Abstract: The effects of nitric oxide（NO）and salicylic acid（SA）on the growth and physiological characteristics，key enzymatic activity of secondary metabolic pathways，the content of organic acid and curcuminoids of in vitro Curcuma longa plantlets were studied. And the medium was supplemented with sodium nitroprusside（SNP）（0，50，100，200，400 and 800 μmol ? L-1） as a donor of NO and salicylic acid（0，5，10，20，40 and 80 μmol ? L-1）. The results showed that NO and SA can adjust the growth and physiological characteristics and promoted the accumulation of secondary metabolites of Curcuma longa in some degree. It raised significantly the contents of chlorophyll，carotenoid，soluble sugar and protein in leaves of Curcuma longa，and activated the activities of phenylalanin ammonia-lyase（PAL），cinnamic acid-4-hydroxylase（C4H）and 4-coumaric acid：CoA ligase（4CL），promoted the accumulation ofcinnamic acid，p-coumaric acid，coffee acid and ferulic acid，and then improved the content of curcumin and demethoxycurcumin，bisdemethoxycurcumin with 200 μmol ? L-1SNP and 10 μmol ? L-1 SA. Therefore，200 μmol ? L-1SNP and 10 μmol ? L-1 SA were conducive to the growth and accumulation of secondary metabolites in Curcuma longa. It suggested that NO and SA have dual nature on secondary metabolites physiological Abstract. characteristics of Curcuma longa.

Key words: Curcuma longa, signal molecule, physiological characteristics, secondary metabolites, curcuminoids