UPTAKE, TRANSLOCATION AND ACTIVITY OF PARAQUAT ON MIKANIA-MICRANTHA HBK GROWN IN DIFFERENT LIGHT CONDITIONS

A glasshouse study was conducted to determine the effect of shade on t he uptake, translocation and activity of paraquat on Mikania micrantha H.B.K. The uptake, translocation and activity of paraquat were signif icantly enhanced at low light intensity. Placement of plants grown ini tially under 75% shade and transferred to 0% shade resulted in signifi cantly higher uptake of paraquat than those initially grown under 0% a nd 50% shade. The uptake and activity of paraquat were also significan tly increased when treated plants were placed in darkness. The rate of efflux of paraquat from leaf segments of plants grown in high light i ntensity was considerably slower than from plants grown in low light i ntensity.