This paper reported the dynamic change of gutta-percha content during callus culture of Eucommia ulmoides Oliv.The results showed that there was a relative close relationship existing between the synthesis of gutta-percha and the growth period of calluses.In callus subculture,the gutta content increased with the times of callus subculture.Once callus was formed,the gutta-percha started to accumulate.The gutta-percha content has a peak value from subculture generation 5 to generation 8;it could reach 94.38% ...