BIOLOGIA PLANTARUM 37 (3): 449-451, 1995 BRIEF COMMUNICATION Isolation and characterization of NaC! resistant cell line of mulberry K. KATHIRAVAN, A. SHAJAHAN and A. GANAPATHI Department of Biotechnology, Bharathidasan University, Tiruchirapalli - 620 024, Tamil Nadu. lndia Abstract The selected NaCI tolerant clones of Morus alba L. cv. MR 2 grow better at higher concentration of NaC1 than non-selected clones, With increasing NaCl concentration the Na +, CI" and proline content increased more and K + and Ca 2+ content decrease less in selected clones in comparison with non-selected ones. Key words: calcium,chloride, Morus alba, potassium,proline, sodium The development of mulberry (Morus alba L.) cultivars tolerant to salinity may lead to increase in productivity of silk worm (Bombyx mori U) in saline lands. Through cell culture techniques, salt tolerant cell lines were selected and regenerated in many plants (for review see e.g. Stavarek and Rains 1984). In the present study we report the procedure of salt tolerant cell line selection in mulberry. Further to understand the mechanism of salt tolerance, we estimated the Na +, K+, Ca 2+ and CI- ions and free proline content in mulberry callus cultures. Hypocotyl segments (Icm) from in vitro raised 10 d old seedlings ofMorus alba cv. MR 2 were cultured on MS medium (Murashige and Skoog 1962) containing 1.0 mg dm -3 of indole-3-acetic acid (IAA) and 1.0 mg dm -3 of benzyladenine (BA). The cultures were incubated at 27 + 2 ~ under dark. After 45 d, soft and friable calli (500 + 50 mg) obtained from the explants were transferred to medium with 0 - 1.0 % NaCI for selection of salt tolerant cell line. The culture conditions were the same as described above. At the end of 5th week more than 75 % of these calli exhibited arrested growth at and above 0.5 % of NaCI. A small portion of calli which showed continued growth and healthy appearance at 0.5 % of NaCl were grown on the medium with the same NaCl concentration for 8 months. These clones were considered as salt tolerant. Calli maintained on the NaCl free medium were referred as non-selected clones. Received 14 September 1994, accepted 19 November 1994. 449