Abstract: To investigate the effects of GSH on tolerance to water deficit stress（WDS）in cut rose ‘Samantha’ and the response of AsA-GSH cycle to WDS in petals of cut roses，we pretreated the stem bases of cut rose flowers with exogenous GSH and BSO，the specific inhibitor of GSH key biosynthetic enzyme γ-ECS，to increase or decrease GSH content of cut rose petals respectively. The results showed that GSH pretreatment increased water recovery rate after 24 h WDS and prolonged vase life significantly；On the contrary，BSO pretreatment decreased the GSH content of petals and then，reduced the tolerance to WDS in cut roses. GSH pretreatment increased the total GSH content and reduced GSH content of petals substantially during WDS and water recovery，as well as AsA content. GSH pretreatment promoted the activities of APX and GR，which were two key enzymes in AsA-GSH cycle，but MDA content decreased. Contrary results were obtained in BSO pretreatment. These results suggested that GSH enhanced the tolerance to WDS through the promotion of antioxidant capability of AsA-GSH cycle in cut roses.

Key words: rose, cut flower, water deficit stress, GSH, GR, APX