Cadmium fate and tolerance in rice cultivars
Tóm tắt
Cadmium (Cd) is present in all soils, usually as a trace constituent, but it can reach higher levels in agricultural soils. Cd can then be absorbed by plants and become a potential risk to human health. Once taken up by a plant, there are mechanisms for heavy metal detoxification in the plant. Here, a cadmium-tolerant and a cadmium-sensitive rice cultivars were grown hydroponically to investigate the effects of cadmium (Cd) applied at low levels on uptake and transport, subcellular distribution and binding forms of Cd in rice plants. Our results showed that increasing the Cd treatment from 1.0 μM to 5.0 μM Cd increased the shoot Cd content by 55% in the cadmium-tolerant cultivar, and by 108% in the cadmium-sensitive cultivar. For the cadmium-tolerant cultivar, increasing Cd treatment from 1.0 μM to 5.0 μM increased the root Cd content by 116%, whereas for the cadmium-sensitive cultivar, increasing Cd treatment from 1.0 μM to 5.0 μM increased the root Cd content by 80%. Further, the ratio of Cd accumulation in shoots over roots decreased from 0.19 to 0.14 in the cadmium-tolerant cultivar, while it increased from 0.20 to 0.26 in the cadmium-sensitive cultivar, showing that the transportation ability for Cd was different between the two tested rice cultivars. At the higher Cd level of 5.0 μM, most of the Cd in the plants was localized in cell walls and vacuoles in both cultivars, whereas small portions of Cd were distributed in the cytoplasm, suggesting that the important metabolic and physiological processes were not impaired under Cd stress. Furthermore, the major portions of Cd in the cells were combined with organic acids, proteins and polysaccharide, and were consequently detoxified. The difference in the distribution of cadmium in rice plants resulted in the difference in Cd tolerance between the two rice cultivars used. It can be concluded that the retention of Cd in root cell walls, compartmentation of Cd into vacuoles and the suppressed transportation of Cd from roots to shoots are the most important mechanisms involved in the detoxification of Cd in rice plants.
Tài liệu tham khảo
Adriano D.C. (1986) Trace elements in the terrestrial environment, Springer-Verlag, New York.
Alexander P.D., Alloway B.J., Dourado A.M. (2006) Genotypic variations in the accumulation of Cd, Cu, Pb and Zn exhibited by six commonly grown vegetables, Environ. Pollut. 144, 736–745.
Arao T., Ae N., Sugiyama M., Takahashi M. (2003) Genotypic differences in cadmium uptake and distribution in soybeans, Plant Soil 251, 247–253.
Brune A., Urbach W., Dietz K.J. (1994) Compartmentation and transport or zinc in barley primary leaves as basic mechanisms involved in zinc tolerance, Plant Cell Environ. 17, 153–162.
Cattani I., Romani M., Boccelli R. (2008) Effect of cultivation practices on cadmium concentration in rice grain, Agron. Sustain. Dev. 28, 265–271.
Diao W.-P., Ni W.-Z., Ma H.-Y., Yang X.-E. (2005) Cadmium pollution in paddy soil as affected by different rice (Oryza sativa L.) cultivars, B. Environ. Contam. Tox. 75, 731–738.
Gárate A., Ramos I., Manzanares M., Lucena J.J. (1993) Cadmium uptake and distribution in three cultivars of Lactuca spp., B. Environ. Contam. Tox. 50, 709–716.
Ghani A., Wahid A., Javed F. (2008) Effect of cadmium on photosynthesis, nutrition and growth of mungbean, Agron. Sustain. Dev. 28, 273–280.
Guo Y., Marschner H. (1995) Uptake, distribution and binding of cadmium and nickel in different plant species, J. Plant Nutr. 18, 2691–2706.
Guo B., Liang Y.C., Li Z.J., Guo W. (2007) Role of salicylic acid in alleviating cadmium toxicity in rice roots, J. Plant Nutr. 30, 427–439.
Han F., Shan X., Zhang S., Wen B., Owens G. (2006) Enhanced cadmium accumulation in maize roots — the impact of organic acids, Plant Soil 289, 355–368.
Herawati N., Suzuki S., Hayashi K., Rivai I.F., Koyamal H. (2000) Cadmium, copper, and zinc levels in rice and soil of Japan, Indonesia, and China by soil type, B. Environ. Contam. Tox. 64, 33–39.
Larsson E.H., Asp H., Bornman J.F. (2002) Influence of prior Cd2+ exposure on the uptake of Cd2+ and other elements in the phytochelatin-deficient mutant, cad1-3 of Arabidopsis thaliana, J. Exp. Bot. 53, 447–453.
Liang Y.C., Zhu Y.G., Xia Y., Li Z., and Ma Y.B. (2006) Iron plaque enhances phosphorus uptake by rice (Oryza sativa L.) growing under varying phosphorus and iron concentrations, Ann. Appl. Biol. 149, 305–312.
Liu J.G., Wang D.K., Xu J.K., Zhu Q.S. Wong M.H. (2006) Variations among rice cultivars on root oxidation and Cd uptake, J. Environ. Sci. 18, 120–124.
Liu J.G., Qian M., Cai G.L., Yang J.C., Zhu Q.S. (2007) Uptake and translocation of Cd in different rice cultivars and the relation with Cd accumulation in rice grain, J. Hazard. Mater. 143, 443–447.
Milone T.M., Sgherri C., Clijsters H., Flavia N.I. (2003) Antioxidative responses of wheat treated with realistic concentration of cadmium, Environ. Exp. Bot. 50, 265–276.
Ni T.H., Wei Y.Z. (2003) Subcellular distribution of cadmium in mining ecotype Sedum alfredii, Acta Bot. Sin. 45, 925–928.
Nishizono H. (1987) The role of the root cell wall in the heavy metal tolerance of Athyium yokoscense, Plant Soil 101, 15–20.
Page V., Feller U. (2005) Selective transport of Zinc, Manganese, Nickel, Cobalt and Cadmium in the root system and transfer to the leaves in young wheat plants, Ann. Bot. 96, 425–434.
Prasad M.N.V. (1995) Cadmium toxicity and tolerance in vascular plants, Environ. Exp. Bot. 35, 525–545.
Prasad M.N.V. (2004) Heavy Metal Stress in Plants (from Biomolecules to Ecosystems), Springer, Berlin.
Ramos I., Esteban E., Lucena J.J., Gárate A. (2002) Cadmium uptake and subcellular distribution in plants of Lactuca sp. Cd-Mn interaction, Plant Sci. 162, 761–767.
Sanità di Toppi L., Gabbrielli R. (1999) Response to cadmium in higher plants, Environ. Exp. Bot. 41, 105–130.
Sharma R.K., Agrawala M., Marshallb F. (2007) Heavy metal contamination of soil and vegetables in suburban areas of Varanasi, India, Ecotox. Environ. Safe. 66, 258–266.
Sun Y.H., Li Z.J., Guo B., Chu G.X., Wei C.Z., Liang Y.C. (2008) Arsenic mitigates cadmium toxicity in rice seedlings, Environ. Exp. Bot., in press.
Tang S.R. (2000) The distribution of heavy metal in the leaves extraction of Elsholtzia haichowensis and Commelina communis, Plant Physiol. 36, 128–129 (in Chinese).
Vögeli-Lange R., Wagner G.J. (1990) Subcellular localization of cadmium and cadmium-binding peptides in tobacco leaves, Plant Physiol. 92, 1086–1093.
Wagner G.J. (1993) Accumulation of cadmium in crop plants and its consequences to human health, Adv. Agron. 51, 173–212.
Wani A., Khan M.S., Zaidi A. (2007) Cadmium, chromium and copper in greengram plants, Agron. Sustain. Dev. 27, 145–153.
Weigel H.J., Jāger H.J. (1980) Subcellular distribution and chemical form of cadmium in bean, Plant Physiol. 65, 480–482.
Wissenmeier A.H., Klotz F., Horst W.J. (1987) Aluminum induced callose synthesis in roots of soybean (Glycine max L.), J. Plant Physiol. 129, 487–492.
Wójcik M., Vangronsveld J., Tukiendorf A. (2005a) Cadmium tolerance in Thlaspi caerulescens I.Growth parameters, metal accumulation and phytochelatin synthesis in response to cadmium, Environ. Exp. Bot. 53, 151–161.
Wójcik M., Vangronsvedld J., Haen J.D. (2005b) Cadmium tolerance in Thlaspi caerulescens? Localization of cadmium in Thlaspi caerulescens, Environ. Exp. Bot. 53, 163–171.
Wu F.B., Dong J., Qian Q.Q., Zhang G.P. (2005) Subcellular distribution and chemical form of Cd and Cd-Zn interaction in different barley genotypes, Chemosphere 60, 1437–1446.
Yang Q.W., Lan C.Y., Wang H.B., Zhuang P., Shu W.S. (2006) Cadmium in soil-rice system and health risk associated with the use of untreated mining wastewater for irrigation in Lechang, China, Agr. Water Manage. 84, 147–152.
Zhao F.J., Harmon R.E., Lombi E., McLaughlin M.J., McGrath S.P. (2002) Characteristics of cadmium uptake in two contrasting ecotypes of the hyperaccumulator Thlaspi caerulescens, J. Exp. Bot. 53, 535–543.