Studies On Plant Regeneration Of Rose Cultivars And Genetic Transformation Of Rosa Hybrida'Samantha'Using Leaflet Explants

Roses (Rosa hybrida L.) are popular because of the colorful, fragrant, concurrent flowers. Roses are widely planted in China, and they are important materials for landscaping in cities. Being one of the four famous cut-flower species in the world, roses are of great commercial important. This study optimized the regeneration and genetic transformation system of R. hybrida 'Samantha' by using in vitro grown leaflet explants. A plant regeneration system was also established for other 15 rose cultivars via direct organogenesis. The major results of this study were introduced separately as following:1. The direct organogenesis system of R. hybrida 'Samantha' was optimized by testing the effects of dark-time and carbohydrate on regeneration. The results showed: being cultured on induction medium (l/2MS+1.5mg/L TDZ+0.05mg/L NAA+10mg/L AgNO₃+3%Gluose+0.25 % GEL) for 15d in darkness and then transferred on multiplication medium (MS+0.5mg/L BA+0.004mg/L NAA+ 0.1mg/L GA₃) under light, leaflets of Samantha showed the highest frequency of adventitious bud regeneration, which is more than 95.0%, and higher 60% of the buds grew into shoots, with about 2.0 shoots per leaflet, after 4 weeks culture on the Multiplication Medium. The adventitious bud regenerate from petiole and the cutting of main vein.2. A plant regeneration system via direct organogenesis was established for 15 rose cut-flower cultivars. Effects of genotypes and combinations of different plant growth regulators were evaluated, and we found that genotypes had significant effects on regeneration frequency. R. hybrida 'Montezuma' showed higher adventitious buds regeneration than the others on all the 8 induction media with TDZ, with the highest bud induction frequency of 86.5% and plant regeneration frequency of 50.0%. R. hybrida 'Grand Gala' showed the lowest adventitious buds regeneration with frequency of 5.7% and R. hybrida 'Papilon' with the lowest plant regeneration frequency of 2.9%. When the ratio of cytokini (TDZ) and auxin (NAA) in induction medium was 10-30, most genotypes obtained the highest plant regeneration. At the same time, we used 8 genotypes to test the effect of BA on plant regeneration, and the results showed that though adventitious bud could be induced, no plants were obtained.3. An Agrobacterium tumefaciens-mediated transformation system was optimized for...