GROWTH RESPONSE OF MAIZE (ZEA MAYS L.) TO METAL TOXICITY
This study evaluated the phytotoxic effects of lead (Pb) and zinc (Zn) as Pb(NO3)2 and Zn(NO3)2 on maize (Zea mays L) considering the plants’ growth indices, biomass as well as soil parameters and soil microorganisms after treatment. The results showed that plant growth significantly reduced with increasing concentrations (100,150 and 200 mgkg-1) of Pb and Zn contamination. The results indicated significant inhibitory effect on the growth parameters (stem height, root length, leaf area, fresh and dry weight) measured, compared to control experiment. This study therefore revealed that the heavy metals have harmful effects on maize’s growth. Consequently, the consumption of such contaminated cereal by man and animals can lead to their death after the metals have biomagnified in their systems. Lead and Zn application in general, affected the vegetative growth; both fresh and dry weights were reduced with increasing concentrations of the metals. These results show that these metals are toxic to human and animal health. As a result, farmers should be encouraged to use water from good source for irrigation and also cultivate on metal-free soils if possible to save lives.
AOAC.1990. Official Methods of Analysis. 15th Editionn., AOAC, Washington, DC., USA. pp: 200-210.
Arun, K.S, Carlos, C, Herminia, L, Avudainayagam,S. 2005. Chromium toxicity in Plants. Environmental International : 31:739-753pp
Azmat, R. S. Hasan. 2008. Photochemistry of light harvesting pigments of Lens culinaris under Al stress. Pakistan. Journal of Botany, 40(2): 779-784.
Barcelo, I., Posxhenrieder, C. 1985. Effect of chromium (VI) on mineral element composition of bush beans. Journal of Plant Nutrition.8: 211-217pp
Fodor F., Sarvari E., Lang F., Szigeti Z., Cseh E., 1996. Effects of Pb and Cd on cucumber depending on the Fe-complex in the culture solution. Journal of Plant Physiology. 148(3/4): 434-
Haas, A.R.C., Brusca, J.N .1961. Effects of chromium on Cirrus and Avocado grown in nutrient solution.CIII. Agriculture .IS:10-11
Hutchinson T.C., Symington, M.S. 1997. Persistence of metal stress in a forested ecosystem near Sudbury, 66 years after closure of the O’Donnell roast bed. Journal of Geochemistry.Exploration.58:323-330.
Kibria, M.G, Islam, M., Osman, K.T.2009. Effects of lead on growth and Mineral Nutrition of Amaranthus gangeticus L. and Amaranthus oleracea L. Soil and Environment 28(1): 1-6pp
Kopittke, P.M, Asher, C.J, Kopittke, R.A, Menzies N.W, 2007. Toxic effects of Pb 2+ on Growth of cowpea (Vigna unguiculata).Environmental Pollution 150, 280-287pp
Kumar G., S. Kesarwani. 2004. Cytotoxic effect of mercuric chloride in root meristem of Lens culinaris . Medik. International Journal of Mendel 21(1-2): 41-42.
Kuperman, R.G, Carreiro, M.N.1997. Soil heavy metal concentrations, microbial biomass and enzyme activities in a contaminated grassland ecosystem. Soil Biology. Biochemistry.29:179-190
Lone .M.I, He, Z., Stoffella, P.J., Yang .X. 2008. Phytoremediation of heavy metal polluted soils and water: Progresses and perspectives, Journal of Zhejiang University Science 9: 210-220.
Malkowski, E., A. Kita, W. Galas, W. Karez., K. Michael .2000. Lead distribution in corn seedlings (Zea mays L.) and its effect on growth and the concentration of potassium and calcium. Plant Growth Regulation, 37: 69-76.
Masakazu, A., Nagumo, T.1997. Effect of heavy metal accumulation in apple orchard soils on microbial biomass and microbial activities. Soil Science. Plant Nutrition. 43:601-612.
Mohamad Abou Auda., Emad El Shakh Ali .2010. Cadmium and Zinc toxicity on growth and Mineral nutrients of Carrot (Daucus carota).Pakistan Journal of Botany 42(1): 341-351pp
Peter, M.K, Colin, J.A, Rosemary, A.K, Neal, W.M .2007. Toxic effects of Pb2+on Growth of Cowpea (Vigna unguiculata).Environmental Pollution .150, 280-287pp
Rajapaksha, R. M. C. P, Tobor-Kapłon, M. A., E. Bååth, 2004. Metal Toxicity affects Fungal and Bacterial Activities in Soil Differently Applied and Environmental Microbiology. 70 (5) 2966-2973pp
White R. 2006. Principles and Practice of Soil Science: The Soil as a Natural Resource, 4th Edition . Blackwell. 250-310pp
Wu, F., Zhang, G., Dominy, P. 2003. Four barley genotypes respond differently to cadmium: lipid peroxidation and activities of antioxidant capacity. Environmental and Experimental Botany, 50: 67–78.