Romanian Biotechnological Letters Vol. , No. x, Copyright © 2017 University of Bucharest Printed in Romania. All rights reserved ORIGINAL PAPER 1 Comparative Study of Cd, Pb, and Ni removal potential by Salvinia natans (L.) All. and Lemna minor L.: Interactions with Growth Parameters Received for publication, May, 23, 2016 Accepted, February, 10, 2017 ZELIHA LEBLEBİCİ 1 *, MUSA KAR 1 AND VESILE YALÇIN 2 1 University of Nevşehir Hacı Bektaş Veli, Faculty of Science and Arts Department of Molecular Biology and Genetics, Nevşehir, Turkey 2 University of Ömer Halisdemir, Institute of Science and Technology, Department of Biology, Niğde, Turkey. *Address for correspondence to: University of Nevşehir Hacı Bektaş Veli, Faculty of Science and Arts Department of Molecular Biology and Genetics, 50300, Nevşehir, Turkey. Tel:+90 0384 2281000 zleblebici@nevsehir.edu.tr Abstract The aim of this study was to identify the biological responses and phytoremediation capability of two aquatic macropyhtes: Salvinia natans and Lemna minor. Lemna and Salvinia species were exposed to different concentrations of Pb, Cd, and Ni for 7 days. The bioconcentration factors (BCF) of heavy metals from water to these two aquatic macropyhtes were estimated and the removal potential of heavy metals was assessed. After 7 days, some biological parameters were measured, including metal accumulations in leaves, photosynthetic pigmentations, Lipid peroxidation activity, and growth rates. For S. natans, the highest Pb accumulation was found in 50 mg l -1 concentration. The amount of chlorophyll a (chl a) in L. minor was reduced to a minimum value of 0.120 mg g -1 with the 8 mg l -1 Cd concentration. The Relative Growth Rate (RGR) values of both plants were negatively associated with metal treatment. The levels of Malondialdehyde (MDA) in S. natans increased to a maximum value of 7.174 nmol/g with 50 mg l -1 at Pb concentration-dependent and time-depended action. S. natans was a more effective Pb and Ni accumulator than L. minor, but L. minor was a more effective Cd accumulator than S. natans. Our findings might be useful for the phytoremediation of water polluted with heavy metals. Keywords: Heavy metal, Bioconcentration factor, Salvinia natans, Lemna minor, lipid peroxidation. 1. Introduction There are inadequate fresh water resources throughout the world. Fresh water reservoirs and wetlands are under a heavy metal pollution threat from municipal, industrial waste, agricultural, mining, and urban activity. The presence of heavy metals in fresh water resources causes several serious health disorders in plants, animals, and people [1]. Because of water shortages, scientists have focused on the management of fresh water waste, water purification, and re-use [2]. There are several methods for removing heavy metals from water, including chemical precipitation, membrane filtration, electrolysis, reverses osmosis, and adsorption. As the most versatile method, reverse osmosis is most commonly used, but these methods demonstrate different levels of efficiency to different metal removal. Moreover, if the metal contaminated water volume is high, the process of decontamination becomes a very expensive operation. The primary processes by which heavy metals are removed from aquatic environments are physical, biological, and biochemical, and the removed metals will be held in water, biota, and suspended solids. The domination of one of them will depend on the composition of the system, pH, redox condition, and pollutant nature [3]. Phytoremediation is the preferred method for cleaning up contaminated areas because of its high efficiency and low pricing. Despite these advantages, few plant species are known to