利用花楸树人工控制授粉后的未成熟合子胚进行体细胞胚的诱导培养,通过石蜡切片、扫描电镜和透射电镜对合子胚和体细胞胚的发生发育过程进行组织、细胞观察.结果表明:1)体细胞胚发生进程与合子胚相似,均经历了球形期、心形期、鱼雷形期,最终发育成成熟胚;2)直接发生和间接发生在愈伤组织表面的体细胞胚均为单细胞起源,间接发生在愈伤组织内部的体细胞胚存在单细胞起源,同时还存在可能的多细胞起源;3)子叶和愈伤组织表面发生的体细胞胚在发育早期均具明显的胚柄,鱼雷形胚期胚柄退化;4)愈伤组织内部发生的体细胞胚没有胚柄;5)与合子不同,胚性细胞的第1次分裂为均等分裂;6)多细胞原胚周围降解的细胞具有细胞程序性死亡的形态特征.%Somatic embryos (SE) were induced from young zygotic embryos (ZE) of Sorbus pohuashanensis obtained after artificial pollination. The developmental process of ZE and SE was observed with paraffin section, scanning electron microscopy and transmission electron microscopy. The results showed that; 1) Somatic and zygotic embryogenesis underwent a similar course, by passing through globular, heart-shaped, torpedo-shaped stages and then reached mature stage; 2) SE derived from ZE cotyledons originated directly from single epidermis cell or indirectly occurred from single surface cell or inner cell of the embryogenic callus, but some of the indirectly occurred SE was possibly developed from multi-cell aggregates inside the embryogenic callus; 3) SE regenerated from single cells of ZE cotyledon epidermal and embryogenic callus surface had obvious suspensors during the early developmental stage, but they disappeared during torpedo-shaped stage; 4) There were no suspensors observed in SE regenerated inside embryogenic callus. 5) The first division of SE embryogenic cells was equally split, which was different from that of ZE; 6) Degradative cells around multicellular somatic preembryos displayed similar morphological patterns of programmed cell death.
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