase and pistil primordium differentiation phase took about one month,the higher concentration of exogenous GA₃ the more obvious the effects of treatments were.To 'Jin Jianghong',the differentiation process of 100mg/L GA₃ treatment was as same as the control.Treatments of GA₃ 300mg/L and GA₃ 500mg/L were 15 days and 25 days ahead respectively to the control at the end of the process. To 'Ying Xionghua',treatments of GA₃ 100mg/L,300mg/L and GA₃ 500mg/L were 10 days,20 days and 25 days ahead respectively to the control at the end of the process.'Ying Xionghua' was more sensitive than 'Jin Jianghong' to GA₃ treatments. These treatments also made the bud autumn-sprout from leaf bud through jarovization directly.Considering the effects of GA₃ on process and autumn-sprouting, GA₃ 300mg/L treatment was the best one.(4)Exogenous GA₃ had obvious effects on date of germination,length of flower steam and stretch of it,size of flower,blossom stage.To 'Zi Furong',high concentration of GA₃ treatments improved the bud narrowness.The flower steam stretched nearly 20 cm and the flower size reached 13.8 cm×10cm under GA₃ 500mg/L treatment.The blossom date was three days earlier than the treatment of GA₃ 300mg/L.To 'Qi HuaLushuang',treatment could advance the germination and blossom date.The flower size and the length of the flower steam were advanced only by GA₃ 500mg/L treatment.The flower steam reached 65cm long,the flower size reached 14.5 cm×11cm and the blossom date was five days earlier than the control.It is suitable to be used to adjust the blossom stage and forcing culture as one of main measures.