通过对不同银杏外植体的离体培养和显微切片观察,研究了银杏不同外植体的体胚发生、不定芽诱导及不定根发生的过程.主要结果如下:(1)银杏成熟胚培养20 d后,具有完整的子叶和胚芽,胚芽、胚轴处有分泌腔的存在；未成熟胚(大子叶胚)可观察到子叶和胚芽原基.小子叶胚形成的愈伤组织中可观察到两细胞、四细胞、多细胞原胚至球形胚的发育； (2)子叶外植体培养过程中外皮层细胞首先启动分化,逐渐在外皮层及皮层周围形成分生细胞团,最终形成不定芽.(3)银杏芽苗不定根发生为诱发生根型,起源于维管形成层与髓射线交叉处的细胞,20d后可观察到成型的不定根.(4)探讨了银杏不定芽或体胚难以成活的原因.%The differentiation process including somatic embryogenesis in different Ginkgo explants in vitro culture were studied by cytological observation. The results show that (1) two complete cotyledons and a embryo bud were observed in mature embryos and several secretory acavitives appeared in maturation region of embryo buds, hypocotyls, cotyledons and radicles after culturing 20 days; two incomplete cotyledons and a embryo bud primordia were found in large cotyledon embryos. The proembryo of two cells, four cells, multi-cellular, and globular embroy were developed from the callus of the small cotyledon embryos. (2)The differentiation of cotyledon explants started from epidermal cells, and gradually formed meristematic cell mass in the cortical cells, and eventually adventitious buds were observed. (3)The adventitious roots of Ginkgo originated in the cells at the cross of vascular cambium and vascular rays. (4)The type of rooting belongs to induction type by root primordium. The formed adventitious roots were observed after 20 days.
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