Fermentation Pilot Plant 45 3.3 General applications The most important fields of research for industrial applications, plant cell tissue and organ cultures are clonal propagation and secondary metabo- lite production. Plants cultivated in vitro have great changes in their morphological features, from cell tissue to differentiated embryo, roots, shoots or plantlets Applications to Secondary Metabolite Production. Plant tissue culture is a potential method for producing secondary metabolites. Both shikonins(Fujita and Tabata 1987)]and ginseng saponins(Ushiyama etal 1986)[] have now been produced on a large scale by this method. However, the important secondary metabolites are usually produced by callus or cell suspension culture techniques. the amounts of some metabolites in the cell have exceeded the amounts of metabolites in the cells of the original plants grown in the soil. So it is expected that cell culturing may be applicable to industrial processes for the production of useful secondary metabolites. It is common knowledge that when a cell culture is initiated and then transferred, the productivity of the metabolite decreases(Kurz and Constabel, 1979).19) Once productivity decreases, it becomes very difficult to arrest or reverse the decrease. In order to avoid this phenomenon, many cell strains were screened to select those which would maintain metabolite productivity. Some metabo- lites such as anthocyanins, shikonins, vinca alkaloids, and ubiquinones have been reported to have increased their productivity significantly. Deus Neumann and Zenk(1984) ol have checked the stability of the productivity of the selected cell strains reported in the literature and noted that the production of some metabolites such as anthraquinone Morinda citrifolia), rosmalinic acid (Colius blumei), visnagin (Ammi visnaga), diosgenin (Dioscorea deltoidea, etc were stable after several subcultures, but some metabolites such as nicotine(Nicotiana rustica), shikonin(Lithospermum erythrorhizon), ajmalicine(Catharanthus roseus), rotenoids( Derris elliptica) anthocyan(Daucus carota), etc, were shown to be unstable after several subcultures Clonal Plant Propagation. Plants are propagated clonally from vegetative tissue or organs via bypass sex. Conventional clonal propagation can be performed by leafor stem cutting and layering or dividing ofthe plants however the efficiency is very low. Recently, many plants were propagated efficiently through tissue culture. This technique was first reported in 1960 by G. Morell] for the propagation of orchids and since then, many plants have been propagated by tissue culture. Today there are many commercialFermentation Pilot Plant 45 3.3 General Applications The most important fields of research for industrial applications, plant cell tissue and organ cultures are clonal propagation and secondary metabo￾lite production. Plants cultivated in vitro have great changes in their morphological features, from cell tissue to differentiated embryo, roots, shoots or plantlets. Applications to Secondary Metabolite Production. Plant tissue culture is a potential method for producing secondary metabolites. Both shikonins (Fujita and Tabata 1987)r'I and ginseng saponins (Ushiyama et al., 1986)[*] have now been produced on a large scale by this method. However, the important secondary metabolites are usually produced by callus or cell suspension culture techniques. The amounts of some metabolites in the cell have exceeded the amounts of metabolites in the cells of the original plants grown in the soil. So it is expected that cell culturing may be applicable to industrial processes for the production of useful secondary metabolites. It is common knowledge that when a cell culture is initiated and then transferred, the productivity of the metabolite decreases (Kurz and Constabel, 1979).['1 Once productivity decreases, it becomes very difficult to arrest or reverse the decrease. In order to avoid this phenomenon, many cell strains were screened to select those which would maintain metabolite productivity. Some metabo￾lites such as anthocyanins, shikonins, vinca alkaloids, and ubiquinones have been reported to have increased their productivity significantly. Deus￾Neumann and Zenk ( 1984)[1°1 have checked the stability of the productivity of the selected cell strains reported in the literature and noted that the production of some metabolites such as anthraquinone (Uorinda citrofoliu), rosmalinic acid (Colius blumei), visnagin (Ammi visnaga), diosgenin (Dioscoreu deltoidea), etc., were stable after several subcultures, but some metabolites such as nicotine (Nicotiana rusticu), shikonin (Lithospermum erythrorhizon), ajmalicine (Catharanthus roseus), rotenoids (Derris eliptica), anthocyan (Duucus carota), etc., were shown to be unstable after several subcultures. Clonal Plant Propagation. Plants are propagated clonally from vegetative tissue or organs via bypass sex. Conventional clonal propagation can be performed by leaf or stem cutting and layering or dividing ofthe plants, however the efficiency is very low. Recently, many plants were propagated efficiently through tissue culture. This technique was first reported in 1960 by G. Morel["] for the propagation of orchids and since then, many plants have been propagated by tissue culture. Today there are many commercial