Ocimum basilicum L. seedlings were exposed to diff erent concentrations of Cr (0-8 mg L-1 of Cr3+) to evaluate the cellular localisation of chromium, plant accumulating capacity, and potential cellular defence mechanisms against Cr stress. | R. BISHEHKOLAEI, H. FAHIMI, S. SAADATMAND, T. NEJADSATTARI, M. LAHOUTI, F. T. YAZDI Research Article Turk J Bot 35 (2011) 261-268 © TÜBİTAK doi: Ultrastructural localisation of chromium in Ocimum basilicum Roya BISHEHKOLAEI1,*, Hamid FAHIMI1, Sara SAADATMAND1, Taher NEJADSATTARI1, 2 3 Mehrdad LAHOUTI , Forouzan Tabatabaei YAZDI 1 Department of Biology, Science and Research Branch, Islamic Azad University, Tehran - IRAN 2 Department of Biology, Faculty of Science, Ferdowsi University of Mashhad, Mashhad - IRAN 3 Department of Animal Science, Faculty of Agriculture, Ferdowsi University of Mashhad, Mashhad - IRAN Received: Accepted: Abstract: Ocimum basilicum L. seedlings were exposed to different concentrations of Cr (0-8 mg L-1 of Cr3+) to evaluate the cellular localisation of chromium, plant accumulating capacity, and potential cellular defence mechanisms against Cr stress. Dried plant tissues (roots and shoots) were exposed to X-ray microanalysis for element determination (including Cr, Cu, Zn, Co, Ni, and Mo). Results showed that the highest amount of Cr had accumulated in the roots of the plants treated with 8 mg L-1 of Cr3+, while less Cr was transported to the shoots. TEM micrographs of Ocimum basilicum root cortex cells exposed to 4, 6, and 8 mg L-1 of Cr3+ revealed dense granular metal deposits in the periplasmic zone along the cell walls; such deposits were not observed in leaf mesophyll cells. Root cortical cells of the control seedlings grown in the absence of Cr3+ exposures were void of such granular metal deposits. While Cr was the predominant element, lower amounts of Cu, Zn, Co, Ni, and Mo were also detected in the chromium bearing deposits analysed by X-ray microanalysis. Formation of Cr bearing deposits in the root cells of Ocimum basilicum may have the effect of maintaining relatively low cytoplasmic concentration of the element and possibly reduce the toxic effects of chromium on cellular .
