87 Philippine Journal of Science 142 (1): 87-96, June 2013 ISSN 0031 - 7683 Date Received: ?? Feb 20?? Key Words: alleviate, arbuscular mycorrhizal fungi, copper, Desmodium cinereum, phytoremediation, toxicity *Corresponding author: nelly_aggangan@yahoo.com 1 Department of Crop Protection, College of Agriculture, Central Luzon State University, Science City of Muñoz, Nueva Ecija 2 Forest Biological Sciences, College of Forestry and Natural Resources, University of the Philippines, Los Baños, College, Laguna 3 National Institute of Molecular Biology and Biotechnology, University of the Philippines Los Baños, College, Laguna Joden M. Adiova 1 , Nelson M. Pampolina 2 and Nelly S. Aggangan 3* The effect of arbuscular mycorrhizal fungi (AMF) inoculation on copper (Cu) uptake and toxicity of Desmodium cinereum (Kunth) D.C. was studied. This legume produces large amount of biomass that can serve as buffer in areas with high concentration of Cu. Pre-germinated seeds of D. cinereum inoculated and non-inoculated with AMF were grown in sand-soil mixture treated with increasing Cu concentration (0, 400, 800, 1200, 1600ppm Cu). Increasing Cu concentration gave a corresponding reduction on height, diameter, leaf area, and biomass of the plants. Root growth and nodule formation at 1200 and 1600ppm Cu level were inhibited (p<0.05 and p<0.01, respectively). Mycorrhizal inoculation increased plant height, biomass, and stem diameter at lower Cu level. Inoculation enhanced nodulation and also improved phosphorus concentration in the leaves, stem and roots at 0 and 400ppm Cu level. Increasing Cu concentration resulted to a greater Cu accumulation in the roots while Cu concentration on stem and leaves remained at a normal level. Inoculation with AMF increased Cu uptake of roots and stem at 800, 1200, and 1600ppm Cu levels. The ability of mycorrhizal fungi to improve Cu uptake, increase plant growth, increase phosphorus uptake, and promote growth of other beneficial microorganisms such as nitrogen fixing bacteria (as exemplified by the nodulation in the roots) for D. cinereum, make it an ideal tool for phytoremediation of Cu contaminated sites. Effect of Arbuscular Mycorrhizal Fungi Inoculation on Growth and Cu Uptake and Toxicity of Desmodium cinereum (Kunth) D.C. INTRODUCTION Copper (Cu) is the third most used commercial metal because of its availability and attractive properties (Fjällborg and Dave 2003). Likewise, it is also one of the most common and problematic heavy metal (HM) soil pollutants. Since Cu can be released both naturally and through human activity, it is very common in the environment. It is often found near mines, industrial settings, landfills and waste disposals causing problems to humans. Increasing widespread pollution has caused vast areas of land to become unproductive and hazardous for both wildlife and human population. Utilization of these lands for agricultural and development purposes require a safe and efficient decontamination. Reclamation of lands contaminated with heavy metals (HMs), however, is a very