Development somatic embryos

Another feature of apoplast during SE are the changes in the thickness of the cell wall (Fig. 6). Information about the necessity of the pjresence of the thick cell wall aroimd developing somatic embryos showed that in some examples such an isolation is necessary (Dubois et al., 1991 Schwendiman et al., 1990 Verdeil et al., 2001). The thickening of the cell walls in the... 

Find, J.I. (1997). Changes in endogenous ABA levels in developing somatic embryos of Norway spruce (Picea abies (L.) Karst.) in relation to maturation medium. 

A 65 kDa biotinylated polypeptide accumulates specifically in developing seeds of soybean. We believe that this polypeptide is analogous to the 60 kDa biotinylated protein that accumulates in developing somatic embryos of carrot (4, 5). Antibodies to this latter protein immunoprecipitate half the ACCase activity found in extracts from somatic embryos of carrot (6). Thus, the 60 kDa biotinylated protein of carrot is a subunit of a second form of ACCase. 

B. A somatic embryo at a later stage of development. C. Somatic embryo beginning to germinate, comparable to the whole embryo shown in Figure 5A. 

Because they are biochemically similar to zygotic embryos (3,4), somatic embryos also present an opportunity for vitro production of numerous secondary plant products which are associated with seeds. For example, essential oil, flavor, and aroma components found in seeds of celery (5), cocoa (6,7), and oil palm (8) are produced by somatic embryos. The ability to control and develop this process may permit more economical and reliable production of certain plant products on an industrial level. 

Low 2,4-D treated embryos accumulated 2.4 ug each of the IIS protein found in alfalfa seed, while the 50 uM-treated embryos accumulated less than 20 ng each (Figure 4). This result indicates that the level of storage protein accumulation is related to normalization of embryo development and may represent a useful assay to assess somatic embryo quality (4). The maxiumum level of protein accumulation is less than 107o of the level expected for alfalfa seed, however, suggesting that there is additional room for improvement in somatic embryo quality. 

A critical difference with zygotic embryos is that somatic embryos are never surrounded by an endosperm and that they do not develop a suspensor. In addition, somatic embryo are often larger than zygotic embryos. The morphological diversity and the lower rates of germination seen in somatic embryos compared to zygotic... 

Sexual contra somatic embryo development The involvement of DM domain genes... 

With regard to the initial steps of the development of a somatic embryo, the induction process is generally initiated by the action of a selected auxin (the most used auxin for most species is 2,4-Dichlorophenoxiacetic acid (2,4-D)) (Nomma Komamine, 1986 Jimenez,... 

In nature, auxins are produced in apical and root meristems, young leaves, seeds and developing fruits, and their main functions are cell elonj tion and expansion, suppression of lateral buds, etc. (Opik RoUe, 2005). In somatic embryogenesis this is considered one of the most important elements producing cell polarity and asymmetrical cell division. In general, relatively high auxin concentrations (2,4-D, lAA, etc.) favor callus formation and the induction process (cell polarity). Afterwards, when the induction stage has been achieved, it is necessary to reduce or eliminate the auxins in order to initiate the bilateral symmetry and the expression of the somatic embryos. 

Kevers, C Gaspar, T. Dommes, J. (2002). The beneficial role of different auxins and polyamines at successive stages of somatic embryo formation and development of Panax ginseng in vitro. Plant cell. Tissue and Organ Culture, Vol.70, No.2, pp. 181-188, (August 2002), ISSN 0167-6857... 

Growth inducers Concentration (mg/1) Treatment for somatic embryo development References... 

Table 7. Other growth inducers during callus induction stage and treatment for somatic embryo development...

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