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We have bred low glucosinolate (GSL) winter oilseed rape lines carrying the fertility restorer for the CMS Ogu-INRA system. The original restorer line BO20 contained 31μmol/g GSL in seeds, but by crossing this line with various low GSL CMS lines, followed by repeated selection of fertile segregants, we were able to obtain fertile lines with a mean GSL content in seeds of 11.8 μmol/g. This result confirmed that the gene(s) controlling the GSL content are not closely linked to the fertility restorer gene. The results confirm, that the SCAR marker SG34 is closely associated with the fertility restoring allele, and facilitates so the selection of fertile segregants; however, the marker is unable to distinguish between the homozygous and the heterozygous Rfrf genotypes.

Using a radioligand-binding assay we have identified a Ca2+- dependent high-affinity D-myo-inositol-1,4,5-trisphosphate (InsP3) binding site in a membrane vesicle preparation from Chenopodium rubrum. Millimolar concentrations of Ca2+ were required to observe specific binding of [3H]InsP3. A stable equilibrium between bound and free ligand was established within 5 min and bound [3H]InsP3 could be completely displaced by InsP3 in a time- and concentration-dependent manner. Displacement assays indicated a single class of binding sites with an estimated dissociation constant of 142 [plus or minus] 17 nM. Other inositol phosphates bound to the receptor with much lower affinity. The glycosaminoglycan heparin was an effective competitor for the binding site (inhibitor concentration for 50% displacement = 534 nM). ATP at higher, although physiologically relevant, concentrations (inhibitor concentration for 50% displacement = 241 [mu]M) also displaced [3H]InsP3 from the receptor. Recent studies in animals have highlighted the importance of Ca2+ regulation of InsP3-induced Ca2+ release. The potential for the operation of similar regulatory mechanisms in plants is discussed.

Transgenic plants carrying isopentenyl transferase (ipt) gene and normal tobacco plants (Nicotiana tabacum L.) were analyzed to compare their phytohormone status. Total cytokinin (zeatin, zeatin riboside, isopentenyladenine and isopentenyladenosine) level and free IAA content were always higher in shoots regenerated from transgenic culture although the concentrations were lower in roots. In transgenic plants, IAA-oxidase activity was lower and the concentration of its protectant chlorogenic acid was increased. Transgenic plants also contained lower concentrations of ABA.

Somatic embryogenesis offers a tremendous potential for the micropropagation of conifers with a relatively long reproduction cycle and low fructification frequency, and those in which traditional micropropagation by axillary budding is ineffective. The Norway spruce represents an excellent example of this. Moreover, the Norway spruce is one of the most abundant conifers in Northern and Central Europe whose population is endangered by pollution and insects in some areas. The multiplication of particular genotypes which have a higher degree of resistance to such unfavourable environments is of great current concern. The potential advantages of production of plants through somatic embryogenesis over cutting of plants derived from organogenesis in P. abies are an almost unlimited number of plants obtained from one donor plant within a short period of time, the possibility of cryopreservation of embryogenie cell lines, the future prospect of reducing labour and embling costs resulting from the fact that the technique is amenable to automation, and finally, the possibility of rejuvenating mature trees identified as elite genotypes by this method.