Abstract: Abscisic acid （ABA）， a kind of phytohormone in plants， is involved in the regulation of many physiological properties as a signal molecule. Alginate oligosaccharides （AOS） prepared from degradation of alginate could regulate ABA synthesis， and stimulate endogenous ABA accumulation in wheat. In the present study， it was shown that AOS induced ABA synthesis mainly through up-regulating expression of ABA biosynthesis-related genes， i.e. TaNCED， TaAOX and TaBG. After fluridone treatment， no ABA accumulation was induced by AOS anymore. The results suggested that AOS induced endogenous ABA production may be achieved by ABA synthesis of signaling pathways.

Key words: alginate oligosaccharides, ABA synthesis, TaNCED, TaAOX, TaBG