ORIGINAL PAPER Cadmium stress-induced oxidative stress and role of nitric oxide in rice (Oryza sativa L.) Piyalee Panda • Shwetosmita Nath • Th. Thorny Chanu • Gauri Dutta Sharma • Sanjib Kumar Panda Received: 8 July 2010 / Revised: 12 December 2010 / Accepted: 3 January 2011 / Published online: 21 January 2011 Ó Franciszek Go ´rski Institute of Plant Physiology, Polish Academy of Sciences, Krako ´w 2011 Abstract Cadmium (Cd) is a potential environmental phytotoxicant. The generation of reactive oxygen species (ROS) due to Cd stress is responsible for the induction of oxidative stress in plants. On the other hand, SNP, a NO donor is known to have effect on Cd-induced oxidative stress in plants. We evaluated the effect of NO on the regulation of Cd stress in the rice (Oryza sativa L.) variety MSE-9. Cd treatment was given in the form of 50, 100 and 200 lM, whereas for interaction study, 100 lM of Cd and 100 lM of SNP were used. The result showed that Cd-induced oxidative stress in MSE-9 by generating ROS. However, when SNP was given with Cd stress, it was seen that SNP treatment regulated the stress metabolism in rice seedlings under Cd toxicity by generating NO. It can be said that the SNP in combination with Cd treatment might possess the way to protect rice seedlings under Cd stress. Keywords Cd Á NO Á SNP Á ROS Á Rice Abbreviations Cd Cadmium NO Nitric oxide SNP Sodium nitroprusside ROS Reactive oxygen species APX Ascorbate peroxidase CAT Catalase GR Glutathione reductase POX Guaiacol peroxidase SOD Superoxide dismutase DTNB Dithionitrobenzoic acid h Hour TBA Thiobarbituric acid TCA Trichloroacetic acid GSH Glutathione ASC Ascorbate Introduction Cadmium (Cd) is a potential environmental phytotoxicant which exists with high water solubility. The main sources of its pollution on agricultural soils are the use of phos- phate fertilizers, dispersal of sewage sludge, mining and atmospheric deposition of industrial emission (Pinto et al. 2004; Kuriakose Saritha and Prasad 2008). In living organisms, Cd accumulation results into cytotoxic, muta- genic and carcinogenic effect (Kuriakose Saritha and Prasad 2008). In plants, Cd is known to cause physio- logical and morphological effects such as stunted growth, chlorosis and decreased reproducibility. Leaf chlorosis, leaf and root necrosis, general decrease in growth are the main symptoms of Cd toxicity in plants (Hernandez and Cooke 1997). Cd interacts with proteins and nucleic acids, as a result affects enzyme activities and causes alteration in membrane permeability (Sanita di Toppi and Gabbrielli 1999) leading to the loss of membrane function (Khan et al. 2007). At the cellular level, the possible underlying mechanisms may be the bindings of Cd to sulfhydryl and carbonyl groups or the replacement of essential cofactors Communicated by G. Bartosz. P. Panda Á S. Nath Á Th. T. Chanu Á G. D. Sharma Á S. K. Panda (&) Department of Life Science and Bioinformatics, Plant Biochemistry and Molecular Biology Laboratory, School of Life Sciences, Assam (Central) University, Silchar 788 011, India e-mail: drskpanda@gmail.com 123 Acta Physiol Plant (2011) 33:1737–1747 DOI 10.1007/s11738-011-0710-3