Abstract: A sand culture experiment was conducted in a growth chamber to study the responses of the growth and osmotic regulation substances of Cichorium intybus L. cv. Commander seedlings to the exogenous NO donor, sodium nitroprusside (SNP, 0.2 mmol·L^-1), under salt stress (140 and 280 mmol·L^-1 of NaCl). As compared with the control, the leaf area, length, width, and relative water content (RWC) of seedlings  under the salt stress had an obvious decrease whereas the leaf proline content increased significantly (P<0.05), and the decrement and increment were timedependent. The highperformance liquid chromatography (HPLC) analysis further indicated that the fructose, glucose and sucrose contents in the seedling’s roots under salt stress decreased after an initial increase, and the root 1-kestose and nystose contents decreased sharply under the stress of 140 mmol·L^-1 of NaCl but increased somewhat under the stress of 280 mmol·L^-1 of NaCl. Pretreatment with SNP not only alleviated the inhibitory effects of salt stress on the leaf growth and RWC, but also made the leaf proline and nystose contents increased significantly (P<0.05) and the leaf fructose, glucose and sucrose contents decreased. It was suggested that exogenous NO could enhance the resistance of C. intybus seedlings against salt stress by increasing the seedling’s water retention capacity and promoting the synthesis of osmotic regulation substances proline and fructan, especially nystose.

Key words: transgenic Bt rice, Nilaparvata lugens, triazophos, deltamethrin, resurgence.