Abstract: Plant oligosaccharides extracted from wheat cell wall was used to treat the suspension-cultured cells and calli of the crop,and subsequently phytoalexins were isolated from the treated materials.The phytoalexin induced and accumulated through oligosaccharides treatment possessed a relatively significant inhibition to the wheat headblight(Gibbercl-la seae(Schw.)Petch,Fusarium gramineaum Schwabe).Cytological examinations indicated that the mentioned inhibition was originated from the fact that phytoalexins made the hyphal tips swollen, disorganized and broken, resulting in inhibition of the pathogen propagation.Meanwhile, the oligosaccharides were also applied to treat wheat plants in fields.The oligosaccharides at suitable concentration were capable of lessening the infection of rust and powdery mildew diseases to wheat plants,thus improving disease-resistance of the wheat varieties.

Key words: Wheat, Oligosaccharide, Phytoalexin, Inhibition effect, Disease resistance