Molecular biology and genetic engineering have become increasingly important for modern plant breeding during the last years. This is why these methods are also very interesting for the breeding of ornamental plants. The successful transformation of the flower color of a Petunia hybrida mutant in 1987 (Meyer et al.) initiated the manipulation of ornamental plants for specifically economic reasons. The results are not only important for basic research but are also economically viable for ornamental breeders. This study introduces the basic methods and techniques for the transformation of all kinds of plants (above all ornamental plants). The Agrobacterium tumefaciens-system, the particle gun and the "floral dip"-technique were the methods used to transform plants. At our department we established a method to clone binary vectors and to transform them into A. tumefaciens. The so-established A. tumefaciens helped us to transform genes, that we had cloned in our department, into different kinds of plants. Besides the Kanamycin-NPT II system, which is often used for selection, a binary vector was cloned with a selection based on hygromycin. This vector can be used for plants (e.g. pelargonium) that are selectable but cannot be selected on the basis of kanamycin or for the second transformation of plants already transformed with another selection marker. Successful gene delivery to pelargonium hypocotyls and expression of the foreign genes was demonstrated by histochemical GUS-staining. A modified form of the "leaf disc" method was used to tranform petunia, osteospermum and pelargonium. The 'floral-dip' method was applied to transform Arabidopsis thaliana. With the help of PCR-analysis, plants regenerated under selection conditions were surveyed to find out whether a T-DNA integration has taken place. These plants were then multiplied in vitro. Enzym tests with petunia plants that had been transformed with a FHT antisense-construct showed a much reduced enzym activity. This is why it is most likely that FHT is successfully stopped by the function of the antisense construct. By means of a particle gun the petals of genetic defined white flowering mutant of Matthiola incana were introduced as a test-system for the foreign gene expression concerning anthocyan biosynthesis. Petals of zantedeschia bombarded through the same method with a ANS construct showed a clearly red colouring in the areas where the particles had hit. It is most likely that the possible block in the anthocyan synthesis is removed through the gen expression and that therefore perlargonidin derivates are created.     «

Molecular biology and genetic engineering have become increasingly important for modern plant breeding during the last years. This is why these methods are also very interesting for the breeding of ornamental plants. The successful transformation of the flower color of a Petunia hybrida mutant in 1987 (Meyer et al.) initiated the manipulation of ornamental plants for specifically economic reasons. The results are not only important for basic research but are also economically viable for ornament...     »