Uptake of bromide by two wetland plants (Typha latifolia L. and Phragmites australis Cav. Trin. ex Steud.)


Xu, SP, Leri, AC, SCB Myneni, and PR Jaffe. 2004. “Uptake of bromide by two wetland plants (Typha latifolia L. and Phragmites australis Cav. Trin. ex Steud.Environmental Science & Technology 38: 5642-5648.


The successful use of bromide (Br-) as a conservative tracer for hydrological tests in wetland systems requires minimal Br- loss due to plant uptake. The uptake of Br- by two wetland plants, cattail (Typha latifolia L.) and reed grass (Phragmites australis (Cav.) Trin. ex Steud), was investigated in greenhouse flow-through microcosms. Concentrations of Br- and other pertinent constituents in sediment pore water were measured at 2 cm depth increments in the sediment column. The vertical Br- concentration profiles in the sediments clearly revealed Br- uptake by T. latifolia and by P. australis. X-ray spectroscopy studies of bromine in plant samples revealed the accumulation of Br- in root and leaf tissues. Plant transpiration was found to significantly concentrate dissolved species in sediments and was accounted for in the calculations of Br- uptake rates. Michaëlis−Menten kinetics satisfactorily describe Br- uptake by T. latifolia. The uptake of Br- by P. australis, however, showed unique features that could not be described using Michaëlis−Menten kinetics. The addition of chloride (Cl-) effectively inhibited Br- uptake, and the uptake of Cl- and Br- by T. latifolia was shown to follow dual-substrate Michaëlis−Menten kinetics. Results of this study indicate that the use of Br- for tracer experiments in vegetated wetland systems should be evaluated with great caution.