Asian Journal of Plant Sciences1682-39741812-5697Asian Network for Scientific Information10.3923/ajps.2006.598.606Zea mays L.) Seedlings under Conditions of Copper and Cadmium Stress]]>Radhouane Chaffai Ali Tekitek Ezzedine El Ferjani 4200654This study focuses on the comparative effects of copper and cadmium on the organic acid content and exudation in maize (Zea mays L.). We have also discussed the role of organic acids in copper and cadmium tolerance. The maize seedlings were grown in hydroponics for 8 days and then treated with 100 μM copper or cadmium for 4 days. The copper reduced more than cadmium root fresh wt and shoot dry wt, while Cd had more decreasing effect on root dry wt. Analysis of organic acids in root exudates showed that citrate exudation was not affected by both metals, suggesting that root exudation was not involved in copper or cadmium tolerance in maize. This prompted us to investigate the role of organic acids in internal tolerance mechanism. Total organic acids were decreased in roots but remained unchanged in shoots of Cu and Cd-treated plants. However, malate content decreased substantially in roots by 68 and 53%, respectively with Cu and Cd. The marked increase in the content of citrate with both metals in roots, as well as in those of malate with Cu and citrate with Cd in shoots, underlined the main role of these organic acids in Cu and Cd tolerance in maize.]]>Baszyski, T., M. Krol, Z. Krupa, M. Ruszkowska, U. Wojcieska and D. Wolinska,1982108385395Bradford, M.M.,197672248254Cathala, N. and L, Salsac,1975Zea mays L.) and sunflower (Helianthus annuus L.).]]>426583Chaffai, R. and E.El-Ferjani,2005Zea mays L.).]]>16473Chaffai, R., T. Ali and E. El Ferjani,2005Zea mays L.).]]>8649655Clijsters, H. and F. Van-Assche,198573140Delhaize, E., P.R. Ryan and P.J. Randall,1993Triticum aestivum L.) (II. Aluminum-stimulated excretion of malic acid from root apices).]]>103695702Fox, T.C. and M.L. Guerinot,199849669696Foy, C.D., R.L. Chaney and M.C. White,197829511566Gallego, S.M., M.P. Benavides and M.L. Tomaro,1996121151159Godbold, D.L., W.J. Horst, J.C. Collins, D.A. Thurman and H. Marschner,1984Deschampsia caespitosa.]]>1165969Gupta, B. and S. Mukherji,19778295106Gupta, U.C.,19791979pp: 255-288pp: 255-288Hahlbrock, K. and D. Scheel,198940347369Jarvis, S.C., L.H.P. Jones and M.J. Hopper,197644179191Javis, S.C. and D.W. Whitehead,198160275286Kishinami, I. and J.M. Widholm,1987Nicotiana plumbaginifolia suspension cultures.]]>28203210Lee, K.C., B.A. Cunningham, G.M. Paulsen, G.H. Liang and R.B. Moore,19763646Lee, J., R.D. Reeves, R.R. Brooks and T. Jeffre,19871710331035Li, X.F., J.F. Ma and H. Matsumoto,2002242235243Ma, J.F., S. Hiradate, K. Nomoto, T. Iwashita and H. Matsumoto,1997Hydrangea. Identification of Al form in the leaves.]]>11310331039Ma, J.F., S.J. Zheng, H. Matsumoto and S. Hiradate,1997390569570Ma, J.F., S.J. Zheng, H. Matsumoto and S. Hiradate,1997390569570Ma, Z. and S.C. Miyasaka,1998118861865Ma, J.F.,200041383390Macnair, M.R.,19811981pp: 177-207pp: 177-207Mathys, W.,197740130136Miyasaka, S.C., J.G. Buta, R.K. Howell and C.D. Foy,199196737743Ojima, K., H. Abe and K. Ohira,198425855858Ouzounidou, G., E.P. Eleftheriou and S. Karatagfis,1992Thlaspi ochroleucum (Cruciferae).]]>70947957Pineros, M.A. and L.V. Kochian,2001125292305Salt, D.E., C.R. Prince, I.J. Pickering and I. Raskin,199510914271433Sandmann, G. and P. Boger,1980Scenedesmus.]]>985359Sandman, G. and P. Boger,198066797800Sanita di Toppi, L.S. and R. Gabbrielli,199941105130Shen, R., T. Iwashita and J.F. Ma,200455131136Shioi, Y., H. Tamai and T. Sasa,197819203209Shioi, Y., H. Tamai and T. Sasa,1978Ankistrodesmus falcatus by copper.]]>44434438Stiborova, M., M. Doubranova, A. Brezinova and A. Friedrich,1986181373379Stiborova, M., M. Doubranova, A. Brezinova and A. Friedrich,1986181373379Thurman, D.A. and J.L. Rankin,1982Deschampsia caespitosa.]]>91629635Tomsett, A.B. and D.A. Thurman,198811383394Trivedi, S. and L. Erdei,19922+ and K+ and on the influx and translocation of K+ in wheat of low and high K+ status.]]>8494100Tukendorf, A. and T. Baszynski,1985Avena sativa grown on excess copper.]]>1205763Watanabe, T., M. Osaki and T. Tadano,2000Melastoma malabathricum L.).]]>2000pp: 4750Wu, L., D.A. Thurman and A.D. Bradshaw,1975Agrostis stolonifera.]]>75225229Zheng, S.J., J.F. Ma and H. Matsumoto,1998117745751