Ginkgo Biloba L. Tissue Culture And Sex Identification And Regulation Of Plantlets In Vitro Cultured

Ginkgo biloba L., a typical dioecious perennial gymnosperm, is the only living representative of the older Ginkgoales left in the Tertiary. It is therefore called the "living fossil". It is of importance in many fields, such as food, medicine, timber, health, horticulture, and ecology, etc. So it's exclusive economic and ecological species in China. The present paper studied on embryo culture in vitro, callus induction and differentiation, axillary buds sprouting and growth. At the same time, sex differentiation of tissue-cultured plantlets was regulated with Gibberellin(GA₃) and Ethephon, and its male and female were identified by superoxide dismutase isoenzyme, esterase isoenzyme and peroxidase isoenzyme and ATP content.Results indicated that: a. embryo sprouting rate was high in 1/4MS and 1/2MS media and plantlets were stronger. Mature embryo was likely to germinate compared with immature embryo, b. 2,4-D with BA were excelled to NAA with KT in callus induction, whereas NAA with KT were good in callus subculture. And NAA at 2.0mg/L with 1.0mg/L KT were selected for callus production and long-term maintenance for immature embryo hypocotyl because its callus were milk-white, tightness and high-quality in subculture, c. MS+TDZ1.5mg/L+NAA0.1mg/L was optimized for adventitious buds regeneration, MS+BA0.5mg/L+NAA0.1mg/L was suited for sprouting of axillary buds. d. Endosperm extract, Casein hydrolysate and Active carbon had greatly effect on Ginkgo tissue culture. They can increase differentiation rate of adventitious buds, as well as enhance germination of embryo and axillary buds, and improve growth situation of plantlets. Among the additive, Endosperm extract was the best and made the differentiation rate of adventitious buds increased to 5.24%. e. There had no obvious difference in superoxide dismutase isoenzyme, esterase isoenzyme and ATP content between male and female. But peroxidase isoenzyme had obvious and steady difference between them and can act as an indication to identify the male and female in Ginkgo tissue-cultured plantlets. Gibberellin(G A3) and Ethephon used in tissue-cultured plantlets could induce the variation of sexual ratio. GA₃ could induce more male plants and male rate was the highest at 10mg/L GA₃. More female plants were induced by Ethephon and the highest female rate was achieved at Ethephon concentration of Smg/L.