Despite the rich biodiversity of flora in the tropical region, the ability of tropical plants to perform economical and high-efficiency phytoremediation of heavy-metal soil contamination has been poorly investigated. This paper describes pot studies conducted to identify and exploit the heavy metal tolerance of 16 tropical plant species. Greenhouse studies were conducted with varying amounts of cadmium (Cd) and zinc (Zn) spiked into a standard amount of soil grown with the test plants. The physiological response of the plants was determined by chlorophyll fluorescence Fv/Fm ratios. Lantana camara, Spathiphyllum cannaeflium, Nerium oleader, and Hibiscus rosa-sinensis exhibited high Cd tolerance as their Fv/Fm ratios showed that they were not under physiological stress at 300 ppm Cd at day 12. From the Zn experiment, only Belamchanda chinensis had chlorophyll fluorescence Fv/Fm ratios of 0.6 at 4,000 ppm Zn, although no sign of phytotoxicity was evident at that concentration. Hymenocallis littoralis, Hymenocallis littoralis 'Variegata', Dracaena reflexa 'Song of India', and Dracaena reflexa 'Aurea Variegata' all displayed unhealthy levels of Fv/Fm ratios with Zn exposure. The results were used to compare the plants' heavy metal tolerance and phytoextraction potential. Paper at http://www.srcosmos.gr/srcosmos/generic_pagelet.aspx?pagelet=Article% 20summary&pub_id=9839