Increasing Rhynchostylis retusa’s Callus Formation by Immersing Explant in Ascorbic Acid and Planting on Activated Charcoal Contained Medium

The aimed of this research is to increase Rhynchostylis retusa callus formation through immersing explants in ascorbic acid and planting it on activated charcoal contained medium. It's an experimental research that consist of three factors; i.e. immersion explants in ascorbic acid (immersed and not immersed), kind of in-vitro culture medium (not-contained (as control), pro-analysis activated charcoal contained and commercial activated charcoal contained), and the type of expants (leaf and root). The source of explants used are 18 months after planting (map) Rhynchostylis retusa orchids plants in in-vitro cultures. The explants condition (the level of browning) and callus formation (the percentage of callus forming explants, the time of callus appearance, and callus diameters) were observed at8 weeks after planting (wap).The result show that callus formation can be induced by medium that contain activated charcoal of both kind (pro-analysis or commercial).Combination of the treatment with explants immersionin ascorbic acid before planting can increase the callus formation. The root explants form higher callus diameters (0,563 mm) than leaf (0,298 mm).