Abstract: Flavonoids were a class of 2-phenylchromone compounds produced by plants.They have many biological activities and were widely distributed in plants.The diverse physiological and biochemical properties of flavonoids make them involved in many interactions between plants and environmental factors,including the exchange of information with microorganisms and protection against phytophagous insects and pathogenic bacteria.Flavonoids were also an important class of allelochemicals.Flavonoids interact with a variety of environmental factors,including biological and non-biological aspects;this article describes the interaction of flavonoids in plant and biological environment.

Key words: flavonoids, biological environment, plant defense, allelopathy