Pakistan Journal of Biological Sciences1028-88801812-5735Asian Network for Scientific Information10.3923/pjbs.2007.1865.1869G. etunicatum) Fungus on Antioxidant Enzymes Activity under Zinc Toxicity in Lettuce Plants]]>FarshianShadi KharaJalil MalekzadehParviz 1120071011Zinc is one of the eight trace elements which are essential for the normal healthy growth and reproduction of crop plants. Plants possess cellular mechanisms that may be involved in the detoxification of heavy metals and thus confer plants a better tolerance against them. Arbuscular mycorrhizal fungi colonization is one of these mechanisms. Here, the effect of mycorrhizal fungus G. etunicatum on Zn toxicity tolerance through enhanced activity of some of antioxidant enzymes has been studied. Treatments were applied in triplicates of two factorial analyses: a) mycorrhizal and non-mycorrhizal; b) 5 levels of Zinc (0, 1.5, 3.5, 5.5, 7.5 mM). Zinc was added to modified Hoagland's nutrient solution (with half P concentration). Plants were grown in growth chamber for 10 weeks. Toxicity symptoms such as necrosis and chlorosis appeared on the leaves. Activity of detoxifying enzymes Guaiacol peroxidase (GUPX) and Ascorbate peroxidase (APX) were measured. GPX activity in roots and shoots of mycorrhizal and non-mycorrhizal plants was increased. Also, APX activity increased in roots and shoots of mycorrhizal and non-mycorrhizal plants. Root length colonization (RLC) was measured by gridline intersect method. Mycorrhizal colonization decreased due to Zinc exposure. The results indicate the probable role of arbuscular mycorrhizal colonization in stress tolerance.]]>Allen, R.D.,199510710491054Baisak, R., D. Rana, P.B.B. Acharya and M. Kar,199435489495Chen, B.D., X.L. Li, H.Q. Tao, P. Christie and M.H. Wong,200350839846Bolan, N.S.,1991134189207Burleigh, S.H., B.K. Kristensen and I.E. Bechmann,20035210771088Cakmak, I. and W.J. Horst,1991Glycine max).]]>83463468Chang, C.J. and C.H. Kao,19982O2 metabolism during senescence of rice leaves: Changes in enzyme activities in light and darkness.]]>251115Chaoui, A., S. Mazhoudi, M. Ghorbal and E. El-Fergani,1997Phaseolus vulgaris L.).]]>127139147Clemens, S.,2001212475486Dueck, T.A., P. Visser, W.H.O. Ernst and H. Schat,198618331333Elstner, E.F.,1982337396Fontes, R.L.F. and F.R. Cox,19951818931906Giovannetti, M. and B. Mosse,198084489500Harmens, H., N.G.C.P.B. Gusmao, D.P.R. Hartog, J.A.C. Verkeij and W.H.O. Ernst,1993Silene vulgaris.]]>141309315Heggo, A., A. Angle and R.L. Chaney,199022865869Hetrick, B.A.D., G.W.T. Wilson and D.A.H. Figge,199486171179Jakobsen, I., L.K. Abbott and A.D. Robson,1992Trifolium subterraneum L. 1: Spread of hyphae and phosphorus inflow into roots.]]>120371379Johansen, A., I. Jakobsen and E.S. Jensen,1992122281288Kothari, S.K., H. Marschner and V. Romheld,1991131177185Lee, C.W., M.B. Jackson, M.E. Duysen, T.P. Freeman and J.R. Self,199636705712Leyval, C., K. Turnau and K. Haselwandter,19977139153Li, X.L., E. George and H. Marschner,19911364148Li, X.L. and P. Christie,200142201207Liu, A., C. Hamel, R.I. Hamilton and B.L. Ma,2000Zea mays L.) grown in soil at different P and micronutrient levels.]]>9331336Marschner, H.,199856203207Nielsen, J.D. and A. Jensen,1983Medicago sativa).]]>70165172Ott, T., E. Fritz, A. Polle and A. Schutzendubel,2002Paxillus involutus (Bartsch) Fr. and its reaction to cadmium.]]>42359366Phillips, J.M. and D.S. Hayman,197055158161Rauser, W.E.,1999311948Ren, F., T. Liu, H. Liu and B. Hu,199316393405Rout, G.R. and P. Das,200323311Shah, K., R.G. Kumar, S. Verma and R.S. Dubey,200116111351144Smith, S.E. and D.J. Read,19972nd Edn.,Tong, Y.P., R. Kneer and Y.G. Zhu,2004979Weckx, J.E.J. and H.M.M. Clijsters,1996Phaseolus vulgaris as a result of root assimilation of toxic amounts of copper.]]>96506512Weissenhorn, I., C. Leyval, G. Belgy and J. Berthelin,1995Zea mays L.) in pot culture with contaminated soil.]]>5245251Zhu, Y.G., S.E. Smith, F.A. Smith,2001Triticum aestivum L.) differing in P uptake efficiency.]]>88941945