玉米茎尖培养研究(Ⅱ)--体细胞胚胎发生的组织细胞学研究

以玉米茎尖分生组织为外植体，在离体培养条件下诱导体细胞胚胎(胚状体)发生。组织细胞学观察表明，玉米茎尖分生组织在离体培养条件下可直接产生胚性愈伤组织，后者在继代培养中发生胚状体。多数胚状体起源于愈伤组织的表层细胞和表层之下的几层细胞，少数产生于愈伤组织的较深层。胚状体发生于单细胞，发育过程与合子胚大致相似。多数胚状体发育正常，具有一个芽端和一个胚根端。少数胚状体形成具多个芽端而共用一个胚根端的次生连体胚。胚状体发生不同步。胚状体只有在分化培养基上才能发育成熟。

Histological and cytological study on somatic embryogenesis of cultured shoot apices of maize

Somatic embryogenesis was studied in the in vitro culture of shoot tip meristem of maize. Observation on the culture' sections showed that embryogenic calli were probuced directly from the shoot tip meristem,embryoids were produced from the cells of the surface layer and inner layers of the embryogenic callus. The developmental program of the embryoid was similar to that of the zygotic embryo. Most embryoids with a root-shoot axis developed normally,few developed unnormally into integrated embryos with a multiple-shoot apex. The embryoids developed unsynchronously and maturated only on the medium for differentiation.