In vitro conservation of ornamental plants by slow growth storage

In vitro culture plays a prominent role in the selection, propagation and conservation of ornamental plants, fulfilling increasing market demands in terms of genetic and sanitary quality of the produced material. The present research is ongoing, aiming to optimize the conservation in vitro of selected lines of Anthurium, Ranunculus and Carex by slow growth storage. The study evaluates the effects of different storage temperatures (6 and 10°C, in dark conditions) and sucrose concentrations (30 or 60 g/L) on the maximum time of conservation and the regrowth potential of shoots in post-conservation. Data recorded periodically during the conservation period consisted of the survival and quality evaluation of shoots. Relative Growth Rate (RGR index) was also evaluated during both the storage period and in post-conservation, and compared to shoots in standard culture conditions. The species showed a marked growth reduction under the imposed climatic conditions. Although the stored material showed symptoms of oxidation (Anthurium) and etiolation (Ranunculus), a good regrowth potential was observed after the storage. Regardless of medium sucrose content, better storage condition for Anthurium was at 10°C. Differently, Ranunculus adapted well to both the tested temperatures, showing a superior quality of shoot cultures when stored on the medium supplemented with 60 g/L sucrose. Maximum conservation time was 8 months (Anthurium) and 9 months (Ranunculus). A similar experiment is presently in progress with a shoot culture line of Carex.