Rhizosphere effect of different aquatic plants on phosphorus depletion

A series of pot experiments with Alternanthera philoxeroides,Typha latifolia,Sagittaria sagittifolia and Phragmites communis were conducted to assess the phosphorus depletion effect in the rhizosphere.The ratio of root to shoot,root morphology,phosphorus uptake efficiency and phosphorus utilization efficiency were analyzed.An obvious variation in phosphorus concentrations between the rhizosphere soil and non-rhizosphere soil was observed.The water-soluble P contents in the rhizosphere soil of A.philoxeroides,T.latifolia,S.sagittifolia and P.communis were reduced by 81%,42%,18%and 16%,respectively,compared with that in the non-rhizosphere soil.A.philoxeroides had the highest phosphorus uptake efficiency(1.32 mg/m),while T.latifolia achieved the effective phosphorus depletion by the strong rooting system and the high phosphorus uptake efficiency(0.52 mg/m).T.latifolia not only used phosphorus to produce biomass economically,but also adjusted carbon allocation to the roots to explore the soil for more available phosphorus.A.philoxeroides and T.latifolia were more effective in depleting phosphorus in the rhizosphere than S.sagittifolia and P.communis.