Somatic embryogenesis, the initiation of embryos from previously differentiated somatic cells, is a unique process in plants. This volume expands our view of a subject that is important for plant biotechnology, genetics, cell biology, development, and agricultural applications. All chapters present the latest research progress, including functional genomic, genetic, and proteomic approaches. A special focus is placed on the effects of stress, environment, and plant growth regulators on embryogenesis. The role of genes such as <EM>Leafy Cotyledons and <EM>Baby Boom in defining and maintaining cell competence is discussed.
Plant Cell Monogr (2) A. Mujib · J. ˇSamaj: Somatic Embryogenesis DOI 10.1007/7089_021/Published online: 20 October 2005 © Springer-Verlag Berlin Heidelberg 2005
Storage Proteins and Peroxidase Activity During Zygotic and Somatic Embryogenesis of Firs (Abies sp.) A. Kormut’ák (u) · B. Vooková Institute of Plant Genetics and Biotechnology, Slovak Academy of Sciences, Akademicka 2, P.O. Box 39A, 950 07 Nitra, Slovakia
[email protected]
Abstract Somatic embryogenesis was initiated from immature embryos of Abies concolor (Gord. et Glend), A. numidica De Lann. and A. cilicica Carr., A. alba Mill. as well as in hybrid fir A. cilicica × A. nordmanniana. Soluble protein profiles and peroxidase activity were compared in developing zygotic and somatic embryos of silver fir (A. alba Mill.). On the basis of sodium dodecyl sulfate polyacrylamide gel electrophoresis of soluble proteins a high degree of homology was established between the two types of embryos. A higher peroxidase activity was registered throughout zygotic embryogenesis than during somatic embryo development but the opposite was true at the stage of mature embryos. Isoperoxidase composition reflected more efficiently the developmental stages of zygotic embryogenesis than those of somatic embryogenesis.
1 Introduction Somatic embryogenesis has become a major tool in the study of plant embryology, as it is possible in culture to manipulate cells of many plant species to produce somatic embryos in a process that is remarkably similar to zygotic embryogenesis (Thorpe 2000). Induction of somatic embryogenesis in the genus Abies has been demonstrated in five pure species: A. alba (Hristoforoglu et al. 1995; Schuller et al. 2000), A. nordmanniana (Nørgaard and Krogstrup 1991, 1995), A. balsamea (Guevin et al. 1994), A. fraseri (Guevin and Kirby 1997; Rajbhandari and ˇáková and Häggman 1997). Stomp 1997) and A. cephalonica (Krajn In our laboratory, embryogenic cultures of hybrid firs have been derived from immature A. alba × A. alba, A. alba × A. nordmanniana (Gajdoˇsová et al. 1995), A. alba × A. cephalonica, A. alba × A. numidica (Salajová et al. 1996) and mature A. alba × A. cephalonica zygotic embryos (Salajová and Salaj 2003/2004).
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A. Kormut’ák · B. Vooková
2 Somatic Embryogenesis of Abies sp. 2.1 Initiation of Embryogenic Tissue from Immature Zygotic Embryos Embryogenic tissue was induced from immature embryos of A. concolor (Gord. et Glend), A. numidica De Lann. and A. cilicica Carr. derived from self-pollination as well as in hybrid fir from interspecific crosses A. cilicica × A. nordmanniana. Immature seeds were surface-sterilized for 10 min in 10% H2 O2 . Endosperms containing embryos (from July) or embryos after excision from the megagametophyte (from August) were plated on Schenk and Hildebrandt (SH) initiation medium (Schenk and Hildebrandt 1972) with 1 mg l–1 benzylaminopurine and 2% sucrose. The medium was solidified with 0.3% Phytagel. The cultures were kept in the dark at 21–23 ◦ C. After 4–8 weeks of explant cultivation, white, mucilaginous extrusi