EFFECTS OF LIQUID, TEMPORARY IMMERSION BIOREACTOR AND SOLID CULTURE SYSTEMS ON MICROPROPAGATION OFLILIUM LEDEBOURII VIA BULBLET MICROSCALES-AN ENDANGERED VALUABLE PLANT WITH ORNAMENTAL POTENTIAL

Lilium ledebourii (Baker) Boiss. (Liliaceae) is a critically endangered lily species native to northern Iran, where it is protected by law. In order to develop a cost effective method for largescale propagation, the effects of three culture systems (solid, liquid and temporary immersion) and two types of cytokinins [6-Benzyladenine (BA) and Thidiazuron (TDZ)] were studied on the in vitro plant regeneration of L. ledebourii. To establish the protocol, we used in vitro regenerated bulblets obtained from bulb scale segments that were cultured on solid Murashige and Skoog (MS) media as starting material. The bulblet microscale transverse thin cell layers were cultured on MS solid medium containing 3% sucrose and different combinations of plant growth regulators. Choice of both, the culture system and the type of cytokinin, affected the differentiation of explants. Two types of calli formed on explants: type I callus was embryogenic, while type II callus was shoot organogenesis. The highest percentage (94%) of embryogenic callus was obtained when calli were transferred on MS solid media supplemented with 0.54 μM α-Naphthaleneacetic acid (NAA) and 0.44 μM BA. In addition, it was also observed that the use of temporary immersion bioreactor resulted in a significantly lower amount of shoot organogenesis rather than solid culture systems. Seventy percent of the plantlets were successfully acclimatized to exvitro conditions and were phenotypically similar to the mother plants