EFFECT OF SUCROSE ON GROWTH AND GALANTHAMINE PRODUCTION IN SHOOT-CLUMP CULTURES OF NARCISSUS-CONFUSUS IN LIQUID-SHAKE MEDIUM

In order to produce galanthamine, an alkaloid currently being tested i n Alzheimer's disease therapy, we have used in vitro organ cultures of Narcissus confusus (Amaryllidaceae) plants starting from two differen t explants: double scale segments with basal plate from bulbs (organog enic cultures), and mature seeds (callogenic-organogenic cultures). Sh oot-clumps were induced from buds obtained from twin-scales and from o rganogenic calluses on a MS medium supplemented with 1 mg l(-1) 2,4-D and 5 mg l(-1) BA. Shoot-clumps were then developed partially submerge d in a liquid medium. After one month of precondition, the shoot-clump s were cultured in liquid media with different concentrations of sucro se, from 3% to 18% (w/v) for 14 days. The growth of the regenerated pl ants treated with 9% sucrose was significantly greater. Under a photop eriod 16 h light/8 h dark, the shoot-clump cultures subjected to the t wo highest sucrose concentrations gave rise to higher dry weight/fresh weight ratios. Different doses of sucrose affected not only the alkal oid profile in the shoot-clump tissues but also that excreted to the m edium. In all cases, shoot cultures of N. confusus were capable of gal anthamine biosynthesis, with the best results at 9% sucrose concentrat ion.