Allium cepa var. agrogarum L. seedlings grown in nutrient solution were subjected to increasing concentrations of Cd2+ (0, 1, 10, 100 μM). Variation in tolerance to cadmium toxicity was studied based on chromosome aberrations, nucleoli structure and reconstruction of root tip cells, Cd accumulation and mineral metabolism, lipid peroxidation, and changes in the antioxidative defense system (SOD, CAT, POD) in leaves and roots of the seedlings. Cd induced chromosome aberrations including C-mitoses, chromosome bridges, chromosome fragments and chromosome stickiness. Cd induced the production of some particles of argyrophilic proteins scattered in the nuclei and even extruded from the nucleoli into the cytoplasm after a high Cd concentration or prolonged Cd stress, and nucleolar reconstruction was inhibited. In Cd2+-treated Allium cepa var. agrogarum plants the metal was largely restricted to the roots; very little of it was transported to aerial parts. Adding Cd2+ to the nutrient solution affected mineral metabolism. For example, at 100 μM Cd it reduced the levels of Mn, Cu and Zn in roots, bulbs and leaves. Malondialdehyde content in roots and leaves increased with treatment time and increased concentration of Cd. Antioxidant enzymes appear to play a key role in resistance to Cd under stress conditions.
AMENÓS M, CORRALES I, POSCHENRIEDER C, ILLÉŠ P, BALUŠKA F, and BARCELÓ J. 2009. Different effects of aluminum on the actin cytoskeleton and Brefeldin A-sensitive vesicle recycling in root apex cells of two maize varieties differing in root elongation rate and aluminum tolerance. Plant Cell Physiology 50: 528-540.
AMMAR WB, NOUAIRI I, ZARROUK M, and JEMAL F. 2007. Cadmium stress induces changes in the lipid composition and biosynthesis in tomato (Lycopersicon esculentum Mill.) leaves. Journal of Plant Growth Regulation 53: 75-85.
BAKER AJM, MCGRATH SP, SIDOLI CMD, and REEVES RD. 1994. The possibility of in situ heavy metal decontamination of polluted soils using crops of metal-accumulating plants. Resources, Conservation and Recycling 11: 41-49.
BEAUCHAMP C, and FRIDOVICH I. 1971. Superoxide dismutase: improved assays and an assay applicable to acrylamide gels. Annual Biochemistry 44: 276-287.
BEERS RF, and SIZER IW. 1952. Colorimetric method for estimation of catalase. Journal of Biological Chemistry 195: 133-139.
BENAVIDES M, GALLEGO MS, and TOMARO ML. 2005. Cadmium toxicity in plants. Brazilian Journal of Plant Physiology 17: 21-34.
BOOMINATHAN R, and DORAN PM. 2003. Cadmium tolerance and antioxidative defenses in hairy roots of the cadmium hyperaccumulator Thlaspi caerulescens. Biotechnology and Bioengineering 83: 158-167.
BROADLEY MR, WILLEY NJ, WILKINS JC, BAKER AJM, MEAD A, and WHITE PJ. 2001. Phylogenetic variation in heavy metal accumulation in angiosperms. New Phytologist 152: 9-27.
BURZYŃSKI M, and ZUREK A. 2007. Effects of copper and cadmium on photosynthesis in cucumber cotyledons. Photosynthetica 45: 239-244.
CHEN F, WANG F, SUN HY, CAI Y, MAO WH, ZHANG GP, VINCZE E, and WU FB. 2010. Genotype-dependent effect of exogenous nitric oxide on Cd-induced changes in antioxidative metabolism, ultrastructure, and photosynthetic performance in barley seedlings (Hordeum vulgare). Journal of Plant Growth Regulation 29: 394-408.
CHO UH, and SEO NH. 2005. Oxidative stress in Arabidopsis thaliana exposed to cadmium is due to hydrogen peroxide accumulation. Plant Science 168: 113-120.
DUAN XC. 2003. The study on the trace elements in the free growing vine of harvested tuber dioscoreas. Journal of Guangxi Normal University 21: 122-123.
EKMEKÇI Y, TANYOLAÇ D, and AYHAN B. 2008. Effects of cadmium on antioxidant enzyme and photosynthetic activities in leaves of two maize cultivars. Journal of Plant Physiology 165: 600-611.
FOJTA M, FOJTOVA M, HAVRAN L, PIVONKOVA H, DORCAK V, and SESTAKOVA I. 2006. Electrochemical monitoring of phytochelatin accumulation in Nicotiana tabacum cells exposed to sub-cytotoxic and cytotoxic levels of cadmium. Analytica Chimica Acta 558: 171-178.
JIANG WS, LIU DH, and XU P. 2009. Cd-induced system of defence in the garlic root meristematic cells. Biologia Plantarum 53: 369-372.
KATO M, and SHIMIZU S. 1987. Chlorophyll metabolism in higher plants. VII. Chlorophyll degradation in senescing tobacco leaves: phenolic-dependent peroxidative degradation. Canadian Journal of Botany 65: 729-735.
LI HS. 2000. Principles and Techniques of Plant Physiological Biochemical Experiment, 260-263. Higher Education Press, Beijing.
LI LJ, LIU XM, GUO YP, and MA EB. 2005. Activity of the enzymes of the antioxidative system in cadmium-treated Oxya chinensis (Orthoptera Acridoidae). Environmental Toxicology and Pharmacology 20: 412-416.
LIU D, JIANG W, and GAO X. 2003/2004. Effects of cadmium on root growth, cell division and nucleoli in root tips of garlic. Plant Biology 47: 79-83.
LIU DH, KOTTKE I, and ADAM D. 2007. Localization of cadmium in the root cells of Allium cepa by energy dispersive X-ray analysis. Biologia Plantarum 51(2): 363-366.
LIU DH, ZOU JH, WANG M, and JIANG WS. 2008. Hexavalent chromium uptake and its effects on mineral uptake, antioxidant defence system and photosynthesis in Amaranthus viridis L. Bioresource Technology 99: 2628-2636.
LIU DH, XU P, MENG QM, ZOU J, GU JG, and JIANG WS. 2009. Pb/Cu effects on the organization of microtubule cytoskeleton in interphase and mitotic cells of Allium sativum L. Plant Cell Reports 28: 695-702.
MA JF, UENO D, ZHAO FJ, and MCGRATH SP. 2005. Subcellular localization of Cd and Zn in the leaves of a Cd-hyperaccumulating ecotype of Thlaspi caerulescens. Planta 220: 731-736.
MARKOVSKA YK, GORINOVA NI, NEDKOVSKA MP, and MTTEVA KM. 2009. Cadmium-induced oxidative damage and antioxidant responses in Brassica juncea plants. Biologia Plantarum 53(1): 151-154.
MOBIN M, and KHAN NA. 2007. Photosynthetic activity, pigment composition and antioxidative response of two mustard (Brassica juncea) cultivars differing in photosynthetic capacity subjected to cadmium stress. Journal of Plant Physiology 164: 601-610.
MUŃOZ N, GONZÁLEZ C, MOLINA A, ZIRULNIK F, and LUNA CM. 2008. Cadmium-induced early changes in O2 o-, H2O2 and antioxidative enzymes in soybean (Glycine max L.) leaves. Journal of Plant Growth Regulation 56: 159-166.
NOUAIRI I, BEN AMMAR W, BEN YOUSSEF N, DOUJA DAOUD BM, GHORBEL MH, and ZARROUK M. 2006. Comparative study of cadmium effects on membrane lipid composition of Brassica juncea and Brassica napus leaves. Plant Science 170: 511-519.
PRASAD MNV. 1995. Cadmium toxicity and tolerance in vascular plants. Environmental and Experimental Botany 35: 525-545.
QADIR S, QURESHI MI, JAVED S, and ABDIN MZ. 2004. Genotypic variation in phytoremediation potential of Brassica juncea cultivars exposed to Cd stress. Plant Science 167: 1171-1181.
QIN R, JIAO YQ, ZHANG SS, JIANG WS, and LIU DH. 2010. Effects of aluminum on nucleoli in root tip cells and selected physiological and biochemical characters in Allium cepa var. agrogarum L. BMC Plant Biology 225(10): 1471-1482.
RADOTIC K, DUCIC T, and MUTAVDZIC D. 2000. Changes in peroxidase activity and sisozymes in spruce needles after exposure to different concentrations of cadmium. Environmental and Experimental Botany 44: 105-113.
ROMERO-PUERTAS MC, RODRIGUEZ-SERRANO M, CORPAS FJ, GOMEZ M, DEL RIO LA, and SANDALIO LM. 2004. Cadmium-induced subcellular accumulation of O2- and H2O2 in pea leaves. Plant, Cell and Environment 27: 1122-1134.
SHAFI M, BAKHT J, HASSAN MJ, RAZIUDDIN M, and ZHANG GP. 2009. Effect of cadmium and salinity stresses on growth and antioxidant enzyme activities of wheat (Triticum aestivum L.). Bulletin of Environmental Contamination and Toxicology 82: 772-776.
SHELDON S, SPEERS WC, and LENHMAN JM. 1981. Nucleolar persistence in embryonal carcinoma cells. Experimental Cell Research 132: 185-192.
SHI GR, CAI QS, LIU CF, and WU L. 2010. Silicon alleviates cadmium toxicity in peanut plants in relation to cadmium distribution and stimulation of antioxidative enzymes. Journal of Plant Growth Regulation 61: 45-52.
SKÓRZYŃSKA-POLIT E, and KRUPA Z. 2006. Lipid peroxidation in cadmium-treated Phaseolus coccineus plants. Archives of Environmental Contamination and Toxicology 50: 482-487.
STEPHAN UW, and PROCHAZKA Z. 1989. Physiological disorders of the nicotianamine-auxotroph tomato mutant chloronerva at different levels of iron nutrition. I. Growth characteristics and physiological abnormalities as related to iron and nicotianamine supply. Acta Botanica Neerlandica 38: 147-153.
TIRYAKIOGLU M, EKER S, OZKUTLU F, HUSTED S, and CAKMAK I. 2006. Antioxidant defense system and cadmium uptake in barley genotypes differing in cadmium tolerance. Journal of Trace Elements in Medicine & Biology 20: 181-189.
VAN DER MAEM AA, MASTROBATTISTA E, OOSTING RS, HENNINK WE, KONING GA, and CROMMELIN DJA. 2006. The nuclear pore complex: the gateway to successful non-viral gene delivery. Pharmaceutical Research 23: 447-459.
VERMA K, SHEKHAWAT GS, SHARMA A, MEHTA SK, and SHARMA V. 2008. Cadmium induced oxidative stress and changes in soluble and ionically bound cell wall peroxidase activities in roots of seedling and 3-4 leaf stage plants of Brassica juncea (L.) czern. Plant Cell Reports 27: 1261-1269.
VOSTRIKOVA TV, and BUTORINA AK. 2006. Cytogenetic responses of birch to stress factors. Biological Bulletin 33: 185-190.
WAHID A, and GHANI A. 2008. Varietal differences in mung bean (Vigna radiata) for growth, yield, toxicity symptoms and cadmium accumulation. Annals of Applied Biology 152: 59-69
WANG M, ZOU JH, DUAN XC, WS, and LIU DH. 2007. Cadmium accumulation and its effects on metal uptake in maize (Zea mays L.). Bioresource Technology 98: 82-88.
XU P, ZOU J, MENG QM, ZOU JH, JIANG WS, and LIU DH. 2008. Effects of Cd2+ on seedling growth of garlic (Allium sativum L.) and selected physiological and biochemical characters. Bioresource Technology 99: 6372-6378.
ZHANG SS, ZHANG HM, QIN R, JIANG WS, and LIU DH. 2009. Cadmium induction of lipid peroxidation and effects on root tip cells and antioxidant enzyme activities in Vicia faba L. Ecotoxicology 18: 814-823.
ZOU J, XU P, LU X, JIANG WS, and LIU DH. 2008. Accumulation of cadmium in three sunflower (Helianthus annuus L.) cultivars. Pakistan Journal of Botany 40: 759-765.
ZOU JH, YU KL, ZHANG ZG, JIANG WS, and LIU DH. 2009. Antioxidant response system and chlorophyll fluorescence in chromium (vi)-treated Zea mays L. Seedlings. Acta Biologica Cracoviensia Series Botanica 51: 23-33.