Morphological Differentiation Of Apple Floral Bud And Cloning And Expression Analysis Of Genes Related To Flower Inition

Apple (Malus domestica Borkh.)is one of the most important fruit trees in the world,whose value is just less then grape.Fruit buds of apple are mixed (i.e. contain both vegetative and floral structures)and borne on fruit spurs and/or terminally or laterally on one year-old shoots depending on cultivar ,age and vigour of the tree .We observed floral bud morphological development of three cutivars:'Starkrimson','Gala'and'Fuji'from June to November and three apple homologous fragments of AFL1 AFL2and MdTFL1 were analyzed to determine the relationship between floral bud formation and floral gene expression by RT-PCR .1. The times when flower buds begin to develop their morphological differentiation arejuly 22th,july 22th and july 2th, in'Starkrimson','Gala'and'Fuji',respectively.The peak period of flower bud differentiation are Augest 22th to September 22th , Augest 22th to September 22th ,July 2th to September 12th, respectively.2. Flower bud morphological development of apple can be divided into 7 stages. Vegetative meristem was flat and called stage 1.Pronounced doming of the apex marked stage 2,during stage 3,the domed meristem initiated four to six lateral floral meristems and substending bracts .Terminal meristem converting to terminal floral meristem marked stage4,during stage 5 , the terminal floral meristem proceeded directly with sepal inition and then lateral floral meristems proceeded with sepal inition respectively in stage6.During stage 7,all the floral meristems complete their sepal inition .3. RNA from apple cultivars'Starkrimson','Gala'and'Fuji'buds is extracted by modified-SDS method, and the RNA is detectived by formaldehyde denaturing agarose gel electrophoresis and RT-PCR an ideal target fragment is obtained. The method is stable and reliable, and suitable for RNA extraction from single apple bud rather then the method of CTAB and RNAplant kit.4. The best annealing temperature of AFL1 is 59℃,and then AFL2 59℃,TFL1 54℃.the best contamination of Mg2+ is 1.5mM,the best contamination of dNTP is 225μM.5. AFL1 and AFL2 begin to express in the period of physiological differentiation ,in the other hand ,the expression of TFL1 disappread in the period of physiological differentiation, and nucleotid acid sequence of AFL1 and MdTFL1 are researched.