Nitrogen(N)is an important nutrient element of plants.Lacking N will affect plant growth even survival.To adapt to low N,plants have evolved a set of adaptive responses,such as deduction of growth,reduction of photosynthesis,and accumulation of anthocyanins.Anthocyanins are a branch of flavonoids with protective effects to plants under certain oxidative stress conditions.For example,anthocyanins have been reported to scavenge ROS in plants grown under high light condition.Under nutrient stress conditions such as N & P depletion,plants also accumulate large amount of anthocyanins,however,the functions of the increased anthocyanin accumulation remain obscure.Brassinosteroids(BRs)are steroidal phytohormones that play important roles in plant responses to different stresses.Recently,we found that BR could increase plant tolerance to low N stress and enhance low N-induced anthocyanin accumulation.These results suggest that BR may increase plant tolerance to low N partially through the enhanced anthocyanin accumulation.To understand whether and how anthocyanins increase plant tolerance to low N,we are investigating the effects of low N-and BR-induced anthocyanin accumulation on ROS production.