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ARS Home » Southeast Area » Gainesville, Florida » Center for Medical, Agricultural and Veterinary Entomology » Chemistry Research » Research » Publications at this Location » Publication #240793
Title: Effects of arsenic on nitrogen metabolism in arsenic hyperaccumulator and non-hyperaccumulator ferns

Author
item SINGH, N - University Of Florida
item MA, L. Q. - University Of Florida
item Vu, Joseph
item RAJ, A. - National Botanical Research Institute - India

Submitted to: Environmental Pollution
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/19/2009
Publication Date: 9/1/2009
Citation: Singh, N., Ma, L., Vu, J.C., Raj, A. 2009. Effects of arsenic on nitrogen metabolism in arsenic hyperaccumulator and non-hyperaccumulator ferns. Environmental Pollution. 157:2300-2305.

Interpretive Summary: Arsenic (As) contamination in soils often leads to groundwater contamination and As toxicity in plants, humans and animals. The fern Pteris vittata, which is extremely efficient in extracting As from soils and translocating it into its above-ground biomass, can be potentially used in the remediation of As-contaminated soils. However, genotypic differences in As-tolerance/accumulation have been found within fern species, and the impacts of As on growth and metabolism on various fern plants are not well understood. In this study, USDA-ARS, University of Florida and Indian Botanical Research Institute scientists investigated the effects of As, added to the root growth medium, on biomass and nitrate metabolism in two contrasting fern species: Pteris vittata, an As hyperaccumulating fern, and Pteris ensiformis, an As non-hyperaccumulating fern. The results show that As had adverse effects on fern biomass and nitrate-metabolizing proteins, and such impacts were more evident in P. ensiformis than in P. vittata, indicating the difference in sensitivity and tolerance of the two ferns to As. The adverse effects on nitrate-metabolizing proteins were also accompanied by similar decreases in plant nitrate concentrations, which were likely the result of reduced nitrate uptake and translocation in fern tissues.

Technical Abstract: This study investigated the effects of arsenic on the in vitro activities of the enzymes (nitrate reductase and nitrite reductase) involved in nitrate metabolism in the roots, rhizomes, and fronds of two four-month old fern plants, Pteris vittata, an arsenic-hyperaccumulator, and Pteris ensiformis, an arsenic non-hyperaccumulator. The arsenic treatments (0, 150, and 300 µM as sodium arsenate) in hydroponics had adverse effects on the root and frond dry weights, and this effect was more evident in P. ensiformis than in P. vittata. Nitrate reductase and nitrite reductase activities of arsenate-treated plants were reduced more in P. ensiformis than in P. vittata. This effect was accompanied by similar decreases in tissue nitrate concentrations. Therefore, this decrease is interpreted as being indirect, i.e., the consequence of the reduced nitrate uptake and translocation in the plants. The study shows the difference in the tolerance level of the two Pteris species with varying sensitivity to arsenic.