The Histological Observation Of Peach Somatic Embryogenesis And Screening Of Peach Genetic Trasformation System By Agrobacterium-mediated Method

Peach cultivars 'Tiantaowang','Shuguang' and '97-8-4'(Jingyu×Zaohong2) etc. weretaken to study sterility propagating system in vitro, and get 'Huaguang','Shuguang' and'Jintong5' leaves from aseptic seedlings under vegetative propagation. Somaticembryogenic was studied by histological observation with 'Tiantaowang' and 'Qinguang2'cotyledons as controls.'Qinguang2' and '97-8-4' hypocotyls were taken as experimentalmaterials to carry on preliminary explorations about PpLox-3genetic transformation byagrobacterium-mediated method in this study. The main results are as follows:(1) Some optimal treatments were beneficial to the establishment of sterility system,including obtaining explant from water culture, peeling off scales of leaf bud beforedisinfection, taking G medium as basal medium, using0.1%HgCl2as disinfectant.Differences existed on other factors between different cultivars. Leaf buds which length wasless than2cm were taken as explant for 'Tiantaowang' and'97-8-4', and Leaf buds whichlength was more than2cm was suitable for 'Shuguang'. The optimal disinfection treatmentfor 'Tiantaowang' was disinfecting for10min with0.1%HgCl2. The results of disinfecting'Shuguang' for8min showed best.(2) Typical characteristics such as single-cell proembryos, multicellular proembryos,globular embryos, and V-type vascular bundles were observed during the leaf and cotyledonsomatic embryogenic histological observation. Conducting tissues and mature somaticembryos were differentiated successfully in embryogenic cells clusters during cotyledonsomatic embryogenic. In leaf callus, non embryogenic tissues started to disintegrate asembryogenic tissues's differentiation, which made embryogenic tissue independent andphysiological isolation happened. Leaf embryogenic callus differentiate some conductingtissues such as spiral vessels and V-type vascular bundles but conducting tissues in leafembryogenic tissues didn't happen and mature leaf somatic embryogenic did not form.(3) The optimal combination of agrobacterium-mediated method on peach hypocotylstransforming PpLox-3was: hypocotyls without preculture, infecting by agrobacteriumbacteria which was centrifuged for8min, and resuspended until OD600was0.5, inoculated onbacteriostatic medium of600mg/L Cef, and screening on medium of20mg/L Kan.