J. Bio. & Env. Sci. 2015 438 | Pilevar et al. RESEARCH PAPER OPEN ACCESS Impact of multi-walled carbon nanotubes on seed germination and seedling growth of Cichorium intybus L. Zarin Taj Pilevar, Homa Mahmoodzadeh * , Ali Eshaghi Department of Biology, Faculty of Science, Mashad Branch, Islamic Azad University, Mashad, Iran Key words: carbon nanotubes, Cichorium intybus, germination indices, Seedling biomass. Article published on January 19, 2015 Abstract A medicinal plant was evaluated for the effect of multi-walled carbon nanotubes (CNTs) using germination and seedling growth of Cichorium intybus L. The experimental treatments included four concentrations of multi- walled carbon nanotubes (10, 50, 100 and 200 ppm ) and control without carbon nanotubes. Results indicated that among the Cichorium intybus germination indices, germination percentage, mean germination time and weighted germination index was not affected by treatments, however phytotoxicity was observed at 10 ppm CNTs , since a significant reduction in RGP,GR and GI was observed. In addition, plumule length, radicle length, seedling fresh and dry weight and vigor index were not affected by carbon nanotubes concentrations, significantly. Seedling fresh weight at 100 ppm concentration of carbon nanotubes was higher than the untreated control. It is concluded that treatment with multi-walled carbon nanotubes reatments have more inhibitory effects on germination indices of Cichorium intybus in comparison to seedling growth phase. *Corresponding Author: Homa Mahmoodzadeh homa_mahmoodzadeh@yahoo.com Journal of Biodiversity and Environmental Sciences (JBES) ISSN: 2220-6663 (Print), 2222-3045 (Online) http://www.innspub.net Vol. 6, No. 1, p. 438-445, 2015