Salicylic acid alleviates NaCl-induced changes in the metabolism of Matricaria chamomilla plants Jozef Kova´cˇik Æ Borˇivoj Klejdus Æ Josef Hedbavny Æ Martin Bacˇkor Accepted: 7 April 2009 / Published online: 21 April 2009 Ó Springer Science+Business Media, LLC 2009 Abstract Influence of 100 mM NaCl and 50 lM salicylic acid (SA) and their combination on the metabolism of chamomile (Matricaria chamomilla) during 7 days was studied. NaCl reduced growth and selected physiological parameters and SA in combined treatment (NaCl ? SA) reversed majority of these symptoms. Application of SA reduced NaCl-induced increase of Na ? in the rosettes, but not in the roots. Accumulation of total amino acids was stimulated in NaCl-treated roots, especially due to excep- tional increase of proline (4.4-fold). Among phenolic acids, accumulation of protocatechuic acid was the most enhanced in NaCl-exposed leaf rosettes (ca. 3-fold) while chlorogenic and caffeic acids in the roots (2.4- and 2.8-fold, respec- tively). Total soluble phenols increased after NaCl and SA treatments, but root lignin content was not affected. Activity of phenylalanine ammonia-lyase and shikimate dehydroge- nase increased in response to NaCl, but cinnamyl alcohol dehydrogenase was not affected and polyphenol oxidase decreased. Stress parameters were elevated by NaCl treat- ment (superoxide radical and malondialdehyde content, activities of catalase, ascorbate- and guaiacol-peroxidase) and substantially prevented by SA, while accumulation of hydrogen peroxide decreased. Overall, SA showed strong beneficial properties against NaCl-induced negative symp- toms. Protective effect of SA was the most visible at the level of guaiacol-peroxidase and through amelioration of stress parameters and mineral nutrient contents. Keywords Chamomile (Matricaria chamomilla) Á Mineral nutrition Á Oxidative stress Á Phenols Á Salicylate Abbreviations CAD Cinnamyl alcohol dehydrogenase DW Dry weight MDA Malondialdehyde PAL Phenylalanine ammonia-lyase PPO Polyphenol oxidase ROS Reactive oxygen species SKDH Shikimate dehydrogenase Introduction Environmental stress, irrespective of its nature, enhances reactive oxygen species (ROS) formation, thereby acti- vating both protective mechanism and cellular damages. Soil salinity is important abiotic stress limiting productivity and geographical distribution of plants. Excess of NaCl has adverse effect on uptake of water and nutrients, photo- synthesis and growth, and also stimulates ROS overpro- duction (Stevens et al. 2006; Roussos et al. 2007; Sawada et al. 2008). On the other hand, specific level of ROS are considered to be involved in signalling cascades leading to increased antioxidative protection (Stevens et al. 2006; Vital et al. 2008). In the case of salinity, superoxide radical was found to play a crucial role in signalling the NaCl- induced upregulation of antioxidative enzyme activities and stress tolerance (Vital et al. 2008). Besides enhancement of antioxidative enzymes activity, plants also synthesise low molecular compounds, such as J. Kova´cˇik (&) Á M. Bacˇkor Department of Botany, Institute of Biology and Ecology, Faculty of Science, P. J. S ˇ afa´rik University, Ma´nesova 23, 041 67 Kosice, Slovak Republic e-mail: jozkovacik@yahoo.com B. Klejdus Á J. Hedbavny Department of Chemistry and Biochemistry, Mendel University of Agriculture and Forestry Brno, Zemeˇdeˇlska´ 1 613 00 Brno, Czech Republic 123 Ecotoxicology (2009) 18:544–554 DOI 10.1007/s10646-009-0312-7