Hindawi Publishing Corporation he Scientiic World Journal Volume 2013, Article ID 176295, 10 pages http://dx.doi.org/10.1155/2013/176295 Research Article Antioxidant Capacity as a Marker for Assessing the In Vitro Performance of the Endangered Cistus heterophyllus Antonio López-Orenes, Antonio F. Ros-Marín, María A. Ferrer, and Antonio A. Calderón Departamento de Ciencia y Tecnolog´ ıa Agraria, Universidad Polit´ ecnica de Cartagena, Paseo Alfonso XIII 48, 30203 Cartagena, Spain Correspondence should be addressed to Antonio A. Calder´ on; antonio.calderon@upct.es Received 27 August 2013; Accepted 7 October 2013 Academic Editors: T. Berberich, V. Hocher, and G. Kocsy Copyright © 2013 Antonio L´ opez-Orenes et al. his is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Cistus heterophyllus subsp. carthaginensis is an endemic and endangered species from the SE Mediterranean coastal region of Spain. Within the framework of the eforts aiming to species conservation, in vitro culture techniques could be of interest. he aim of this study was to evaluate the antioxidant capacity of C. heterophyllus shoot cultures as a possible marker of in vitro performance. he efects of ive diferent basal salt formulations and cytokinin levels on in vitro performance and antioxidant capacity were examined. K + /Na + and Ca 2+ /Na + ratios initially present in culture media greatly afected the antioxidant capacity (the lower the ratios the higher the antioxidant capacity). Increasing concentrations of BA resulted in higher antioxidant capacity. he results obtained point to antioxidant capacity as being a marker of incidence of stress conditions in in vitro cultured C. heterophyllus. A good correlation was found between antioxidant capacity and total soluble phenolics present in Cistus extracts. Catechin was identiied in all the extracts and its levels were found to change parallel to the antioxidant capacity, pointing to a prominent role played by this lavonoid in C. heterophyllus defence against oxidative stress, which in turn afects the in vitro performance of this species. 1. Introduction he genus Cistus comprises around 20 species with a pre- dominantly Mediterranean distribution [1]. Cistaceae species are main components of the shrublands in this area and they are also prominent members of the understory vegetation beneath Mediterranean forests. hese species seem to be essential for the development of some processes taking place in several Mediterranean ecosystems and hence the importance of preserving them ([2] and references herein). Furthermore, many species of this botanical family, if not all of them, have been used since ancient times in folk medicine ([3] and references herein) and as ornamental plants, which encourages the interest for these plants and their conservation. Cistus heterophyllus subsp. carthaginensis is a beautiful endangered plant whose European population is exclusively located in the provinces of Valencia and Murcia, in eastern Spain. Valencia population is reduced to only three spon- taneously grown plants, being the Murcia population com- posed of no more than two dozen pure specimens associated to a sparse Pinus halepensis copse. hese scant populations are severely threatened by several factors including low prop- agation and germination rates, hybridization with C. albidus, deforestation, and soil contamination due to wastes generated from extraction and processing of mineral resources (mainly Pb- and Zn-containing residues). As a result, this species is included in the critically endangered category (CR) of the red list guidelines by the Flora Commission of the Spanish Committee of the International Union for Conservation of Nature (IUCN) [4]. In vitro multiplication techniques have oten been suc- cessfully utilized in propagation of rare and endangered species of plants, including some belonging to the genus Cistus [5], and therefore can contribute to the protection of plant genetic resources. However, the introduction and