Abstract: Using sodium nitrop russide ( SNP) as a nitric oxide (NO) donor and its scavenger PTIO (2-phenyl-4, 4, 5, 5-tetra
methylimidazoline-1-oxyl-3-oxide) , the effects of nitric oxide treatment on respira
tion, ethylene p roduction, relative membrane permeability, MDA content and activities of COX ( cytochrome
oxidase) , AO ( ascorbic acid oxidase) and PPO (polyphenol oxidase) of cut rose were studied. The results
showed that NO resulting from 0.1 mmol·L^-1 SNP aqueous solution decreased wilt rate, increased fresh
mass, p rolonged vase life, inhibited COX, AO and PPO activities, decreased the resp iration rate and ethylene
p roduction, delayed the resp iration and ethylene peaks, and slowed down the increase ofMDA content and the
relative membrane permeability. The treatment of PTIO stimulated COX, AO and PPO activities, increased
the resp iration rate, accelerated the increase ofMDA content and relative membrane permeability under SNP
treatment, but inhibited the ethylene p roduction. Those results indicated that NO might participate in regula
tion of terminal oxidases in resp iration.

Key words: Rose, Rosa hybrida, Respiration, Terminal oxidase, Senescence