石刁柏胚乳愈伤组织内胚胎发生的组织细胞学观察

HISTOCYTOLOGICAL OBSERVATION ON EMBRYOGENESIS IN ENDOSPERM CALLUS OF ASPARAGUS OFFICINALIS L.

石刁柏(Asparagus officinalis L.)的幼嫩胚乳接种于MS+NAA 5ppm+6-BA 1ppm和MS+NAA 1ppm+6-BA 0.5ppm的培养基上诱导产生愈伤组织。将愈伤组织转移到MS+6-BA 1ppm+NAA 0.5ppm的分化培养基上,培养30天后即可形成胚状体,组织细胞学观察表明:胚状体起源于愈伤组织内或近表层的单个胚性细胞。在胚状体发生的早期阶段,观察到与柳叶菜型和藜型胚胎发育大致相似的细胞分裂方式,从而出现了T型或线型的四个细胞的原胚。在多细胞原胚及球形胚期具有单列或不规则排列的多细胞胚柄。石刁柏胚乳愈伤组织中的胚胎发生是不同步的,在同一块愈伤组织的切片中可以观察到不同发育阶段的胚状体。在外形上还可以观察到一个子叶、两个子叶或四个子叶等多种不同形态的胚状体。一部份胚状体能发育成完整小植株。

This paper reports the somatic embryogenesis in endosperm culture of A. officinalis L. The calli were produced from immature endosperm on MS+6-BA1 ppm+NAA 5Ppm and MS+G-BA 0.5 ppm+NAA 1 ppm media. The embryoids were formed from the calli on medium MS+6-BA 1ppm+NAA 0.5ppm. Histocytological observation on the endosperm callus showed that most embryoids were originated from single embryonic cells, inside and near surface layers of the callus. The developmental sequence of the embryonic cell was generally similar to that of the zygotic embryos. The first division of embryonic initial cell produced two-cell proembryo i. e. the terminal cell and basal cell. The way of division of two-cell proembryo was similar to that of the onagrad type and the chenopodiad type. The T type and line type four-cell proembryo in the endosperm callus were found. The multicellular proembryo and globular embryo possessed uniserial or untidy disposal multi-cellular suspensor. The mature embryoids can develop into plantlets.The production of the embryoids from cellus was not synchronous. So embryoids of different development stages could be observed in the same callus. The cmbryoids possessed one, two or four cotyledons.