Impact of arsenic on uptake and bio-accumulation of antimony by arsenic hyperaccumulator Pteris vittata.

Individual uptake of As and Sb species in Pteris vittata have been investigated, but little information is available how uptake is affected if both metalloids are simultaneously present in different amounts. We investigated the uptake of antimony and its speciation in Pteris vittata cultivated in quartz substrate with, versus without, co-contamination with arsenic and a contaminated soil for 7 weeks. Applying HPLC-ICP-MS technique Sb(V), Sb(III), As(III), and As(V) could be identified as main species in aqueous extracts of roots and fronds with up to 230 mg kg(-1) of total Sb in the roots. Adding increasing amounts of As to the quartz substrate resulted in increasing uptake of Sb. In contrast to As, which is readily transferred to the fronds, Sb is primarily accumulated in the roots with Sb(V) being the dominant species (>90% of Sb). The addition of As doesn't result in enhanced translocation of Sb into the fronds.

Course of uptake of weed-borne nitrogen by maize, tested with (15)n.

Abstract The course of uptake of weed-borne nitrogen by maize was tested with (15)N in a pot experiment with silty loam after common growth of maize and Chenopodium album L., and mulching the weed in the 5-leaf stage of maize. Harvests 4,8 and 12 weeks after mulching show that the maize took up 35, 63 and 70% of the weed-borne nitrogen, resp., in consequence of a rapid and almost complete mineralization. The portion of weed-borne nitrogen in total N of the maize was 16% at all harvest dates. The differences in yield between weeded and unweeded maize were not significant neither at 5-leaf stage nor at corn maturity.