Sucrose metabolism and indoleglucosinolate production of immobilized horseradish cells

The problem of transient primary or secondary metabolism remaining a persis ting problem in plant cell cultures is discussed. Since secondary metabolit es occurred mainly in differentiated tissues, an effort was made to mimic t he cell-to-cell contact of multicellular organisms. Sucrose metabolism and indoleglucosinolate production from immobilized cells of Armoracia rustican a were investigated. Immobilization acted by reducing the assimilation of t he hexoses released into the culture medium. Although sucrose hydrolysis oc curred prior to uptake, the decrease of acid invertase activity in immobili zed cells was accompanied by an increased yield (2-3-fold) of the intracell ular sucrose. Glucosinolates accumulated as indolic forms only during the s tationary stage of cell growth. Their amount in immobilized cells may be in creased 2-fold compared to the control cultures. On the other hand intracel lular sucrose concentration declined whilst the cleavage activity of sucros e synthase increased simultaneously with production of indole-3-methyl- and 4-hydroxy-indole-3-methyl-glucosinolates Thus, the role of cell immobiliza tion in the biosynthesis of indoleglucosinolates is discussed.