| 1. |
- Hjortswang, H I, et al.
(författare)
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KNOTTED1-like homeobox genes of a gymnosperm, Norway spruce, expressed during somatic embryogenesis
- 2002
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Ingår i: Plant physiology and biochemistry (Paris). - 0981-9428 .- 1873-2690. ; 40:10, s. 837-843
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Tidskriftsartikel (refereegranskat)abstract
- Two Norway spruce (Picea abies (L.) Karst.) genes belonging to class I of the KNOTTED1-like homeobox (KNOX) genes, HBK2 and HBK3, were cloned with PCR-based methods. The expression of these and a previously characterised related gene, HBK1, in different organs and during somatic embryogenesis was studied with RTPCR. Transcripts of all three genes were detected in stems, roots and in cone buds, but not in needles. HBK1 and HBK3 are expressed throughout development in a normal cell line with embryogenic potential and in a cell line unable to form somatic embryos. HBK2 is expressed in the normal cell line, but not in the developmentally arrested cell line. This suggests that the HBK2 gene is involved in the somatic embryo development.
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| 2. |
- Högberg, Karl-Anders, et al.
(författare)
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Critical factors affecting ex vitro performance of somatic embryo plants of Picea abies
- 2001
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Ingår i: Scandinavian Journal of Forest Research. - : Informa UK Limited. - 0282-7581 .- 1651-1891. ; 16:4, s. 295-304
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- The potential to use somatic embryos for large-scale propagation of elite genotypes, for integration into breeding programmes and for connecting breeding and mass propagation, is receiving much attention. However, before the methods are applied it is important that the plants regenerated via somatic embryogenesis grow as expected, i.e. as seedlings or cuttings. Growth of somatic embryo plants is under a cumulative influence of a number of treatments given during the in vitro phase and during the ex vitro establishment phase. The aim of this study was to identify treatments with a negative influence on the subsequent growth of somatic embryo plants of Norway spruce (Picea abies L. Karst.). Based on the results, the time of contact with abscisic acid during somatic embryo maturation and the length of continuous light treatment (CLT) during the first growth period strongly affect the height growth during two successive growth periods. In both cases longer treatments exerted negative effects. Based on these results a new method was set up, which includes: (1) prematuration treatment of the suspension culture in a growth regulator-free medium, by which the maturation step is synchronized and contracted; and (2) a two-phase germination treatment, first on a solidified medium and then in a liquid medium. This treatment avoids extended CLT during the first growth period. Another advantage of the two-phase germination treatment is a better root-system development. Somatic embryo plants produced according to this method can be transferred directly from in vitro conditions to the greenhouse.
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