Abstract: Effects of grafting on growth, physiologicalmetabolism and hypoxia tolerance were studied incucumber (Cucumis sativus L. ) grafted on smooth luffa (Luffa cylindrica Roem. ) and grown in nutrient solution. The results showed that grafting significantly increased hypoxia tolerance of grafted cucumber seedlings.Plant height, stem thickness, fresh mass, dry mass of grafted seedlings and the activity of SOD, POD, CAT and APX in both leaves and roots of grafted seedlingswere markedly higher than those grown on own-roots after 8 days of hydroponic hypoxia stress. Similarly, root activity, the content of chlorophyll, net photosynthetic rate, stomatal conductance, intercellular CO₂ concentration and transpiration rate were significantly higher than those grown on own2roots under hypoxia stress. However, the rate of O₂^·
production of grafted seedlings was lower than that grown on own-roots after 8 days of hydroponic hypoxia stress. The higher levels of antioxidation and higher photosynthetic rate may be involved in higher hypoxia tolerance of grafted seedlings.

Key words: Cucumber, Graft, Hypoxia stress, Reactive oxygen, Photosynthetic characteristics