Embryo globular

Recognized embryos Globular Intermediate Torpedo Total... 

Espinasse, A. and Lay, C., Shoot regeneration of callus derived from globular to torpedo embryos from 59 sunflower genotypes, Crop Sci., 29, 201-205, 1989. 

Our data indicate that the formation of somatic globular embryos is accompanied by the accumulation of storage protein transcripts. Figure 9.6 illustrates that transcripts for the synthesis of gibberellic acid also accompany the formation of somatic embryos. These microarray hybridizations experiments have been entered into the GEO (Gene Expression Omnibus) database of NCBI at http //www.ncbi.nlm.nih.gov/geo. For complete details on interpretation of the data, see Thibaud-Nissen et al ... 

Fig. 4. Differential morphology between monocotyledonous and dicotyledonous somatic embryos after the globular stage, a) and a ) Ideogram and real Agave tequilana (monocotyledonous) somatic embryo, respectively, b) and b ) Ideogram and real Carica papaya (dicotyledonous) somatic embryo, respectively, r - radicle, am - apical meristem, p -protoderm, cp - cotyledonar paimordium.

Fig. 1. Different developmental stages of somatic embryos from the example of Arabidopsis (A-globular B-heart C-torpedo D-late torpedo E and F-mature bar = 200 pm).

Symplasmic communication within somatic embryos is also not well-described. It was shown for barley androgenic embryos that the symplasmic barrier exists between protodermis and the rmderlying tissues up to the late globular stage, in the isolation of... 

On the other hand, inhibitors such as ABA (abscisic acid) are used in the further stages of somatic embryogenesis. They cause the maturation of somatic embryos through globular, heart-shaped, torpedo and cotyledonary stages (Fig. 1), and in the final stage -their development into the seedling. Moreover, ABA increases the resistance of cells to stress conditions. 

The polar transport of auxin in early globular embryos is essential for the establishment of bilateral symmetry during plant embryogenesis. Interference with this transport causes a failure in the transition from axial to bilateral symmetry and results in the formation of embryos with fused cotyledons (Liu et at, 1993). 

Fig. 4. An embryogenic structure derived from an embryogenic callus used as explant (A), developed an embryogenic callus (B) after 90 days of culture in medium 1. After transferring embryogenic callus to medium 11, callus with somatic embryos at different stages occurred. Piece of callus with pro-embryos (C), globular embryo (D), coleopHlar embryo (E) and germinating embryo (F). Bar= 1mm. Coleoptile [c], germinative pore [gp], pro-embryo [pro]...

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