The study is to provide reference for the application of Phyllostachys rivalis in vegetation restoration of wetland and hydro-fluctuation belt taking P.rivalis that can survive under long-term flooded conditions as memory materials.Biomass and the contents of main nutrient elements in annual bamboo rhizome roots were investigated in a pot experiment with treatments of artificial irrigation water supply(CK) and flooding six months(TR).The effect of long-term flooded conditions on nutrient stoichiometric characteristics of P.rivalis rhizome roots was analyzed.The results showed that:(1)In TR,N,P,Mg and Ca contents of P.rivalis rhizome roots in soil decreased significantly and Fe content increased dramatically compared to CK.Meanwhile,N,K and Ca contents of rhizome roots in soil were significantly lower and Fe content was significantly higher than that of rhizome roots in water.(2)In TR,C/N,C/P,C/K and P/K ratios of rhizome roots in soil were significantly higher than that of rhizome roots in CK,and C/K,N/K and P/K ratios were also significantly higher than that of rhizome roots in water.(3)There were very significant positive correlations among C,N and P contents of root in water and soil under TR.In CK,C content of root was significantly positive correlated with P,K and the N-P correlation is also significant.In view of correlation coefficient,the correlations of C-N,N-P and N-K of rhizome roots in soil under TR were weakened.Meanwhile,the correlations of C-P,C-K and P-K were enhanced.In TR,C-N,C-P,N-P and N-K correlations of rhizome roots in soil were weaker than that of rhizome roots in water,C-K and P-K correlations were stronger than that of rhizome roots in water.(4)Biomass and C,N,P,K,Mg,Ca contents of rhizome roots in TR were significantly lower 19.46%,42.04%,36.55%,41.39%,60.06% and 38.46% than that of rhizome roots in CK,Fe content dramatically increased 5.5 times compared to CK.And in TR,the nutrient accumulation in soil was significantly higher than that in water.The results indicated that the equilibrium absorption of nutrient was hindered by the long-term flooded stress in rhizome roots of P.rivalis,but the utilization efficiency of nutrient was enhanced.And the rhizome roots in soil and water had the characteristics of division of cloning.Rhizome roots in water mainly played a role in the absorption of oxygen to response to oxygen-deficient environment.It was an important ecological countermeasure of P.rivalis to adapt to long-term flooded environment.