Optimizing A Protocol For Plantlet Regeneration Via Somatic Embryogenesis Of Quercus Variabilis

Quercus variabilis is an important tree species for afforestation,which have great economic value. It is very important to quickly propagation of excellent trees,genetic improvement and gene resource preservation through somatic embryogenesis plant regeneration for this species.Immature zygotic embryos were used as explants to induce somatic embryos,this paper investigated the effects of different culture methods,the different additives on the proliferation,maturation and germination of somatic embryos in Quercus variabilis and analyzed the changes of endogenous polyamine in somatic embryos so as to optimize the protocol for plantlet regeneration via somatic embryogenesis of Quercus variabilis and give foundation for establishing an efficient regeneration system of somatic embryos in Quercus variabilis. The main results were described as follows:1)The proliferation of somatic embryos in Quercus variabilis was mainly indirectly somatic embryogenesis.The changes of culture methods and addition of organic additives could promote proliferation of embryogenic callus.After optimizing,the culture medium for proliferation of embryogenic callus was MS+3% Sucrose+0.3% Agar+1.0mg/L 6-BA+0.25 mg/L NAA+200 mg/L CH+400 mg/L Glu.2)During the process of maturation in Quercus variabilis,the normal maturation of somatic embryos was significantly promoted by ABA. PEG as osmolyte,the addition of it could improve the tolerance to dehydration of somatic embryos.After optimizing,the culture medium for maturation of somatic embryos was MS+5% Sucrose+0.6%Agar+5g/L PVP +0.5mg/L ABA+20 mg/L PEG.3)After maturation in the culture medium with ABA and PEG,cold and partial drying treatment could improve the rate of germination to 90% and the rate of plantlet conversion to 38.9% in Quercus variabilis.4)The embryogenic callus of Quercus variabilis was cultured in the proliferation medium with the addition of CH and Glu. In the somatic embryos which growed into the early cotyledon stage, the total content of endogenous polyamine reduced.The contents of Put were in the fall, contents of Spd and Spm were on the increase. 5)During the process of maturation of somatec embryos in Quercus variabilis,addition of ABA and PEG adjusted the contents of every endogenous polyamine to keep low Put/Spd value to reduce the occurrence of secondary somatic embryos and improve the normal development of somatic embyos and increase the germination rate significantly.