Study On The Physiology And Biochemistry Changes And The Differential Gene Expression In The Process Of Off Season Flower Bud Differentiation Of Longan Induction By KC1O₃

Trees of Shixia longan(Dimocarpus longan Lour.cv.Shixia)were used as materials to study the biological and biochemical mechanism of longan flower formation induced by KC1O₃.The changes of endogenesis hormones, relationship between hormones,protein and nucleic acid content,as well as the differential gene expression in the process of flower formation were studied.The main results of the study showed that:1.KC1O₃ promoted off-season flowering of longan significantly with 100%of treated trees flowering and 43.5%of shoots of each tree carrying flowers.2,The content of IAA increased sharply in the leaves and decreased in the buds and branches during the physiological differentiation phase and in morphological differentiation phase after inducation.The content of GA₃ decreased too in the leaves and buds during the physiological differentiation phase,but it increased in morphological differentiation phase,while in the branches it had no change.The content of ABA kept in a high level after inducation in the buds and increased in the leaves and branches in physiological differentiation phase,but in morphological differentiation phase it decreased.The content of ZR kept in a high level after inducation.3,The ratio of ZR/IAA,ZR/GA₃,ABA/GA₃ and ZR/ABA in the leaves increased sharply after inducation,but there was no changes for the ratio of ZR/ABA in branches;the ratio of ABA/IAA in branches increased in physiological differentiation phase,while the ratio decreased in leaves and branches.In morphological differentiation phase it was reversed.IAA/GA₃ was stable during the inducation.4,The content of solubility protein,dissolubility protein and total protein in the leaves increased sharply after inducation;The content of solubility protein in the buds increased sharply,dissolubility protein decreased sharply, but the total protein did not change.The content of total protein in branches was also stable,but solubility protein and dissolubility protein were reversed.5,The content of DNA,RNA and nucleic acid in leaves on flowering shoots,buds and vegetative shoots increased sharply after inducation,but the contents of DNA,RNA and nucleic acid in different tissues were different. The peak of DNA content in leaves,buds and branches appeared at 40 days after inducation,while the peak of RNA and nucleic acid showed up 50 days after inducation,being 10 days later.6,Two methods of distilling total RNA in longan tissue,which were convenient and efficient,were obtained.The two methods were named improved SDS method and improved CTAB method combining Isopropanol depositing.7,The DDRT-PCR reaction system and amplification procedure suitable for longan tissue were optimized.The optimized DDRT-PCR reaction system meant that a 25μl amplification reaction consisted of 1.0μmol.L^-1primer,1.8 mmol.L^-1Mg²⁺,100μmol.L^-1dNTP,2.0UrTaq DNA and 100ng cDNA.The best result was obtained when DDRT-PCR amplification procedure was carry out under anneal temperature of 42℃.The optimized PCR amplification procedure in Thermecycler was as follow:5.0min at 94℃for 1cycle,followed by1.0min at 94℃,2.0min at 42℃and,1.5min at 72℃for 40 cycles,10.0 min at 72℃for final extention,4℃conservation production.8,16 pairs of polymorphic DDRT-PCR primers with clear bands for longan were selected from 78 primer combinations.9,A set of differential gene expression segments was separated successfully during the procedure of flower bud differentiation induced by KC1O₃ by applying the techniques of mRNA differential display...