title: Accumulation, detoxification, and genotoxicity of heavy metals in Indian mustard (Brassica juncea L.).
abstract: Plants of Indian mustard (Brassica juncea L.) were exposed to different concentrations (15, 30, 60, 120 microM) of (Cd, Cr, Cu, Pb) for 28 and 56 d for accumulation and detoxification studies. Metal accumulation in roots and shoots were analyzed and it was observed that roots accumulated a significant amount of Cd (1980 microg g(-1) dry weight), Cr (1540 microg g(-1) dry weight), Cu (1995 microg g(-1) dry weight), and Pb (2040 microg g(-1) dry weight) after 56 d of exposure, though in shoot this was 1110, 618, 795, and 409 microg g(-1) dry weight of Cd, Cr, Cu, and Pb, respectively. In order to assess detoxification mechanisms, non-protein thiols (NP-SH), glutathione (GSH) and phytochelatins (PCs) were analyzed in plants. An increase in the quantity of NP-SH (9.55), GSH (8.30), and PCs (1.25) micromol g(-1) FW were found at 15 microM of Cd, however, a gradual decline in quantity was observed from 15 microM of Cd onwards, after 56 d of exposure. For genotoxicity in plants, cytogenetic end-points such as mitotic index (MI), micronucleus formation (MN), mitotic aberrations (MA) and chromosome aberrations (CA) were examined in root meristem cells of B. juncea. Exposure of Cd revealed a significant (P < 0.05) inhibition of MI, induction of MA, CA, and MN in the root tips for 24 h. However, cells examined at 24 h post-exposure showed concentration-wise recovery in all the endpoints. The data revealed that Indian mustard could be used as a potential accumulator of Cd, Cr, Cu, and Pb due to a good tolerance mechanisms provided by combined/concerted action of NP-SH, GSH, and PCs. Also, exposure of Cd can cause genotoxic effects in B. juncea L. through chromosomal mutations, MA, and MN formation.
authors.affiliation: Biotechnology Division, Institute of Himalayan Bioresource Technology, Palampur, (H.P.), India. seth_bhu@yahoo.co.in
authors.forename: C S
authors.initials: CS
authors.lastname: Seth
authors.forename: V
authors.initials: V
authors.lastname: Misra
authors.forename: L K S
authors.initials: LK
authors.lastname: Chauhan
mesh_terms: D001673:Biodegradation, Environmental; D001692:Biological Transport / Q000187:drug effects; D002104:Cadmium / Q000378:metabolism / Q000633:toxicity; D002869:Chromosome Aberrations / Q000187:drug effects*; D005978:Glutathione / Q000187:drug effects / Q000378:metabolism*; D018519:Meristem / Q000187:drug effects / Q000378:metabolism; D019216:Metals, Heavy / Q000378:metabolism* / Q000633:toxicity; D048629:Micronuclei, Chromosome-Defective / Q000187:drug effects; D008940:Mitotic Index; D009149:Mustard Plant / Q000187:drug effects / Q000378:metabolism*; D009152:Mutagenicity Tests; D054811:Phytochelatins / Q000187:drug effects / Q000378:metabolism*; D018517:Plant Roots / Q000187:drug effects / Q000378:metabolism; D018520:Plant Shoots / Q000187:drug effects / Q000378:metabolism; D012639:Seeds / Q000187:drug effects / Q000378:metabolism; D013438:Sulfhydryl Compounds / Q000378:metabolism*; D013997:Time Factors
chemical_list: D019216:Metals, Heavy; D013438:Sulfhydryl Compounds; D002104:Cadmium; D054811:Phytochelatins; D005978:Glutathione