Abstract:The rhizomes of Cymbidium sinense (Andr.) Willd. were incubated in the medium of 1/2 MS + NAA + BA + La3 + . La3 + was highly effective on the regulation of the development and metabolism of rhizome, probably enhancing the activity of hormones. When the La3 + -treated steins were compared with the control, it was found that the growth rate was enhanced by 78 % increase in increment rate of fresh weight apparently resulting in better growth and having more branches; The photosynthesis rate and respiratory rate was 61% and 9% higher respectively; Protein synthesis was promoted revealing much content of about 45 kD peptides; and in addition the development of shoots was faster.