Abstract: In this paper, the growth characteristics, biosynthesis pattern of secondary metabolites and carbon consumption in the liquid culture of Cajanus cajan hairy root were studied. Results showed that the metabolic cycle of C.cajan hairy root was 25 days including the experienced delayed phase, growing fast phase and steady phase. In C.cajan hairy root growth cycle, its growth rate and consumption of carbon were highly related, the faster growth rate, the more carbon consumption. With the growth rate becoming steady, carbon consumption leveled off. The contents of apigenin and genistein in the hairy root increased with the time increasing but became steady in the moderate growth period.

Key words: Cajanus cajan, hairy root, growth cycle, carbon consumption, secondary metabolites