Studies on the callus induction,tissue culture and secondary metabolism regulation of Eucommia ulmoides were carried out in a controlled illuminating incubator.The main results obtained were as fol- lows:( 1 ) the callus induction rate( CIR) was significantly influenced by the explantcharacters.CIR of ex- plant derived from the leaves of the coarse- bark cultivar is92 .61 %± 1 0 .0 2 % ,significantly higher than 30 .93%± 1 0 .1 6% of the smooth- bark one. CIR of the explantderived from 1 0~ 1 5 d- old l...