Screening Ornamentals for Their Potential as As Accumulator Plants

Arsenic-based pesticides, herbicides and insecticides are used in horticultural operations resulting in soil contamination around greenhouse structures. Phytoremediation and phytostabilization are two techniques for treating arsenic (As) contaminated soil. Several ornamental plant species, Iris (Iris savannarum), switchgrass (Panicum virgatum), Tithonia rotundiflora, Coreopsis lanceolata, sunflower (Helianthus annuus), and marigold (Tagetes erecta), were evaluated for their potential use as accumulator plants. Based on dry weight, tithonia and coreopsis were most sensitive to As. Tithonia had an 85% reduction in dry weight at 0.75 mg As L-1 and coreopsis a 65% reduction at 2.25 mg As L-1 solution concentration. Iris dry weight increased with increasing solution concentrations but As did not accumulate in tissue. At the high As rate, marigold and sunflower had uptake ratios of 7.4 and 16.6, respectively, and translocation factors near one. Both show little effect of As toxicity on dry weights production, therefore, are appealing candidates for phytoremediation and phytostabilization. Switchgrass and iris can be harvested multiple times a year, making them candidates for phytostabilization.