花形成是果树育种和产量的基础。木本果树与草本植物在成花转变过程具相似的分子基础和显著的习性差别。FT被多数研究者认同是假想的成花素，已用模式植物嫁接证明可通过韧皮部向顶端分生组织转运并促进成花。成年木本果树及超表达FT转化苗作砧木却不能使童期接穗提早成花，表明FT移动受上部接穗的信号限制。本项目拟以克里曼丁橘分别与超表达FT:GFP或FLC:GUS转基因枳正、反嫁接，以GFP荧光和GUS染色分别示踪研究FT及FLC在柑橘中的传导能力、方向、途径和分配规律;利用克里曼丁橘与枳属间SNP差异、蛋白组分析和实时定量，比较超表达FT或FLC时砧穗间RNAs和蛋白信号交流及与成花基因表达关系，以探明顶端分生组织与基端叶片之间成花信号类型、传导方式及相互作用，进一步丰富植物阶段转变和生殖发育调控理论，并为砧穗互作研究、采用嫁接方式加速育种和性状遗传规律研究，以及利用转基因材料生产非转基因果实探索新路。

Flowering is the foundation of fruit breeding and production. Perenial woody plant shares similar molecular mechanism in flowering formation with annual model plants but differed greatly in flowering habit. FT has been considered to be the hypothesized florigen which was capable of graft-transmission from leaves to shoot tip through phloem and promoting flower transition in shoot apical meristem. However, the juvenile scion from woody plants could not be induced early flowering by using rootstock of both adult tree and FT-overexpressed transgenic plants, which was supposed to produce abundant FT protein. Thus we hypothesize that the movement of FT protein may possibly restrained by signals imported from the scion. In this project, Clementina citrus will be grafted up/down to transgenic Poncirus trifoliata carried fusion gene of FT:GFP or FLC:GUS respectively driven by CaMV 35S promoter. Transduction ability of FT or FLC will be evaluated by tracing of the GFP fluorescence and GUS activity respectively in the phloem between the scion and rootstock, as well as the transduction route and the rule for distribution. The signals in the form of RNAs and protein exchanging between rootstock and scion will be analyzed by use of the great mass of SNP variations between Clementina and Poncirus trifoliata and proteinomics methods of iTRAQ (isobaric tag for relative and absolute quantitation) respectively. Real-time PCR will be performed to analysis the relationship between imported signals of RNAs or protein and gene expression changes in flowering related genes. Based on above analysis, the results will reveal whether flowering signals are transmissible between shoot apical meristem and leaves, as well as their forms, transmission route and distribution rule, so as to enhance our knowledge about plant phase development and flowering transition. Also, the fulfill of this project will do helpful as reference for study of the interaction between rootstock and scion, and provide theoretical foundation for accelerating fruit breeding and utilization of transgenic plants to produce un-transgenic fruit.