Environmental Monitoring and Assessment (2006) 121: 233–244 DOI: 10.1007/s10661-005-9117-1 c  Springer 2006 EFFECTS OF COPPER SULFATE AND COPPER NITRATE IN AQUATIC MEDIUM ON THE RESTORATION POTENTIAL AND ACCUMULATION OF COPPER IN STEM CUTTINGS OF THE TERRESTRIAL MEDICINAL PLANT, PORTULACA OLERACEA LINN S. MOHANAPRIYA 1 , P. SENTHILKUMAR 1 , S. SIVAKUMAR 2,∗ , M. DINESHKUMAR 1 and C. V. SUBBHURAAM 1 1 Department of Environmental Sciences, Bharathiar University, Coimbatore 641 046; India; 2 Institute for Ocean Management, Anna University, Chennai – 600 025, India ( ∗ author for correspondence, e-mail: ssivaphd@yahoo.com) (Received 13 June 2005; accepted 4 November 2005) Abstract. The stem cuttings of the terrestrial, ornamental plant, Portulaca oleracea, grew well in distilled water by producing adventitious roots and leaves. However, when exposed to various concentrations of sulfate and nitrate salts of copper resulted in a suppression of root growth, increase in initiation time of roots and sprouts and decay of stem cuttings from the cut open end, decrease in number of leaves with an increase in concentration of copper in the growth medium. Accumulation of copper increased with increasing concentrations of both copper sulfate and copper nitrate. However, copper accumulation was greater in copper nitrate than in copper sulfate treatment. Hence, copper in the presence of nitrate is more toxic than in the presence of sulfate. The accumulation factors in all treatment concentrations were greater than 1, hence P. oleracea is a copper accumulator. Keywords: accumulation, copper, hydroponic culture, phytoextraction, Portulaca oleracea 1. Introduction Copper has been observed in many plant species to cause reduction in the lev- els of photosynthetic pigments in leaves, including chlorophylls a and b and ac- cessory pigments such as carotenoids (Van Assche and Clijsters, 1990). Copper has also been reported to directly affect the photosynthetic apparatus by interact- ing with several enzymes involved in chlorophyll biosynthesis (De Fillipis and Pallaghy, 1994). The Phytotoxic effect of Cu has been reported in Pinus pinea L. Pinus Ait, Fraxinus angustifolia Vahl. (Arduini et al., 1996), Iris pseudacorus (Barbolani et al., 1986), Azolla filiculoides (Sela et al., 1988), Zea mays (Morel et al., 1986), Polygonus cuspidatum (Sela et al., 1988; Nizhizono et al., 1989), Avicennia marina (MacFarlane and Burchett, 2001), Poa annua L., Dactylis glom- erata L. Senecis vulgaris L. Mypochoeris radicata L., and Andryala integrifolia L. (Brun et al., 2002). These and the usage of Cu as fungicide and its use in the control of algae and vascular plants in aquatic bodies reiterate its toxic nature. Several lab tests have been recommended to assess the toxicity of sub- stances/elements on vascular plants with several endpoints of measurement.