Advances in Natural and Applied Sciences, 3(3): 432-437, 2009 ISSN 1995-0748 © 2009, American Eurasian Network for Scientific Information This is a refereed journal and all articles are professionally screened and reviewed ORIGINAL A RTICLE 432 Corresponding Author: Sreeramanan Subramaniam, School of Biological Sciences, Universiti Sains Malaysia (USM), Minden Heights, 11800, Penang, Malaysia. Tel:604-6533528 Fax:604-6565125 E-mail:sreeramanan@usm.my Establishment of in Vitro Phalaenopsis Violacea Plant Cultures from Flower-stalk Cuttings Sreeramanan Subramaniam , Xavier Rathinam, Ranjetta Poobathy and Umarani Sinniah 1,2 2 1 3 School of Biological Sciences, Universiti Sains Malaysia (USM), Minden Heights, 11800, Penang, Malaysia, 1 Department of Biotechnology, AIMST University, Batu 3½ , Jalan Bukit Air Nasi, Bedong , 08100, Kedah, 2 Malaysia, Department of Crop Sciences , Faculty of Agriculture, Universiti Putra Malaysia, 43400, Seri Kembangan, 3 Selangor, Malaysia. Sreeramanan Subramaniam, Xavier Rathinam, Ranjetta Poobathy and Umarani Sinniah: Establishment of in Vitro Phalaenopsis Violacea Plant Cultures from Flower-stalk Cuttings: Adv. in Nat. Appl. Sci., 3(3): 432-437, 2009. ABSTRACT Phalaenopsis species are much sought after in the orchid flower industry due to their long-flowering periods and their large-sized flowers. There is a need to hasten the micropropagation process and to improve the quality of the Phalaenopsis plantlets through optimization of medium components. Three experiments were carried out in this research to test the following parameters: direct shoot regeneration from nodal explants of Phalaenopsis violacea flower stalks on half-strength MS medium added with different cytokinins (1- benzylaminopurine or BAP, thidiazuron or TDZ, and zeatin) under various concentrations; the effects of different cytokinin concentrations on protocorm-like body (PLB) induction from leaf segments of the orchid; and the effects of different cytokinin concentrations on the orchid’s PLB proliferation rates. Among the three cytokinins tested, BAP produced the highest percentages of induced shoots from the nodal explants of the flower stalks, after 8 weeks of culture. Both 0.8 μM and 1.0 μM BAP resulted in the conversion of 100% nodal explants to shoots, with each corresponding to the formation of 3.7 and 2.9 shoots per nodal explant respectively. Half-strength semi-solid MS media containing 0.6 μM, 0.8 μM and 1.0 μM BAP induced PLBs in 60%, 70% and 50% of the leaf segments respectively, with 0.6 μM also producing the highest PLB proliferation rate at 75% after 12 weeks of culture. Among the TDZ concentration series, 0.6 μM induced 60% of the explants into shoot formation, producing 2.6 shoots per explants, with both 0.6 μM and 0.8 μM producing PLBs from 40% of the leaf segments. Zeatin produced low percentages of nodal explant conversions and shoot formation with the lowest PLB induction and proliferation rates. Key words: Phalaenopsis violacea, protocorm-like body (PLB), benzylaminopurine (BAP), thidiazuron (TDZ), zeatin. Introduction The Phalaenopsis (Orchidaceae), also known as the moth orchids, are mostly found in the Southeast Asian region, with a few exceptions in Taiwan, Sikkhim to Australia and the Pacific (Teob, 1989). Highly profitable in flower markets around the globe (Chen and Chang, 2006), the Phalaenopsis is regarded as the most popular orchid genus in the horticultural industry due to the aesthetic value and durability of the flowers, as well as the adaptability of the plants to room environment. Phalaenopsis violacea have greenish white flowers with purple pigment around the sepals and the lip. P. violacea are native to the peninsular Malaysia and are closely